Smoking effect on DNA methlyation in peripheral mononuclear cells

Lung cancer is the leading cause of cancer death in the United States, accounting for approximately 160,000 deaths annually. Most lung cancer is detected at an advanced stage resulting in a poor 5-year survival of 15 % which has not significantly improved in recent years.1 Since 87 % of lung cancer cases are attributable to smoking, it is intuitive to screen for lung cancer in these high risk individuals.2 However, there is no current recommended screening program for current or former smokers, though multiple noninvasive screening modalities are being investigated. This study examines epigenetic alterations of mononuclear cell DNA in the peripheral blood and the association with smoking exposure. Specific epigenetic profiles in these cells may parallel carcinogenic changes in the lung, thus ultimately serving as a noninvasive screening tool for lung cancer and other diseases associated with epigenetic alterations. Epigenetic processes, including DNA methylation, are essential for normal development and differentiation, while perturbations in this process via aging and environmental exposures have been implicated in disease.3 Patterns of DNA methlyation are altered in neoplasia; hypermethylation of promoter regions causes inappropriate gene silencin