Immunotherapy and patients treated for cancer with microsatellite instability

Abstract

Microsatellite instability (MSI) is a tumor phenotype linked to somatic or germline (Lynch syndrome) inactivating alterations of DNA mismatch repair genes. A broad spectrum of neoplasms exhibits MSI phenotype, mainly colorectal cancer, endometrial cancer, and gastric cancer. MSI tumors are characterized by dense immune infiltration and high load of tumor neo-antigens. Growing evidence is accumulating on the efficacy of immune checkpoint inhibition for patients treated for MSI solid tumors. We present a comprehensive overview of MSI phenotype, its biological landscape and current diagnostic methods. Then we focus on MSI as a predictive biomarker of response to immune checkpoint inhibition in the context of colorectal cancer and non-colorectal tumors.

Keywords: Cancer colorectal; Cancer de l’endomètre; Checkpoint immunitaires; Colorectal cancer; Déficience du système de réparation de l’ADN; Endometrial cancer; Immune checkpoint; Lynch syndrome; Mismatch repair deficiency; Nivolumab; Syndrome de Lynch.