Abstract
Nicotine replacement therapy (NRT) is a valuable, proven, and U.S. Food and Drug Administration-approved tool for smoking cessation. However, the discoveries of functional nicotinic acetylcholine receptors (nAChR) on lung epithelial and cancer cells and of nAChR polymorphisms associated with lung cancer risk, in addition to a large number of preclinical studies indicating that nicotine may promote or facilitate cancer development and growth, have prompted concern that NRT, although important for smoking cessation, may actually augment lung carcinogenesis. Therefore, it is of great public health interest that two independent studies reported in this issue of the journal (Murphy and colleagues, beginning on page 1752, and Maier and colleagues, beginning on page 1743) showed that nicotine given in drinking water at a dose to achieve blood concentrations in mice similar to those achieved in people receiving NRT did not enhance lung carcinogenesis or tumor growth in several mouse models of lung cancer. Effective non-nicotine alternatives to NRT, such as varenicline and bupropion, are also available and perhaps better than NRT for smoking cessation therapy. In the near future, nicotine vaccines will likely be added to the smoking cessation armamentarium. However, the normal and pathophysiologic role of nicotine, nAChRs, and the signaling pathways they activate in lung epithelial cells and lung cancer still requires elucidation.