MSH2 and cancer: Patients with pathogenic variants in MLH1 and MSH2 have a higher risk of developing cancer than those with mutations in MSH6 and PMS2.4, 5, 6, 7 These mutations lead to microsatellite instability-high (MSI-H) status, significantly increasing the risk of cancers, particularly of the colon and rectum, endometrium, urinary tract, and small intestine.