Since HNF-1B can also be expressed less frequently in variable tumors of the non-pancreaticobiliary origin, especially of the kidney, Müllerian tract, lung, gastroesophageal, bladder, and prostate carcinomas, the concurrent use of other markers such as TTF-1, PAX-8, WT-1, CAIX, NKX3.1, p40, and PSA as a panel to rule out other organ primaries, and correlation with imaging studies and/or endoscopic findings are important to refine the diagnosis. The gene discussed is KLK3; the disease is prostate carcinoma.