Reduced expression of p53 and cyclin A in intraductal mucin-hypersecretingneoplasm of the pancreas compared with usual pancreatic ductal adenocarcinoma

OBJECTIVE: Intraductal mucin-hypersecreting neoplasm (IMHN) of the pancreas , a slow-growing malignancy with a favorable prognosis, is distinctly categ orized from the high-grade malignancy of the more common ductal adenocarcin oma. The aim of the present study was to clarify the molecular differences underlying the biological differences between IMHN and ductal adenocarcinom a of the pancreas. METHODS: The expression of p53 and cyclin A in IMHN was compared with that in ductal adenocarcinoma of the pancreas immunohistochemically. RESULTS: In IMHN, the incidence of p53 and cyclin A ascertained by positive nuclear staining was significantly lower than that in ductal adenocarcinom a. Furthermore, in ductal adenocarcinoma, p53 and cyclin A are topographica lly coexpressed. CONCLUSIONS: These results suggest that the overexpression of p53 and cycli n A plays a role in the tumorigenesis of pancreatic ductal adenocarcinoma, and sparse expression of both antigens in IMHN may partly contribute to its low-grade malignant characteristics. (Am J Gastroenterol 1999; 94.2263-226 7. (C) 1999 by Am. Coll, of Gastroenterology).