目的：探讨表皮生长因子受体（ＥＧＦＲ）和ｐ２１蛋白表达与肺癌发生发展的关系及其两者的对应关系。方法：应用免疫组化Ｓ－Ｐ法对６３例肺癌及其癌旁组织进行了同位ＥＧＦＲ及ｐ２１蛋白的检测。结果：肺癌ＥＧＦＲ阳性率７７．７８％，其阳性率与病理类型及临床分期无关（Ｐ＞０．０５）。癌旁组织ＥＧＦＲ阳性率６７．９２％，其中增生组阳性率（７９．０６％）显著高于无增生组（３７．５０％）（Ｐ＜０．０１）。肺癌中ｐ２１蛋白的阳性率４７．６２％。腺癌阳性率显著高于鳞癌（Ｐ＜０．０５）。大细胞癌均阴性。ｐ２１蛋白表达与肺癌转移及临床分期无关。癌旁组织ｐ２１蛋白阳性率４５．７１％，增生组阳性率（６２．７９％）显著高于未增生组（１８．５１％）（Ｐ＜０．０１）。ＥＧＦＲ及ｐ２１蛋白在肺癌中的表达经χ２检验未显示一致性关系。结论：ＥＧＦＲ及ｐ２１蛋白过度表达和活性增强与癌旁上皮细胞增生有密切关系，并在肺癌发展过程中起作用，可能是肺癌发生的早期事件。ｐ２１蛋白及ＥＧＦＲ在肺癌中可能相互独立起作用。 Objective: To investigate the relationship between the expression of epidermal growth factor receptor (EGFR) and p21 protein and the occurrence and development of lung cancer and their corresponding relationship. METHODS: Immunohistochemical S-P method was used to detect EGFR and p21 protein in 63 lung cancer tissues and adjacent tissues. Results: The positive rate of EGFR in lung cancer was 77.78%. The positive rate was not related to the pathological type and clinical stage (P>0.05). The positive rate of EGFR was 67.92% in adjacent tissues, and the positive rate in proliferative group (79.06%) was significantly higher than that in non-proliferating group (37.50%) (P<0.01). The positive rate of p21 protein in lung cancer was 47.62%. The positive rate of adenocarcinoma was significantly higher than that of squamous cell carcinoma (P<0.05). Large cell carcinomas were negative. The expression of p21 protein has nothing to do with the metastasis and clinical stage of lung cancer. The positive rate of p21 protein in adjacent tissues was 45.71%, and the positive rate in proliferative group (62.79%) was significantly higher than that in non-proliferative group (18.51%) (P<0.01). The expression of EGFR and p21 protein in lung cancer did not show a consistent relationship by chi-square test. Conclusion: The overexpression and activity of EGFR and p21 protein are closely related to the proliferation of adjacent epithelial cells, and play a role in the development of lung cancer. It may be an early event of lung cancer. The p21 protein and EGFR may play independent roles in lung cancer.