Canadian Journal of
Volume 9 | Issue/numéro 4
pathology pathologie Revue canadienne de
IMHMV Case RepoRt
PM 43490512
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Canadian Association of Pathologists Association canadienne des pathologistes
&JHIUI"OOVBM 3FTJEFOU3FWJFX$PVSTF
TIVSTEBZ JanVBSZ1 to SunEBZ JanVBSZ1, 201 | Hilton Garden Inn - Toronto Airport West
COURSE DIRECTORS Penny J. Barnes, MD, FRCP(C) (Halifax, NS) Jagdish Butany, MBBS, MD, FRCPC (Toronto, ON)
WHO SHOULD ATTEND? This course is open to all Canadian trainees, US trainees, CAP-ACP resident members as well as non-members and pathologists. Priority will be given to PGY5 and PGY4 residents who are members of the CAP-ACP. Limited availability is also extended to non MD Laboratory Professionals at a fee per day.
OBJECTIVES An experienced faculty team has been assembled to collaborate on the topics and presentation of the course material to provide attendees with a practical review of major topics in the specialty of Anatomical Pathology. Your
faculty of skilled pathologists will focus on what you need to know in preparation for the examination. At the end of the meeting participants will be able to: 1.
Review and update core medical knowledge in preparation for the Royal College of Physicians and Surgeons of Canada certification examinations in Anatomic Pathology, General Pathology, and Hematological Pathology.
2.
Develop strategies for optimal preparation and exam performance in the written, practical, and oral components of the examination, and understand examination formats
3.
Discuss and assess the significance of new findings and observations in the context of current literature
4.
Demonstrate competence in the non-medical expert CanMEDS roles, in particular laboratory management and quality assurance
ACCREDITATION The Canadian Association of Pathologists’/Association canadienne des pathologistes Residents Review Course is accredited by the Canadian Association of Pathologists. This event is an Accredited Group Learning Activity (Section 1) as defined by the Maintenance of Certification program of The Royal College of Physicians and Surgeons of Canada.
For more information and to register: www.cap-acp.org/rrc.php
Canadian Journal of
Volume 9 | issue 4 eDItoR-IN-CHIeF George M Yousef, MD, PhD FRCPC (Path) eDItoR eMeRItUs J. Godfrey Heathcote, MA, MB, BChir, PhD, FRCPC FoUNDING eDItoR Jagdish Butany, MBBS, MS, FRCPC MaNaGING eDItoR Deborah McNamara eDItoRIaL CoNteNt MaNaGeR Heather Dow
pathology
Official Publication of the Canadian Association of Pathologists
table of Contents
4 9 20
aRt DIReCtoR Sherri Keenan traNsLatIoN Lorraine Boury Jocelyne Demers-Owoka Éliane Fréchette pUbLIsHING aGeNCy Clockwork Communications Inc. PO Box 33145, Halifax, NS, B3L 4T6 902.442.3882 /
[email protected]
Copyright Canadian Association of Pathologists (CAP-ACP). All rights reserved. Reprinting in part or in whole forbidden without express written consent from CAP-ACP. Publications Mail Agreement No. 43490512 ISSN 1918-915X (print) ISSN 1918-9168 (online) Return undeliverable Canadian addresses to: Clockwork Communications Inc PO Box 33145 Halifax, NS B3L 1K3
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Molecular Pathology Corner: Commentary: Overview of PD-L1 Testing Author: Michelle R. Downes MBBChBAO, MRCSI, MD, FRCPC.
Contemporary Issues: Overutilization of Lab Tests in Medicine: Achieving Smart Testing Through Collaboration Authors: Michelle Sholzberg MDCM, MSc, FRCPC and Lisa K. Hicks MD, MSc, FRCPC
Case RepoRt 24
Idiopathic Myointimal Hyperplasia of Mesenteric Veins: A Diagnosis not to Miss in Patients with Bowel Ischemia Authors: Hui Wang MD; Sheev Dattani MD; Mary Kinloch MD, FRCPC; Dilip Gill MD, FRCSC; and Chaturika Herath MD, FRCPC.
Canadian Journal of Pathology is a peer-reviewed journal published four times per year, by Clockwork Communications Inc., on behalf of the Canadian Association of Pathologists. We welcome editorial submissions to
[email protected]. We cannot assume responsibility or commitment for unsolicited material. Any editorial material, including photographs, that are accepted from an unsolicited contributor, will become the property of the Canadian Association of Pathologists.
Letter from the Editor-in-Chief: Open Access Journals: The Future of Scientific Publishing?
ReseaRCh aRtiCle 30
41 50
Invasive Breast Carcinomas with Equivocal HER2 in situ Hybridization Test Results: An Ongoing Challenge for Pathologists and Oncologists Authors: Gillian C Bethune MD, FRCPC; Daniel Veldhuijzen Van Zanten MD; Tallal Younis MD, FRCPC; and Penny J Barnes MD, FRCPC.
Evaluation of the B-LactaTM Test for the Rapid Detection of Extended Spectrum Beta Lactamases Directly from Rectal Swabs Authors: Manal Tadros MBBS, PhD, FRCPC; Prameet M. Sheth PhD, FCCM; Bridget Tam MLT, BSc; and Zafar Hussain MD, FRCPC.
Adipose and Intestinal Immunopathology in Obesity Related Insulin Resistance Authors: Helen Luck, Shawn Winer MD, FRCPC, PhD, and Daniel A. Winer MD, FRCPC.
Revue canadienne de pathologie | volume 9, numéro 4 | www.cap-acp.org
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LETTER FROM THE EDITOR-IN-CHIEF OPEN ACCESS JOURNALS: THE FUTURE OF SCIENTIFIC PUBLISHING? he pros and cons of open access publishing is an oftendebated and controversial topic. Open access (OA) journals are online publications that are freely available to any reader. Online publishing allows establishment of new business models for publishers and has become a dominant distribution method for scientific journals. The number of OA journals has dramatically increased, over the past 20 years, with over 10,000 OA journals currently available.
T
The obvious benefit of open access is that these journals are available to the reader at no cost. This is valuable to the scientific community, especially in developing countries, and in fields such as global health. Other benefits include faster publication and increased visibility. The additional argument that "free" journals result in more citations and increased journal impact factor has been challenged. Most costs of traditional publishing are borne by the reader (or an institution's library) and/or supported by advertising revenue while in the OA model it is common for the author to pay for publication (usually in the form of both an "article processing charge" and then a "post-acceptance fee"). Authors often retain copyright of their OA article, publications are usually indexed in scholarly databases, and a legitimate OA journal will have an impact factor. It must be emphasized that legitimate OA journals have a formal arms-length peer-review process although some nonpeer review models, such as the pre-print server bioRXiv from Cold Spring Harbor Laboratory or the post publication review process of f1000research, also exist. It has been argued that charging an article processing fee leads to the acceptance of more substandard articles in order to increase income but some studies refute this. So-called "predatory publishers"1 produce OA publications that have significant article processing charges and conduct little or no peer review. It can sometimes be difficult for researchers to distinguish between journals from predatory publishers and those from legitimate publishers that follow ethical standards in publishing. Publishers that send you unsolicited e-mails to submit a manuscript to an OA journal are almost certainly "predatory." 4
Canadian Journal of Pathology | Volume 9, Issue 4 | www.cap-acp.org
Historically, OA journals did not have the reputations and impact factors of established traditional journals. But this is certainly changing. Some authors may be burdened by the cost of OA submission and/or publication fees, although full or partial waivers may be available for authors with limited financial capability, and this can further limit the content of OA journals. There are many variations of open access journals including “full open access”, “hybrid open access,” when only partial content is freely available or the authors must pay an extra "open access fee" to ensure free access to their article, and “delayed open access,” when the content is restricted for a period of time and then becomes freely available. This latter OA model is used by the Canadian Journal of Pathology. For the Canadian Journal of Pathology publication costs are covered by dues paid by members of the Association and by advertising revenue. CAP-ACP provides both print and online versions of the journal. We are looking in to the option of having an “online only” portion of the journal that would include full article French translations, abstracts of scientific meetings, etc. Moving forward, we need to start a dialogue about how to cover the increasing costs of publication. Currently, different strategies are available, including publication fees, payment for colour figures, increased advertising revenue, etc. Both open-access and traditional pay-for-access journals have their pros and cons with the OA model having greater foreseeable impact and the pay-for-access potentially better maintaining the quality and reputation of scientific literature. The long-term sustainability of the OA publication model is not yet proven. The discussion will continue to evolve in the coming years. Reference: 1. https://en.wikipedia.org/wiki/Predatory_open_access_ publishing Accessed October 5th, 2017. George M. Yousef MD, PhD, FRCPC(Path) Editor-in-Chief, Canadian Journal of Pathology
Irvaym B. Barsoum MD, MSc, PhD; Michael Carter MD, PhD; Hala Faragalla MD, FRCPC; Louis Gaboury, M.D., Ph.D., F.R.C.P.(C), F.C.A.P.; John Gartner, MD CM, FRCPC; Laurette Geldenhuys, MBBCH, FFPATH, MMed, FRCPC, MAEd, FIAC; Zeina Ghorab MD, MSc; Nadia Ismiil, MBChB, FRCPC; Jason Karamchandani, MD; Adriana Krizova MD, MSc, FRCPC; David Munoz, MD, MSc, FRCPC; Christopher Naugler, MD, FRCPC; Tony Ng, MD, PhD FRCPC; Sharon Nofech-Mozes, MD; Maria Pasic, PhD, FCACB; Aaron Pollett, MD, MSc, FRCPC; Rola Saleeb MD; Harman Sekhon, MD, PhD, FCAP; Monalisa Sur, MBBS, FCPath, MMed., MRCPath, FRCPC; Aducio Thiesen, MD, PhD, MSc, FRCPC; Stephen Yip, MD, PhD, FRCPC.
INteRNatIoNaL eDItoRIaL boaRD Emma H. Allott PhD, University of North Carolina, USA; Fredrik Bosman, MD, PhD, University of Lausanne, Switzerland; Daniel Chanm, PhD, DABCC, FACB, Johns Hopkins University School of Medicine, USA; Runjan Chetty, MB BCh, FRCPA, FFPath, FRCPath, FRCPC, FCAP, Dphil, University of Tornto, Canada; Kumarasen Cooper ,MBChB, Dphil, FRC path, University of Pennsylvania, USA; Brett Delahunt, BSc Hons BMedSc MB ChB MD FRCPA FFSc FRCPath, University of Otago, New Zealand; Sunil R Lakhani, BSc (Hon), MBBS, MRCPath, MD, FRCPath, FRCPA, The University of Queensland, Australia; Virginia A. LiVolsi, MD, MASCP, University of Pennsylvania, USA; Ricardo Lloyd, MD, PhD, University of Wisconsin, USA; Jesse Mckenney, MD, Cleveland Clinic, USA; Chris Meijer, MD, PhD, VU University, The Netherlands; George Netto, MD, PhD, Johns Hopkins University School of Medicine, USA; Isobel Scarisbrick, PhD, Mayo Clinic, USA; Manfred Schmitt, Dr. rer. nat., Dr. med. habil. (Ph. D., M.D. sci.), Dipl.-Biologist, Technical University, Munich, Germany; Iris Schrijver, MD, Stanford University, USA; Andreas Scorilas, PhD, University of Athens, Greece; Ming Tsao, FRCPC, MD, University of Toronto, Canada; Mark Wick, MD, University of Virginia, USA.
CoMItÉ De RÉDaCtIoN Irvaym B. Barsoum M. D., M. Sc, Ph.D; Michael Carter M. D., Ph. D; Hala Faragalla, M. D., FRCPC; Louis Gaboury, M. D., Ph. D., FRCPC, FCAP; John Gartner, M. D. CM, FRCPC; Laurette Geldenhuys, MBBCH, FFPATH, MMed, FRCPC, MAEd, FIAC; Zeina Ghorab M. D.; Nadia Ismiil, MBChB, FRCPC; Jason Karamchandani, M. D.; Adriana Krizova M. D., M. Sc, FRCPC; David Munoz, M. D., M. Sc, FRCPC; Christopher Naugler, M. D., FRCPC; Tony Ng, M. D., Ph. D., FRCPC; Sharon Nofech-Mozes, M. D.; Maria Pasic, Ph. D., FCACB; Aaron Pollett, M. D., M. Sc, FRCPC; Rola Saleeb M. D.; Harman Sekhon, M. D., Ph. D, FCAP; Monalisa Sur, MBBS, FCPath, MMed., MRCPath, FRCPC; Aducio Thiesen, M. D., Ph. D, M. Sc, FRCPC; Stephen Yip, M. D., Ph. D, FRCPC.
CoMItÉ De RÉDaCtIoN INteRNatIoNaL Emma H. Allott Ph. D, Université de North Carolina, É.-U.; Fredrik Bosman, M. D., Ph. D., Université de Lausanne, Suisse; Daniel Chanm, Ph. D., DABCC, FACB, faculté de médecine de l’Université Johns Hopkins, É.-U.; Runjan Chetty, MB BCh, FRCPA, FFPath, FRCPath, FRCPC, FCAP, Dphil, Université de Toronto, Canada; Kumarasen Cooper ,MBChB, Dphil, FRC path, Université de la Pennsylvania, É.-U.; Brett Delahunt, B. Sc Hons BMedSc MB ChB MD FRCPA FFSc FRCPath, Université d’Otago, Nouvelle-Zélande; Sunil R Lakhani, B. Sc (Hon), MBBS, MRCPath, M. D., FRCPath, FRCPA, Université de Queensland, Australie; Virginia A. LiVolsi, M. D., MASCP, Université de la Pennsylvanie, É.-U.; Ricardo Lloyd, M. D., Ph. D, Université du Wisconsin, É.-U.; Jesse Mckenney, M. D., Clinique de Cleveland, É.-U.; Chris Meijer, M. D., Ph. D., Université VU, Pays-Bas; George Netto, M. D., Ph. D., faculté de médecine de l’Université Johns Hopkins, É.-U.; Isobel Scarisbrick, Ph. D., Clinique Mayo, É.-U.; Manfred Schmitt, Dr. rer. nat., Dr. med. habil. (Ph. D., M.D. sci.), Dipl.-Biologist, Université polytechnique, Munich, Allemagne; Iris Schrijver, M. D., Université Stanford, É.-U.; Andreas Scorilas, Ph. D., Université d’Athènes, Grèce; Ming Tsao, FRCPC, M. D., Université de Toronto, Canada; Mark Wick, M. D., Université de la Virginie, É.-U.
CoMItÉ De RÉDaCtIoN
eDItoRIaL boaRD
eDItoRIaL boaRD
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LETTRE DU RÉDACTEUR EN CHEF
LES REVUES À LIBRE ACCÈS : L’AVENIR DE LA PUBLICATION SCIENTIFIQUE?
