The influence of polymorphisms of certain metabolizing enzymes on levels of urinary metabolites, as well as on DNA adducts, are summarized in Table 5.There was no significant effect of CYP1A1 genotype (Ile/Ile, Ile/Val or Val/Val) on levels of 1-OHP or DNA adducts. Similarly, there was no significant effect ofGSTT1 (null or positive) or GSTM1 (null or positive) genotypes on urinary 1-OHP or DNA adduct levels. Total PAH expo- sure levels, as well as the calculated B[a]P equivalents, were not significantly different in the subjects grouped by genotype for any of the three studied genes.