Objective:To detect the expressions of FLIP,Smac and survivin in small－cell lung carcinoma (SCLC) and poorly differentiated squamous－cell carcinoma (PDSCC),and analyze the correlation between the expressions of FLIP,Smac and survivin and clinical pathologic features and prognosis. Methods:The expressions of FLIP,Smac and survivin were detected by S－P immunohistochemical stain in SCLC and PDSCC. Protein and mRNA expressions of FLIP,Smac and survivin in normal lung tissue,SCLC and PDSCC were examined by Western blot and reverse transcription－polymerase chain reaction (RT－PCR),respectively. Results:One－year survival rate was 64.5%,60.5%,and 68.6%in total population studied,SCLC,and PDSCE,respectively;the expressions of FLIP,Smac and survivin were not related to sex,age,lymph node metastasis and smoking either in SCLC or in PDSCC (P > 0.05). Smac was significantly correlated with clinical stages and survival rates after treatment (P < 0.05). Protein and mRNA expressions of Smac in normal lung tissues were significantly higher than those in tumor tissues (P < 0.001),while protein and mRNA expressions of FLIP and survivin in normal lung tissues were significantly lower than those in tumor tissues (P < 0.001). Conclusion:Low expression of Smac in carcinoma tissues indicates low survival rate,and Smac may be an independent prognostic indicator. The combination of the detection of FLIP,Smac and survivin in cancer tissues may be helpful to predict prognosis.