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n sujet souvent débattu et controversé se rapporte au pour et au contre de la publication en libre accès. Les revues à libre accès se réfèrent à des publications en ligne mises gratuitement à la disposition de n’importe quel lecteur. La publication en ligne permet d’établir de nouveaux modèles d’affaire pour les éditeurs et constitue dorénavant une méthode de distribution dominante pour les revues scientifiques. Le nombre de revues à libre accès a considérablement augmenté au cours des vingt dernières années avec plus de 10 000 revues à libre accès actuellement disponibles. L’avantage évident des revues à libre accès réside dans le fait que ces dernières sont gratuites pour le lecteur, ce qui est très utile pour la communauté scientifique, tout particulièrement dans les pays en voie de développement et dans les domaines comme la santé mondiale. Parmi les autres avantages, notons la rapidité de la publication et la visibilité accrue. L’argument additionnel voulant que les revues « gratuites » génèrent davantage de citations et un facteur d’impact accru de la revue a été mis au défi. Avec les méthodes traditionnelles de publication, la plupart des coûts sont supportés par le lecteur (ou la bibliothèque d’un établissement) et (ou) appuyés par des recettes publicitaires tandis qu'avec le modèle à accès libre, il est courant que l’auteur paie pour la publication (habituellement sous la forme de « frais de gestion d’article » et ensuite de « frais après l’acceptation »). Les auteurs conservent souvent les droits d’auteur de leur article à libre accès, les publications sont habituellement répertoriées dans les bases de données scientifiques et une revue à libre accès sérieuse aura un facteur d’impact. Il convient de souligner que les revues à libre accès sérieuses impliquent un processus officiel de révision par les pairs indépendant bien que certains modèles non révisés par des pairs, comme le serveur de préimpression bioRXiv du Cold Spring Harbor Laboratory ou le processus de révision après publication de f1000research, existent également. Certains ont avancé que le fait de facturer des frais de gestion pour les articles mène à l’acceptation davantage
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d’articles inférieurs aux normes dans le but d’accroître le revenu, mais d'autres études réfutent cet argument. Les soidisant « éditeurs abusifs »1 impriment des publications à libre accès exigeant d’importants frais de gestion d’articles, mais ils n'effectuent que peu ou pas de révision par les pairs. Il est parfois difficile pour les chercheurs de distinguer les revues publiées par des éditeurs abusifs de celles publiées par des éditeurs légitimes respectant les normes d’éthique en matière d’édition. Les éditeurs vous envoyant des courriels non sollicités pour soumettre un manuscrit dans une revue à libre accès sont presque assurément des « éditeurs abusifs ». Historiquement, les revues à libre accès ne possédaient pas la réputation ni le facteur d’impact des revues traditionnelles bien établies, mais cette tendance est certainement en train de changer. Certains auteurs peuvent avoir de la difficulté à défrayer les coûts de soumission et (ou) les frais de publication associés à une revue à libre accès, même si une exemption complète ou partielle peut être offerte aux auteurs ayant des ressources financières limitées, et cela peut encore davantage restreindre le contenu des revues à libre accès. Il existe de nombreuses variations de revues à libre accès, notamment les modèles « libre accès intégral » ou « libre accès hybride », soit lorsque seulement une partie du contenu est accessible gratuitement ou que les auteurs doivent débourser des « frais de libre accès » additionnels pour offrir le libre accès à leur article, ainsi que le modèle « libre accès décalé », soit quand le contenu est interdit pour une période de temps et devient ensuite gratuit. C’est ce dernier modèle de libre accès qu’utilise la Revue canadienne de pathologie. Les coûts de publication de la Revue canadienne de pathologie sont couverts par les cotisations payées par les membres de l’Association et par les recettes publicitaires. Le CAP-ACP fournit les versions imprimé et en ligne de la revue. Nous contemplons l’option d’offrir une portion de la revue « en ligne seulement » qui inclurait des articles traduits en français dans leur intégralité, des résumés de
LettRe DU RÉDaCteUR eN CHeF (suite) colloques scientifiques, etc. Pour aller de l’avant, nous devons entamer un dialogue sur la façon de couvrir les coûts de publication à la hausse. Différentes stratégies sont actuellement disponibles, notamment les frais de publication, le paiement pour les figures de couleur, une hausse des recettes publicitaires, etc. Les revues à libre accès et les revues traditionnelles à accès payant ont leurs avantages et leurs inconvénients : le modèle à libre accès ayant un impact prévisible plus grand et le modèle à accès payant permettant possiblement de préserver davantage la qualité et la réputation de la littérature scientifique. La durabilité à long terme du modèle de publication à libre accès n’a pas encore été démontrée. La discussion se poursuivra pour évoluer au cours des prochaines années. Référence : 1. https://en.wikipedia.org/wiki/Predatory_open_access_ publishing Consulté le 5 octobre 2017.
George M. Yousef, M. D., Ph. D., FRCPC(Path) Rédacteur en chef, Revue canadienne de pathologie
All peer-reviewed articles appearing in this publication have undergone a double blind peer-review process. The views or opinions expressed in this Journal are those of the authors and contributors, and do not necessarily reflect those of this Journal, the editors, the editorial board, the publisher of this Journal, or the Canadian Association of Pathologists (CAP-ACP). Although the CAP-ACP has made reasonable efforts to ensure accuracy the articles herein, the Journal, the editors, the editorial board, the publisher of this Journal, or the CAP-ACP, take no responsibility whatsoever for any errors, omissions, or any consequences of reliance on any material or the accuracy of any information contained in this publication. In the event of a discrepancy, between the original and translated versions of the texts, the original version shall take precedence. The mention of trade names, commercial products or organizations, and the inclusion of advertisements in the Journal does not imply endorsement by this Journal, the editors, the editorial board, the publisher of this Journal or the CAP-ACP. This publication is copyright in its entirety. Material may not be reprinted, stored in a retrieval system, or copied without the written permission of CAP-ACP. Contact through www.cap-acp.org.
Revue canadienne de pathologie | volume 9, numéro 4 | www.cap-acp.org
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Upcoming Events • CAP-ACP Annual Scientific Meeting – July 7 to 10, 2018 in Quebec City, QC
• 8th Annual Resident Review Course – January 11 to 14, 2018 in Mississauga, ON
• Surgical Pathology Education Day – January 27, 2018, at Toronto General Hospital • CAMP 2018 Special Topic: Genitourinary Pathology – February 2 to 3, 2018, in Whistler, BC • Day of Bilingual Pathology in Florida – February 24, 2018, in Tampa, Florida
• Banff Pathology Course: Pulmonary, Thoracic & Lung – September 12 to 15, 2018, in Banff, AB
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MoleCulaR pathology CoRneR This article was peer-reviewed.
KeywoRds: immune checkpoint, pd-l1, biomarker.
CoMMeNtaRy: oVeRVIew oF pD-L1 testING author:
Michelle R. Downes1,2 MBBChBAO, MRCSI, MD, FRCPC.
affiliations:
1
Anatomic Pathology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada. Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
2
The author is an advisory board member for PD-L1 testing for AstraZeneca and Hoffman-La Roche. The author declares that there are no other perceived conflicts of interest regarding the publication of this paper. The author has provided CAP-ACP with non-exclusive rights to publish and otherwise deal with or make use of this article, and any photographs/images contained in it, in Canada and all other countries of the world.
The interaction of programmed cell death 1 (PD-1) with programmed cell death ligand 1 (PD-L1) is a key checkpoint in the immune system.
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he interaction of programmed cell death 1 (PD-1) with programmed cell death ligand 1 (PD-L1) is a key checkpoint in the immune system. These checkpoints play a critical role in modulating the immune response to inflammation and maintaining selftolerance. Dysregulation of these inhibitory pathways can lead to autoimmune disease. PD-1 is expressed on immune cells (T cells, B cells, natural killer cells) with PD-L1 expression occurring on antigen presenting cells (activated T cells, macrophages) and on certain neoplastic cell populations.1 When T cells become activated, induction of PD-1 expression occurs which serves to limit the inflammatory response in peripheral tissues. The interaction of PD-1 with its ligand PDL1 inhibits kinases that are involved in T cell activation, resulting in downregulation of the T cell response.
Tumours can exploit this by altering the expression of immune checkpoint proteins (eg inducing PD-L1 expression) and in doing so generate an immunosuppressive tumour microenvironment which facilitates evasion of the host immune system. 2 Recently the oncologic potential of immune checkpoint inhibition has been recognized and explored with the development of specific monoclonal antibodies targeting PD-1 or PD-L1. Therapeutic drugs that block either PD-1 or PD-L1 results in loss of the inhibitory action that occurs when PD1 binds with PD-L1. This allows the cytotoxic T cells (CD8+) to mount a response to the neoplastic cells. Multiple clinical trials across numerous tumour sites have shown both improved objective response rates and extended survival compared with
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MoleCulaR pathology CoRneR pD-L1 testING (cont.) conventional therapies in the setting of advanced and metastatic disease.3 These results led to the Food and Drug Administration (FDA) granting approval for anti PD-1/PD-L1 drugs in melanoma, renal cell carcinoma, nonsmall cell lung carcinoma (NSCLC) and bladder cancer. Further approvals are anticipated in head and neck squamous cell carcinomas. Despite the promising results, not every tumour type will respond to checkpoint blockade with PD-1/PD-L1 inhibitors. Further, within responsive cancer subtypes, not every individual patient will benefit. The identification of patients most likely to derive clinically meaningful benefit from PD-1/PD-L1 inhibition currently relies on the assessment of PD-L1 protein expression in the tumour (high/low or positive/negative). The expression level of PD-L1 (assessed immunohistochemically) is used as a predictive biomarker to
identify patients who are PD-L1 high (positive) and thus more likely to respond to immune checkpoint inhibitors. Currently, each of the available anti PD-1/PD-L1 drugs has been developed in tandem with a specific in vitro diagnostic (IVD) immunohistochemical kit used to assess an individual’s PD-L1 status (see Table 1). This poses several challenges for both pathologists and medical oncologists as iterated below. Health Canada has approved two drugs (to date), Pembrolizumab (Merck & Co Inc, Kenilworth, NJ) and Nivolumab (Bristol-Myers Squibb, Lawrenceville, NJ) for use in NSCLC, renal cell carcinoma and melanoma. The Pembrolizumab approval for NSCLC requires the determination of PD-L1 status using a validated PD-L1 assay. The companion diagnostic assay being most widely used is the 22C3 pharmDx test (Table 1). In the US, the
Table 1: PD-L1 assay systems Drug
Vendor
Antibody Clone SP142
Atezolizumab
Genentech/Roche
Durvalumab
AstraZeneca
SP263
Nivolumab
Bristol-Myers Squibb
28-8
Pembrolizumab Merck
22C3
Platform Ventana Benchmark Ultra with Optiview amplification and detection Ventana Benchmark Ultra with Optiview detection DAKO EnVision Flex with AutostainerLink 48 DAKO EnVision Flex with AutostainerLink 48
Cut off % NSCLC UC HNSCC TC IC≥5 No ≥50 algorithm IC ≥10 TC ≥25 TC ≥5, ≥50 TC ≥50
TC or IC ≥25 TC≥1 or ≥5 TC +IC ≥10 (CPS)
TC≥25 TC ≥1,5,10 TC +IC ≥20 (CPS)
TC= tumour cell. IC= immune cell. CPS= combined proportion score. NSCLC= non-small cell lung cancer, UC= urothelial carcinoma, HNSCC= head and neck squamous cell carcinoma. 10
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MoleCulaR pathology CoRneR pD-L1 testING (cont.)
the potential for test interchangeability is being actively explored
FDA has approved PD-1/PD-L1 inhibitors in bladder cancer without the requirement for a companion diagnostic assay which puts the associated PD-L1 IVD into the category of a complimentary assay (suggested to be used to determine PDL1 status but not required). Each IVD kit has been developed to be platform specific for use on either Ventana or DAKO which limits some laboratories in terms of the testing that they can perform. Further, each assay assesses PD-L1 expression to be read in a different manner. Some antibodies mark tumour cells, some mark the immune cells and some can stain both tumour and immune cells. The threshold for determining a “positive” or PD-L1 high score varies between kits and even within a given kit, it is dependent on the tumour site being tested such that a positive PD-L1 result for one cancer site would be considered negative when testing a different disease site. Issues surround the determination of which tissue samples should be tested (primary versus metastases), assessment of biopsy versus resection material and the development of protocols controlling pre-analytical variables prior to testing. An additional issue concerns the reading and interpretation of PD-L1. It is acknowledged that scoring of immune cells is more challenging than scoring tumour cells with poor interobserver concordance reported4,5 and it may be that specific training would be required for assays that stain the immune infiltrate. There may also be an expectation that institutions using these assays would have a reasonable annual volume of cases so that pathologists could maintain their
interpretative skill set. It is also worth noting that there is no “gold standard” or back up diagnostic test that can be used for borderline results unlike other established predictive biomarkers. Given the multitude of available tests and the limitations posed by the “one assay - one drug” paradigm, the potential for test interchangeability is being actively explored with recent publications looking at assay concordance specifically in the context of NSCLC. The published data suggests that most of the commercially available assays show analytical similarities and concordance in terms of number of tumour cells stained with more variability in immune cell staining. 4-7 In Europe, the SP263 antibody has recently received the European CE mark (EU declaration of conformity) allowing SP263 to be used to identify NSCLC patients suitable for therapy with both Pembrolizumab and Nivolumab in addition to Durvalumab (AstraZeneca, Wilmington, DE). This is the first cross platform approval and it remains to be determined whether other jurisdictions will follow suit. In a similar manner, interest in laboratory developed tests (LDT) is high with interesting publications comparing non-IVD PD-L1 antibodies such as E1L3N (Cell Signalling Technology) with the commercially available IVD kits. The reports suggest that there are analytic similarities in terms of number of cells stained with both methods.4,8 The era of immuno-oncology is here and PD-L1/PD-1 monotherapy is the first of the immune checkpoint class of drugs deployed in clinical practice. The
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MoleCulaR pathology CoRneR pD-L1 testING (cont.)
Treatment decisions are being informed by the level of PD-L1 expression
evolution of combinatory therapy is ongoing with immune checkpoint inhibitors being used in combination with CTLA-4 inhibitors and also standard chemotherapy. While the PD1/PD-L1 pair is the most established of the immune checkpoints from the clinical perspective, additional immune checkpoint molecules (eg TIM3, LAG3) are under investigation and are in early phase clinical trials. The improved outcome of patients with advanced and metastatic disease treated with checkpoint inhibitors is a great clinical success and is set to revolutionize care in certain cancer types. Treatment decisions are being informed by the level of PD-L1 expression which requires assessment with an assay that is easy to interpret with good inter-observer concordance. The challenges that face laboratories in implementing these assays are complex and with the possibility of imminent Health Canada approvals for several indications, it is likely that requests for PD-L1 testing will soon become commonplace. REFERENCES: 1. Adachi K, Tamada K. Immune checkpoint blockade opens an avenue of cancer immunotherapy with a potent clinical efficacy. Cancer Sci. 2015;106:945-50. 2. Pardoll DM. The blockade of immune checkpoints in cancer immunotherapy. Nat Rev Cancer. 2012;12:252-64. 3. Topalian SL, Taube JM, Anders RA, Pardoll DM. Mechanism-driven biomarkers to guide immune checkpoint blockade in cancer 12
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therapy. Nat Rev Cancer. 2016; 16:275-87. 4. Rimm DL, Han G, Taube JM, Yi ES, Bridge JA, Flieder DB, et al. A prospective, multi-institutional, pathologist-based assessment of 4 immunohistochemistry assays for PD-L1 expression in non-small cell lung cancer. JAMA Oncol. 2017;3:1051-58. 5. Scheel AH, Dietel M, Heukamp LC, Jöhrens K, Kirchner T, Reu S, et al. Harmonized PD-L1 immunohistochemistry for pulmonary squamous-cell and adenocarcinomas. Mod Pathol. 2016;29:1165-72. 6. Hirsch FR, McElhinny A, Stanforth D, Ranger-Moore J, Jansson M, Kulangara K, et al. PD-L1 immunohistochemistry assays for lung cancer: results from phase 1 of the Blueprint PD-L1 IHC assay comparison project. J Thorac Oncol. 2017;12:208-22. 7. Ratcliffe MJ, Sharpe A, Midha A, Barker C, Scott M, Scorer P, et al. Agreement between programmed cell death ligand-1 diagnostic assays across multiple protein expression cut offs in non-small cell lung cancer. Clin Cancer Res. 2017;23:3585-91. 8. Schats KA, Van Vré EA, De Schepper S, Boeckx C, Schrijvers DM, Waelput W, et al. Validated programme cell death ligand 1 immunohistochemistry assays (E1L3N and SP142) reveal similar immune cell staining patterns in melanoma when using the same sensitive detection system. Histopathology. 2017;70:253-63.
Anatomical Pathologist Locum Laboratory Medicine Eastern Health
McGill Cytopathology Review Course
The Laboratory Medicine Program of Eastern Health invites applications for the position of locum Anatomical Pathologist. All applicants must be eligible for licensure to practice by the College of Physicians and Surgeons of Newfoundland and Labrador. In addition, applicants must have Certification with the Royal College of Physicians and Surgeons of Canada in Hematological Pathology or equivalent.
May 14 – 15, 2018 Montréal, Québec, Canada Course Director: Dr. Manon Auger
Salary and benefits for this position are to be paid in accordance with the Memorandum of Agreement for salaried physicians in Newfoundland and Labrador.
