Cytochrome P450-2E1 and glutathione S-transferase mu polymorphisms among Caucasians and mulattoes from Brazil

The variable interindividual ability to metabolize environmental toxicants, also known as metabolic polymorphism, may be of substantial importance in the modulation of cancer risk. The ethnic distribution of these polymorphis ms could be interesting in order to establish an association with cancer ri sk or even to establish selective advantage of some genotypes. Cytochrome P 450 2E1 (CYP2E1) is a secondary enzyme that can metabolize ethanol, and glu tathione S-transferase (GSTM1) is thought to be involved in the detoxificat ion of epoxides and polycyclic aromatic hydrocarbons. Mutation in these gen es was investigated in a random sample of healthy subjects from Sao Paulo, Brazil, which included 206 Caucasians and 86 mulattoes. Pst I restriction f ragment length polymorphism (RFLP) in the 5'-flanking region of the CYP2E1 gene has been identified in 10.2% of Caucasian individuals and in 11.6% of mulattoes. For GSTM1 the frequency of the null genotype was significantly h igher in Caucasian individuals (60.2%) than in mulattoes (41.9%). Allele fr equencies were (1) CYP2E1 locus: P = 0.949. q = 0.051, se(p)= se(q)= 0.011 among Caucasians: and p = 0.942; q = 0.058; se(P)= se(q)= 0.018 among mulat toes: and (2) GSTM1 locus: p = 0.224, q = 0.776, se(p) = se(q)= 0.022 among Caucasians: and p = 0.353; q = 0.647; se(p)= se(q)= 0.041 among mulattoes.