Background: Apoptosis and cell proliferation in patients with adenocarcinoma of the lung have not been well described with relation to fine-needle aspiration biopsies (FNABs). To investigate the contribution of apoptosis to the growth of adenocarcinoma of the lung, both apoptosis and cell proliferation were analysed for correlation with the grade of the tumor.
Patients and methods: Fifty tumors from 50 patients with adenocarcinoma of the lung were studied. Twelve tumors were well-differentiated, 22 were moderately differentiated and 16 were poorly differentiated. The detection of DNA fragments in situ using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling (TUNEL) assay was applied to investigate active cell death (apoptosis) and the MIB-1 antigen was used to investigate cell proliferation.
Results: The TUNEL indices were 0.55±0.09, 0.90±0.33 and 3.1±0.99 in well-, moderately and poorly differentiated adenocarcinoma of the lung respectively. The MIB-1 antigen labeling indices were 7.1±0.12, 14.3±3.5 and 28.7±6.9, respectively, in the same order of tumor differentiation. The differences in both TUNEL and MIB-1 labeling indices were significant between well-, moderately and poorly differentiated adenocarcinoma of the lung and a positive correlation was found between the TUNEL indices and the MIB-1 indices.
Conclusion: Apoptosis (cell death) and cell proliferation increases as the grade of differentiation decreases in adenocarcinoma of the lung, suggesting a rapid turn over of the tumor cells in tumors with a lower grade of differentiation.