Rarely, people develop mesothelioma without any obvious exposure to asbestos or erionite. The cause in these cases is unknown (idiopathic or spontaneous mesothelioma). In such cases, people may have experienced unknown exposure to asbestos or erionite. Most risk factors for mesothelioma involve different sources of exposure to.
Other risk factors, such as genes you inherit or exposure to simian virus 40, known as SV40, have not been shown to cause mesothelioma. The risk of developing mesothelioma is closely related to the amount of asbestos a person is exposed to and the duration of exposure. People exposed at a young age, for a long time, and at higher levels are more likely to develop this cancer. Even so, most people exposed to asbestos, even in large numbers, do not get mesothelioma.
Other factors, such as a person's genes or having had radiation therapy in the past, may make them more likely to develop mesothelioma when exposed to asbestos. The diagnosis of mesothelioma without exposure to asbestos is rare. Exposure to asbestos is the number one risk factor and the most common underlying cause of mesothelioma. There are possible explanations for diagnoses without known exposure.
Most people exposed to asbestos never develop mesothelioma. This indicates that other factors may be involved in determining if a person has mesothelioma. For example, you could inherit a predisposition to cancer or some other condition could increase your risk. Recent studies have shown that many mesotheliomas harbor somatic mutations of BAP-1, NF2 and, to a lesser extent, SETD2, TP53, DDX3X, ULK2, RYR2, CPAF45, SETDB1 and DDX51.124. Deletions of the 9p21 region containing p16INK4a, p15, p14 and MTAP are common in mesotheliomas.
Because of the very different potencies of exposure to chrysotile versus exposure to commercial amphiboles in mesothelioma production and the importance of dose, latency and tumor site, appropriate groups for these characteristics would be needed to determine whether germline mutations of BAP-1 really increase the risk of mesothelioma from exposure to asbestos. Baumann et al.110 reported survival data from 23 patients with germline mutations in BAP-1 and concluded that germline BAP-1 mutated mesotheliomas are associated with longer survival than usual sporadic mesotheliomas. Roughly speaking, between 60 and 90% of mesotheliomas in US women (pleural and peritoneal sites, respectively) and a substantial proportion of peritoneal mesotheliomas in men are probably not related to asbestos. A recent review of SEER data found that the risk of mesothelioma following external-beam radiation increased with longer latency and showed a stronger association with peritoneal mesothelioma.
The vast majority of cases of mesothelioma are caused by exposure to asbestos at work or home, but there are more and more causes of mesothelioma without exposure to asbestos. People with a genetic predisposition to mesothelioma and exposed to asbestos in the long term have the highest risk of developing mesothelioma. Currently, the majority of pleural mesotheliomas (70 to 90%) in men in Europe and North America are attributable to exposure to asbestos; for peritoneal mesothelioma the proportion is lower. In substantially less than 1% of patients with mesothelioma (when there is no exposure to external agents), mesothelioma will be induced by a specific hereditary genetic mutation; scientific evidence currently supports the role of BAP-1.Testa et al.101 reported that 7.7% (2 of 2) of spontaneous mesotheliomas (BAP-1 germline mutations); however, 3 subsequent series totaling approximately 300 apparently sporadic cases examined with targeted deep sequencing revealed that only 1 patient had a germline mutation, 103-105, which resulted in the which indicates that cases of BAP-1 germline cancer syndrome account for at most a very small percentage of all mesotheliomas.
Mesothelioma doctors will order CT imaging and other tests based on your history of exposure to asbestos to determine if you are developing mesothelioma. While many mesotheliomas are linked to exposure to asbestos, not all of them are, and there is increasing information about other causes of mesothelioma. . .