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Genetic polymorphisms influence variability in benzene metabolism in humans
A M Rossi1, C Guarnieri, S Rovesti
1Pisa University, Department of Human and Environmental Sciences, Genetics and Environmental Mutagenesis, Italy. a.m.rossi@geog.unipi.it
Pharmacogenetics
|April 26, 2000
Summary
Genetic variations in CYP2D6, GSTT1, and NQOR influence benzene metabolism. These genetic polymorphisms explain individual differences in benzene metabolite excretion, suggesting they are risk factors for benzene-induced health effects.
Area of Science:
- Environmental Health
- Toxicology
- Human Genetics
Background:
- Occupational exposure to benzene, a known carcinogen, occurs in various environments.
- Individual susceptibility to benzene toxicity varies significantly due to differences in metabolic pathways.
- Understanding genetic factors influencing benzene metabolism is crucial for risk assessment.
Purpose of the Study:
- To investigate the role of genetic polymorphisms in the urinary excretion of benzene metabolites.
- To identify specific genetic variations that explain inter-individual differences in benzene biotransformation.
- To assess the contribution of CYP2D6, GSTT1, and NQOR polymorphisms to benzene metabolic variability.
Main Methods:
- Studied 59 non-smoking city bus drivers occupationally exposed to benzene.
- Measured benzene exposure, urinary benzene metabolites (unmodified benzene, t,t-MA, PMA), and creatinine levels.
- Determined genetic polymorphisms at CYP2E1, CYP2D6, GSTT1, GSTP1, GSTM1, and NQOR loci using PCR-based methods.
Main Results:
- GSTT1 null genotype correlated with significantly higher trans,trans-muconic acid (t,t-MA) excretion.
- Lack of NAD(P)H:quinone oxidoreductase (NQOR) activity and CYP2D6 extensive metabolism were associated with significantly lower S-phenylmercapturic acid (PMA) excretion.
- CYP2E1, GSTM1, and GSTP1 polymorphisms did not show a significant role in benzene biotransformation differences.
- Biological and lifestyle factors did not confound the observed correlations.
Conclusions:
- CYP2D6, GSTT1, and NQOR genetic polymorphisms significantly contribute to explaining metabolic variability in benzene exposure.
- These identified polymorphisms are potential risk factors for benzene-induced adverse health effects.
- Further research into genetic susceptibility can refine occupational health guidelines for benzene exposure.