A comprehensive guide to MMR testing in gynecological and gastrointestinal cancers
In the last 15 years, mismatch repair (MMR) protein status has become one of the essential tools for diagnostic, prognostic, and therapeutic interventions in colorectal carcinoma (CRC) and endometrial carcinoma (EC) patient care. While MMR assessment with immunohistochemistry (IHC) protein analysis is routine in large Canadian laboratories, this test suffers from its deceptive simplicity, disguising the nuance of pathologist proficiency readout. Given the high prevalence of MMR-deficient tumours in CRC (18-20%) and ECs (25-28%), and the importance of treatment and prognostic options for patients, it is paramount that pathologists have a comprehensive understanding of the pre-analytical, analytical, and post-analytic steps of MMR IHC implementation and interpretation for success. This article aims to review MMR testing in CRC and EC and provide strategies to address common pitfalls encountered with MMR interpretation in daily pathology practice.
Authors
- Mary Kinloch (ORCID: https://orcid.org/0000-0002-0092-0312)
- Lynn Hoang
- Qinghao Li (ORCID: https://orcid.org/0000-0002-1634-7274)
- David F. Schaeffer (ORCID: https://orcid.org/0000-0002-7341-1308)
- Tami Lin (ORCID: https://orcid.org/0000-0002-4516-651X)
Institutions
- University of British Columbia (CA)
- Saskatchewan Health Authority (CA)
- Vancouver General Hospital (CA)
- University of Saskatchewan (CA)
Publication Details
- Journal
- Canadian Journal of Medical Specialties
- Published
- 2025-05-07
- DOI
- https://doi.org/10.63838/001c.137824
- Primary Topic
- Ovarian cancer diagnosis and treatment
- Type
- article
- Field-Weighted Citation Impact
- 0.00