Effect of cigarette smoke on gene expression in mammary epithelial cells [gene expression]

Recent epidemiological studies demonstrate that both active and involuntary exposure to tobacco smoke increases the risk of breast cancer. Little is known, however, about the molecular mechanisms by which tobacco smoke contributes to breast carcinogenesis. To investigate these mechanisms we have analyzed gene expression and methylation in MCF 10A mammary epithelial cells chronically exposed to aqueous cigarette smoke extract (CSE). CSE was prepared weekly and added to the cell cultures at a concentration equivalent to 0.001 cigarettes/ml. Two clones were isolated after 13 weeks of treatment and expanded in the same concentration of CSE for 8 additional weeks. Mock-treated samples were prepared in parallel.