Lung Cancer Lung cancer is a carcinoma that develops in the epithelial cells that form the interior lining to the lungs. The airways get the most exposure to inhaled pollutants, thus most people who get lung cancer are smokers. Lung cancer is not just one disease. There are many types of cancer that form in the lungs most of which you can only see through a microscope. The most common cancer of the lungs is epidermoid. It is also known as squamous carcinoma because its cells look like a flat surface called a squamous cell. This cancer produces keratin, a substance found in skin and hair, which can be seen in