Environmental Epigenomics: Applications of Epigenetic Biomarkers to Investigate Epigenetic Alterations from Environmental Exposures

Over the past decade, evidence has shown that epigenetic mechanisms play an important role in human disease susceptibility and cancer. Studies of potential human carcinogens have been expanded to include those that do not appear to damage DNA directly but rather alter gene expression patterns through epigenetic mechanisms such as alterations in DNA methylation, histone modifications/chromatin alterations, and microRNA. Given that almost 25 % of all human diseases are estimated to be caused by environmental exposures, here we review current studies of xenobiotic exposures for which there is growing mechanistic evidence for indirect DNA alteration through epigenetic mechanisms. Also described are common variations in genes that may modify epigenetic alterations in blood and tumor DNA. Epidemiological methods used to incorporate epigenetic alterations into studies of disease etiology as well as current methods used to apply and critically evaluate study results reporting associations between environmental exposure and disease are described.