What Causes Malignant Mesothelioma?

Researchers have found several factors that increase a person’s risk of mesothelioma , but it’s not yet clear exactly how all of these factors might cause this cancer.

Cancers, including mesotheliomas, occur when the DNA in cells is damaged. DNA is the chemical in each of our cells that makes up our genes – the instructions for how our cells function. We usually look like our parents because they are the source of our DNA. But DNA affects more than how we look. Some genes control when cells in the body grow, divide into new cells, and die. Changes in these genes may cause cells to grow out of control, which can lead to cancer.

Asbestos exposure is the main cause of pleural mesothelioma. About 8 out of 10 people with mesothelioma have been exposed to asbestos. When asbestos fibers are breathed in, they travel to the ends of small air passages and reach the pleura, where they can cause inflammation and scarring. This may damage cells’ DNA and cause changes that result in uncontrolled cell growth. If swallowed, these fibers can reach the abdominal lining, where they can have a role in causing peritoneal mesothelioma. But most people exposed to asbestos, even in large amounts, do not get mesothelioma.

Radiation treatments for other cancers have been linked to mesothelioma in some studies. Radiation can damage the cells’ DNA, leading to out-of-control cell growth.