What is Mesothelioma?

Mesothelioma is an aggressive form of cancer that affects the mesothelium, a protective membrane that covers internal organs of the body including the lungs, heart and abdominal organs. Mesothelioma can develop at any of these sites, but approximately 75% of the time it is the lung lining, or pleura, that is affected.

Exposure to Asbestos

Each year, 2,000 to 3,000 people in the United States are diagnosed with mesothelioma. The only universally accepted cause of mesothelioma is exposure to asbestos. Asbestos is the general name given to a group of minerals which can be separated into durable threads or fibers. Because it is resistant to heat, fire, electricity and chemicals, asbestos was used in thousands of industrial, construction, automotive and commercial products through the years. Unfortunately, the indestructible properties which make asbestos so effective in these products are also what make asbestos extremely toxic to the human body.

Asbestos fibers are finer than human hair and invisible. The fibers are easily inhaled and, because of their long thin shape, are often immune to the body’s natural defense mechanisms against foreign bodies entering the airways. The fibers are able to proceed past the lung and lodge into the pleura.

Inflammation and Fibrosis

Over the course of 20 to 60 years, the fibers can cause inflammation and fibrosis which damage the DNA of the mesothelial cells lining the pleura and lead to the appearance of malignant tumors. If left untreated, the tumors can spread throughout the pleural space as a sheet of fibrous tissue which surrounds the lung, exerting increasing pressure on the lungs and surrounding organs.

Malignant mesothelioma (all sites): Age-adjusted death rates

(per million population) by state, U.S. residents age 15 and over, 2001–2010



Age-adjusted rates for the disease of interest have not been calculated for states with less than 10 reportable deaths, and where the number of years with reportable deaths is less than 10.

See Appendix for information about data sources, methods, ICD codes, and limitations.

Source: Mortality multiple cause-of-death data from National Center for Health Statistics, National Vital Statistics System. Population estimates from U.S. Census Bureau.

Date Posted: September 2014

For information on proper diagnosis, treatment and coping with Mesothelioma, please read:
Mesothelioma: A Patient’s Roadmap