Smoking-related DNA adducts in human cervical biopsies

Cervical biopsy samples were taken from 35 women (19 smokers, 5 ex-smokers and 11 non-smokers) aged between 30 and 72, undergoing hysterectomy. DNA was isolated and analysed using 32P-postlabelling, with butanol extraction enhancement of the adducts. Resolution of the adducts was by thin-layer chromatography on polyethyleneimine (PEI)-cellulose. The pattern of adducts was similar to that of smoking-related adducts detected in other tissues and consisted mainly of a diagonal zone of radioactivity. The levels of adducts in DNA from the 19 smokers and a recent ex-smoker ranged from 1.93 to 6.04 adducts/10(8) nucleotides (mean = 3.67, SD = 1.36), in DNA from non-smokers from 1.35 to 3.98 (mean = 2.10, SD = 0.79) and in samples from ex-smokers from 2.57 to 3.35 (mean = 2.86), SD = 0.32). The increase in adduct levels in smokers compared with non-smokers was highly significant (Mann-Whitney test p = 0.002, one-tailed). These results are consistent with the hypothesis that smoking-related cervical cancer results from exposure to genotoxic components of cigarette smoke that become activated to DNA-binding products in this tissue.