Inactivating mutations and hypermethylation in MMR genes (i.e. MSH2, MSH6, MLH1, PMS1, and PMS2) lead to the development of Lynch syndrome and microsatellite instability (MSI), conferring a 70% lifetime risk of colorectal cancer (CRC) and an increased risk of developing other cancers [4]. The gene discussed is MRC1; the disease is cancer.