What’s the Primary Cause of Mesothelioma?

example of chrysotile asbestos ore, showing natural fibrous habit and greenish coloration.
A sample of chrysotile asbestos showing the mineral’s natural fibers.

Asbestos is the primary cause of mesothelioma cancer. It is the main factor for several asbestos-related illnesses. Many people diagnosed with mesothelioma experienced asbestos exposure from their jobs. Others received exposure while serving in the military. These occupations required handling asbestos products.

Mesothelioma incidence rates rose during the 20th century due to a lack of awareness. At the same time, industries expanded their use of asbestos. Cancer risk arises from six types of asbestos fibers. They can occur in nature or in certain products, such as talc.

How Does Asbestos Cause Mesothelioma?

Inhaling or swallowing asbestos traps it in the body. The fibers become stuck in mesothelial tissues. These sensitive tissues line and protect vital organs. Here, asbestos fibers create the inflammation, scarring and cell damage that cause mesothelioma.  

Diagram showing how asbestos develop
Asbestos damages mesothelial cells and mutates them into cancerous mesothelioma cells.

There is a dose-response relationship between asbestos and disease development. This means your risk of getting cancer increases with every exposure.

Mesothelioma can form in different parts of the body. Pleural mesothelioma develops when asbestos gets stuck in cells of the pleura. The pleura tissue lines and protects the outside of the lungs.

Fibers that travel to the abdomen can become stuck in the peritoneum. This tissue lines the abdominal cavity. Asbestos fibers here lead to the peritoneal form of this cancer.

In rarer cases, asbestos can travel to the heart and testes. This leads to the pericardial and testicular forms of this cancer.

Asbestos and Uncontrolled Cell Growth

Asbestos causes cell and DNA damage that leads to uncontrolled cell growth. Cells are small biological structures that make up every part of the human body.

DNA is the hereditary material in our cells passed down from our parents in our genes. DNA code tells our cells how to function. Asbestos fibers can damage this code.

Asbestos fibers become lodged in vital tissues and accumulate with repeated exposure. Over time, the fibers cause scarring and inflammation. This damages DNA and turns normal cells into cancer cells. Without DNA regulation, uncontrolled cell growth causes abnormal cell accumulation. These cells develop into mesothelioma tumors.

Asbestos fibers take an average of 20 to 60 years to turn healthy cells into cancer. This latency period makes diagnosis challenging until decades after exposure, when symptoms develop. By this point, cancer may begin to spread through the body.

Mesothelioma starts in mesothelial cells. These cells form protective membranes called mesothelium. The mesothelium tissue covers the lungs, abdomen and heart.

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Mesothelioma Causes vs. Risk Factors

A risk factor is anything that increases the odds of developing a disease. Most mesothelioma risk factors involve different sources of asbestos exposure. They may also include genetic factors, zeolite minerals and radiation. Another risk is the polio vaccine between 1955 and 1963. This contaminated vaccine bore simian virus 40 (SV40).

Diagram showing how asbestos develops into pleural and peritoneal mesothelioma
Diagram shows how pleural and peritoneal mesothelioma are caused.

More than 125 million people are at risk of occupational asbestos exposure. About 1.3 million workers in construction and general industry remain at risk of asbestos exposure in the U.S.

Primary Risk Factors for Mesothelioma:

  • Military asbestos exposure
  • Occupational asbestos exposure
  • Living with someone who worked with asbestos
  • Environmental asbestos exposure
  • DIY automotive and home renovation projects

Smoking often gets mistaken as a mesothelioma risk factor. Smoking cigarettes and asbestos exposure together elevate the risk of lung cancer. On its own, it does not increase the risk of developing mesothelioma.

Occupational Asbestos Exposure

Asbestos exposure arose from thousands of commercial, industrial and domestic products. Examples include drywall, insulation, piping, glues, tiles and cement.

About 8% to 13% of people who work with asbestos-containing products develop mesothelioma. The risk is highest for people who worked with the raw mineral.

Construction workers and firefighters face asbestos while working in old buildings. Exposure can happen during renovation, demolition or disaster response.

Veterans also cope with higher rates of cancer. The U.S. armed forces used asbestos in every branch of the military. Those who served in the Navy faced the highest risk of exposure. Asbestos helped reduce fires in ships.

Secondhand Exposure to Asbestos

Secondary exposure happens when asbestos fibers on someone’s body put others at risk. The fibers may travel home on asbestos workers’ clothing, tools, hair or skin. Others nearby may inhale or ingest these fibers. This exposure causes mesothelioma and related diseases.

Barbers and ceramics workers used talc contaminated with asbestos. Bringing these fibers home caused cancer in many of their family members.

Environmental Asbestos Exposure

Asbestos is a natural mineral. Living near large deposits in hilly or mountainous regions is environmental exposure. Minimal amounts of the mineral can fill the air in these regions. This exposure is most dangerous near former asbestos mines.

In June 2009, the U.S. Environmental Protection Agency declared a public health emergency in Libby, Montana. The hazard arose from a vermiculite mine in the town. Asbestos sources nearby contaminated the mine. The agency has since cleaned up the area. Despite the effort, thousands of residents suffer from asbestos-related diseases, including mesothelioma.

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Preventing Mesothelioma

Occupational asbestos exposure is the primary cause of mesothelioma. The best way to prevent mesothelioma is to follow workplace safety regulations. Protect yourself by learning more about asbestos at work and home.

Be cautious of old homes containing asbestos materials. Hire a professional asbestos abatement company. They can test and remove asbestos materials. If you or a loved one has a history of asbestos exposure, don’t wait for symptoms to arise to talk to your doctor. Early detection offers the best opportunity for effective mesothelioma treatment.

Common Questions About Mesothelioma Causes

Is asbestos the only cause of mesothelioma?

Approximately 80% of mesothelioma cases are caused by known exposure to asbestos. Studies have shown that radiation treatment for other cancers or certain genetic markers may increase the risk of developing mesothelioma. However, asbestos remains the only proven primary cause of the disease.

What is the relationship between mesothelioma and Simian virus 40 (SV40)?

In some studies, researchers have found human mesothelial cells to be uniquely susceptible to simian virus 40. They’ve suggested that the virus and asbestos may act as co-carcinogens.

SV40 has been detected in human tumors including mesothelioma tumors. Evidence for SV40 as a possible cause for mesothelioma is conflicting. 

Polio vaccines were made from rhesus monkey kidney cells, which can be infected with SV40. From 1955 to 1963, an estimated 10 to 30 million people in the U.S. were inadvertently exposed to SV40-contaminated polio vaccinations, but higher rates of cancer have not been reported in those who received the contaminated vaccines.

Who is at risk for mesothelioma?

Occupational asbestos exposure is the primary cause of mesothelioma. Construction workers, firefighters, industrial workers, power plant workers and shipyard workers have the greatest risk of asbestos exposure.

Families of blue-collar workers are at risk of secondary asbestos exposure and mesothelioma. People who worked with asbestos would often carry fibers home on their skin, hair, clothes and tools.

There is no safe amount of exposure to asbestos due to the size and shape of asbestos fibers. The risk of developing mesothelioma is greater with increased exposure to asbestos. Trace amounts of asbestos on clothes and skin are enough to cause mesothelioma by secondary exposure.

What should I do if I think I am developing mesothelioma?

If you are experiencing respiratory symptoms or other signs of mesothelioma and have a history of asbestos exposure, talk with your physician about being screened for the disease.

Mesothelioma doctors will order CT imaging scans and other tests based on your history of asbestos exposure to determine if you are developing mesothelioma.

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