GNAS and pancreatic intraductal papillary-mucinous neoplasm: This result suggests that not all IPMNs harboring GNAS mutation are detectable by liquid-biopsy; however, GNAS mutation detection in cfDNA is a 100% positive predictive value for the presence of IPMN since there was no IPMN case in which GNAS mutation was positive in the cfDNA but negative in tissues.