RNF43 and gastric cancer: RNF43 is a negative regulator of Wnt signaling, and mutation of RNF43 is frequently found in CRC and endometrial cancers [38, 44], gastric cancer [45], neoplastic cysts of the pancreas including intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) [46, 47].