RNF43 and pancreatic intraductal papillary-mucinous neoplasm: β‐Catenin and its downstream target glutamine synthetase were highly expressed in the pancreata of 6‐month‐old Rnf43−/−; KrasG12D mice with IPMN and PanIN (Figure 7A), suggesting that deficient Rnf43 and mutated Kras activate Wnt/β‐catenin signaling.