4-AMINOBIPHENYL-DNA ADDUCTS IN LARYNGEAL TISSUE AND SMOKING-HABITS - AN IMMUNOHISTOCHEMICAL STUDY

4-Aminobiphenyl (4-ABP)-DNA adducts and p53 overexpression were evalua ted in laryngeal biopsies from 38 patients by immunohistochemical meth ods. Samples were categorized as tumors (n = 9), polyps (n = 28) or no rmal tissue (n = 1), 4-ABP-DNA adducts were evaluated with a quantitat ive immunoperoxidase method using monoclonal antibody 3C8 in both the lesion and adjacent tissue, Relative staining intensity data showed a log-normal distribution and values found in adjacent tissue from smoke rs were significantly higher (median: 173.5, geometric mean: 159.9) th an those measured in adjacent tissue from non-smokers (median: 75.5, g eometric mean: 7.40). Statistical significance was assessed both by no n-parametric testing on raw data (P = 0.0007 on rank sum test) and by parametric testing on log-transformed data (P = 0.0002 on an unpaired t-test), Furthermore, relative staining intensity in the lesional tiss ue showed the same significant difference between smokers and non-smok ers in patients affected by polyps, whereas no significant difference was detected in patients with laryngeal tumors. Overexpression of p53, also measured with an immunoperoxidase method, was observed in 44% of the malignant tumors and in 3.5% of the polyps, This work demonstrate s that CABP-DNA adducts can be evaluated in laryngeal tissue and are r elated to smoking exposure.