Objectives: Familial adenomatous polyposis (FAP) is an inherited disorder characterized by multiple colorectal polyposis and is frequently associated with a variety of extracolonic lesions. However, neoplastic lesions of the biliary tract system, excluding those of the ampulla of Vater, are extremely rare in FAP, and the impact of APC alterations on their tumorigenesis remains unclear. We aimed to clarify the relationship between germline variants and somatic variants in the APC gene in biliary tract neoplasms (BTNs) of FAP patients.
Shiraishi et al. (Fri,) studied this question.