The influence of polymorphisms of certain metabo- lizing 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.