Abstract: Objective: To investigate the expression of Bax, Livin and Survivin and relationship between their expression and clinicopathological factors in non-small cell lung cancer, in order to provide further theoretical basis for clinical diagnosis and treatment of lungcancer. Methods：The expression of Bax, Livin and Survivin protein was detected by immunohistochemistry two-step techniques (PV). Results：The rates of positive expression of Bax、Livin and Survivin were respectively 42.50%、80.00%，65.00%、10.00% and 50.00%、0% in the non-small cell lung cancer tissues and in the normal lung tissues. The rates of positive expression of Bax and Livin were 23.81%、63.16% and 85.71%、42.11% in patients with lymph node metastasis and in patients with no lymph node metastasis.The rates of positive expression of Bax and Livin were 55.56%、15.38% and 51.85%、92.31% inⅠ, Ⅱstage patients and Ⅲ, Ⅳstage patients.The positive expression rate of Survivin in patients with well- middle-differentiated (39.29%) was significantly lower than that in patients with poorly differentiated(75.00%).The differences were all statistically significant (P <0.05).There was negative correlation between the expression of Bax and Livin in the non-small cell lung cancer（r＝－0.4294，P＜0.05）.There was no correlation between the expression of Bax and Survivin,and with no correlation between the expression of Livin and Survivin in the non-small cell lung cancer(P> 0.05). Conclusion: The increase of the expression of Bax in non-small lung cancer inhibited the invasiveness of tumors cell and tumors metastasi -s.Livin could be correlated with carcinogenesis of non-small cell lung cancer. The high-expression of Livin may enhanced the invasiveness of tumors cell and promoted tumors metastasis.Survivin could be correlated with tumors histologic -al differentiation degree and carcinogenesis of non-small cell lung cancer.There was negative correlation between the expression of Bax and Livin in the non-small cell lung cancer.It indicated that there could be the same pathway in the proceeding of non-small cell lung cancer. There was no correlation between the expression of Bax and Survivin, Livin and Survivin in the non-small cell lung cancer.It suggested that there could be a different pathway in the proceeding of non-small cell lung cancer.

Key words: non-small cell lung cancer, Bax, Livin, Survivin