TOBACCO SMOKE-ASSOCIATED N7-ALKYLGUANINE IN DNA OF LARYNX TISSUE AND LEUKOCYTES

The presence of N7-alkylguanine adducts in DNA was analysed in a group of 46 patients with larynx tumours, All patients were subjected to la ryngectomy and the tissues accessible for analysis by P-32-post-labell ing assay were larynx tumour, larynx non-tumour and peripheral blood l eucocytes. N7-Alkylguanine adducts were detected in all the studied DN A samples, The average level of N7-alkylguanines was 26.2/10(7) nucleo tides in tumour cells, 22.7/10(7) in non-tumour cells and 13.1/10(7) i n blood leucocytes. There was a significantly higher level of N7-alkyl guanines in the larynx tissues in males than in females, The effect of tobacco smoking on DNA adduct levels was shown by an increase in the average levels of N7-alkylguanines in the subject groups classified ac cording to their smoking habits. A moderate age-related increase in le vels of N7-alkylguanine was demonstrated in larynx tumour tissue, The levels of N7-alkylguanine adducts in larynx cells were compared with t hat of aromatic DNA adducts, Pearson correlation coefficients (0.28 fo r tumour tissue and 0.30 for non-tumour tissue) indicate independent f ormation and removal of N7-alkylguanine and aromatic DNA adducts resul ting from tobacco smoke exposure.