HNF4A and pancreatic intraductal papillary-mucinous neoplasm: In high-grade non-invasive IPMN, pan-promoter HNF4α was increased in the basal compartment (p = 0.0049) but the surface IPMN epithelium exhibited increased P1 isoform-specific expression relative to basally located cells at the stromal interface (p = 0.0001).