For further information:
For more information regarding Eastern Health and practicing in Newfoundland and Labrador please contact: Lisa Andrews at
[email protected].
https://muhc-cme.mcgill.ca/CYTO2018
[email protected]
Thank You to Reviewers The CJP Editorial Board wishes to acknowledge the following pathologists and scientists who reviewed articles published in Volume 9 (2017) of the Canadian Journal of Pathology: Ivraym Barsoum
Christopher Naugler
Marie-Anne Brundler
Rola Saleeb
Fadi Brimo
Aaron Pollett
Michael Carter
Roderick Simpson
Laurette Geldenhuys
Aducio Thiesen
Kiran Jakate
Stephen Yip
Hala Faragalla
Emma Helen Allott Adriana Krizova
Monalisa Sur Bing Wang
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Th he Banff Pathology P y Course o iss a collaborat ative effort of the Can anadian Association of Pathologists (C CAP--ACP), Department n of Laboratory Meedicine and Pathology y, University of Albert r a and the Department n of Pathology and d Laboratory Medicine, Uni U versity of Calg a arry to provide a continuing medical education activity forr practicing patholo ogists and residents in i training. a
Ba B anff Centr e e fo or Arts and Creativit r y, former o ly known w as The Banff Centre, locatted in Banff, Alberta, was a established in 1933 as the he Banff School of Dramaa.
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and will provide a forum ffor or sharing inffformation ormation on current moleecular diagnostics in the era of personalized medicine. e.
OBJECTIVE ES After attendin ng this course, participants will be able to: Ȉ
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RubRique de pathologie MoléCulaiRe Cet article a été révisé par des pairs.
Mots Clés : point de contrôle immunitaire, pd-l1, biomarqueur
CoMMeNtaIRe : apeRçU De L’aNaLyse De pD-L1 auteur :
Michelle R. Downes1,2, MBBCh, BAO, MRCSI, M.D., FRCPC
affiliations: 1Département d’anatomie pathologique, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada 2 Laboratoire de médecine et de pathologie, Université de Toronto, Toronto, Ontario, Canada
L’auteure est membre du comité consultatif pour l’analyse de PD-L1 d’AstraZeneca et de F. Hoffmann-La Roche. Elle ne déclare aucun autre conflit d’intérêts apparent relativement à la publication de cet article. L’auteure a accordé à la CAP-ACP le droit non exclusif de publier et d’utiliser cet article, et toute image ou toute photographie qu’il renferme, ou d’en disposer autrement, au Canada et partout ailleurs dans le monde.
La version originale du présent manuscrit a été soumise en anglais, puis traduite en français par Éliane Fréchette, traductrice agréée. La traduction en français de cet article a été révisée par Sophie Camilleri-Broët, M.D., Ph. D.
L’interaction entre la protéine de mort cellulaire programmée de type 1 (PD-1) et le ligand de cette dernière (PD-L1) constitue un point de contrôle clé du système immunitaire.
L
’interaction entre la protéine de mort cellulaire programmée de type 1 (PD-1) et le ligand de cette dernière (PD-L1) constitue un point de contrôle clé du système immunitaire. Ce genre de point de contrôle joue un rôle crucial dans la modulation de la réponse immunitaire à l’inflammation et dans le maintien de la tolérance au soi. Par conséquent, le dérèglement de ces voies inhibitrices peut provoquer l’apparition de maladies auto-immunes. PD-1 est exprimée sur les cellules immunitaires (cellules T, cellules B, lymphocytes NK), tandis que PD-L1 est exprimée sur les cellules présentatrices d’antigènes (cellules T activées, macrophages) et sur certaines populations de cellules néoplasiques1. Quand des cellules T sont activées, l’expression de PD-1 est induite de manière à limiter la réaction inflammatoire dans les tissus périphériques. L’interaction entre PD-1 et son ligand, PD-L1, inhibe les kinases qui participent à l’activation des cellules T, provoquant ainsi une régulation négative de la réponse des cellules T. Les tumeurs peuvent exploiter cette faille en
modifiant l’expression des protéines des points de contrôle immunitaires (par exemple, en induisant l’expression de PD-L1). Ce faisant, elles donnent lieu à un microenvironnement tumoral immunosuppresseur qui facilite l’évasion du système immunitaire de l’hôte2. Récemment, le potentiel oncologique de l’inhibition des points de contrôle immunitaires a été reconnu et exploré grâce au développement d’anticorps monoclonaux spécifiques qui ciblent PD1 ou PD-L1. Les médicaments thérapeutiques qui bloquent PD-1 ou PD-L1 engendrent une baisse de l’action inhibitrice qui survient lorsque PD-1 se lie à PD-L1. Ce phénomène permet aux cellules T cytotoxiques (CD8+) de réagir à la présence de cellules néoplasiques. Plusieurs essais cliniques portant sur différents sites tumoraux ont démontré une amélioration des taux de réponse objectifs et une augmentation du taux de survie, comparativement aux traitements conventionnels dans un contexte de maladie avancée et métastatique3. Ces
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RubRique de pathologie MoléCulaiRe aNaLyse De pD-L1 (suite) résultats ont mené à l’approbation par la Food and Drug Administration (FDA) de médicaments anti-PD-1/PDL1 pour traiter le mélanome, l’adénocarcinome du rein, le carcinome bronchopulmonaire non à petites cellules (CBNPC) et le cancer de la vessie. D’autres homologations sont prévues en lien avec le traitement du
carcinome épidermoïde de la tête et du cou. Malgré ces résultats prometteurs, ce ne sont pas tous les types de tumeurs qui réagiront au blocage des points de contrôle à l’aide des inhibiteurs de PD1/PD-L1. Ce ne sont pas non plus tous les patients atteints de types de cancers positifs qui tireront avantage de ces traitements.
Tableau 1 : Systèmes de détection de PD-L1 Médicament
Fournisseur
Atézolizumab
Genentech/Roche
Durvalumab
AstraZeneca
SP263
Nivolumab
Bristol-Myers Squibb
28-8
Pembrolizumab Merck
Clone de l’anticorps SP142
22C3
Plate-forme
CBNPC CT ≥ 50 CI ≥ 10
OptiView DAB IHC Detection KitMC et OptiView Amplification KitMC sur l’instrument VENTANA BenchMark ULTRAMC OptiView CT ≥ 25 DAB IHC Detection KitMC sur l’instrument VENTANA BenchMark ULTRAMC CT EnVision MC FLEX sur l’Autostainer Link 48MCde Dako CT ≥ 50 EnVision FLEXMC sur l’Autostainer Link 48MC de Dako
Pourcentage seuil CU EMSTC CI ≥ 5 Aucun algorithme
CT ou CI ≥ 25
CT ≥ 25
CT ≥ 1 ou ≥5
CT ≥ 1, 5, 10
CT + CI ≥ 10 (SPC)
CT + CI ≥ 20 (SPC)
CT = cellule tumorale CI = cellule immunitaire SPC = score de proportion combiné CBNPC = cancer bronchopulmonaire non à petites cellules, CU = carcinome urothélial, EMSTC = épithélioma malpighien spinocellulaire de la tête et du cou 16
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RubRique de pathologie MoléCulaiRe aNaLyse De pD-L1 (suite)
le potentiel d’interchangeabilité des différents tests est activement étudié
La détection des patients les plus susceptibles de tirer des bienfaits cliniquement significatifs de l’inhibition de PD-1/PD-L1 repose actuellement sur l’évaluation de l’expression de la protéine PD-L1 dans la tumeur (élevée/faible ou positive/négative). Le niveau d’expression de PD-L1 (analysé par immunohistochimie) est utilisé comme biomarqueur prédictif pour déceler les patients dont le niveau d’expression est élevé (positif) et qui sont donc plus susceptibles de réagir à des inhibiteurs des points de contrôle immunitaires. Chacun des médicaments anti-PD-1/PD-L1 offerts jusqu’à présent a été mis au point de pair avec une trousse immunohistochimique de diagnostic in vitro (DIV) utilisée pour évaluer le statut PD-L1 des patients (voir le tableau 1). Comme indiqué ci-dessous, cette réalité pose de nombreux défis chez les pathologistes et les oncologues. Santé Canada a approuvé deux médicaments (à ce jour), le pembrolizumab (Merck & Co., Inc., Kenilworth, NJ) et le nivolumab (Bristol-Myers Squibb, Lawrenceville, NJ), pour traiter le CBNPC, l’adénocarcinome du rein et le mélanome. L’homologation du pembrolizumab pour le traitement du CBNPC exige l’établissement du statut PD-L1 au moyen d’une épreuve PD-L1 validée. La méthode diagnostique compagnon la plus couramment utilisée est le test 22C3 pharmDx (tableau 1). Aux États-Unis, la FDA a approuvé l’utilisation d’inhibiteurs de PD-1/PDL1 pour le traitement du cancer de la vessie, sans toutefois exiger le recours à une épreuve diagnostique associée. Le DIV afférent de PD-L1 devient donc une méthode diagnostique complémentaire (on suggère de l’utiliser pour déterminer le statut PD-L1, mais il n’est pas obligatoire de le faire). Toutes les trousses de DIV ont été conçues pour être employées sur les plates-formes Ventana ou DAKO, ce qui limite certains laboratoires par rapport
aux tests qu’ils peuvent réaliser. En outre, chaque épreuve demande une lecture de l’expression de PD-L1 différente. Certains anticorps mettent en évidence les cellules tumorales, d’autres marquent les cellules immunitaires et d’autres encore peuvent marquer les deux types cellulaires (cellules tumorales et immunitaires). Qui plus est, le seuil qui sert à déterminer si un marquage est PD-L1 « positif » ou élevé varie entre les différentes trousses et même au sein d’une même trousse. Comme il dépend du site tumoral analysé, un résultat PDL1 positif associé à un site serait considéré comme négatif pour un autre site. Des questions se posent quant à la nature des échantillons de tissus qui devraient être analysés (primaires vs métastatiques), à la méthode de prélèvement (biopsie vs résection) et à l’élaboration de protocoles visant à contrôler les variables préanalytiques avant la réalisation des tests. Un autre enjeu touche la lecture et l’interprétation des résultats associés à PD-L1. En effet, il est reconnu que le marquage des cellules immunitaires est plus difficile à analyser que celui des cellules tumorales (une faible concordance inter-observateurs est d’ailleurs rapportée)4,5. Une formation spécifique à l’étude de l’infiltrat immunitaire pourrait être requise. On pourrait également s’attendre à ce que les établissements qui ont recours à ces méthodes aient un volume annuel de cas raisonnable qui permette aux pathologistes de maintenir leur capacité d’interprétation. Il convient aussi de noter qu’il n’existe pas de « test de référence » ou de méthode diagnostique de substitution pour analyser les résultats « limites », contrairement à d’autres biomarqueurs prédictifs établis. Compte tenu de la multitude de tests accessibles et des limites que pose le paradigme « une épreuve, un médicament », le potentiel d’interchangeabilité des différents tests est activement étudié. Des publications
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RubRique de pathologie MoléCulaiRe aNaLyse De pD-L1 (suite)
Les décisions relatives au traitement sont guidées par le niveau d’expression de PD-L1
récentes se sont d’ailleurs penchées sur la concordance des méthodes dans le contexte particulier du CBNPC. Les données publiées laissent entendre que la plupart des épreuves offertes sur le marché montrent des similitudes analytiques et une certaine concordance en ce qui a trait au nombre de cellules tumorales colorées (une variabilité plus importante a été observée relativement à la coloration des cellules immunitaires)4-7. En Europe, l’anticorps SP263 a récemment obtenu l’homologation européenne « CE » (déclaration de conformité de l’Union européenne), qui permet l’utilisation de SP263 pour cibler les patients atteints d’un CBNPC qui, en plus de prendre du durvalumab (AstraZeneca, Wilmington, DE), pourraient bénéficier d’un traitement à base de pembrolizumab ou de nivolumab. Il s’agit de la première homologation multi-plate-forme; on ignore encore si d’autres autorités emboîteront le pas. De façon similaire, l’intérêt pour les tests mis au point par des laboratoires est élevé. Des publications intéressantes comparent d’autres anticorps PD-L1 (non associés à une trousse de DIV), notamment le E1L3N (Cell Signalling Technology), avec les trousses de DIV offertes sur le marché. Les rapports portent à croire qu’il y aurait des similitudes analytiques entre les deux méthodes quant au nombre de cellules colorées4,8. L’ère de l’immuno-oncologie est arrivée, et la monothérapie PD-L1/PD1 est la première catégorie de médicaments associée aux points de contrôle immunitaires utilisée dans la pratique clinique. L’évolution des traitements combinatoires est constante, à une époque où les 18
inhibiteurs des points de contrôle immunitaires sont employés conjointement avec les inhibiteurs de CTLA-4 et la chimiothérapie classique. Bien que la paire PD-1/PD-L1 représente le plus connu des points de contrôle immunitaires sur le plan clinique, d’autres molécules qui constituent elles aussi des points de contrôle immunitaires (par exemple, TIM3, LAG3, etc.) font l’objet d’études et d’essais cliniques de première phase. L’amélioration des résultats pour les patients aux prises avec des maladies avancées et métastatiques traités à l’aide d’inhibiteurs de points de contrôle est un grand succès clinique appelé à révolutionner les soins liés à certains types de cancer. Les décisions relatives au traitement sont guidées par le niveau d’expression de PD-L1. Or, l’établissement de ce statut nécessite le recours à une épreuve facile à interpréter à laquelle est associée une bonne reproductibilité interobservateurs. Les défis auxquels sont confrontés les laboratoires au moment de mettre en œuvre ces épreuves sont complexes. Malgré tout, avec la possibilité de l’homologation imminente par Santé Canada de plusieurs indications, il y a fort à parier que les demandes d’analyse de PD-L1 deviendront bientôt monnaie courante.
immunotherapy. Nat Rev Cancer. 2012;12:252-264. 3. Topalian SL, Taube JM, Anders RA, Pardoll DM. Mechanism-driven biomarkers to guide immune checkpoint blockade in cancer therapy. Nat Rev Cancer. 2016;16:275-287. 4. Rimm DL, Han G, Taube JM et al. A prospective, multi-institutional, pathologist-based assessment of 4 immunohistochemistry assays for PD-L1 expression in non-small cell lung cancer. JAMA Oncol. 2017 (ePub accessible avant la version imprimée). doi : 10.1001/ jamaoncol2017.0013. 5. Scheel AH, Dietel M, Heukamp LC et al. Harmonized PD-L1 immunohistochemistry for pulmonary squamous-cell and adenocarcinomas. Mod Pathol. 2016;29:1165-1172. 6. Hirsch FR, McElhinny A, Stanforth D et al. PD-L1 immunohistochemistry assays for lung cancer: results from phase 1 of the Blueprint PD-L1 IHC assay comparison project. J Thorac Oncol. 2017;12:208-222. 7. Ratcliffe MJ, Sharpe A, Midha A et al. Agreement between programmed cell death ligand-1 diagnostic assays across multiple protein expression cut offs in non-small cell lung cancer. Clin Cancer Res. 2017 (ePub accessible avant la version imprimée). doi : 10.1158/1078-0432.CCR-162375.
RÉFÉRENCES 1. Adachi K, Tamada K. Immune checkpoint blockade opens an avenue of cancer immunotherapy with a potent clinical efficacy. Cancer Sci. 2015;106:945-950. 2. Pardoll DM. The blockade of immune checkpoints in cancer
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8. Schats KA, Van Vre EA, De Schepper S et al. Validated programmed cell death ligand 1 immunohistochemistry assays (E1L3N and SP142) reveal similar immune cell staining patterns in melanoma when using the same sensitive detection system. Histopathology. 2017;70:253-263.
Applications and nominations are currently being accepted for the following 2018 awards JUNIOR SCIENTIST AWARD Deadline: February 15, 2018
Background/Purpose This annual award is offered by the CAP-ACP to recognize meritorious scientific work, experimental or non-experimental, in the field of Pathology by a young investigator. Award Entitlement The successful applicant will be invited to present their work in a 30-minute platform presentation as part of the Scientific Program of the Annual Meeting of the Association. The CAP-ACP will defray the expenses of the successful applicant, according to CAP-ACP guidelines, to attend the meeting. LEADERSHIP IN EDUCATION AWARD Deadline: January 1, 2018
Background This award was established in December 2012 at the joint suggestion of the Awards Committee, the Continuing Professional Development Committee and the Pathology Education Section. Purpose To recognize a member of the CAP-ACP who has shown leadership in education in the CAP-ACP. LEADERSHIP IN PATIENT SAFETY & QUALITY ASSURANCE AWARD Deadline: January 1, 2018
Background This award was established by the Section of Patient Safety and Quality Assurance in 2013. Purpose To recognize a member of the CAP-ACP who has shown leadership in patient safety and quality assurance in the CAP-ACP.
