[Epidemiology of microsatellite instability across solid neoplasms]

Microsatellite instability (MSI) is a predictive biomarker for the efficacy of immune checkpoint inhibitors, regardless of the tumor type. While clinical characteristics of MSI cancer patients have been largely described in tumor localizations frequently associated with this genetic phenotype (i.e. colorectal cancer, endometrial cancer), it remains poorly characterized in other neoplasms. Pan-tumor high-throughput genome sequence analyses have contributed to the broadening of knowledge about the landscape of MSI. This review aims at synthetizing the literature concerning the frequency of MSI status in solid cancers, according to the cancer stage and the hereditary or sporadic origin of the mismatch repair deficiency. We then check for other cancers frequently associated with MSI and describe the clinical and pathological characteristics that should suggest a MSI phenotype.