bcl-2 and p53 protein expression in non-small cell lung cancers: correlation with survival time

Apoptosis-related genes have received increasing attention in carcinogenesis, drug sensitivity, radiation sensitivity, and patient survival. bcl-2 and mutated p53 genes have been reported to inhibit apoptosis. To determine bcl-2 and p53 protein expression and their impacts on survival time in lung cancers, we studied 99 surgically resected, paraffin-embedded non-small cell lung cancer (NSCLC) specimens by immunohistochemical staining. The bcl-2 protein was expressed in 19.2% of NSCLCs. bcl-2-positive cases were found in 30. 4% of stages I and II carcinomas in 36.8% of squamous cell carcinomas. Patients with bcl-2 expression survived longer than those without. p53 protein was found in 44.4%; there was no significant difference in survival time between patients with and without p53 expression. Patients who were both bcl-2 positive and p53 negative survived significantly longer than those who were bcl-2 negative or p53 positive. These results suggest that bcl-2 protein expression can be histologically specific and stage dependent, and that the bcl-2 protein expression is potentially valuable for prognosis in NSCLC, particularly in the early stages, when bcl-2 protein expression is considered with mutant p53 protein expression.