Lung Cancer: Current Cancer ResearchAbout This Hardback Lung cancer occurs when tumors grow in the lungs due to the uncontrollable division of the cells. Unlike normal cells, cancer cells grow quickly without dying off and cause a buildup of cells. The two major kinds of lung cancers are small cell lung cancer and non small cell lung cancer. A few of its risk factors include exposure to smoke, chemicals or other toxins. Effective diagnosis and treatments have reduced the fatality rate