Lung cancer is the uncontrolled growth of abnormal cells in one or both of the lungs. While normal lung tissue cells reproduce and develop into healthy lung tissue, these abnormal cells reproduce rapidly and never grow into normal lung tissue. Lumps of cancer cells called tumors then form and disrupt the lung, making it difficult to function properly. As with any cancer, each person's genetic pattern influences susceptibility to lung cancer. The fact that lung cancer runs in some families suggests that a predisposition can be inherited. Additionally, certain genetic traits have been identified that make some people more susceptible than others to carcinogens. (http://www.mesothelioma-michigan.com/lcancerct.php).
More than 87% of lung cancer is smoking related. However not all smokers develop lung cancer. Research has shown that polycyclic aromatic hydrocarbons (PAHs)--carcinogenic compounds in cigarette smoke--produce DNA damage patterns that are similar to the p53 mutation patterns found in lung cancer tissues in smokers. Earlier studies had shown that exposure to one specific PAH, benzo[alpha]pyrene diol epoxide, induces guanine adducts at mutational hotspots within the p53 tumor suppressor gene, which is mutated in 60% of human lung cancers. It is thought that these adducts cause problems with lung cell reproduction that may eventually lead to lung cancer. But, whether other PAHs found in cigarette smoke were implicated in the development of lung cancer was unclear. (http://www.respiratoryreviews.com/aug00/rr_aug00_smoking.html) .
Also tobacco-specific nitrosamines (TSNAs) are formed during tobacco curing and processing. TSNAs are chemicals that are suspected of causing lung cancer in humans. In rodent studies, regardless of the where or how it is applied, the TSNA known as NNK produces lung adenomas -benign tumors of epithelial (surface cell) tissue - and lung adenocarcinomas - malignant epithelial tumors with gland-like characteristics.