Pleural mesothelioma affects the lining of the lung and chest cavity known as the pleura.  Asbestos fibers work their way into the passageways of the lungs and then into the pleura. Once there, an unknown chemical reaction causes cancerous cell development.  Common symptoms of Mesothelioma are shortness of breath, pain in the chest and a build up of too much fluid between the linings of the lungs and chest.