After we found the GNAS mutation in cases that had PDAC concomitant with IPMN as well as in cases that had only IPMN from the analysis of the pancreatic juice, we next sequenced tissue samples to determine the possible mutational patterns in IPMN, PDAC derived from IPMN, PDAC that was with concomitant IPMN, and PDAC alone. Here, GNAS is linked to pancreatic intraductal papillary-mucinous neoplasm.