Testing for Microsatellite Instability and Deficient DNA Mismatch Repair

Citing the landmark tumor-agnostic approval of pembrolizumab for patients with microsatellite instability–high (MSI-H)/deficient DNA mismatch repair (dMMR) tumors and the approval of nivolumab/ipilimumab in MSI-H/dMMR colorectal cancer, Vamsi Velcheti, MD, and Hossein Borghaei, DO, MS, discuss the role of MSI-H and dMMR testing in immunotherapy treatment selection.

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