Cellular and molecular biology of biliary tract cancers.

Cancer of the biliary tract has been associated with point mutations of K-ras and beta-catenin proto-oncogenes; alterations of p53, p16, APC, and DPC4 tumor suppressor genes by a combination of chromosomal deletion, mutation, or methylation; and infrequently microsatellite instability. The frequencies of these alterations vary by location and race of the patient, tumor subsite, histology, and associated disease. Advances in the understanding of the genetics of this disease will help in diagnosing biliary tract cancer, screening at-risk patients, and developing therapies.