Mesothelioma starts in cells of the mesothelioma. A cancerous tumor is a group of cancer cells that can grow into and destroy nearby tissue.
It can also spread to other parts of the body. The remain risk factor for plural mesothelioma is exposure to asbestos. In fact most cases of it have been linked to asbestos exposure, usually from high levels of exposure in the workplace, when asbestos fibers in the air are inhered they can get into the lungs fibers that stay in the lungs can travel to the ends of the small airways and enter the pleura limning of the lungs and chest well.
These fibers can injure the cells of the pleura. Many people are exposed to very low level of naturally occuring asbestos in outdoor air in dust that comes from rocks and soil containing asbestos.
People who might be exposed to high levels of asbestos at work include some miners factory workers.