Expression of p53 protein in precursor lesions and adenocarcinoma of human pancreas.

To evaluate the incidence and stage at which p53 alterations occur in human pancreatic carcinogenesis, we examined primary and metastatic carcinomas, carcinoma in situ, and hyperplastic lesions with and without atypia for p53 protein overexpression by immunohistochemical procedure. Overexpression of p53 was observed in 40% (10/25) of primary tumors, 29% (2/7) of metastatic tumors, 36% (5/14) of carcinoma in situ, and 35% (6/17) of hyperplastic lesions. These results suggest that p53 protein overexpression is not only a common genetic alteration but also occurs very early in the development of these tumors. It is suggested that p53 overexpression can be used as a marker to identify precursor lesions that have increased potential to develop into malignant tumors.