Expression of p21(WAF1/CIP1) and p53 proteins in gastric carcinoma: its relationships with cell proliferation activity and prognosis.

The expressions of p21(WAF1/CIP1), p53 proteins, and Ki-67 antigen were investigated immunohistochemically in 190 primary gastric carcinomas. Of the 190 tumors, 40.5% positively expressed p21(WAF1/CIP1) and 42.1% positively expressed p53. The expression of p21(WAF1/CIP1) was significantly associated with clinicopathological factors including gender, tumor size, status of lymph node, and clinicopathological stage (P<0.05 for all), but p21(WAF1/CIP1) expression showed no clear correlation with Ki-67 labeling index. The mean Ki-67 labeling index was significantly higher in p53-positive cases than p53-negative cases (P<0.0001). However, among the clinicopathological factors examined, expression of p53 correlated only with age. Univariate and multivariate survival analyses revealed that clinicopathological stage (P<0.001) and expression status of p21(WAF1/CIP1) (P<0.05) were independent prognostic factors. Neither the expression status of p53 nor the Ki-67 labeling index, however, influenced the prognosis of patients with gastric cancer.