KRAS and pancreatic intraductal papillary-mucinous neoplasm: Since IPMN, like PDAC, harbors frequent K-ras mutations (Satoh et al., 1993b, 1996), the association of MSX2 expression with the tumor grade or clinicopathological features was examined in IPMN tissues to determine whether this gene could be involved in the process of benign-to-malignant progression in IPMN (Satoh et al., 2010).