LLOYD A. KENNEDY PATHOLOGISTS' ASSISTANT AWARD Deadline: February 1, 2018
The Pathologists’ Assistant Award was established in 2007 and was renamed the Lloyd A. Kennedy Pathologists’ Assistant Award in 2010. The bursary is funded by the Department of Pathology and Molecular Medicine at Queen’s University and Kingston General Hospital. It is awarded to a Pathologists’ Assistant in good standing in recognition of his/her outstanding contributions to continuing professional development in the area of medical laboratory practice.
Award Entitlements: • $150 honorarium; • speaking engagement (during the PA Conference - includes travel, accommodation, and complimentary PA conference registration); • certificate presented to the recipient by the Head of the Department of Pathology and Molecular Medicine, Queen’s University; and • acknowledgement during the Saturday evening PA Reception. For application and eligibility criteria please visit www.cap-acp.org/awards.php.
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ConteMporaRy issues
sURUtILIsatIoN Des exaMeNs De LaboratoIRe eN MÉDeCINe : paRVeNIR à expLoIteR Les RessoURCes De MaNIèRe INteLLIGeNte GRâCe à La CoLLaboratIoN auteurs :
Michelle Sholzberg, MDCM, M. Sc., FRCPC1 et Lisa K. Hicks, M.D., M. Sc., FRCPC2
affiliations : 1Département de médecine, Division d’hématologie et d’oncologie; Département de médecine de laboratoire et de pathobiologie; Li Ka Shing Knowledge Institute; Université de Toronto; Hôpital St. Michael, Toronto, Ontario, Canada 2 Département de médecine, Division d’hématologie et d’oncologie; Li Ka Shing Knowledge Institute; Université de Toronto; Hôpital St. Michael, Toronto, Ontario, Canada
Conflits d’intérêts : La Dre Lisa Hicks est la médecin responsable de la campagne Choisir avec soin [Choosing Wisely] à l’hôpital St. Michael, rôle qu’elle joue également auprès de l’American Society of Hematology. Elle et sa collègue Michelle Sholzberg ont coprésidé en novembre 2017 le Laboratory Utilization Symposium, un événement soutenu par l’initiative Choisir avec soin.
RÉSUMÉ Une grande proportion des examens de laboratoire réalisés en médecine est inutile. Cette surabondance représente à la fois un défi colossal et une occasion formidable pour les équipes des laboratoires cliniques. La tension entre la surutilisation et la mise au point de nouveaux tests donne lieu à une limitation des ressources qui complique la tâche des laboratoires au moment de répondre aux besoins cliniques. Par conséquent, s’attaquer au problème que posent les analyses excessives ou inutiles est une façon pour les laboratoires de remédier à la limitation grandissante des ressources. Pour parer efficacement à la surutilisation des examens, des initiatives de collaboration véritable entre les médecins soignants et les cliniciens qui travaillent en laboratoire doivent être mises en œuvre. Si le temps et les ressources dont vous disposez pour changer les choses sont limités, focalisez sur les secteurs où la surutilisation est courante et où le changement est le plus réalisable.
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ConteMporaRy issues This article was peer-reviewed.
KeywoRds: laboratory utilization, blood tests, overutilization
oVeRUtILIzatIoN oF Lab tests IN MeDICINe: aCHIeVING sMaRt testING tHRoUGH CoLLaboratIoN authors:
Michelle Sholzberg1 MDCM, MSc, FRCPC, and Lisa K. Hicks2 MD, MSc, FRCPC.
affiliations:
1
Department Medicine, Division of Hematology/Oncology; Department of Laboratory Medicine and Pathobiology; Li Ka Shing Knowledge Institute; University of Toronto; St. Michael’s Hospital, Toronto, ON, Canada. 2 Department Medicine, Division of Hematology/Oncology; Li Ka Shing Knowledge Institute; University of Toronto; St. Michael’s Hospital, Toronto, ON, Canada.
Conflict of Interests: Dr. Lisa Hicks is the Choosing Wisely Lead at St. Michael’s Hospital and Lead of the Choosing Wisely campaign for the American Society of Hematology. Dr. Lisa Hicks and Dr. Michelle Sholzberg were Chairs of the November, 2017 Laboratory Utilization Symposium, an event supported by Choosing Wisely.
The authors declare that there are no undisclosed conflicts of interest regarding the publication of this paper. All authors have provided CAP-ACP with non-exclusive rights to publish and otherwise deal with or make use of this article, and any photographs/images contained in it, in Canada and all other countries of the world.
ABSTRACT A large proportion of laboratory testing in medicine is unnecessary. This represents both a tremendous challenge and opportunity for clinical laboratory teams. The tension between overutilization and new test development result in resource constraints that make it difficult for labs to meet clinical demands. Therefore, addressing excessive, unnecessary testing is one way for labs to address increasing resource supply limitations. To successfully tackle overutilization in this area, initiatives must meaningfully involve collaboration between bedside and laboratory clinicians. If you have limited time and resources to make a change, focus on the “true low-hanging fruit” - where overuse is common, and where change is most feasible.
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ConteMporaRy issues oVeRUtILIzatIoN oF Lab tests (cont.)
I
t has been suggested that almost fifty percent of clinical laboratory testing may not be necessary.1 Unnecessary tests are those which are unlikely to influence patient care or counselling due to redundancy, lack of clinical relevance, and the use of nonevidence-based testing patterns.1-6 By definition, unnecessary tests do not result in patient benefit; worse, sometimes they can lead to harm by providing misleading information, or by triggering a cascade of tests which may be associated with a risk of downstream adverse events.7 Fifty percent is a staggering estimate of unnecessary laboratory testing – and if accurate, represents both a huge challenge and an opportunity for the clinical laboratory community.
While there is increasing recognition that a substantial amount of lab testing is unhelpful, laboratory utilization continues to grow and new, often expensive laboratory tests are being rapidly developed. In the United States for example, laboratory testing is the facet of healthcare experiencing the most rapid growth in expenditure.8 In Canada, a retrospective cohort study of staff physicians found that the mean yearly lab test expenditure per physician was $27,945 CDN from 2013 to 2014. Primary care physicians accounted for 58% of total expenditures, while hematologists had the largest per capita test-related expenditures.9 The twin pressures of increasing utilization and new test development, mean that clinical laboratories are often faced with financial, time and human resource constraints making it difficult to meet clinical demands. Addressing the problem of unnecessary laboratory tests may be one way for labs to liberate time and money for use in other areas.
Fifty percent is a staggering estimate of unnecessary laboratory testing – and if accurate, represents both a huge challenge and an opportunity for the clinical laboratory community. 22
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But how exactly can a clinical laboratory tackle overutilization and unnecessary testing? The field has been struggling with this problem for several years. Guidelines outlining what constitutes inappropriate testing,10-12 and resources on how to curb testing are available.8,11 However, to effectively address over-testing we need to understand the drivers. In a landmark paper in 2008, Emanuel and Fuchs laid out six factors contributing to what they described as a “perfect storm of overutilization”: medical culture (a need to exhaustively investigate), patient culture, financial incentives, the rapid pace of medical science, direct to consumer marketing, and the market system of healthcare. The market system of healthcare is unique since services are ordered by physicians, who are unaffected by the cost, and received by patients who bear few or none of the lab test-related costs.13 The extent to which each of these factors drives lab testing varies, but it is important to recognize that most of these drivers are outside of the control of the clinical lab. Thus, in our view, to successfully address overutilization in labs, initiatives must be multidisciplinary involving meaningful consultation and collaboration with lab staff, clinicians and in some cases with, patients. One very helpful resource in addressing overutilization in labs is the Choosing Wisely campaign. This initiative began in 2012, and challenges professional medical societies to identify unnecessary tests and treatments in their fields. Choosing Wisely started in the United States and rapidly expanded to Canada. As of writing, Choosing Wisely Canada (CWC) has generated 232 recommendations from 39 different professional societies and other groups.14 In fact, CWC has gone well beyond making recommendations, and has created a wealth of patient education resources and toolkits to help professionals address overutilization. Importantly, of the 232 CWC recommendations, twenty percent address overutilization of laboratory tests.
ConteMporaRy issues oVeRUtILIzatIoN oF Lab tests (cont.)
If you have limited time and resources to make a change, focus on areas where overuse is common, and where change is most feasible.
When the Choosing Wisely campaign began, it was described as an effort to address “low-hanging fruit” in medicine. “Low-hanging fruit” was defined as tests or treatments where there was existing evidence demonstrating a lack clinical utility.15 This definition addresses the rationale for making a change in practice, but it does not address the ease with which one might implement a change. We propose additional criteria for “low-hanging fruit”. If you have limited time and resources to make a change, focus on areas where overuse is common, and where change is most feasible. Multifaceted change strategies that require complex behavior changes are difficult, time-consuming, and often less successful. Strategies that are less complex such as order-set changes, gatekeeping, nudging practice (for instance by changing how test menus are displayed), and hard stops on redundant or “never” tests are much more likely to be successful.16-17
meta-analysis. PLoS One. 2013;8(11):e78962. 2. Song Z, Safran DG, Landon BE, He Y, Ellis RP, Mechanic RE, et al. Health Care Spending and Quality in Year 1 of the Alternative Quality Contract. N Engl J Med. 2011;365:909-18.
major Canadian city. Am J Clin Pathol. 2015;144(1):97-102.
3. Fisher ES, Shortell SM. Accountable Care Organizations Accountable for What, to Whom, and How. JAMA. 2010;304(15):1715-6.
10. National minimum retesting intervals in pathology: A final report detailing consensus recommendations for minimum retesting intervals for use in pathology [Internet]. [updated 2016 Jan; cited 2017 Jul 12]. Available from: https://www.rcpath. org/resourceLibrary/g147minretestingintervalsinpathologydec15-pdf.html.
4. McClellan M, McKethan AN, Lewis JL, Roski J, Fisher ES. A national strategy to put accountable care into practice. Health Aff (Millwood). 2010;29(5):982-90.
11. Lewandrowski K, Sluss P, editors. Utilization management in the clinical laboratory and other ancillary services. 1st ed. Switzerland: Springer; 2017. 303 p.
5. Morgen EK, Naugler C. Inappropriate repeats of six common tests in a Canadian city: a population cohort study within a laboratory informatics framework. Am J Clin Pathol. 2015;144(5):704-12.
12. Naugler C, editor. Lab Literacy for Canadian Doctors: A Guide to Ordering the Right Tests for Better Patient Care. Canada:Brush Education; 2014. 316 p.
6. Miyakis S, Karamanof G, Liontos M, Mountokalakis TD. Factors contributing to inappropriate ordering of tests in an academic medical department and the effect of an educational feedback strategy. Postgrad Med J. 2006;82(974):823-9.
13. Emanuel, E. J. and V. R. Fuchs. The perfect storm of overutilization. JAMA. 2008;299(23): 2789-91. 14. Choosing Wisely Canada [Internet]. [Cited July 12, 2017.] Available from: https://choosingwisely canada.org/recommendations/.
7. Mold JW, Stein HF. The Cascade Effect in the Clinical Care of Patients. N Engl J Med. 1986;314(8):512-4..
15. Brody H. Medicine’s ethical responsibility for health care reform: the top five list. N Engl J Med. 2010;362(4):283-85. 16. Ferrari R, Prosser C. Testing vitamin D levels and choosing wisely. JAMA Intern Med. 2016;176(7):1019-20.
REFERENCES:
8. Physicians ACo. Annual report of the executive vice president 20142015 [Internet]. [updated 2015; cited 2017 Jul 12]. Available from: https://www.acponline.org/about_ acp/who_we_are/annual_report/ 2014-2015/#/evp-message
1. Zhi M, Ding EL, Theisen-Toupal J, Whelan J, Arnaout R. The landscape of inappropriate laboratory testing: a 15-year
9. Naugler C, Thomas R, Turin TC, Guo M, Vaska M, Coapt. Yearly clinical laboratory test expenditures for different medical specialties in a
In our opinion, overutilization in laboratory testing represents a “true low-hanging fruit” as there is ample evidence that many lab tests are not meaningfully contributing to patient care, labs overutilization is common, and many of the change strategies that have been, and can be, employed in this domain are achievable.16-17
17. Fralick M. Hicks LK, Chaudhry H, Goldberg N, Ackery A, Nisenbaum R, et al. REDucing Unnecessary Coagulation Testing in the Emergency Department (REDUCED). BMJ Qual Improv Rep. 2017;6:u221651.w8161.
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Case RepoRt
HypeRpLasIe MyoINtIMaLe IDIopatHIqUe Des VeINes MÉseNtÉRIqUes : UN DIaGNostIC à Ne pas NÉGLIGeR CHez Les patIeNts atteINts D’UNe IsCHÉMIe INtestINaLe auteurs :
Hui Wang, M.D.1; Sheev Dattani, M.D.2; Mary Kinloch, M.D., FRCPC1; Dilip Gill, M.D., FRCSC2; et Chaturika Herath, M.D., FRCPC1
affiliations : 1Département de pathologie et de médecine de laboratoire 2 Département de chirurgie, Université de la Saskatchewan, Saskatoon, Saskatchewan, Canada
RÉSUMÉ L’hyperplasie myointimale idiopathique des veines mésentériques (HMIVM) est une cause rare de la maladie intestinale ischémique. Elle touche généralement les jeunes hommes auparavant en bonne santé, particulièrement dans la région du côlon rectosigmoïde. Les patients aux prises avec une HMIVM qui présentent des signes et des symptômes associés à la maladie inflammatoire chronique de l’intestin (MICI) peuvent facilement faire l’objet d’un mauvais diagnostic clinique. Le diagnostic définitif est habituellement établi au moyen d’une évaluation histopathologique. Dans le présent article, nous décrivons un cas d’HMIVM qui avait d’abord été confondu avec une colite indéterminée. Une maladie de Crohn était également soupçonnée. Le traitement classique avait eu un impact limité, et le patient présentait un mégacôlon toxique nécessitant une résection chirurgicale. L’examen microscopique de l’échantillon prélevé au moment de la colectomie totale avait révélé des caractéristiques associées à la colite ischémique et une hyperplasie myointimale marquée des veines dans la sous-muqueuse et la sousséreuse. Les artères afférentes avaient été épargnées. Ces résultats ont mené à l’établissement d’un diagnostic d’HMIVM. Chez les patients qui développent des symptômes de MICI, mais qui ne présentent pas les caractéristiques endoscopiques propres à la maladie et qui ne répondent pas aux traitements à base de stéroïdes ou d’immunodépresseurs, la présence d’une HMIVM devrait être soupçonnée. Perspective : Cet article présente un cas d’hyperplasie myointimale idiopathique des veines mésentériques (HMIVM). L’HMIVM est une maladie rare diagnostiquée de façon absolue à l’aide d’un examen histopathologique. Elle devrait être envisagée dans le cadre du diagnostic différentiel des patients qui présentent des manifestations cliniques normalement associées à la maladie inflammatoire chronique de l’intestin, mais qui sont réfractaires au traitement classique.
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Case RepoRt This article was peer-reviewed.
KeywoRds: idiopathic myointimal hyperplasia of mesenteric veins (iMhMV), inflammatory bowel disease (ibd), ischemic bowel disease, toxic megacolon, elastic staining
IDIopatHIC MyoINtIMaL HypeRpLasIa oF MeseNteRIC VeINs: a DIaGNosIs Not to MIss IN patIeNts wItH boweL IsCHeMIa authors:
Hui Wang1 MD, Sheev Dattani2 MD, Mary Kinloch1 MD, FRCPC, Dilip Gill2 MD, FRCSC, and Chaturika Herath1 MD, FRCPC.
affiliations:
1
Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, SK, Canada. 2 Department of Surgery, University of Saskatchewan, Saskatoon, SK, Canada.
The authors declare that there are no conflicts of interest regarding the publication of this paper. All authors have provided CAP-ACP with non-exclusive rights to publish and otherwise deal with or make use of this article, and any photographs/images contained in it, in Canada and all other countries of the world.
