Association between GSTP1 CpG methylation and the early phase of lead exposure.

CONTEXT: GSTP1 is induced by lead, and thus serves as a biomarker of lead exposure. Lead exposure changes DNA methylation status. OBJECTIVE: We attempted to prove that the methylation of the GSTP1 promoter plays an important role in lead toxicity. MATERIALS AND METHODS: We conducted a case-control study of 53 workers from a battery plant and 53 age and sex matched healthy volunteers to determine whether the methylation level of the GSTP1 promoter is associated with the risk of lead poisoning. We employed methylation-specific PCR (MSP) in cell models to determine the relationship between the GSTP1 methylation level and lead exposure. RESULTS: We found no association between GSTP1 methylation and lead exposure. The difference in methylation frequencies between the exposure group and the controls was not statistically significant (p = 0.401), and individuals with the methylated GSTP1 gene was not associated with the risk of lead poisoning (adjusted OR = 1.36, 95% CI, 0.22-8.24). CONCLUSION: This study suggests that GSTP1 methylation is not involved in the early phase of lead toxicity. Further studies should be performed to detect the association between GSTP1 methylation and the risk of lead poisoning in later phases.