The Biological Significance of Tobacco-Specific N-Nitrosamines: Smoking and Adenocarcinoma of the Lung
In 1990, at the 15th International Cancer Congress in Hamburg, Germany, a "Round Table Discussion" was held on tobacco-specific N-nitrosamines (TSNA). As reflected in the preceding papers of this Symposium, remarkable progress has been made in the chemistry, biochemistry, and molecular biology related to TSNA and in the epidemiology of tobacco-associated cancer. The epidemiology of smoking and lung cancer, and observations on the changing smoking patterns of consumers of low-yield filter cigarettes, have led to development of a working hypothesis that supports the observation of an increased risk for lung adenocarcinoma (AC) in cigarette smokers. In the united states there has been a steeper rise of the incidence of lung AC than of squamous cell carcinoma of the lung among cigarette smokers. Tobacco contains more than 3000 compounds, including 30 carcinogens, and tobacco smoke has more than 4000 constituents, including about 50 carcinogens.