HNF4A and pancreatic intraductal papillary-mucinous neoplasm: Poorly differentiated invasive components showed a lower HNF4α nuclear expression than low-grade non-invasive IPMN for pan-promoter (p = 0.0384) and P2 (p < 0.0001) isoform groups but not for the P1 isoform group (p = 0.1808) (Supplemental Fig. S1, S2, S3).