APC and Familial adenomatous polyposis: Anywhere from 5 to 10% [19] to as much as 15–30% [20] of CRC may be due to known hereditary conditions, including hereditary non-polyposis colorectal cancer (HNPCC; also known as Lynch syndrome, caused by mutations in mismatch DNA repair genes) and familial adenomatous polyposis (FAP, which is caused by mutations in the APC tumor suppressor gene).