CLDN4 and pancreatic intraductal papillary-mucinous neoplasm: When the authors divided the tumors between high-grade IPMNs (including borderline, carcinoma in situ, and invasive cancers) and low-grade IPMNs (adenomas), significantly elevated levels of claudin-4 mRNA were seen in the high-grade group when compared to the IPMN adenomas [50].