How does lung cancer start Lung cancer is a type of cancer that begins in the tissues of the lungs, usually in the cells lining the air passages. Lung cancer is one of the leading causes of death in the world, and although it can start in any of the two lungs, most lung cancer cases originate in the bronchi cells. Different risk factors play a role in the development of lung cancer, from environmental influences to genetic predisposition and lifestyle choices. The most critical risk factor for the development of the disease is a history of smoking cigarettes. Lung cancer starts when the DNA in normal lung cells mutate, which causes them to grow and divide uncontrollably. These mutant cells then form tumors that invade healthy tissues and disrupt the regular functioning of one’s body. Over time, these malignant growths can affect nearby organs, bones, and lymph nodes, depending on their type and stage. Even though smoking is a major risk factor for this disease, other factors such as ai...