A Smoking Gun? Epigenetic Markers of Tobacco Use History

Epigenetic changes are associated with disease processes as well as with specific environmental exposures related to toxic agents, nutritional factors, and lifestyle.1,2 Our unfolding knowledge of epigenetics may provide the framework for better understanding disease processes and how they are modified by environmental factors; eventually investiga-tors may identify biomarkers for early disease detection and treatment.2 A new study in EHP now shows that past exposures can be detected and possibly even quantified based on the epigenetic footprints they leave on specific genes.3 The study centered on smoking and methylation of the F2RL3 gene, which is involved in platelet activation and, potentially, certain cardiovas-cular functions.3,4 Epigenetic changes are represented by molecular tags tacked onto genes that affect their expression; in methylation, these tags are methyl groups. Environmental exposures and their timing can influ-ence the degree of DNA methylation and the related consequences.5,