The implications of proliferation and apoptosis for lung cancer metastasis

The occurrence of metastatic spread depends on many factors both the condition of the patient and the properties of the tumor. In this investigation the association between proliferation and apoptosis and the incidence of lymph node involvement of patients with non-small cell lung carcinomas was analysed (n=215 patients). In order to analyse the relationship between lymph node metastasis and proliferative activity of the carcinomas, the distribution of cell cycle phases (flow cytometry), the expression of PCNA and cyclin A (immunohistochemistry) was determined. Fas, Fas-ligand, caspase-3 and Bcl-2 were determined by immunohistochemistry. In this retrospective analysis no association between proliferative activity of the tumors and lymph node status was found. In contrast, there existed a correlation between the apoptotic factors and lymph node metastasis. Higher expression of the pro-apoptic factors Fas, Fas-ligand and caspase-3 correlated with a lower incidence of lymph node involvement (Fas-ligand, p=0.004; caspase-3, p=0.007). The trend of an inverse correlation between the anti-apoptotic factor Bcl-2 and metastasis fits well into the present knowledge about the function of the bcl-2 gene. The results obtained from all the patients could be confirmed in patients with squamous cell lung carcinomas.