Urine NNAL in Non-smoking Lung Cancer Cases in Korea

Though tobacco smoking is the primary risk factor for lung cancer (Park et al., 2008; Kamsa-Ard et al., 2013), a significant fraction of lung cancer deaths occur in lifetime non-smokers (Sisti and Boffetta, 2012). Environmental tobacco smoking (ETS) is defined as tobacco smoke produced by an active smoker both from the exhalation of smoked tobacco and by the burning end of the cigarette, which is inhaled by nonsmokers (Florescu et al., 2009). ETS significantly contributes to morbidity and mortality in non-smokers. Exposure to ETS is one important risk factors for lung cancer (Couraud et al., 2012). However, there were some debates about the association between the exposure to ETS and lung cancer development (Brennan et al., 2004). Non-smokers are exposed to tobacco smoke not only in their homes but also in schools, restaurants, cars, buses, and other public places. Tobacco use by a spouse was associated with a 30% excess risk of lung cancer development and the population attributable fractions (PAFs) for individual risk factors ranged from 0.4% to 19.9% (Sisti and Boffetta, 2012). N’-nitrosonornicotine (NNN) and 4(methylnitros