YAP1 and pancreatic ductal adenocarcinoma: The Hippo pathway and especially YAP activity are linked with oncogenic RAS. YAP was reported to function as a critical partner of mutant KRAS in pancreatic ductal adenocarcinoma (PDAC) (33), and the potential of the YAP1 oncogene as a KRAS-independent bypass mechanism has been described in PDAC tumor cells (34).