ABSTRACT Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare cause of ischemic bowel disease. It generally occurs in young, previously healthy male patients with rectosigmoid colon involved. Patients with IMHMV present with signs and symptoms of inflammatory bowel disease (IBD) can be easily misdiagnosed clinically. The definitive diagnosis is usually established by histopathological evaluation. Herein, we present a case of IMHMV that was initially diagnosed as indeterminate colitis with suspicion of Crohn’s disease. The standard treatment had limited effect and the patient presented with toxic megacolon which required a surgical resection. Microscopic examination of the total colectomy specimen revealed features of ischemic colitis with marked myointimal hyperplasia of veins in submucosa and subserosa. Characteristically accompanying arteries were spared. The findings were diagnostic of IMHMV. For patients with IBD symptoms but without specific endoscopic features and refractory to steroid or immunosuppressant, IMHMV should be suspected. Perspective: This article presents a case of idiopathic myointimal hyperplasia of mesenteric veins (IMHMV). IMHMV is a rare disease and definitively diagnosed by histopathological examination. IMHMV should be considered in the differential if patient has clinical manifestations mimicking inflammatory bowel disease but refractory to standard treatment.
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Case RepoRt IMHMV Case RepoRt (cont.) cáÖìêÉ=NK=
INTRODUCTION Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare disease. It was first reported in 1991 by Ganta and Haggitt4 in four male patients with segmental ischemic colitis resulted from occlusion or stenosis of mesenteric veins secondary to myointimal hyperplasia. Most of the published cases occurred in young to middle aged, relatively healthy men.8 Only three cases were reported in female patients.7,11 The rectosigmoid colon is most commonly involved, although the whole colon and terminal ileum can be affected as well. Endoscopic findings are usually nonspecific; including mucosal ulceration, erythema, and edema. Clinical presentations of IMHMV include diarrhea, hematochezia and abdominal pain, which mimic idiopathic chronic inflammatory bowel disease (IBD) and lead to diagnostic dilemmas and treatment pitfalls.
Endoscopy shows ulceration in the proximal rectum with surrounding inflammation and erythema.
CASE PRESENTATION A 61-year-old previously healthy man with a three-month history of significant diarrhea, urgency and abdominal pain was seen initially at a peripheral hospital. He was diagnosed with diverticulitis and treated with antibiotics. There was no resolution of
cáÖìêÉ=OK=
^
_
A: Total colectomy with toxic megacolon from cecum to splenic flexure with maximum dilation of 11cm. B: Descending and sigmoid colon with markedly thickened wall, narrowed lumen and indurated mesentery. 26
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his symptoms thus prompting a visit to our center. Colonoscopy showed a 2centimeter ulcer in the proximal rectum with surrounding inflammation but with areas of normal vascularity (Figure 1). Endoscopic biopsy specimen consisted of two normal-appearing colonic mucosa, and ulcer slough, with presence of fibrinous and inflammatory debris. The findings were non-specific and further investigation was suggested. His working diagnosis was indeterminate colitis with suspicion of Crohn’s disease. The patient was treated with prednisone (40mg po OD) with limited effect. He was eventually given a dose of infliximab (Remicade; Janssen Biotech, Horsham, PA). Two days after the infliximab administration, the patient presented to our emergency department with sepsis and severe abdominal pain. CT findings indicated a toxic megacolon with a massively dilated colon from cecum to splenic flexure. The descending and sigmoid colon were extensively thickened. There was no evidence of free air at the time. After discussion with the patient, the decision was made to proceed with an emergency total colectomy. Gross pathological examination of the resected specimen showed a significantly dilated proximal colon from cecum to splenic flexure with the maximum of 11centimeter dilation. Descending and sigmoid colon were distorted and firm with markedly thickened wall (Figure 2). Microscopically, sections of left colon showed areas of ulceration with fibrinous exudates, mucosal and focal superficial mural necrosis. In less severely affected areas, relatively intact crypts with mucin depletion and lamina propria hyalinization were evident. The features of chronicity as seen in inflammatory bowel disease were not seen. The most dramatic features were in the blood vessels of the colonic wall
Case RepoRt IMHMV Case RepoRt (cont.) cáÖìêÉ=PK=
^
_
f
p
p
f
IMHMV in subserosa (block arrow) with accompanying artery (thin arrow) spared. B: Verhoeff- van Gieson elastic stain highlighting the accompanying spared artery (thin arrow).
f
^
_
f p
p
cáÖìêÉ=QK=
p
f p p
`
p A: IMHMV completely occluding the vein lumen (block arrows) with accompanying arteries spared (thin arrows). B: Verhoeff- van Gieson elastic stain; blocked veins (block arrows) and spared accompanying arteries (thin arrows). C: Immunohistochemistry for smooth muscle actin demonstrating myointimal nature of the hyperplastic process in veins (block arrows).
remote from the areas of ulceration, including those in submucosa and subserosa. There was marked myointimal hyperplasia of veins (Figure 3). Some veins showed complete occlusion of the lumen. The changes were only noted in veins sparing the accompanying arteries, as confirmed by elastic stain. The myointimal nature of proliferative process was highlighted by abundant smooth muscle actin expression in hyperplastic tissue of vein walls (Figure 4). The overall features were diagnostic of IMHMV. The patient’s post-operative hospital stay was uneventful. He tolerated a full diet and the ileostomy was functioning well. The patient was discharged home on post-operative day seven. He was followed up on post-operative day 17. His energy level was slowly improving and he was able to consume over 2000 calories per day. The incisions were well healed and abdominal exam was within normal limits. DISCUSSION The incidence of IMHMV is unknown and there are about 22 cases reported to date.2 IMHMV may be underreported due to the difficulty of making a definitive diagnosis. The majority of the diagnosis of IMHMV was established by histopathological evaluation, which required a full-thickness of colonic wall specimen to reveal the mesenteric venous occlusion secondary to myointimal hyperplasia. Among the published case reports, only one diagnosis11 was made pre-operatively using an endoscopic biopsy specimen. In another case reported by Patel, et al.7, a biopsy in rectosigmoid colon showed ischemic colitis concerning IMHMV. The patient developed perforation soon after colonoscopy and the colonic resection specimen examination confirmed the diagnosis of IMHMV. Those two cases suggest that pre-operative diagnosis maybe possible if there is a high suspicion of IMHMV. A full-thickness surgical biopsy is preferred for the
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Case RepoRt IMHMV Case RepoRt (cont.)
Generally, histopathological findings of IMHMV showing ischemic injuries vary from superficial mucosal necrosis to transmural necrosis with vascular congestion and focal fibrosis.
definitive diagnosis prior to colonic resection.5 The etiology of IMHMV is poorly understood, but less likely associated with IBD since no remarkable inflammatory features were observed in our case or other reports. In addition, this disease is curable by surgical resection of the ischemic colon. Our patient, as well as other patients reported, was refractory to IBD standard treatment, but recovered completely and no recurrence of intestinal symptoms noticed on follow up. The outcome, in turn, indicates IMHMV is irrelevant to a systemic inflammatory disorder. Abu-Alfa et al.1 proposed that IMHMV is caused by an acquired traumatic segmental arteriovenous fistulization because mesenteric veins in patients with this disease closely resemble arterialized vessels from saphenous vein bypass grafts or dialysis fistulae. Sherman and colleagues9 reviewed 68 bowel resection specimens and demonstrated a significant association of prior trauma to the resected bowel segment and focal myointimal hyperplasia of mesenteric veins. Their findings support the trauma hypothesis that was brought up by AbuAlfa et al. 1 Nevertheless, our patient had no previous bowel injury and the etiology of this case remains unknown. The common complications of IMHMV include perforation, bowel obstruction and bleeding.6 Of the 22 reported cases, our patient is the second IMHMV patient to develop toxic megacolon as a complication.4 Toxic megacolon is mainly caused by inflammation, infection, ischemia, and malignancy.3 In addition, it can be potentially triggered by colonoscopy, barium enema, rapid discontinuation of steroids, chemotherapy, and several medications that slow colonic motility (anticholinergics, narcotics, antidiarrheal).3 In our case, ischemia resulted from complete or partial venous occlusion secondary to myointimal hyperplasia (Figure 3 &
28
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Figure 4), induced the development of toxic megacolon. Our patient was on prednisone treatment but tapered gradually. Steroids do not contribute to the pathogenesis of toxic megacolon. Infliximab is a well-known medication for IBD treatment; also, it induces quick response and remission in IBDassociated toxic megacolon. 10 Apparently, infliximab is not a risk factor for megacolon development. No microscopic abnormalities were noticed in nerve endings in the colon in this case. Generally, histopathological findings of IMHMV showing ischemic injuries vary from superficial mucosal necrosis to transmural necrosis with vascular congestion and focal fibrosis. Myointimal hyperplasia of small to medium-sized mesenteric veins is observed with arteries spared. In our case, prominent occluded veins located in all layers of bowel wall, from submucosa to subserosa of left colon, where the inferior mesentery vasculature distributes. The occlusion/smooth muscle cell hyperplasia of veins can be simply mistaken with arterial occlusion under hematoxylin-eosin staining. Therefore, elastic staining was performed and it confirmed the vasculopathy was confined in veins (Figure 3B, 4B). Further, myointimal nature of proliferative process was confirmed by abundant expression of smooth muscle actin in hyperplastic tissue of vein walls (Figure 4C). In summary, our patient experienced the typical IMHMV diagnosing process. He had clinical presentation mimicking IBD and was on standard treatment with no improvement. Both endoscopic and biopsy findings were non-specific. With development of toxic megacolon secondary to ischemia a colectomy was inevitable. As IMHMV has been gradually recognized, this disease should be suspected clinically if the patient is refractory to steroid or immunosuppressant treatment or biopsy findings is inconsistent with IBD.
Case RepoRt IMHMV Case RepoRt (cont.)
Pathologists should be alert and consider IMHMV in the differential diagnosis of ischemic bowel disease.
6.
7. Pathologists should be alert and consider IMHMV in the differential diagnosis of ischemic bowel disease. Fortunately, segmental colonic resection seems to cure the disease even though there is no effective medical treatment. All the reported IMHMV patients, including our patient, recovered well after surgery and no recurrences were noticed with follow up.
8.
Laskaratos FM, Hamilton M, Novelli M, Shepherd N, Jones G, Lawrence C, et al. A rare cause of abdominal pain, diarrhoea and GI bleeding. Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV). Gut. 2015;64(2):214,350. Patel A, Schneider Y, Saumoy M, Maltz C, Yeo H, Jessurun J, et al. A Case of idiopathic myointimal hyperplasia of mesenteric veins. Am J Gastroenterol. 2015;110(S1):154. Platz J, Hyman N. Idiopathic myointimal hyperplasia of mesenteric veins. Gastroenterol Hepatol. 2012;8(10):700-2.
9.
Sherman J, Kao PC, Brian WA, Blaszyk H. Focal myointimal hyperplasia of mesenteric veins is associated with previous trauma in surgical specimens. Pathol Res Pract. 2006;202(7):517-22.
10. Van Geenen EM, Sachar DB. Infliximab in Crohns diseaseassociated toxic megacolon. J Clin Gastroenterol. 2012;46(4): 321-3. 11. Wangensteen KJ, Fogt F, Kann BR, Osterman MT. Idiopathic myointimal hyperplasia of mesenteric veins diagnosed preoperatively. J Clin Gastroenterol. 2015;49(6): 491-4.
REFERENCES 1.
Abu-Alfa AK, Ayer U, West AB. Mucosal biopsy findings and venous abnormalities in idiopathic myointimal hyperplasia of the mesenteric veins. Am J Surg Pathol. 1996;20(10):1271-78.
2.
Costa MN, Saiote J, Pinheiro MJ, Duarte P, Bentes T, Ferraz OM, et al. Segmental colitis caused by idiopathic myointimal hyperplasia of mesenteric veins. Rev Esp Enferm Dig. 2016:108(12):821-6.
3.
Gan SI, Beck PL. A new look at toxic megacolon: an update and review of incidence, etiology, pathogenesis, and management. Am J Gastroenterol. 2003;98(11):2363-71.
4.
Genta RM, Haggitt RC. Idiopathic myointimal hyperplasia of mesenteric veins. Gastroenterology. 1991;101(2):533-9.
5.
Korenblit J, Matro R, Goldstein S, Burkart A, Baliff J, Frankel R, et al. Idiopathic myointimal hyperplasia of the mesenteric veins. Am Surg 2014;80(6):E152-4.
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ReseaRCh aRtiCle
CaRCINoMes INVasIFs DU seIN assoCIÉs à Des RÉsULtats De tests D’HybRIDatIoN IN sItU ÉqUIVoqUes poUR HeR2 : UN DÉFI aUqUeL FoNt soUVeNt FaCe Les patHoLoGIstes et Les oNCoLoGUes auteurs :
Gillian C. Bethune, M.D., FRCPC1; Daniel Veldhuijzen van Zanten, M.D.1; Tallal Younis, M.D., FRCPC2; et Penny J. Barnes, M.D., FRCPC1
affiliations: 1 Département de pathologie et de médecine de laboratoire 2 Division d’oncologie médicale et Département de médecine, Régie de la santé de la Nouvelle-Écosse et Université Dalhousie, Halifax, Nouvelle-Écosse, Canada Remerciements : Les auteurs remercient le Dr Phillip Clement, M.D., FCRCP, de l’Université de la ColombieBritannique et les Drs R. Michael Shier, M.D., FRCS(C), Stéphane Laframboise, M.D., FRCSC, M. Sc., Lilian Gien, M.D., FRCSC, M. Sc., et Eric Leung, M.D., FRCSC, de l’Université de Toronto pour leur révision et leur approbation des lignes directrices.
RÉSUMÉ Contexte : Les lignes directrices en matière d’évaluation du statut HER2 publiées en 2013 par l’ASCO et le CAP ont entraîné une augmentation des résultats équivoques obtenus par hybridation in situ (ISH) et accru le nombre de répétitions de tests d’ISH. Nous avons cherché à déterminer quelles étapes étaient suivies lorsque les résultats d’un examen par hybridation in situ en fluorescence (FISH) étaient équivoques et avons tenté de mesurer l’impact clinique de la répétition d’un tel test. Méthodes : Nous avons effectué la vérification de nos dossiers de pathologie moléculaire sur une période de deux ans à partir de la mise en œuvre des lignes directrices de 2013 de l’ASCO et du CAP dans le but de recenser des cas de cancer du sein primitif associés à au moins un score de FISH HER2 équivoque. Les cas ayant fait l’objet d’un test FISH ont été passés en revue afin de déterminer 30
quelles étapes avaient été suivies pour établir un résultat définitif quant au statut HER2. Par ailleurs, les dossiers médicaux des patients concernés ont été examinés pour recueillir de l’information sur les traitements. Résultats : Parmi les 561 cas qui avaient été soumis à un test FISH visant à définir le statut HER2, 71 tumeurs étaient associées à au moins un score compris dans la plage dite « équivoque ». La marche à suivre subséquente incluait l’évaluation de noyaux supplémentaires (> 120) dans l’ensemble des 71 cas (100 %), le recours à de nouveaux observateurs dans 37 des cas (52 %) et la réalisation d’autres tests FISH dans 16 des cas (23 %). Huit cas ont finalement été jugés HER2 positifs après que des efforts additionnels aient été déployés; trois après la répétition des examens et cinq, à la suite de la réalisation de mesures par d’autres observateurs. Parmi les huit cas
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qui présentaient une amplification, tous affichaient des résultats qui tendaient vers les seuils de positivité associés au nombre de copies du gène HER2 ou au rapport HER2:CEP17. Conclusions : La valeur clinique ajoutée potentielle de la répétition des tests d’ISH lors de l’obtention de résultats équivoque est la plus élevée lorsque les scores se rapprochent des seuils liés à un statut HER2 positif. Perspective : Les catégories d’ISH en lien avec HER2 ont été modifiées, donnant lieu à un plus grand nombre de cas équivoques. Ce projet a pour objectif de mettre en lumière le travail qui doit être réalisé lorsqu’un résultat HER2 équivoque est obtenu par ISH et de fournir des données qui soutiennent l’adoption d’une approche plus ciblée relativement à la répétition des tests d’ISH.
ReseaRCh aRtiCle This article was peer-reviewed.
KeywoRds: heR2 testing, breast cancer, guidelines, equivocal category.
