Microsatellite Instability Status and Mismatch Repair Defects Testing in Endometrial Cancer - Insights from the Multicenter E-PEC Trial

Q: What is the main purpose of the multicenter E-PEC trial analysis?

To evaluate trends in MMR and MSI testing and related molecular diagnostics in Germany over 2018–2022, and to assess associated molecular diagnostics and immune checkpoint inhibitor use.

Q: Which molecular tests showed the strongest increase between 2018 and 2022?

TP53 testing increased the most, rising from 13.1% to 78.6%, and MSI testing increased from 82.9% to 97.4%. POLE and L1CAM rose from near-absence in 2018 to measurable rates by 2022.

Q: What conclusion is drawn about testing adoption in routine care?

Implementation of MMR and MSI testing increased rapidly and substantially in German clinical practice, suggesting successful translation into routine care, though guideline uptake appeared time-shifted.

Sep 30, 2026

Uploaded by Jordan Avery

Mismatch repair (MMR) and microsatellite instability (MSI) testing are key biomarkers for molecular classification of endometrial cancer, shaping adjuvant treatment choices and eligibility for immune checkpoint inhibition. Despite guideline calls for universal testing, real-world adoption differs across settings. This retrospective multicenter German study (2018–2022) quantified yearly testing trends for MSI, MMR, POLE, TP53, and L1CAM and examined associated diagnostic and therapeutic use.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Abstract

Background

Methods

Results

Conclusions

Introduction

Article Microsatellite Instability Status and Mismatch Repair Defects Testing in Endometrial Cancer—Insights from the Multicenter E-PEC Trial Büsra Eser 1,*, David Papior 1, Jon Salmanton-García 2,3,4,5, Oliver A. Cornely 2,3,4,5,6, Bernd Morgenstern 7, Clarissa Herpel 7, Julia C. Radosa 8, Anas Almuheimid 8, Bahriye Aktas 9,10, Laura Weydandt 9,10, Julia Wittenborn 11, Philipp Meyer-Wilmes 11, Verena Friebe 12, Christiane Leidinger 12, Rainer Kimmig 1 and Fabinshy Thangarajah 1 Academic Editor: Kotaro Kitaya Received: 29 November 2025 Revised: 21 December 2025 Accepted: 22 December 2025 Published: 27 December 2025 Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. 1 Department of Gynecology and Obstetrics, Medical Faculty, University Hospital of Essen, University of Duisburg-Essen, 45147 Essen, Germany; [fabinshy.thangarajah@uk-essen.de](fabinshy.thangarajah@uk-essen.de) (F.T.) 2 Institute of Translational Research, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Faculty of Medicine, University Hospital Cologne, University of Cologne, 50931 Cologne, Germany 3 Clinical Trials Centre Cologne (ZKS Köln), Faculty of Medicine, University Hospital Cologne, University of Cologne, 50931 Cologne, Germany 4 Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf (CIO ABCD), University of Cologne, 50931 Cologne, Germany 5 Department I of Internal Medicine, European Confederation for Medical Mycology (ECMM) Excellence Center, University of Cologne, 50931 Cologne, Germany 6 German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, 50931 Cologne, Germany 7 Department of Gynecology and Gynecologic Oncology, Center for Integrated Oncology (CIO Aachen, Bonn, Cologne, Düsseldorf), Faculty of Medicine, University Hospital Cologne, University of Cologne, 50937 Cologne, Germany 8 Department of Gynecology and Obstetrics, University Hospital of Homburg, 66424 Homburg, Germany 9 Department of Gynecology, University Hospital of Leipzig, 04103 Leipzig, Germany 10 Comprehensive Cancer Center Central Germany, Partner Site Leipzig, 04103 Leipzig, Germany 11 Department of Obstetrics and Gynecology, Center for Integrated Oncology (CIO Aachen, Bonn, Cologne, Düsseldorf), University Hospital of RWTH Aachen, 52074 Aachen, Germany 12 Department of Gynecology and Obstetrics, University Hospital of Düsseldorf, 40225 Düsseldorf, Germany * Correspondence: buesra.eser@uk-essen.de; Tel.: +49-0201-7233441 Abstract Background: Mismatch repair (MMR) and microsatellite instability (MSI) testing have become essential biomarkers in the molecular classification of endometrial cancer (EC), guiding adjuvant treatment decisions and eligibility for immune checkpoint inhibition. Although international guidelines recommend universal testing, real-world implementation remains heterogeneous. This study aimed to evaluate trends in MMR and MSI testing and associated molecular diagnostics in Germany between 2018 and 2022 . Methods: A retrospective multicenter analysis was conducted across German tertiary care centers. Data from patients with histologically confirmed EC between 2018 and 2022 were extracted from standardized electronic pathology records. Annual testing rates for MSI, MMR, POLE, TP53, and L1CAM were analyzed using descriptive statistics and trend analysis (Chisquare test for trend, p < 0.05) . Therapeutic data were collected to assess the use of immune checkpoint inhibitors. Results: There was a significant increase in the annual rates of molecular testing for MSI, POLE, TP53, and L1CAM over the five-year observation period (all p < 0.05) . TP53 testing showed the highest increase (13.1% → 78.6%), while MSI testing rose from 82.9% to 97.4% . Both POLE and L1CAM testing w

FAQs

What is the main purpose of the multicenter E-PEC trial analysis?

To evaluate trends in MMR and MSI testing and related molecular diagnostics in Germany over 2018–2022, and to assess associated molecular diagnostics and immune checkpoint inhibitor use.

Which molecular tests showed the strongest increase between 2018 and 2022?

TP53 testing increased the most, rising from 13.1% to 78.6%, and MSI testing increased from 82.9% to 97.4%. POLE and L1CAM rose from near-absence in 2018 to measurable rates by 2022.

What conclusion is drawn about testing adoption in routine care?

Implementation of MMR and MSI testing increased rapidly and substantially in German clinical practice, suggesting successful translation into routine care, though guideline uptake appeared time-shifted.

Sep 30, 2026

Uploaded by Jordan Avery