Evaluation of DNA Methylation Changes and Micronuclei in Workers Exposed to a Construction Environment

Abstract

Methylation levels in tumor-suppressor genes and repetitive sequences have previously been used to study the relationship between environmental air pollution and epigenetic changes related to cancer. In this study, we measured the methylation profiles of the promoter regions <i>CDKN2A</i>, <i>MLH1</i> and <i>APC</i> and the repetitive sequence <i>LINE-1</i> in 59 workers exposed to the construction environment and in 49 unexposed workers. We also evaluated the micronuclei frequency and levels of trace elements in the blood of all workers. We evaluated of levels of particulate matter and polycyclic aromatic hydrocarbons (PAHs) at the construction site to characterize the environmental exposure. Our findings demonstrated that exposed workers exhibited significantly higher average levels of promoter methylation of <i>CDKN2A</i>, <i>APC</i>, and <i>MLH1</i> genes and increased hypomethylation of the <i>LINE-1</i> in comparison to unexposed workers (all <i>p</i> < 0.05). A higher frequency of micronuclei was observed in the exposed group (2 ± 2) compared to the unexposed group (1 ± 1) with <i>p</i> < 0.001. High levels of particulate matter (51⁻841 μg/m³) and some PAHs were found in samples from the construction environment. In summary, we provide evidence of increased DNA damage and altered <i>DNA</i> methylation of exposed workers, suggesting that genomic approaches to biomonitoring may be an effective way of estimating future cancer risk for construction workers.