GNAS mutation is frequently detected in mucinous neoplasms of appendix (50%) and intraductal papillary mucinous neoplasm (IPMN) of pancreas (81%) (Furukawa et al. 2011; Wu et al. 2011), while the mutation rate in mucinous adenocarcinoma of colorectum, ovary, lung, and breast are relatively lower, even being 0% (Nishikawa et al. 2013). Here, GNAS is linked to pancreatic intraductal papillary-mucinous neoplasm.