INVasIVe bReast CaRCINoMas wItH eqUIVoCaL HeR2 IN sItU HybRIDIzatIoN test ResULts: aN oNGoING CHaLLeNGe FoR patHoLoGIsts aND oNCoLoGIsts authors:
Gillian C Bethune1 MD, FRCPC; Daniel Veldhuijzen van Zanten1 MD; Tallal Younis2 MD, FRCPC; and Penny J Barnes1 MD, FRCPC.
affiliations: 1 Department of Pathology and Laboratory Medicine, Nova Scotia Health Authority and Dalhousie University, Halifax, NS, Canada. 2 Division of Medical Oncology and Department of Medicine, Nova Scotia Health Authority and Dalhousie University, Halifax, NS, Canada. The authors declare that there are no conflicts of interest regarding the publication of this paper. All authors have provided CAP-ACP with non-exclusive rights to publish and otherwise deal with or make use of this article, and any photographs/images contained in it, in Canada and all other countries of the world. ABSTRACT Background: The 2013 ASCO/CAP HER2 testing guideline has resulted in increased in situ hybridization (ISH) equivocal test results and repeat ISH testing. We sought to determine what work-up was performed for an equivocal fluorescent ISH (FISH) result and the clinical impact of any repeat testing. Methods: We performed an audit of our molecular pathology files over a two-year period since implementation of the 2013 ASCO/CAP guidelines to identify primary breast carcinomas with at least one equivocal HER2 FISH score. FISH records were reviewed to determine steps taken to arrive at a final HER2 result. Clinical charts were reviewed for treatment information. Results: Of 561 cases that underwent HER2 FISH testing, 71 tumours had at least one HER2 FISH score in the equivocal range. Work-up included scoring additional nuclei (>120) in all 71 cases (100%), scoring by additional observers in 37 cases (52%), and additional FISH tests in 16 cases (23%). Eight cases were ultimately deemed HER2 positive after additional work-up; 3 upon repeat testing and 5 upon scoring by additional observers. All 8 amplified cases showed results near positive thresholds for HER2 copy number or HER2:CEP17 ratio. Conclusions: The potential added clinical value of repeat ISH testing for equivocal results is greatest when scores are near HER2 positive threshold cutpoints. Revue canadienne de pathologie | volume 9, numéro 4 | www.cap-acp.org
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ReseaRCh aRtiCle eqUIVoCaL HeR2 IsH bReast CaNCeRs (cont.) Perspective: HER2 ISH categories have changed, resulting in more equivocal cases. This project is intended to highlight the work undertaken when a HER2 ISH equivocal result is obtained and to provide supporting evidence for a directed approach to repeat ISH testing.
We sought to determine what additional steps were performed due to an equivocal FISH result and the clinical impact of any repeat testing.
INTRODUCTION Anti-human epidermal growth factor receptor 2 (HER2) therapy, such as trastuzumab and pertuzumab, is a cornerstone component of the systemic therapeutic management for patients with HER2 positive breast cancer. The most recent American Society of Clinical Oncology/ College of American Pathologists (ASCO/CAP) guideline recommendations for HER2 testing in invasive breast carcinoma include some modifications of the definitions for HER2 positive, equivocal, and negative tumours.1,2 One focus of 2013 guideline recommendations was aimed at reducing the potential for false-negative cases. With use of a dual probe in situ hybridization (ISH) assay, ISH positive tumours are now defined as those with a HER2:CEP17 ratio ≥ 2.0 or average HER2 copy number ≥6.0 signals/cell. Conversely, ISH negative tumours are defined as those with a HER2/:CEP17 ratio < 2.0 with a mean HER2 copy number < 4.0 signals/cell. HER2 equivocal tumours are redefined as those with a HER2:CEP17 ratio +8?@' (-8>+'
-8B+'
,8+'
,8-'
' )(E' ' @*E' (,,E' :80' :80' ' B+' (BE' (,,E' :80' :80' '
' B*E' ' *>E' @@E' @*E' -)E' ' +' ,E' :80' :80' :80' '
' B@E' ' )BE' @*E' @,E' @(E' ' -' ,E' :80' :80' :80' '
BL assay performance for the detection of Class A and AmpC ESBL producing organisms using different testing methodologies.
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ReseaRCh aRtiCle rapID DeteCtIoN oF esbL FRoM ReCtaL swabs (cont.) positive in all 5 KPC, 3 NDM isolates and the K1 hyper producer K. oxytoca. All KPC and NDM isolates were confirmed using a multiplex PCR assay for blaKPC and blaNDM developed at the Public Health Ontario Laboratory, Toronto, Canada.10,11 Using isolated colonies, the BL assay had an overall sensitivity of 71% (125/176) for all broad-spectrum beta lactamases tested, including carbapenemases. The sensitivity of the BL test for detecting Class A ESBL was 96% (104/108). In contrast, the sensitivity for the detection of AmpC ESBL was a dismal 15% (8/54). BL was positive in 4 out of 5 isolates that had both Class A and AmpC ESBL Direct Detection of ESBL organisms from rectal swabs. Direct testing for ESBL harbouring organisms was done on 228 rectal swabs. The BL test was evaluated to detect ESBL organisms directly on the swab by one of two methods;(1) specimens were tested by direct addition of the BL reagents to the swab head and incubated for 15-minute at room temperature (140/228); or (2) specimens were initially soaked and incubated in Tryptic soy broth for 4 hours at 37ºC and then tested (88/228) (Table 1). In the 140 direct-on-swab-head specimens, conventional phenotypic methods identified Class A ESBL in 39/140 (28%), AmpC ESBL in 4/140 (3%) and ESBL negative organisms in 97/140 (69%) specimens (Table 1). The direct-on-swab method resulted in an overall assay sensitivity of 56% (24/43). The BL sensitivity was 62% (24/39) for the detection of Class A ESBL (Table 1). The specificity of the BL assay was 99% (96/97; one false positive), PPV for Class A ESBL was 96% (24/25) with a NPV of 87% (101/116). None of the swabs with organisms containing AmpC mechanisms were detected by the BL assay. 46
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Eighty–eight rectal swabs from an additional group of patients were incubated in TSB broth and incubated for 4 hours at 37ºC prior to addition of the BL reagents. Of the 88 specimens tested, conventional phenotypic testing had identified 24/88 (27%) Class A ESBLs, AmpC in 8/88 (9%) and 2/88 (2%) specimens had both Class A and AmpC ESBL phenotypes (Table 1). The assay sensitivity for both Class A and AmpC ESBL using the broth enrichment method was 59%, however the sensitivity of detecting Class A ESBL organisms from broth-soakedswabs was 75% (18/24) with a specificity of 96% (52/54) (Table 1). The PPV was 90%(18/20) and the NPV was 91%(64/70) for Class A ESBL. The BL assay did not detect AmpC lactamases(0/8), or organisms with both Class A and AmpC resistance phenotypes (0/2). DISCUSSION: The BL assay provides a rapid test for the detection of ESBL organisms in culture with the assay demonstrating excellent sensitivity (96%) for the detection of Class A ESBL producing Enterobacteriaceae from colonies. Direct-on-swab resulted in a significant drop in sensitivity (Table 1; 62%). The sensitivity was improved to 75% for the detection of class A ESBL when rectal swabs were incubated in broth for 4 hours before testing. BL had poor sensitivity for detecting AmpC enzymes which has been previously reported.1316 The low sensitivity of BL for the detection of AmpC ESBL mechanism(s) is likely related to the chromogenic cephalosporin base of the BL test HMRZ-86, which is structural similar to cefepime; a cephalosporin that is resistant to hydrolysis by AmpC enzymes.14,15 This testing method would serve to significantly reduce the turn-aroundtime for reporting out ESBL positive organisms. The high PPV of the assay suggests that tested broth-soaked-
ReseaRCh aRtiCle rapID DeteCtIoN oF esbL FRoM ReCtaL swabs (cont.)
This testing method would serve to significantly reduce the turn-around-time for reporting out ESBL positive organisms. The high PPV of the assay suggests that tested broth soaked swabs can be used to report out ESBLpositive results, while negative results would need additional confirmatory testing to detect AmpC ESBL organisms and detect potential false negative Class A ESBL harbouring organisms.
swabs can be used to report out ESBLpositive results, while negative results would need additional confirmatory testing to detect AmpC ESBL organisms and detect potential false negative Class A ESBL harbouring organisms. The BL assay is a rapid economical assay that would be particularly useful for the detection of Class A ESBL organisms in high prevalence settings. Other studies have examined the utility of the BL test to directly detect ESBL organisms from urine specimens. 15 Our study has several limitations; we did not determine the test performance characteristics of the BL assay to different resistance enzymes as molecular testing was not performed. This would have helped in understanding if different AmpC and Class A enzymes have different detection rates. Furthermore, we only evaluated a very small number of CPE isolates precluding our ability to draw any firm conclusions regarding the sensitivity or specificity of the BL test to detect NDM or KPC isolates. However, previous reports have suggested that HMRZ-86 based detection methods may have difficulties detecting NDM CPE isolates that appeared to be influenced by Zn+ ions and the buffer type used in the assay. 10 The importance and need for rapid detection of both ESBL and CPE isolates have led to the development of several rapid tests including the BL assay and the CARBA NP assay for the detection of carbapenamase enzymes. 11,16,17
molecular and/or phenotypic methods. In addition, this rapid test can be used in conjunction with a more specific test for carbapenemase detection such as the Carba NP test, 17 to further facilitate the rapid detection of CPE harbouring Enterobacteriacae.
In conclusion our data suggest that the high specificity of the assay would enable rapid detection of ESBL organisms in clinical specimens and for use as a screening test for ESBL carriage in institutional settings, particularly because of the high sensitivity and specificity for Class A ESBL organisms. Using this rapid test would significantly reduce the time to detection when compared to using
5. Trecarichi EM, Tumbarello M, Spanu T, Caira M, Fianchi L, Chiusolo P, et al. Incidence and clinical impact of extendedspectrum-beta-lactamase (ESBL) production and fluoroquinolone resistance in bloodstream infections caused by Escherichia coli in patients with hematological malignancies. Journal Infect. 2009;58:299-307.
REFERENCES: 1. Knothe H, Shah P, Krcmery V, Antal M, Mitsuhashi S. Transferable resistance to cefotaxime, cefoxitin, cefamandole and cefuroxime in clinical isolates of Klebsiella pneumoniae and Serratia marcescens. Infection. 1983;11:315-7. 2. Gupta N, Limbago BM, Patel JB, Kallen AJ. Carbapenem-resistant Enterobacteriaceae: epidemiology and prevention. Clin Infect Dis. 2011;53:60-7. 3. Schwaber MJ, Navon-Venezia S, Kaye KS, Ben-Ami R, Schwartz D, Carmeli Y. Clinical and economic impact of bacteremia with extended- spectrum-betalactamase-producing Enterobacteriaceae. Antimicrob Agents Chemother. 2006;50:125762. 4. Sidler JA, Battegay M, TschudinSutter S, Widmer AF, Weisser M. Enterococci, Clostridium difficile and ESBL-producing bacteria: epidemiology, clinical impact and prevention in ICU patients. Swiss Med Wkly. 2014;144:w14009.
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ReseaRCh aRtiCle rapID DeteCtIoN oF esbL FRoM ReCtaL swabs (cont.) 6. Clinical and Laboratory Standards Institute (CLSI). Performance standards for antimicrobial susceptibility testing: 23rd informational supplement (M100S23). Wayne, PA: CLSI;2013. 7. Quality Management Program Laboratory Services (QMP-LS). Consensus practice recommendations - antimicrobial susceptibility testing and reporting on bacteriology specimens. Toronto: Ontario Medical Association;2013. 8. Hanaki H, Koide Y, Yamazaki H, Kubo R, Nakano T, Atsuda K, et al. Substrate specificity of HMRZ86 for beta-lactamases, including extended-spectrum beta-lactamases (ESBLs). J Infect Chemother. 2007;13:390-5. 9. Giske CG, Gezelius L, Samuelsen Ø, Warner M, Sundsfjord A, Woodford N. A sensitive and specific phenotypic assay for detection of metallo-β-lactamases and KPC in Klebsiella pneumoniae with the use of meropenem disks supplemented with aminophenylboronic acid, dipicolinic acid and cloxacillin. Clin Microbiol Infect. 2011;17:552-6 10. Hanaki H, Kubo R, Nakano T, Kurihara M, Sunagawa K. Characterization of HMRZ-86: a novel chromogenic cephalosporin for the detection of extendedspectrum beta-lactamases. J Antimicrob Chemother. 2004;53:888-9. 11. Tijet N, Alexander D, Richardson D, Lastovetska O, Low D, Patel S, et al. New Delhi metallo-betalactamase, Ontario, Canada. Emerg Infect Dis. 2011;17:306-7. 12. Tijet N, Boyd D, Patel SN, Mulvey 48
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MR, Melano RG. Evaluation of the Carba NP test for rapid detection of carbapenemase-producing Enterobacteriaceae and Pseudomonas aeruginosa. Antimicrob Agents Chemother. 2013;57:4578-80. 13. Renvoise A, Decre D, AmarsyGuerle R, Huang T, Jost C, Podglajen I, et al. Evaluation of the betaLacta test, a rapid test detecting resistance to thirdgeneration cephalosporins in clinical strains of Enterobacteriaceae. J Clin Microbiol. 2013;51:4012-17. 14. Sekirov I, Roscoe D. Evaluation of a rapid extended spectrum betalactamases/carbapenemase (ESBL/CRO) detection kit in a diagnostic microbiology laboratory. Can J Infect Dis Med Microbiol. 2013;24(SB):29B. 15. Doi Y, Paterson D, Adams-Haduch J, Sidjabat H, O'Keefe A, Endimiani A, et al. Reduced susceptibility to cefepime among Escherichia coli clinical isolates producing novel variants of CMY-2 beta-lactamase. Antimicrob Agents Chemother. 2009;53: 3159-61. 16. Gallah S, Decre D, Genel N, Arlet G. The beta-Lacta test for direct detection of extended-spectrumbeta-lactamase-producing Enterobacteriaceae in urine. J Clinical Microbiol. 2014;52:379294. 17. Vasoo S, Cunningham S, Kohner P, Simner P, Mandrekar J, Lolans K, et al. Comparison of a novel, rapid chromogenic biochemical assay, the Carba NP test, with the modified Hodge test for detection of carbapenemase-producing Gramnegative bacilli. J Clin Microbiol. 2013;51:3097-3101.
