Studies of the precursors of pancreatic cancer have identified RNF43 mutations in both neoplastic cysts of the pancreas (2, 3) and pancreatic intraepithelial neoplasia (PanIN) (4), and recent advances in genome sequencing have identified loss-of-function RNF43 mutations in 5%–10% of pancreatic cancers (5–8). The gene discussed is RNF43; the disease is familial pancreatic carcinoma.