APC and colorectal carcinoma: It has been well demonstrated that mutations or loss of APC on chromosome 5q initiates the pathogenic development of most of colon cancer (CRC), followed by subsequent events including gain-of-function mutation of KRAS on 12p, loss-of-function of DCC on 18q, and loss of tumor suppressor gene p53 on 17p1, 2, 3, 4.