Hereditary non-polyposis colorectal cancer (HNPCC or Lynch syndrome), associated with mismatch repair genes (MLH1, MSH2, MSH6, PMS2) mutations (132) has an estimated life-time risk of 3.7% for developing PC (8.6-fold higher risk) (65, 86, 142). The gene discussed is MLH1; the disease is hereditary nonpolyposis colon cancer.