The easiest way to understand the difference between lung cancer and mesothelioma is that lung cancer is in the lung tissue, while pleural mesothelioma occurs in the layer of tissue lining the outside of the lung.

Smoking is considered the primary cause of lung cancer, and asbestos as the primary cause of mesothelioma. Asbestos can also cause lung cancer. Smoking does not cause mesothelioma. People who have been exposed to asbestos and who also smoke have up to 90 times more likely to be affected with lung cancer than those who do not smoke.