The Natural History of Gene Expression in the Lung Cells of Non-Smokers, Smokers and Ex-Smokers in Health and Disease

Cigarette smoke is responsible for the majority of lung cancers and is the major cause of COPD, the fourth leading cause of death in the United States. Despite the well established causal role of cigarette smoking in lung cancer and COPD, only 10-20% of smokers actually develop these diseases. This suggests that there are genetic predisposing factors that place some individuals at greater risk. Our prior work shows that healthy smokers (cigarette smokers with normal history, physical exam, lung function tests and chest x-rays) and smokers with COPD have marked up and down regulation of greater than 200 genes in the small airway epithelium and alveolar macrophages. There is however, a varied response to smoking among individuals, with some individuals abnormally expressing far fewer genes. The focus of this study is to evaluate the hypothesis that the response of the lung cells to the stress of smoking is unique to each individual but is consistent over time. Furthermore, individuals that stop smoking will each have a unique response, but is constant over time for each individual. By defining the patterns of biologic response over time among smoking, ex-smoking and nonsmoking subjects, we will be able to identify common biologic pathways as potential targets for intervention.