Congratulations to the 2017 Award recipients The CAP-ACP wishes to congratulate all of those who were recognized for their contributions to the CAP-ACP or who won an Association award this year. Award
Recipient
Andrew Herzenberg Award
Kevin Yi Mi Ren
Distinguished Service
Iakovina Alexopoulou
Chairs of Pathology Award in Experimental Pathology - ORAL
Zsuzsanna Lichner Andrew P. Brack
Donald W. Penner Award - ORAL
Ivraym Barsoum
Donald W. Penner Award - POSTER
Emily Goebel
Dr. Donald Rix Award for Resident Travel
Linton David R. Sellen
Dr. Donald Rix Award for Resident Travel
Hematological Pathology Awards - POSTER
Shuo (Amanda) Xu
Hugh Curry Resident Award
Kianoosh Keyhanian
Susan McRae
Hugh Curry Cytotechnologist Award
Dan Winer
Junior Scientist Award
Leadership in Education Award
Leadership in Patient Safety & Quality Assurance Award
Lloyd A. Kennedy Pathologists' Assistant Award Local Organizing Chair Award
Medical Technologist/Technician Award for CPD William Boyd Lectureship President’s Award
Marcio Gomes Jagdish Butany
Martin Grealish
Rosemary Henderson Carolyn McCarville
Guillermo Quinonez Bruce Burns
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ReseaRCh aRtiCle
CHaNGeMeNts IMMUNopatHoLoGIqUes obseRVÉs DaNs Les tIssUs aDIpeUx et L’INtestIN Des patIeNts aUx pRIses aVeC UNe INsULINoRÉsIstaNCe assoCIÉe à L’obÉsItÉ auteurs :
Helen Luck1,2,6; Shawn Winer, M.D., FRCPC, Ph. D.3,4 et Daniel A. Winer, M.D., FRCPC1,2,4,5,6
affiliations : 1Division de biologie cellulaire et moléculaire, Groupe de recherche sur le diabète, Toronto General Research Institute, Réseau universitaire de santé, 101 College Street, Toronto (Ontario) M5G 1L7, Canada 2 Département d’immunologie, Université de Toronto, 1 King’s College Circle, Toronto (Ontario) M5S 3B3, Canada 3 Département de médecine de laboratoire, Hôpital St. Michael, Toronto (Ontario) M5G 1L7, Canada 4 Département de médecine de laboratoire et de pathobiologie, Université de Toronto, Toronto (Ontario) M5S 1A1, Canada 5 Département de pathologie, Réseau universitaire de santé, 200 Elizabeth Street, Toronto (Ontario) M5G 2C4, Canada 6 Adresse actuelle : 10-352 Toronto Medical Discovery Tower, 101 College Street, Toronto (Ontario) M5G 1L7, Canada Remerciements : Tous les auteurs ont contribué à la rédaction du texte, à l’élaboration des figures et à la révision du manuscrit. Daniel A. Winer (D.A.W.) a reçu le Prix des jeunes chercheurs de l’Association canadienne des pathologistes. Il est également titulaire d’une chaire de recherche du Canada et lauréat du Programme de bourses de nouveaux chercheurs du ministère de la Recherche, de l’Innovation et des Sciences de l’Ontario. Helen Luck est détentrice d’une bourse d’études supérieures du Canada – bourse au doctorat (BESC-D) des Instituts de recherche en santé du Canada (IRSC). Ce projet a été financé en partie par les subventions 119414, 142708 et 148385 (D.A.W.) des IRSC; les subventions OG-3-15-5014 et CS-5-12-3886 (D.A.W.) de l’Association canadienne du diabète (désormais Diabète Canada); et une subvention (D.A.W.) de la Fondation J.P. Bickell. RÉSUMÉ L’inflammation chronique de faible intensité des tissus métaboliques est considérée comme l’une des principales causes de l’insulinorésistance associée à l’obésité. Bien que les modifications au profil immunitaire des tissus adipeux engendrées par l’obésité aient fait l’objet d’études approfondies, les travaux de recherche sur les transformations subies par le système immunitaire intestinal demeurent à ce jour peu nombreux. Cette revue a pour objectif de traiter des récents progrès associés aux changements immunologiques observés dans les tissus adipeux viscéraux et l’intestin des personnes qui souffrent d’insulinorésistance. Dans cet article, nous mettrons en lumière les interactions entre l’alimentation, le microbiote intestinal, la barrière intestinale et le système immunitaire intestinal pour montrer le rôle que joue ce réseau dans la manifestation globale de la résistance à l’insuline. 50
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ReseaRCh aRtiCle
KeywoRds: intestinal immune system; adipose inflammation; obesity; insulin resistance; metabolic syndrome.
aDIpose aND INtestINaL IMMUNopatHoLoGy IN obesIty ReLateD INsULIN ResIstaNCe authors:
Helen Luck1,2,6, Shawn Winer3,4 MD, FRCPC, PhD, and Daniel A. Winer1,2,4,5,6 MD, FRCPC.
affiliations: 1Division of Cellular & Molecular Biology, Diabetes Research Group, Toronto General Research Institute (TGRI), University Health Network, 101 College Street, Toronto, ON, Canada. 2 Department of Immunology, University of Toronto, 1 King’s College Circle, Toronto, ON, Canada. 3 Department of Laboratory Medicine, St. Michael’s Hospital, Toronto, ON, Canada. 4 Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada. 5 Department of Pathology, University Health Network, 200 Elizabeth Street, Toronto, ON, Canada. 6 Present Address: 10-352 Toronto Medical Discovery Tower, 101 College Street, Toronto, ON, Canada. aCKNowLeDGeMeNts : All authors contributed to the writing, figure generation, and revision of the manuscript. Daniel A. Winer (D.A.W.) is a recipient of the Canadian Pathology Association Junior Scientist Award, Canada Research Chair, and the Ontario Ministry of Innovation Early Researcher Award. Helen Luck is a recipient of the CIHR Canada Graduate Scholarship-Doctoral (CGS-D) Award. This work was funded in part by Canadian Institutes of Health Research (CIHR) grants 119414, 142708, and 148385 (D.A.W.); Canadian Diabetes Association (now Diabetes Canada) grants OG-3-15-5014 and CS-5-12-3886 (D.A.W.); J.P. Bickell Foundation Grant (D.A.W.).
The authors declare that there are no undisclosed conflicts of interest regarding the publication of this paper. All authors have provided CAP-ACP with non-exclusive rights to publish and otherwise deal with or make use of this article, and any photographs/images contained in it, in Canada and all other countries of the world.
ABSTRACT Chronic low-grade inflammation of metabolic tissues is thought to be a major driver of obesity related insulin resistance and metabolic syndrome. While changes to the immune profile in adipose tissue during obesity have undergone active investigation, alterations to the intestinal immune system have only recently been Revue canadienne de pathologie | volume 9, numéro 4 | www.cap-acp.org
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ReseaRCh aRtiCle aDIpose aND INtestINaL IMMUNopatHoLoGy (cont.) investigated. This review aims to discuss recent advances regarding immunological changes within the visceral adipose tissue and intestine during insulin resistance. We will highlight interactions between diet, gut microbiota, intestinal barrier and the intestinal immune system to show how this intestinal network is implicated in the overall manifestation of insulin resistance.
INTRODUCTION Many factors including poor dietary choices and changing socioeconomic environments are linked to the increasing rate of obesity and metabolic syndrome worldwide. Obesity and metabolic syndrome is intertwined with many comorbidities such as type 2 diabetes, cardiovascular disease, nonalcohol fatty liver disease and cancer. New target avenues for the effective treatment of type 2 diabetes are in high demand as existing therapies are limited and some carry side effects. Therapies that target the immune system (immunotherapy) have gained promising attention in the treatment of many diseases such as cancer and have begun to be explored as a possibility for insulin resistance. There has been great advancement in scientific research on the role of the immune system in obesity and insulin resistance over the past two decades and much of this work has elucidated the immunological changes within the visceral adipose tissue (VAT). More recently, the intestinal immune system has been shown to be involved in the progression of insulin resistance. Here, we highlight recent advances pertaining to the implications of the immune profile of metabolic organs, such as in the VAT, and more recently in the intestine, on insulin resistance. The relationship between the gut microbiota, intestinal barrier and intestinal immune system during obesity will be discussed. UPDATE: IMMUNOLOGICAL CHANGES WITHIN VISCERAL ADIPOSE TISSUE DURING OBESITY Innate VAT is the deep fat surrounding internal organs within the body. Chronic low52
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grade inflammation of VAT is widely accepted to be a major contributor to obesity-related insulin resistance. Both innate and adaptive immune cell populations within the VAT shift to an inflammatory phenotype during dietinduced obesity. Innate immune cells within VAT include macrophages, neutrophils, mast cells, dendritic cells and innate lymphoid cells (ILCs) and their contributions to pathogenesis in obesity have been reviewed extensively.1-5 The morphological signature of inflammation in VAT during insulin resistance is the infiltration of inflammatory macrophages and other immune cells around dying adipocytes to form the so-called “crown-like structures”. Macrophages in VAT are historically classified into M1 or M2 subtypes, though this terminology likely represents an oversimplification of a spectrum of macrophage phenotypes, which also include differences between recruited and resident cells.6 Macrophages of the ‘M1’ phenotype are activated by lipopolysaccharides (LPS), and produce inflammatory cytokines such as TNFα, IL-6 and IL-1β to promote chronic inflammation. Inflammatory cytokines and free fatty acids (FFA) can directly hinder insulin signalling via induction of IKK and JNK1 pathways within adipocytes and other insulin-sensitive tissues. Insulin resistance in VAT also promotes shedding of FFA into circulation and deposition into ectopic tissues like the liver.7 During obesity-induced VAT inflammation, a shift from M2 to M1 macrophage polarization occurs although the mechanisms behind this shift are unclear. Dominant regulators of
ReseaRCh aRtiCle aDIpose aND INtestINaL IMMUNopatHoLoGy (cont.)
The morphological signature of inflammation in VAT during insulin resistance is the infiltration of inflammatory macrophages and other immune cells around dying adipocytes to form the so-called “crown-like structures”.
macrophage polarization inside VAT include adaptive immune cells, which will be discussed below. However, recent data also highlights roles for NKT cells and ILCs in the regulation of macrophage function inside VAT. One possible trigger is the M2 macrophage and adipocyte downregulation of CD1d expression, which may fuel NKT cell inflammatory action to promote M1 polarization.8,9 In addition, another group has recently characterized a distinct type of ILC1s stimulated by IL12 that accumulate and reside in adipose tissue (subcutaneous and visceral) early on during HFD feeding in mice.10 These adipose-resident ILC1s produce sufficient IFNγ to drive early M1 macrophage polarization inside VAT.10 In contrast, ILC2s maintain eosinophils and M2 macrophages in VAT through the production of IL-5 and IL-13, and have been shown to be decreased in obesity related insulin resistance.11,12 Thus, it seems that the initiation and persistence of M1 macrophage accumulation in VAT is a complex process that includes a combination of the downregulation of regulatory mediators and promotion of inflammatory mediators via cross talk of multiple immune populations. Adaptive Although macrophages have been the major focus of immune cells involved in low grade VAT inflammation, the adaptive immune system, including T and B cells, also have been shown to influence VAT inflammation during insulin resistance.1,13-17 Like innate immune cells, T and B cells can release a variety of cytokines in response to a changing homeostatic or inflammatory milieu. T cells, including Th1 and CD8+ T cells, are generally accepted to promote VAT inflammation through the production of IFNγ which stimulates M1 macrophage polarization, while Th2 cells that produce cytokines such as IL4, IL-5, and IL-13 are suppressed.13,16 Tregs inside VAT show some overlapping epigenetic signatures to Th2
cells, and respond to the cytokine ILThey are classically 33.18-20 anti-inflammatory due to the production of IL-10 and TGF-β, and they are also thought to play a protective role inside VAT during obesity insulin resistance, though their role in aging associated insulin resistance is less clear.18,21,22 A T cell depleting but Treg boosting, antiCD3 therapy has shown promise in protecting against insulin resistance in mice and potentially in humans.16,23 Furthermore, some existing diabetes therapies, such as the thiazolidinediones are thought to act directly on Tregs,24 suggesting that T cell modulation is an important target for therapy in obesity related insulin resistance. B cells are generally pathogenic in obesity and B cell deficient mice are protected from insulin resistance. B cells worsen insulin resistance inside VAT mainly through secretion of proinflammatory cytokines which potentiate T cell and macrophage inflammatory function. 15,25 B cells, especially the B2 subset of B cells, worsen insulin resistance upon adoptive transfer into B cell deficient mice or by treatment with a B cell-depleting CD20 antibody.15 These effects may be partially mediated by the leukotriene (LTB4/LTB4R1) signalling pathway.26 Conversely, B1-a B cells, which produce approximately 50% of the B cell derived IL-10 in vivo, are reduced in obesity and ameliorate insulin resistance upon adoptive transfer into B cell-deficient mice fed a HFD.27 A recent study reported that there are indeed changes to the B-cell repertoire selecting for shorter immunoglobulin (Ig) heavy chain CDRH3 sequences suggesting the presence of an antigen-driven response behind the pathogenicity of B cells in insulin resistance.28 Overall, both innate and adaptive immune cells within VAT are crucial to the enhancement or mitigation of inflammation and systemic insulin resistance. However, the factors that drive the inflammatory changes inside
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ReseaRCh aRtiCle aDIpose aND INtestINaL IMMUNopatHoLoGy (cont.) VAT are just beginning to be discovered. One such target might lie within the intestinal immune system makeup, as this system interacts first with the diet and gut microbial metabolites, and may act as the gatekeeper to downstream VAT pathology and associated metabolic abnormalities. OVERVIEW OF THE INTESTINAL IMMUNE SYSTEM The intestinal mucosa contains many components of the intestinal immune system including gut-associated lymphoid tissue (GALT), the largest component of the immune system in the human body. Within the intestine, lymphoid aggregates include the Peyer’s patches in the small intestine, isolated lymphoid follicles found most abundantly in the colon and mesenteric lymph nodes which connects the intestine to the lymphatic system. Many lymphoid cells and antibody producing plasma cells are scattered throughout the lamina propria which lies underneath the epithelium of the intestinal mucosa. Some immune cells are also located within the epithelial layer of the intestine known as intraepithelial lymphocytes (IELs). The epithelial cells or enterocytes work closely with intestinal lymphoid cells to provide a barrier from luminal contents (i.e. microbial and dietary). The epithelium acts to shuttle antibodies into the lumen and coordinate immune responses through recognizing microbial and endogenous patterns as pathogenassociated molecular patterns (PAMPs) through pattern recognition receptors (PRRs), including nod-like receptor (NLR) and toll-like receptor (TLR) innate signalling pathways. Innate immune cells found embedded in or closely associated with the intestinal epithelium include M (microfold) cells, Paneth cells, macrophages, and dendritic cells. In the adaptive system, both B and T cells are found within the lamina propria and lymphoid structures. B cells are predominantly located within the lymphoid aggregates to initiate adaptive immune responses while plasma cells 54
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and T cells respond to encountered pathogens or antigens along with innate immune cells within the lamina propria. INFLUENCE OF GUT DYSBIOSIS AND INTESTINAL PERMEABILITY ON INTESTINAL IMMUNITY IN OBESITY Intestinal homeostasis is largely governed by the intestinal immune system which aids in the regulation of commensal bacteria, defence against pathogens and tolerance of ingested dietary antigens. The development of the intestinal immune system is strongly influenced by the gut microbiota. Gnotobiotic mice have impaired development of the intestinal epithelium and immune system including Peyer’s patches, ILFs and MLNs.29 In addition, lack of a gut microbiota leads to increased susceptibility to enteric pathogens due to insufficiencies in the immune response.29 However, germ-free mice fed a high fat diet (HFD) are protected from weight gain compared to normal chow diet-fed controls suggesting gut microbial influence on diet-induced obesity.30,31 During obesity, an imbalance in intestinal microbial composition known as dysbiosis is linked to worsened metabolic outcome. Substantial research has been performed to target the gut microbiota by means of treatments with pre- and postbiotics to regulate host responses within and outside the intestine to improve insulin resistance.32,33 Certain species of bacteria altered by diet and obesity can induce changes to the immune populations specifically within the intestine. Segmented filamentous bacteria (SFB) can induce Th17 cell differentiation, and have been shown to be reduced with obesity associated with reduced numbers of Th17 immune cells; however, a rebalance of Th17 cells in the gut in turn, regulates the abundance of SFB.34-36 Studies have highlighted the protective responses of specific bacterial species such as Akkermansia muciniphila, Faecalibacterium prausnitzii and Bacteroides fragilis in
ReseaRCh aRtiCle aDIpose aND INtestINaL IMMUNopatHoLoGy (cont.)
