Mesothelioma: What It Is and How It Develops

Mesothelioma is a rare form of cancer that invades mesothelial cells. These are specialized cells that make up the membranes lining the chest, the stomach or abdomen, and the heart. Mesothelial cells form a tissue called mesothelium, producing a lubricating fluid that allows the organs to move without irritating nerves.

Asbestos exposure can cause mesothelioma. If you have mesothelioma, you may have come into contact with asbestos on the job or through a secondhand exposure such as asbestos brought into the home on your spouse’s shoes or clothing. See Asbestos Exposure and Mesothelioma for more details. Some researchers believe that the virus SV40 may also be a factor in the development of mesothelioma.

Cigarette–smoking increases your chances of contracting lung cancer or an asbestos–related disease such as asbestosis, although it does not cause mesothelioma. If you have been exposed to asbestos and smoke cigarettes, you should consider quitting. Your local American Cancer Society and the Centers for Disease Control can provide resources, tips, and support for giving up the habit.
Pleural Mesothelioma Is the Most Common Mesothelioma Type

Pleural mesothelioma or cancer of the pleura is the most common type of mesothelioma, making up about 75% of mesothelioma cases according to the American Cancer Society. The pleura is the membrane that lines the lungs and the chest cavity. If you have developed pleural mesothelioma, you may experience serious breathing problems and chest pain. Your doctor will discuss various treatments to ease these symptoms. (See Mesothelioma Treatment Options for more details.)

Peritoneal mesothelioma is cancer of the peritoneum, which is the lining of the stomach or abdomen. The disease makes up about 10–20% of mesothelioma cases. Mesothelioma may also begin around the pericardium or heart cavity lining, although this is very rare.
Mesothelioma Cell Types

When mesothelioma cells are examined under the microscope, they generally fall into three varieties: epithelioid, sarcomatoid, and mixed/biphasic (RadioGraphics, 1996, Vol. 16, No.3). The tumor cells in epithelioid mesothelioma are typically cube–shaped, and fairly uniform, Most mesothelioma cells are of this type. Sarcomatoid mesothelioma cells have different forms; many are spindle–shaped or elongated. Mixed/biphasic mesothelioma includes both epithelioid and sarcomatoid cells. The treatment options for all three types of cell types are the same, although mesothelioma patients with mostly epithelioid cancer cells seem to have the longest survival rates (American Cancer Society; and Prognosis, RadioGraphics, 1996, Vol. 16, No. 3).
Mesothelioma Prognosis

Many mesothelioma patients do not live beyond two years after diagnosis. Still, there is reason for hope. Many treatments prolong life and ease symptoms. Researchers are constantly on the look–out for new drugs and other mesothelioma treatment methods. See Mesothelioma Treatment Options. Also be sure to look at our sections about promising new chemotherapy drugs and clinical trials.