Most professionals familiar with asbestos exposure automatically assume that a diagnosis of mesothelioma must be the result of such exposure. There have been, however, studies that confirm there may be other causes for mesothelioma. Possibly the most controversial link to mesothelioma is exposure to Simian virus 40 (SV40). This virus has been proven to infect monkeys and apes. During the 1950s, they were used to develop a polio vaccine. In 1961, it was identified that some of these monkeys were infected with SV40 meaning the polio vaccines were likely contaminated as well. By the time SV40 was removed from the polio vaccine supply, 62 percent of all Americans had been inoculated with the potentially contaminated vaccines.
Who is at risk for receiving a diagnosis of mesothelioma? Every cancer patient questions why they got the disease. Most cases of mesothelioma involve asbestos exposure but some patients are about even being exposed. Minute levels of asbestos do exist in the air, water, and soil but most people do not develop mesothelioma cancer from this type of exposure. A majority of mesothelioma patients have had regular exposure to asbestos from employment or direct daily contact with someone who was exposed to asbestos fibers at work. Around 1980, legislation was enacted to protect workers from asbestos exposure, but prior to that, workers in many blue-collar industries were regularly exposed.
Once SV40 was considered a problem, animal studies showed that it was highly carcinogenic. It created significant alarm regarding its cancer-causing potential from the contaminated polio vaccines. In 1993, research showed that infected hamsters with SV40 in the pleural space caused a diagnosis of mesothelioma in 100 percent of the infected animals. This absolutely prompted further study to determine if there was a potential link in humans. Shockingly, a year later, the same group of researchers reported that DNA similar to the SV40 virus was identified in 60 percent of mesothelioma tumors tested. However, another set of researchers failed to identify any SV40 DNA in 50 mesothelioma tumor samples examined.
Of course there is an ongoing debate in regards to the link between SV40 DNA and mesothelioma. There has been some research with evidence that SV40 and asbestos may work together to cause mesothelioma. Cells with chromosomal abnormalities can gain cancer-like characteristics more easily when infected with SV40 compared to cells with normal chromosomes. Furthermore, asbestos fibers can promote the incorporation of viral DNA like SV40 into cells. In addition to the proposition that SV40 could encourage the development of asbestos-induced mesothelioma, it has also been suggested that SV40 may be responsible for mesothelioma found in patients with no asbestos exposure.
In any case, more research is needed to determine the exact role, if any, of SV40 in a diagnosis of mesothelioma development. An absolute connection is yet to be finalized.