目的探讨Ｐ１６，Ｐ５３蛋白和增殖细胞核抗原（ｐｒｏｌｉｆｅｒａｔｉｎｇｃｅｌｎｕｃｌｅａｒａｎｔｉｇｅｎ，ＰＣＮＡ）在胃癌的发生、发展中的作用及临床意义．方法应用免疫组织化学方法，对７７例胃癌和癌旁粘膜组织、２１例胃正常组织中Ｐ１６，Ｐ５３蛋白表达产物和ＰＣＮＡ进行检测，并结合临床资料进行分析．结果胃癌组织中Ｐ１６蛋白的阳性率为２０８％（１６／７７），明显低于癌旁粘膜组织５９７％（４６／７７）和胃正常组织９０５％（１９／２１，Ｐ＜００５）；Ｐ５３蛋白与ＰＣＮＡ在胃癌组织中的阳性率为８０５％（６２／７７）和９２２％（７１／７７），明显高于癌旁粘膜组织４１６％（３２／７７），６４９％（５０／７７）和胃正常组织００％（０／２１，Ｐ＜００５）．Ｐ１６，Ｐ５３蛋白和ＰＣＮＡ阳性表达与胃癌组织学类型、浸润深度、分化程度及淋巴结转移有显著性差异（Ｐ＜００５），与患者年龄、性别、肿瘤大小及部位无关（Ｐ＞００１）．结论Ｐ１６，Ｐ５３蛋白和ＰＣＮＡ的异常表达对胃癌的发生发展、恶性程度、淋巴结转移及预后有密切关系和重要临床意义． Objective To investigate the role and clinical significance of P16, P53 protein and proliferating nuclear antigen (PCNA) in the occurrence and development of gastric cancer. Methods Immunohistochemical method was used to detect the expression of P16, P53 protein and PCNA in 77 cases of gastric cancer and paraneoplastic tissues and 21 cases of normal gastric tissues. The clinical data were used for analysis. Results The positive rate of P16 protein in gastric cancer tissues was 208% (16/77), which was significantly lower than that of adjacent cancerous tissues (59.7%, 46/77) and normal gastric tissue, 90.5% (19/21, P). <005); The positive rates of P53 protein and PCNA in gastric cancer were 805% (62/77) and 922% (71/77), which was significantly higher than that of paratumor mucosa (416%). 32/77), 64.9% (50/77) and 0.0% of normal tissue in the stomach (0/21, P<005). The positive expressions of P16, P53 protein and PCNA were significantly different from histological type, depth of invasion, differentiation and lymph node metastasis of gastric cancer (P<0.05), but not related to age, gender, tumor size and location (P>0). 01). [Conclusion] The abnormal expression of P16, P53 protein and PCNA is closely related to the occurrence and development of gastric cancer, malignancy, lymph node metastasis and prognosis.