RNF43 and pancreatic intraductal papillary-mucinous neoplasm: We also observed a significant increase in the frequency of RNF43 mutations from low-grade, to high-grade, to high-grade invasive IPMN (MG: 5/31; HG: 3/9; Inv: 4/7; P-value = 0.01) using a Cochrane–Armitage trend test.