RESUMO
BACKGROUND: The aim of this study was to assess the relationship between the expression of the 27-kilodalton (kD) bcl-2 protein and survival among nonsmall cell lung carcinoma (NSCLC) patients. METHODS: Paired tissue samples of histologically confirmed tumor and uninvolved lung of 91 randomly selected NSCLC patients were used in this study. The expression of 27-kD bcl-2 proteins in uninvolved lung and tumor tissue specimens was analyzed using Western blot analysis. Overall survival was estimated using the Kaplan-Meier method. The relation between patient survival and expression of the 27-kD bcl-2 protein in uninvolved lung, tumor, and in uninvolved lung and/or tumor tissue specimens was assessed using log-rank tests and Cox proportional hazards multiple regression. RESULTS: The 27-kD bcl-2 protein was expressed in 54% of the uninvolved lung tissue specimens, in 53% of the tumor tissue specimens, and in 70% of the uninvolved lung and/or tumor tissue specimens. When NSCLC patient survival was considered with respect to the expression of the 27-kD bcl-2 protein, a statistically significant shorter survival was observed for patients whose tissue samples expressed the 27-kD bcl-2 protein in the uninvolved lung and in the uninvolved lung and/or tumor (log-rank test, P = 0.008 and P = 0.001, respectively). Cox proportional hazards multiple regression models also showed statistically significant associations between shorter survival and positive 27-kD protein expression in the uninvolved lung (hazard ratio of 2.27; P = 0.05) and in the uninvolved lung and/or tumor (hazard ratio of 5.58, P = 0.008) after controlling for tumor size, stage, the type of surgery received, smoking status, age, and cell type. CONCLUSIONS: In the current study, patients with nonsmall cell lung carcinoma with positive expression of the 27-kD protein bcl-2, either in the uninvolved lung or in uninvolved lung and/or tumor, were found to have significantly poorer postresection survival.
