Malignant mesothelioma forms in the mesothelium, a thin layer of tissues that surrounds the internal organs and cavities.
Mesothelioma symptoms typically take up to 10 to 50 years to become apparent, making it difficult to detect early on and to specify the cause.
While researchers are searching for more causes, most cases of mesothelioma have the same origin — asbestos.
Exposure to asbestos, a mineral once popular in commercial and industrial settings, is the only definitive known cause of malignant mesothelioma.
At least 90 percent of mesothelioma cases are tied to breathing in asbestos fibers.
Other factors patients have claimed to have caused mesothelioma are exposure to zeolites, radiation, simian virus 40, and high aspect ratio nanoparticles (HARNs).