Frequent loss of p16 expression and its correlation with clinicopathological parameters in pancreatic carcinoma.

Expression of the p16 gene product in human primary pancreatic carcinoma (PC) was investigated in paraffin-embedded tissue using a monoclonal antibody against p16 protein, clone G175-405, by means of immunohistochemistry, and the correlation of results with various clinicopathological parameters was evaluated. All six cases of normal pancreas and all but 1 of 20 cases of chronic pancreatitis expressed p16 protein, whereas 37.5% (3 of 8) of cystadenomas and 41. 9% (26 of 62) of PCs lost p16 expression. There was a significant difference between chronic pancreatitis and PC for frequency of the loss of p16 expression (P < 0.01). Moreover, loss of p16 expression in pancreatic malignancy was significantly associated with histological grade (G1 versus G2 and G3, P < 0.01) but not with sex, age, clinical stage, tumor location, or resectability. The survival period was shorter and metastasis is more likely in those cases that did not show p16 expression than those that did.