An immunohistochemical study of the expression of bcl-2 and p53 oncoproteins in pancreatic intraepithelial neoplasia and pancreatic cancer.

Background: The bcl-2 and p53 gene deregulation is frequently involved in several types of malignancies. The purpose of this study was to evaluate the expression of bcl-2 and p53 genes in various types of pancreatic intraepithelial proliferation and in pancreatic cancer and to answer the question of whether they interact in the process of intraductal epithelial proliferation.

Methods: Immunohistochemical staining for p53 and bcl-2 was performed on paraffin embedded sections from 56 patients operated on for pancreatic carcinoma, chronic pancreatitis, and other conditions.

Results: Pancreatic cancer in 100% of cases showed p53 expression and in 27.7% bcl-2 expression. The p53 gene was expressed already in pancreatic intraductal neoplasia and its frequency was significantly rising with an increasing degree of hyperplasia. Normal epithelium of pancreatic ducts and ductules showed a high expression of bcl-2, which was decreasing in the process of intraductal proliferation.

Conclusions: Pancreatic cancer is characterized by a high expression of p53 and a low expression of bcl-2. In pancreatic cancers and pancreatic intraepithelial neoplasia, there is an inverse relationship between the expression of bcl-2 and p53. Malignant behavior of pancreatic cancer may be associated with the phenotype bcl-2-/p53+.