Germline-inactivating mutations in the APC gene, which is a negative regulator of CTNNB1 (gene encoding for β-catenin), were found in patients with a hereditary cancer syndrome termed familial adenomatous polyposis (FAP), which can progress to colorectal carcinomas following concomitant activating mutations in KRAS and inactivating mutations in TP53 [97]. This evidence concerns the gene CTNNB1 and Familial adenomatous polyposis.