Lung cancer is characterized by abnormal cell growth in the tissues of the lungs. The most common causes are associated with tobacco use; the disease is also associated with exposure to pollution and radar, among other things. There are two general types of lung cancer: non-small cell lung cancer and small cell lung cancer. Symptoms of either type include a persistent cough, shortness of breath, and coughing up blood. Treatment options include surgery, chemotherapy, and radiation therapy.