PMS1 and hereditary nonpolyposis colon cancer: Hereditary nonpolyposis colorectal cancer (HNPCC), or Lynch syndrome, is an autosomal dominant germline mutation in DNA mismatch repair (MMR) genes, including MLH1, MSH2, MSH6, PMS2, EPCAM, and PMS1, associated with a 1% lifetime risk of developing SBA [44,45,46,47].