Effect of polymorphic metabolizing genes on micronucleus frequencies among benzene-exposed shoe workers in China

Abstract It is well-known that metabolism of benzene is required for the induction of toxicity and consequent health problems. Therefore, genetic variation in benzene (BZ) metabolism genes can influence health outcomes. However, large population studies are needed to provide more evidence for such relationship. We have conducted a large population investigation (385 BZ-exposed shoe workers and 197 matched healthy controls) on the association between inheritance of certain BZ metabolizing genes and the expression of micronuclei (MN). The latter was based on the cytokinesis-blocked MN assay. We analyzed the polymorphisms of GSTM1 , GSTT1 , GSTP1 (rs1695), CYP2E1 (rs3813867), CYP2E1 (rs2031920), CYP2E1 (rs6413432), mEH exon 3 (rs1051740), mEH exon 4 (rs2234922). Univariate Poisson regression analysis demonstrated that the BZ-exposed workers had significantly increased MN frequency compared with the controls (FR = 1.84, 95% CI: 1.56–2.18; P CYP2E1 rs3813867 mutant allele ( CC  +  GC ) (FR 1.15, 95% CI 1.02–1.29; P  = 0.020) and rs2031920 variant allele ( CT  +  TT ) (FR = 1.23, 95% CI: 1.09–1.37, P CT  +  TT ) (FR = 1.17, 95% CI: 1.04–1.31, P CYP2E1 , however, GSTM1null , GSTT1null , GSTP1 r s1695, rs6413432, rs1051740 and rs2234922 polymorphisms showed no association with MN frequency. Our results indicate that two promoter polymorphisms in the CYP2E1 gene, especially the rs2031920 variant allele, were involved with the BZ-induction of MN and may contribute to risk of cancer among exposed workers.