Arsenic Exposure and Epigenetic Alterations: Recent Findings Based on the Illumina 450K DNA Methylation Array

Arsenic is a major public health concern worldwide. While it is an established carcinogen and associated with a number of other adverse health outcomes, the molecular mechanisms underlying arsenic toxicity are not completely clarified. There is mounting evidence from human studies suggesting that arsenic exposure is associated with epigenetic alterations, including DNA methylation. In this review, we summarize several recent human studies that have evaluated arsenic exposure using the Illumina HumanMethylation 450K BeadChip, which interrogates more than 485,000 methylation sites across the genome. Many of these studies have observed novel regions of the genome associated with arsenic exposure. However, few studies have evaluated the biological and functional relevance of these DNA methylation changes, which are still needed. We emphasize the need for future studies to replicate the identified DNA methylation signals as well as assess whether these markers are associated with risk of arsenic-related diseases.