DNA Ploidy and Proliferative Activity in bcl-2 Expressed Non-small Cell Lung Cancer

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Abstract
The expressions of bcl-2 have been reported recently in non-small cell lung carcinoma (NSCLC*). As oncogensis is believed to involve a number of genetic alterations, there can be differences in DNA ploidy or proliferative activity even in bcl-2 positive cases according to the superimposed genetic events. On the assumption that we might further discern the biologic behavior of bcl-2 positive NSCLC according to the status of DNA ploidy and proliferative activity, we conducted a study for bcl-2 expression with immunohistochemical staining and DNA analysis on 52 surgical specimens of NSCLC. The bcl-2 was positive in 52% (27/52) of specimens, According to the status of bcl-2 expression, there were no significant differences in tumor stages, performance status score and survival time. Among bcl-2 positive NSCLC, aneuploidy and high proliferative activity were noted in 40% and 44%, respectively. In cases with squamous cell carcinoma (SQC**), the proportion of aneuploidy was significantly higher in bcl-2 positive group compared to bcl-2 negative group (p<0.01), which could not be explained with the sole effect of bcl-2. In bcl-2 positive NSCLC, there was no significant survival difference by the status of DNA analysis results. With a Coxproportional hazard model, only T stage was an independent prognostic factor. In bcl-2 expressed NSCLC, proliferative activity and DNA ploidy were not homogeneous, suggesting other genetic alterations. This may explain our results which showed no differences in survival according to the status of the bcl-2 expression.