Doctors and researchers have discovered that almost every person diagnosed with mesothelioma was once exposed to asbestos fibers. Because the time of exposure to the time the cancer develops can be many decades, it is difficult to remember when that exposure to asbestos took place.
How Mesothelioma Occurs
Cancers like mesothelioma happen when the genetic blueprint (the DNA) inside the cells becomes changed so that the cells grow uncontrollably with no signal to stop dividing.
In normal cells, DNA signals when the cell is supposed to divide, how much it is to develop and grow, and when the cell dies. If the DNA is damaged, these signals do not happen and the cells continue to divide and grow even when they are not supposed to.
Cancers often happen in areas of inflammation. For example, when asbestos fibers are inhaled, they travel to the lining of the lungs (the pleura) and settle there. The pleura becomes inflamed for many years until some of the DNA in a cell becomes damaged and begins making cancer cells. If the asbestos fibers are swallowed, they can travel in the abdomen and settle on the areas of the abdomen that line the organs and the abdominal cavity. Inflammation occurs and can eventually lead to peritoneal mesothelioma.
Common Causes for Mesothelioma
Not everyone who is exposed to asbestos gets mesothelioma. Some people are at a greater risk than others. Risk factors for developing mesothelioma include:
- BAP1 Gene Mutation. People who already have DNA damage causing changes in the BAP1 gene are at a higher risk of getting mesothelioma if they are exposed to asbestos.
- Radiation. People who have had radiation therapy for other types of cancer can get inflammation from the radiation that later leads to mesothelioma. Radiation is known to cause changes in cells’ DNA structure.
- Infection with the SV40 Virus. No one knows how or why an infection with this type of virus leads to mesothelioma. Researchers have found that viruses can affect the DNA inside cells that can lead to different types of cancer. SV40 is a monkey-related virus that unfortunately contaminated up to 30 million injections of polio vaccinations given between 1955 and 1963, putting these people at a higher risk of mesothelioma without asbestos exposure.
- Length of time of asbestos exposure. People who have been exposed to a lot of asbestos or who have been exposed to asbestos for a long time are at a greater risk of getting mesothelioma.
- Family members of asbestos workers. When an asbestos worker comes home from work, asbestos fibers are usually still on their clothing. This provides a source of exposure for people who come in contact with contaminated clothing even though they had not been directly working with asbestos.
- Living in a community near an asbestos mine. Those who live near an asbestos mine will have increased amounts of asbestos in the air. They have a greater chance of inhaling or ingesting asbestos fibers because of their close proximity to asbestos near their homes.
- Living in an area where asbestos is in the drinking water. Certain parts of the world have asbestos from rocks that have gotten in contact with the drinking water supply so more asbestos is ingested from tap water.
- Working with asbestos on the job. The following areas of work have been known to put a person at a higher risk of having asbestos exposure: ship builders, automobile workers, railroad workers, insulation manufacturing jobs, factory workers, miners, insulation installers, plumbers, construction workers, gas mask manufacturing workers, naval yard workers, people engaged in older building remodeling, chemical plant workers, power plant workers, auto mechanics, boiler workers
- Exposure to Zeolites. Zeolites are a type of mineral related to asbestos chemically. For example, erionite is a mineral found in the dirt and rocks in certain parts of Turkey. People living in these areas can get mesothelioma without an exposure to asbestos.
- Receiving an injection of Thorium Dioxide. This was found in Thorotrast, which was a radioactive contrast dye used in X-ray procedures prior to the 1950s. It was found to be cancer-causing so its use was discontinued. Some people are still at risk of developing mesothelioma because of a decades-old exposure to Thorotrast.
- Increasing age. Exposure to asbestos never stops putting a person at risk for mesothelioma, even as they get older. About two-thirds of all people with mesothelioma are at least 65 years of age. This is partly because of the latency period of mesothelioma.
- Male gender. Mesothelioma happens to men much more than women. This is likely due to the fact that more men are exposed to asbestos in the workplace.
- Serving on military ships. Asbestos was used since World War II to insulate military ships. Veterans who served on these ships or worked in naval shipyards where these ships were built were unknowingly exposed to asbestos.
Where is Asbestos found?
Asbestos was once thought of as a harmless insulation material, used during and after World War II in thousands of different industrial and home applications. It is found in building insulation, in drywall, in the insulation used to protect electrical wiring, adhesives, glues, acoustic ceiling tiles, shingles, and cements. Most of the time, these products remain harmless, especially since they are often encased behind walls where the fibers can’t reach you.
When these older structures are remodeled or torn down, for example, the risk of asbestos inhalation increases. This possibility should be taken into account whenever dealing with the destruction or remodeling of homes built in the 1940s-1960s. Inadvertent exposure to asbestos can still occur if workers or homeowners are not aware that asbestos was used in the making of their home or business.
Environmental Asbestos Exposure
Asbestos is found naturally in rocks and soil. There are certain areas of the world where there is an increase in asbestos in the soil so that there is a higher chance of developing mesothelioma. Two such areas in the U.S. include El Dorado Hills, California and Libby, Montana. Libby was home to an asbestos-contaminated mine, which was declared a public health hazard in 2009.
There are no active asbestos mines currently in the U.S.; however, people who live where these mines were located are still at risk for asbestos exposure.