Moreover, impaired function of the intestinal barrier occurs during dietinduced obesity with the leakage of bacterial products and antigens beyond the intestinal wall and into circulation.
insulin resistance due to their ability to promote the expansion of intestinal Foxp3+ Tregs either through the production of anti-inflammatory metabolites including short-chain fatty acids (SCFA) or through mediating the TLR2/MyD88 signalling pathway.37-39 In a large metagenomics study, humans with a high bacterial richness (indicated by a high bacterial gene count in fecal DNA) are correlated with higher abundances of anti-inflammatory species such as F. prausnitzii, while humans with low bacterial richness were associated with increased weight gain, inflammation, dyslipidemia and insulin resistance.40 Thus, gut dysbiosis and low bacterial diversity may also be markers of insulin resistance. Moreover, impaired function of the intestinal barrier occurs during dietinduced obesity with the leakage of bacterial products and antigens beyond the intestinal wall and into circulation.41-43 It is thought that intestinal permeability is one of the early triggers to metabolic tissue inflammation and insulin resistance as the gut becomes more permeable as early as after 7 days of HFD feeding.43 Antimicrobial peptides such as RegIIIβ and RegIIIγ are reduced with 10 days of HFD feeding which also contribute to intestinal permeability.34 The leakage of bacterial products such as LPS is termed as metabolic endotoxemia, which activates TLR4 signalling pathway to promote inflammatory responses within the intestine and systemically.42,44 Bacterial products that bind to the bacterial peptidoglycan receptor, NOD1, are also increased in HFD-fed mice and depletion of this receptor attenuated insulin resistance and reduced inflammatory status within the VAT.45 Studies have investigated strategies to combat intestinal permeability and metabolic endotoxemia. Treatment with live A. muciniphila for example, improved insulin resistance, tissue inflammation, gut barrier and metabolic endotoxemia as a result of an increase in endocannabinoids.46 A recent study
examined muramyl dipeptide (MDP), a gram-positive bacteria cell wall derived postbiotic that acts through the NOD2 signalling pathway has been shown to promote insulin sensitizing and antiinflammatory effects within adipose and liver tissues mediated by IRF4.47 Treatment with MDP or a NOD2 activating drug, mifamurtide, improved glucose sensitivity after LPS-induced endotoxemia in obese mice.47 Thus, it is interesting to note that although there is bacterial product leakage in diet-induced obesity, the type of bacterial product can have varying effects on whole-body metabolism. In addition to bacterial products, dietary metabolites also affect the intestinal barrier and intestinal immune system. A diet rich in saturated fats promotes inflammatory cytokine release via activating TLR2 and TLR4 in macrophages,48 while a diet rich in omega-3 polyunsaturated fats may have anti-inflammatory effects via activating GPR120.49 Intake of fruits and vegetables increases the availability of aryl hydrocarbon receptor (AHR) ligands, which have been shown to be beneficial for intestinal barrier integrity by promoting IL-22 responses of intestinal ILCs.50 Dietary fibers are metabolized to SCFA and have also been shown to stimulate enterocytes to promote tolerogenic DCs, Tregs and production of luminal IgA to enhance intestinal homeostasis.51 Bile acids may also ameliorate insulin resistance due to tissue-specific activation of the intestinal farnesoid receptor (FXR), although its implications on the intestinal immune system during obesity is unknown. 52 Moreover, HDL cholesterol levels in humans have been observed to be inversely correlated with Vitamin A deficiency.53 Individuals with metabolic syndrome are more likely to deficient in plasma vitamins A, C, E and D compared to healthy controls.53 Vitamin A and D can alter transcriptional programs of innate and adaptive immune cells such as IL-17 producing and CD8αα T cells, respectively.35,54
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ReseaRCh aRtiCle aDIpose aND INtestINaL IMMUNopatHoLoGy (cont.)
Interesting observations have already emerged in characterizing intestinal adaptive immune cells during diet-induced obesity in both murine and human studies.
Thus, the availability of dietary metabolites is also critical to the development and maintenance of the intestinal immune system which can alter downstream insulin resistance. IMMUNOLOGICAL CHANGES WITHIN THE INTESTINE DURING OBESITY Innate General inflammatory shifts occur in both the small and large intestine with dietinduced obesity such as the increase in NF-κB, TNFα, IFNγ, and IL-1β combined with a decrease in antiinflammatory markers such as IL-10 and IL-22.55 Morphologically, the intestines do not manifest with discrete macrophage infiltrates such as the fat, but do show changes to immune cell compositions (Figure 1). Moreover, there is an overall change to some morphological parameters, such as the enlargement of villi in the small intestine.56 An alteration to the immune profile of the intestine during obesity is undergoing active investigation. As mentioned briefly before, pattern recognition receptors (PRR) that recognize lipoprotein (TLR2), LPS (TLR4), flagellin (TLR5) nucleic acids (TLR7/9) and peptidoglycan (NOD1 and 2) have been implicated in in the context of obesity.45,48,57-59 In addition, distinct innate immune populations and their functions are also affected by dietinduced obesity. For example, some subsets of ILC3s, including NKp46+ 56
CD4- ILC3s, are abundant in the intestine, and have been found to be reduced in the colon lamina propria of HFD-fed mice.60 This group of ILCs is important for antimicrobial defence through maintenance of the intestinal barrier and GALT at least partly due to the production of IL-22. IL-22 mRNA and expression of other cytokines such as IL-10, IL-17A, IL-17F have been shown to be decreased in the mouse intestine during diet-induced obesity.34 This decrease in IL-22 production by ILCs may also be due to reduced aryl hydrocarbon (AHR) ligands originally derived from intake of fruits and vegetables.50 Interestingly, exogenous IL-22 therapy has been shown to improve insulin resistance, intestinal permeability, intestinal ER stress, and adipose and liver metabolism in obese mice.61,62 Data regarding changes to the macrophage and dendritic cell populations in the intestine are less clear as intestinal macrophage migration inhibitory factor (MIF) has been shown to be increased during HFD feeding,63 but others have reported no difference in macrophage and DC infiltration and accumulation early after HFD feeding.43 However, a recent report has highlighted that colonic pro-inflammatory macrophages enter the high fat diet exposed intestine in a CCL2-dependent manner to promote low grade inflammation and insulin resistance.64 Consistently, in obese humans, macrophage (CD68+), mature DC (DCLAMP) and natural killer (NK) cells densities have been reported to be increased within the jejunum.56 Rectosigmoid mucosal biopsies of obese postmenopausal women show that the number of macrophages decrease with weight loss along with reduced concentrations of TNFα, IL-1β, IL-8 and MCP-1.65 Eosinophils which are important for antimicrobial and antiinflammatory effects in the gut,66 have been shown be decreased after 1 week of HFD feeding in mice and this reduction is associated with increased paracellular permeability in the ileum.43 Intestinal
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neutrophil infiltration is not a feature of diet-induced obesity in mice.60 Further investigation of other intestinal innate immune subsets during obesity including MAIT cells, tolerogenic macrophages and DCs, and mast cells is warranted. Adaptive Interesting observations have already emerged in characterizing intestinal adaptive immune cells during dietinduced obesity in both murine and human studies. Our group and others have demonstrated that the percentages of IFNγ producing T cells are increased while Tregs are reduced within the small and large intestine during HFD feeding in mice.34,35,60 In obese humans, upper intestinal (jejunal) CD8+ intraepithelial and lamina propria T cells are increased and express the CD8αβ co-receptors rather than the frequently encountered CD8αα co-receptor.56 Whether this increase in obesity related intraepithelial lymphocytes is a previously unrecognized cause for an idiopathic increased IEL count in upper intestinal biopsies remains to be seen. IFNγ produced by T cells can contribute to the reduction of tight junction protein expression within the intestinal epithelium resulting in increased intestinal permeability.60 On the contrary, IL-17 producing T cells are generally reduced in the murine small intestine during obesity and are associated with changes to the gut microbiota and vitamin A deficiency.34,35 Transfer of gut tropic Th17 cells ameliorated insulin resistance and promoted a shift towards a healthy microbiota.35 Densities of B cells (CD20+) do not appear to be altered in obese humans.56 Further studies in humans and animal models are required to determine if intestinal B cell subsets, such as those that produce the abundantly found intestinal IgA, play a role in obesity. CURRENT MODEL: SHIFTING FOCUS TO THE INTESTINAL IMMUNE SYSTEM IN INSULIN RESISTANCE
ReseaRCh aRtiCle aDIpose aND INtestINaL IMMUNopatHoLoGy (cont.) cáÖìêÉ=NK=bÑÑÉÅí=çÑ=ÇáÉí=~åÇ=ãáÅêçÄáçí~=çå=íÜÉ=áåíÉëíáå~ä=Ä~êêáÉê=~åÇ=áããìåÉ=ëóëíÉã=ÇìêáåÖ=çÄÉëáíóK=
Consumption of a balanced diet high in indigestible fibres (short-chain fatty acids (SCFA)) and fruits and vegetables (AHR ligands) contributes to intestinal homeostasis by providing beneficial dietary metabolites and a healthy and diverse gut microbiota. Healthy lean individuals maintain an intact intestinal barrier regulated by antimicrobial peptides (AMPs) produced by Paneth and epithelial cells, mucins produced by goblet cells and anti-inflammatory or reparative cytokines (IL-17, IL-10, TGF-β, IL-22) produced by antimicrobial and barrier defense immune cell types (Th17, Tregs, ILC3 and eosinophils). During obesity, poor dietary choices that include high saturated fats and cholesterol result in an imbalanced and reduced richness of the gut microbiota. Saturated fats can induce intestinal epithelial ER stress and, in conjunction with microbial components such as LPS, can trigger innate sensing pathways (PAMPs and PRRs such as TLR4) to induce inflammatory cytokine release (TNFα and IL-1β). A combination of the changes to the diet and gut microbiota, reduced AMPs and inflammatory cytokines damage the intestinal barrier (i.e. tight junction proteins) resulting in increased intestinal permeability. Leakage of bacterial products into systemic circulation also results in metabolic endotoxemia. Moreover, the leakage of bacterial and dietary components beyond the intestinal wall result in an inflammatory shift mediated by the intestinal immune system including inflammatory APCs, NK cells, Th1 and CD8+ T cells, while suppressing the amount and function of tolerogenic immune cell types. In addition, during obesity CD8+ intraepithelial lymphocytes (IELs) express the αβ co-receptor rather than the αα coreceptor. Many of these cell types can also produce IFNγ to further damage the intestinal barrier and contribute to the inflammatory milieu within the intestine and systemically to worsen downstream insulin resistance. Revue canadienne de pathologie | volume 9, numéro 4 | www.cap-acp.org
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ReseaRCh aRtiCle aDIpose aND INtestINaL IMMUNopatHoLoGy (cont.)
With the growing amount of evidence, it is convincing that the interactions in the intestine between the diet, gut microbiota, intestinal barrier, and intestinal immune system play a critical role in the manifestation of insulin resistance.
58
With the growing amount of evidence, it is convincing that the interactions in the intestine between the diet, gut microbiota, intestinal barrier, and intestinal immune system play a critical role in the manifestation of insulin resistance.55 Consuming a Western diet contributes to dysbiosis of the gut microbiota, which alters the dietary metabolites (i.e. SCFA, AHR ligands) and bacterial components available in the lumen and absorbed by the intestine (Figure 1). Bacterial components activate innate immune sensors (TLRs and NLRs) in intestinal epithelial cells and in innate immune cells in the lamina propria, and lead to the expression of pro-inflammatory cytokines (i.e. TNFα, IL-1β) and recruitment of adaptive immune cells such as Th1 and CD8+ cells which produce inflammatory cytokines (i.e. IFNγ). These pro-inflammatory cytokines are associated with the reduction of antimicrobial and barrier defense immune cell types (i.e. ILC3s, Th17, Tregs, eosinophils) in the intestine. Furthermore, this reduction in intestinal barrier maintaining immune populations are further influenced by the altered composition of bacterial and dietary metabolites (i.e. SCFA, AHR ligands) associated with a high fat, low fiber diet. This overall change in immune cell composition within the intestine directly contributes to barrier dysfunction of the intestinal wall, resulting in the leakage of bacterial products and antigens. Intestinal antigens and immunostimulatory components enter into systemic circulation to promote inflammation in tissues such as the VAT (Figure 2). Some bacterial components, such as LPS, are also thought to be transported to VAT through physiological lipid uptake processes, such as through chylomicrons.67 Other bacterial products enter into portal circulation to fuel lowgrade inflammatory changes in the liver, which is also emerging as a critical center of immune mediated control of glucose homeostasis.68
insulin resistance, with a compounded effect to perpetuate overall insulin resistance. This model by no means is unidirectional and likely works in a large network of organ or physiological systems including the nervous, gastrointestinal, endocrine, and cardiovascular systems, in addition to the immune system. For instance, low-grade inflammatory changes in the gut could potentially alter intestinal hormone secretion, including GLP-1,69 or impinge on gut-brain neurological axes,70 which impacts whole body glucose homeostasis. It is therefore not to our surprise that complications of many organ systems arise as a result of obesity related insulin resistance. Nonetheless, targeting the immune system and its microbial and dietary triggers, specifically in the intestine, is evolving to be a possible new avenue to pursue in the prevention, regulation and treatment of insulin resistance.
Overall, chronic low-grade inflammation within metabolic tissues ultimately lead to Canadian Journal of Pathology | Volume 9, Issue 4 | www.cap-acp.org
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WHY DOES
PD-L1 TESTING MATTER?
Immunotherapy decisions are informed by PD-L1 expression1-5 Current antibodies used in immuno-oncology target the PD-1/PD-L1 and CTLA-4 inhibitory checkpoint pathways. The treatment prevents tumour cells from taking advantage of the T-cell inhibitory pathways and escaping the immune response.
PD-L1 is not a binary marker6 Depending on the tumour expression levels of PD-L1, patients are likely to respond differently to different therapies.7 PD-L1 High PD-L1 Low/Neg
More likely to respond to PD-1/ PD-L1 inhibition with monotherapy2 May be best suited for combination therapy2
PD-L1 test to inform treatment decision
AstraZeneca is committed to enabling access to high-quality, validated assays for the purposes of treatment decision making Striving for the utmost confidence in patient treatment decisions led AstraZeneca to commission large-scale PD-L1 assay concordance studies in NSCLC8,9, UC10 and HNSCC11, and to be actively involved in the cross-industry Blueprint initiative to establish assay concordance in NSCLC.12 Data from Blueprint12, AZ9 and other8,13,14 studies in NSCLC build optimism that most PD-L1 assays (22C3, SP263, 28-8) are compatible and can potentially be interchanged using different algorithms. PD-L1 assays
Visit www.iDbladder.ca and www.iDlung.ca for more information References: 1. He J. et al. Development of PD-1/PD-L1 pathway in tumor immune microenvironment and treatment for non-small cell lung cancer. Sci Rep. 2015; 5:13110. doi:10.1038/srep13110. 2. Postow M.A. et al. Immune checkpoint in blockade in cancer therapy. J Clin Oncol. 2015;33(17):1974-82. 3. Gettinger SN et al. First-line monotherapy with nivolumab (NIVO; anti-programmed death-1 [PD-1]) in advanced non-small cell lung cancer (NSCLC): Safety, efficacy and correlation of outcomes with PD-1 ligand (PD-L1) expression. J Clin Oncol. 2015;33(Suppl):abstract 8025. 4. Garon EB et al. Pembrolizumab for the Treatment of Non–Small-Cell Lung Cancer. N Engl J Med. 2015;372:2018-2028. 5. Hellman MD et al. CheckMate 012: Safety and efficacy of first-line (1L) nivolumab (nivo; N) and ipilimumab (ipi; I) in advanced (adv) NSCLC. J Clin Oncol. 2016;34(Suppl):abstract 3001. 6. Patel SP and Kurzrock R. et al. PD-L1 expression as a predictive biomarker in cancer immunotherapy. Mol Cancer Ther. 2015;14(4):847-56. 7. Antonia S. et al. Safety and antitumour activity of durvalumab plus tremelimumab in non-small-cell lung cancer: a multicenter, phase 1b study. Lancet Oncol. 2016;17(3):299-308. 8. Rimm DL. et al. A prospective, multi-institutional, pathologist-based assessment of 4 immunohistochemistry assays for PD-L1 expression in non-small cell lung cancer. JAMA Oncol. 2017; doi: 10.1001/jamaoncol.2017.0013. 9. Ratcliffe MJ et al. Agreement between programmed cell death ligand-1 diagnostic assays across multiple protein expression cutoffs in non-small cell lung cancer. Clin Cancer Res 2017; 23(14); 3585–91. 10. Scott M.L. et al. Assessment of heterogeneity of PD-L1 expression in NSCLC, HNSCC, and UC with Ventana SP263 assay. Journal of Clinical Oncology 2016; 35(15suppl) published ahead of print. 11. Ratcliffe MJ. et al. A comparative study of PD-L1 diagnostic assays in squamous cell carcinoma of the head and neck. Annals of Oncology 2016; 27 (Suppl. 6): VI328-350. 12. Hirsch F.R. et al. PD-L1 IHC assays for lung cancer: Results from Phase I of the Blueprint PD-L1 IHC assay comparison project. J Thorac Oncol. 2017;12(2):208-22. 13. Brunnström H et al. PD-L1 immmunohistochemistry in clinical diagnostics of lung cancer: inter-pathologist variability is higher than assay variability. Modern Pathology 2017; 1-11. 14. Adam J et al. Multicentric French harmonization study for PD-L1 IHC testing in NSCLC. J Thorac Oncol. 2017;12(15): PL04a.04.
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