Cigarette smoking alters the pattern of genes expressed in cells lining the airways, and some of these changes do not return to normal after smoking cessation, lab studies show. This may explain why ex-smokers remain at risk for lung cancer. Dr. Avrum Spira from Boston University School of Medicine and colleagues identified genes normally expressed in airway cells, and then looked at how gene expression changed with cigarette smoking and whether changes were reversible when smoking was discontinued. In people who were currently smokers, 97 genes were expressed differently than in people who had never smoked, according to the results reported in the Proceedings of the National Academy of Sciences.
