Reduced expression of p53 and cyclin A in intraductal mucin-hypersecreting neoplasm 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 categorized from the high-grade malignancy of the more common ductal adenocarcinoma. The aim of the present study was to clarify the molecular differences underlying the biological differences between IMHN and ductal adenocarcinoma 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 adenocarcinoma. Furthermore, in ductal adenocarcinoma, p53 and cyclin A are topographically coexpressed.
CONCLUSIONS: These results suggest that the overexpression of p53 and cyclin 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.