APC and Familial adenomatous polyposis: PSCs are observed in the apc gene related to Familial Adenomatous Polyposis (FAP) [4,5], the brca1 and 2 genes related to Familial Breast Cancer [6-8] and the Mismatch Repair genes related to Hereditary Non-Polyposis Colorectal Cancer (HNPCC) [9,10].