Oncogenes and tumor suppressor genes

Expression of p53 protein in pancreatic adenocarcinoma. Relationship to cigaret smoking

We studied the expression of p53 gene product in pancreatic adenocarcinomas of the usual ductal type to determine its relationship to cigarette smoking and its usefulness as an independent prognostic indicator. Twenty-six resection specimens of pancreatic adenocarcinoma were examined by immunohistochemistry using an antigen retrieval solution and monoclonal PAb1801 and polyclonal CM1 antibodies on paraffin-embedded material. Specific nuclear p53 expression for both PAb1801 and CM1 was identified in seven cases (27%). In all cases immunoreaction was confined to neoplastic cells. Three of four (75%) tumors from patients who had never smoked showed immunoreaction, whereas only three of 14 (21%) tumors from smokers showed positive staining. Cases with positive staining had shorter mean survival (6.3 mo) than cases that failed to stain (9.8 mo), but the difference was not statistically significant in this small study. There was no statistically significant association between p53 immunoreactivity and other clinicopathologic parameters. Our findings indicate that abnormalities of p53 gene in pancreatic adenocarcinomas may not be directly related to cigarette smoking. Those patients who survived the longest tended to have tumors negative for p53 immunostaining. p53 immunoreaction may be a useful feature in distinguishing adenocarcinoma from chronic pancreatitis in small biopsies.