The overall ORs for KRAS and GNAS mutations in IPMN patients were 7.444 (95 % CI 3.850–14.392; P < 0.001, Q = 4.540, I2 = 0.000) and 30.194 (95 % CI 7.143–127.622; P < 0.001, Q = 0.787, I2 = 0.000), compared with those mutations in MCN, respectively (Fig. 2). The gene discussed is GNAS; the disease is pancreatic intraductal papillary-mucinous neoplasm.