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Malignant mesothelioma is a rare malignancy arising from the mesothelial cells of the pleural or peritoneal surfaces. Mesothelioma can arise from the pleura (pleural mesothelioma), peritoneum (peritoneal mesothelioma), pericardium (pericardial mesothelioma), or tunica vaginalis (testicular mesothelioma). In the United States, there are approximately 3000 new cases of mesothelioma reported annually. Eighty percent of these occur as pleural mesothelioma, and this will be the focus of this chapter.
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The development of mesothelioma is most clearly associated with prior asbestos exposure (1). Asbestos was (and continues to be in some parts of the world) an important and affordable industrial resource due to its resistance to heat and combustion. Asbestos was used in shipbuilding, in car brakes, in the production of cement, and as insulation. There are two main forms of asbestos known as amphiboles and chrysotile. Amphiboles are long thin asbestos fibers and are felt to be the most carcinogenic of the asbestos fibers. Chrysotile asbestos has also been associated with mesothelioma, although the frequency may be less than with amphibole asbestos (1). The latency period between the time of asbestos exposure to development of mesothelioma can be 20–40 years. These unique features reflect the population of patients who develop mesothelioma including asbestos miners, plumbers, pipefitters, or those who worked in shipbuilding industries. In the United States, mesothelioma is a disease of Caucasian men reflecting the population of asbestos workers in the 1960s and early 1970s. The median age of patients diagnosed with mesothelioma is in the mid-60s, although, in the Surveillance Epidemiology and End Results (SEER) database from the United States, the median age is over 70 years. Approximately 80% of patients who develop mesothelioma are men. Women who develop mesothelioma also may have worked in industries that used asbestos, although there are reports of secondary exposure for example from clothing of spouses who worked directly with asbestos (2). The estimated incidence of mesothelioma worldwide also reflects the use of asbestos in different regions of the world. It is estimated that the cumulative worldwide incidence of mesothelioma will not peak for another 10–20 years. However, in the United States some estimates suggest that this may have already occurred, while in Europe, Australia, and Japan, where common asbestos use occurred until much later than in the United States, the incidence may not peak for another 15–20 years (3). In addition, asbestos is still extensively used in many developing countries suggesting that the worldwide incidence of mesothelioma will continue to rise.
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Other etiologic factors besides asbestos can also increase the risk of developing mesothelioma. For example, numerous cases have been reported in patients who have previously received ionizing radiation such as that used to treat Hodgkin lymphoma or other malignancies (4). Genetic factors may also play a role. Germline mutations in the BRCA-associated protein-1 (BAP1) gene were reported in two families with multiple affected generations (5). ...