Immunoperoxidase detection of polycyclic aromatic hydrocarbon-DNA adducts in mouth floor and buccal mucosa cells of smokers and nonsmokers

Tobacco smoking is a major risk Factor For oral cancer; mouth floor and buc cal mucosa are among the most and least cancer-prone subsites, respectively , in the oral cavity. We investigated the applicability of immunohisiochemi stry of smoking-induced DNA adducts in oral cells for assessing the exposur e to carcinogens, and estimating the risk for oral cancer. Polycyclic aroma tic hydrocarbon (PAH)-DNA adducts were measured in mouth Floor and buccal m ucosa cells of smokers (n = 26) and nonsmokers (n = 22) by means of a semiq uantitative immunoperoxidase assay. Smokers had elevated levels of PAH-DNA adducts compared to nonsmokers in their mouth floor cells (0.045 +/- 0.022 versus 0.022 +/- 0.016, P = 0.0008 arbitrary units of immunohistochemistry) as well as in their buccal mucosa cells (0.058 +/- 0.028 versus 0.028 +/- 0.012, P = 0.001). Also, there was a correlation between the levels of PAH- DNA ad-ducts in mouth floor cells and those in buccal mucosa cells (r = 0.4 , P = 0.01). Furthermore, PAH-DNA adduct levels in both mouth floor and buc cal mucosa cells were significantly related to current smoking indices (amo unt of tar and number of cigarettes consumed per day). Expectedly, the leve ls of PAH-DNA adducts neither in mouth floor cells nor in buccal mucosa cel ls, both being short-lived cells, were related to smoking history index (pa ck years). The levels of PAH-DNA adducts, however, in mouth floor cells as the cancer prone cells were lower than those in buccal mucosa cells (0.037 +/- 0.023 versus 0.044 +/- 0.026, P = 0.04). We conclude that immunohistoch emistry of PAH-DNA adducts in oral cells can be used For exposure assessmen t of tobacco-related carcinogens, however, it cannot be used for oral cance r risk estimation. (C) 2000 Wiley-Liss, Inc.