[Influence of nicotine addiction on telomerase activity in malignant non-small cell lung tumors]

Telomerase synthesizes telomeric DNA repeats at the ends of eukaryotic chromosomes and inhibits the natural senescence of different cells. Its increased activity in malignant tumors is considered to be an independent prognostic factor of the disease course. Aim of the study was valuation of influence of prolonged tobacco smoking on telomerase expression in non-small cell lung cancer (NSCLC). The study comprised 33 patients with NSCLC (divided into two groups: smokers - n=21 and nonsmokers n=12), who had telomerase activity quantitatively assessed (PCR-ELISAPLUS, ROCHE, Mannheim, Germany) in aspirates collected from peripheral lung tumors through transthoracic fine-needle biopsy. No statistically significant differences were found between the studied groups with regard to the clinical stage of tumor. Telomerase activity in biopsy samples from smoking patients was higher than in samples from nonsmoking patients (statistically insignificant difference p=0.09). It was found that telomerase activity in tumor cells was significantly lower in patients smoking less than 40 pack years in comparison to patients smoking more than 40 pack-years (p=0.01). Telomerase activity in NSCLC cells correlated significantly with clinical stage of tumor in all the patients (r=0.66 for nonsmokers and r=0.58 for smokers; p< or =0.01), and in the smokers' group - additionally with pack-years (r=0.47; p=0.04). Tobacco smoking by patients with non-small cell lung cancer increases telomerase activity in tumor cells.