EXPRESSION OF BCL-2- PROTEIN IN SMALL-CELL LUNG-CANCER

The expression of the proto-oncogene bcl-2, whose main function appear s to be an inhibition of apoptosis, was investigated in 164 casks of p rimary small cell lung cancer by means of immunohistochemistry in a re trospective analysis. One-hundred twenty-five cases (76%) demonstrated expression of bcl-2. There was no difference in serum LDH levels and proliferative activity between the two groups. An analysis revealed a median survival time of 12 months for patients with bcl-2 positive tum ors compared to 9.5 months for patients with bcl-2 negative tumors. Al though statistical significance is not achieved, there is a trend towa rds longer survival in patients whose tumors express bcl-2, This tende ncy is also reflected by a higher rate of complete remission after che motherapy: 40% in patients with bcl-2 + tumors versus 27% in patients with bcl-2- tumors, In multivariate analysis, tumor stage followed by Karnofsky index were the most valuable predictors for complete remissi on. LDH and tumor stage were most predictive for 1-year survival. Bcl- 2 expression is frequent in SCLC and may reflect a less aggressive mec hanism of transformation and a higher susceptibility to cytostatic tre atment.