What is mesothelioma?

Mesothelioma is a unique cancer that starts from the mesothelium, the membrane lining that contains the body cavities. Mesothelioma can arise from the pleura (lining of the lungs), pericardium (sac around the heart), peritoneum (abdominal lining), and tunica vaginalis testis (lining of the male reproductive organs). The majority of mesothelioma cases originate from the pleura.

Epidemiology and Cause of Mesothelioma

Mesothelioma occurs everywhere in the world. In the United States, it is estimated that ~3000 new cases of mesothelioma occur each year. Western Europe has over 5000 new cases/year and China estimates 4000 new cases/year.

The main cause of mesothelioma is environmental and well-established; patients have often been exposed to asbestos fibers in their work or living area. Asbestos is a long thin silicate mineral and has been linked not only to mesothelioma but also to pneumoconiosis and lung cancer. Asbestos was a popular material used in insulation and construction because it had desirable properties of heat/fire and chemical resistance. The fibers are hazardous when they become airborne and are inhaled or swallowed. There are 2 main classes of asbestos: serpentine and amphibole. Serpentine minerals (chrysotile) account for 95% of the asbestos in buildings in the United States. The amphibole group consists of 5 types of asbestos – amosite, crocidolite, anthophyllite, tremolite, and actinolite. Amosite is called the brown asbestos and is found in building materials. The types of asbestos that are most carcinogenic are amosite and crocidolite. However, chrysolite also is hazardous and is linked to development of mesothelioma in people.

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