Evidence for apoptosis in non-small cell lung carcinoma. Relationship with cell kinetics and prognosis

OBJECTIVE: To investigate cell death via apoptosis in non-small cell lung carcinoma (NSCLC) and its correlation with proliferative indices and follow-up. STUDY DESIGN: In 38 cases of NSCLC (21 squamous cell carcinomas and 17 adenocarcinomas) we analyzed apoptosis by nuclear morphology and in situ DNA fragmentation end labeling and the cell kinetics by an autoradiographic method with tritiated thymidine and by immunohistochemistry with anti-proliferating cell nuclear antigen (anti-PCNA) antibodies. We also evaluated mitotic frequency. Apoptotic index (AI) was correlated with the thymidine and PCNA labeling indices (T-LI and PCNA-LI, respectively) and with the mitotic index. RESULTS: The percentage of proliferating cells (T-LI range, 0.1-20.1%; PCNA-LI range, 0-14.7%) was generally considerably higher than that of apoptotic cells (range, 0-8%) and of mitotic cells (range, 0.1-1%). Survival at six years was significantly higher in patients with high levels of apoptosis and low T-LI values. CONCLUSION: AI and T-LI are independent and very useful prognostic factors in NSCLC. A high percentage of proliferating cells in terms of T-LI correlates with poor prognosis, whereas a high AI indicates a favorable outcome.