Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy

The evidence-based clinical guideline “Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy” will help pathologists optimize testing methods to better identify and evaluate patients with cancer who may be eligible for immunotherapies known as checkpoint inhibitors.

This CAP guideline includes six recommendations and three good practice statements grounded in reviewed clinical evidence to specify which assay pathologists and oncologists should use to assess microsatellite instability (MSI)-high or mismatch repair (MMR) status. The recommendations impact testing for patients with colorectal, endometrial, gastroesophageal, small bowel, and other types of cancer. In addition, it provides guidance on the role of tumor mutational burden in MMR testing and the evaluation for Lynch Syndrome.

Status: Active

Published ahead of print: August 3, 2022

Originally published: October 2022

Download the following tools and resources to help implement the guideline:

• Summary of Recommendations
• Methodology Supplement (Supplemental Digital Content)
• Teaching Presentation
• Frequently Asked Questions
• Infographic

Association for Molecular Pathology
Fight Colorectal Cancer

Review more upcoming CAP evidence-based guidelines by the Center.