Epidemiology of lung cancer: smoking, secondhand smoke, and genetics.

The link between smoking and development of lung cancer has been demonstrated, not only for smokers but also for those exposed to secondhand smoke. Despite the obvious carcinogenic effects of tobacco smoking, not all smokers develop lung cancer, and conversely some nonsmokers can develop lung cancer in the absence of other environmental risk factors. A multitude of genetic factors are beginning to be explored that interact with environmental exposure to alter the risk of developing this deadly disease. By more fully appreciating the complex interrelationship between genetics and other risks the development of lung cancer can be more completely understood.