PIG-A gene mutation as a genotoxicity biomaker in polycyclic aromatic hydrocarbon-exposed barbecue workers

Background: The PIG-A gene mutation assay is a valuable tool for measuring in vivo gene mutations in blood cells. The human PIG-A assay, used as a potential genotoxicity biomarker, is minimally invasive, sensitive, and cost-efficient; however, the relationship between carcinogen exposure and PIG-A mutations is not well understood. Methods: We investigated the genotoxic effect of red blood cells using PIG-A assay and lymphocyte cytokinesis-block micronucleus test in barbecue restaurant workers (N = 70) exposed to polycyclic aromatic hydrocarbons (PAHs) and self-identified healthy control subjects (N = 56). Urinary PAH metabolites were measured to evaluate internal exposure levels. Results: Multivariate Poisson regression showed that the PAH-exposed workers exhibited significantly higher PIG-A mutant frequency (MF) (8.04 +/- 6.81 x 10(- 6)) than did the controls (5.56 +/- 5.26 x 10(- 6)) (RR = 0.707, 95% CI: 0.615-0.812, P < 0.001). These results indicate that PAH exposure is a risk factor for elevated PIG-A MF. The frequencies of micronuclei (MN) and nuclear buds (NBUD) in the PAH-exposed workers (MN: 3.06 +/- 2.07 parts per thousand, NBUD: 1.38 +/- 1.02 parts per thousand) were also significantly higher than in the controls (MN: 1.46 +/- 0.64 parts per thousand, P < 0.001; NBUD: 0.70 +/- 0.60 parts per thousand, P < 0.001). Additionally, PIG-A MFs showed better associations with several urinary hydroxylated PAH metabolites (P2-OH-Flu = 0.032, r(2-OH-Flu) = 0. 268; P2-OH-Phe = 0.022, r(2-OH-Phe) = 0.286; P3-OH-Phe = 0.0312, r(3-OH-Phe) = 0.270; P4-OH-Phe = 0.018, r(4-OH-Phe) = 0.296), while the increase in MN, NPB, and NBUD frequencies was not associated with any OH-PAH metabolites; and high-PAH-exposed workers showed the highest PIG-A MFs. Furthermore, there was a significant association between PIG-A MF and PAH exposure levels (Chi-square test for trend, P = 0.006). Conclusions: Our results indicate that an increase in PIG-A MF in barbecue workers could reflect the response to PAH exposure, providing evidence of its potential as a genotoxicity biomarker in human risk assessment.

Automated summary

The study found that barbecue workers exposed to PAHs had significantly higher PIG-A mutant frequency compared to controls, suggesting it could serve as a genotoxicity biomarker in human risk assessment.