The ABC of APC

Familial adenomatous polyposis (FAP) is an autosomal dominant inherited dis ease characterized by the presence of adenomatous polyps in the colon and r ectum, with inevitable development of colorectal cancer if left untreated. FAP is caused by germline mutations in the adenomatous polyposis coil (APC) gene. Somatic mutations in the APC gene are an early event in colorectal t umorigenesis, and can be detected in the majority of colorectal tumours. Th e APC gene encodes a large protein with multiple cellular functions and int eractions, including roles in signal transduction in the wnt-signalling pat hway, mediation of intercellular adhesion, stabilization of the cytoskeleto n and possibly regulation of the cell cycle and apoptosis. The fact that AP C is an integral part of so many different pathways makes it an ideal targe t for mutation in carcinogenesis. This review deals with our understanding to date of how mutations in the APC gene translate into changes at the prot ein level, which in turn contribute to the role of APC in tumorigenesis.