GNAS and pancreatic intraductal papillary-mucinous neoplasm: Nine (Fritz et al. 2009; Hosoda et al. 2015; Kaino et al. 1999; Kobayashi et al. 2008; Kondo et al. 1997; Kuboki et al. 2015; Lee et al. 2014; Singhi et al. 2014; Wu et al. 2011b) and seven (Hosoda et al. 2015; Ideno et al. 2015; Kuboki et al. 2015; Lee et al. 2014; Singhi et al. 2014; Takano et al. 2014; Wu et al. 2011b) studies addressed KRAS and GNAS mutations in IPMN patients, according to the macroscopic duct type, respectively (Table 4).