We evaluated genetic alterations such as K-ras mutation, p53 overexpression, microsatellite instability (MSI), and alterations of the polyadenine tract present in the transforming growth factor beta receptor type II (TGFbetaRII) gene in 126 biliary tract cancers: 75 gallbladder cancers, 33 bile duct cancers, and 18 ampullary cancers.
RER was found in 17 cases (4 with gastric, 12 with colorectal, and 1 with gallbladder cancer), and 10 of those (3 with gastric and 7 with colorectal cancer) showed mutations of the RII gene.