Detection of DNA adducts in human nasal mucosa tissue by 32P-postlabeling analysis

Nasal epithelium is an easily accessible tissue that is potentially useful for human biomonitoring studies aimed at evaluating exposure to airborne carcinogens. We have devised a simple technique, which causes minimum distress to the informed patient, to obtain very small but sufficient biopsies from the inferior or middle turbinate head. DNA adducts were measured by 32P-postlabeling assay in nasal mucosa of nine cigarette smokers (including two subjects who had given up smoking shortly before sampling), two former smokers and 10 non-smoker healthy donors. None of the subjects reported other recent exposures to mutagens or carcinogens. Using the nuclease P1 technique, a mean adduct level of 4.8/10(8) bases and a specific spot pattern, the diagonal radioactive zone, were found in smokers, whereas non-smokers showed a significantly lower global level of DNA adducts, i.e. 1.4/10(8) bases, and no diagonal zone. Another important result was the presence of a significant association between DNA adduct level and the number of cigarettes smoked daily. These preliminary findings suggest that the level of DNA adducts measured from biopsies of the nasal mucosa is a reliable marker of exposure to cigarette smoking and uphold its use in biomonitoring exposures to other airborne DNA binding compounds.