Tumours with deficient DNA mismatch repair (dMMR) leading to a microsatellite instability-high (MSI-H) phenotype are characterized by a high burden of immunogenic mutations and, thus, an immunological ‘hot’ microenvironment that is associated with high sensitivity to immune-checkpoint inhibitors. In this Review, the authors discuss the epidemiology, biology, pathogenesis, clinical diagnosis and treatment of MSI-H/dMMR tumours, highlighting idiosyncrasies associated with specific pathogenetic alterations and tumour histologies.
- Margherita Ambrosini
- Paolo Manca
- Filippo Pietrantonio
