Microsatellite instability as a unique characteristic of tumors and a predictor of response to immune therapy

Abstract

Deficiency of the mismatch repair system is a unique molecular disorder that occurs in most types of tumors and leads to development of microsatellite instability (MSI) in them. The development of a hypermutated phenotype and related high immunogenicity are typically associated with more favorable prognosis as well as a high sensitivity to immunotherapy with inhibitors of immune checkpoint inhibitors. This review presents the current views on the diagnosis, prognostic and predictive significance of MSI in various tumors, as well as their response to immunotherapy.