Not surprisingly, HNF-1B was strongly immunoreactive with nuclear and/or cytoplasmic patterns in 13 of 15 (86.7%) intrahepatic and extrahepatic cholangiocarcinomas, 13 of 18 (72.2%) ampullary adenocarcinomas, and 13 of 14 (92.9%) gallbladder adenocarcinomas. The gene discussed is HNF1B; the disease is gallbladder adenocarcinoma.