Abstract:Objective：To study the expression of Ki-67 antigen and p53 protein in human gastric carcinoma, and the relation of the 2 parameters to biological behavior and prognosis. Methods：The expressions of Ki-67 antigen and p53 protein were determined by immunohistochemistry technique in 232 patients with gastric carcinoma. Results：The expression intensity of Ki-67 antigen was directly proportional to that of p53 protein(P<0.001). The expression levels of Ki-67 antigen and p53 protein were both closely correlated with regional lymph node metastasis, but not with patient′s sex, age and tumor size, location, histological type, infiltration depth, distant metastasis, nor pTNM stage. The 3-year survival rate of those with positive expression of Ki-67 antigen or p53 protein was higher than those with negative expression(P=0.006,0.007).The 3-year survival rate of the group Ki-67－/p53－ was significantly higher than the other three groups(Ki-67－/p53＋, Ki-67＋/p53－, Ki-67＋/p53＋) (P=0.011, 0.017, 0.001). Multivariate survival analysis confirmed that p53 protein expression was independently associated with the 3-year survival rate (P=0.002). Conclusions：Ki-67 antigen and p53 protein expression levels were both significantly correlated with regional lymph node metastasis and prognosis. P53 protein expression is an independent indicator of gastric carcinoma prognosis. Combined analysis of Ki-67 antigen and p53 protein expression showed that positive expression of anyone of them suggests a poor prognosis.