Mesothelioma Causes

Mesothelioma is a highly aggressive cancer that is difficult to both diagnose and treat. Between 2,000 and 3,000 cases of malignant mesothelioma are diagnosed each year in America, and these figures are projected to increase throughout the next decade. A significant amount of research has been conducted on potential mesothelioma causes (also known as mesothelioma etiology) and scientific discoveries continue to help medical professionals further understand how this cancer develops.

What Causes Mesothelioma?

An overwhelming body of scientific and medical evidence has proven that the primary cause of malignant mesothelioma is exposure to asbestos. Approximately 80 percent of mesothelioma tumors are attributable to asbestos exposure.

Other risk factors that may cause malignant mesothelioma include:

• Radiation: Some mesothelioma patients with no traceable history of asbestos exposure do share a history of radiation exposure. Around 45 cases of mesothelioma following radiation therapy have been reported and discussed in medical literature.
• Nonasbestos Mineral Fibers: A few nonasbestos mineral fibers have been linked to malignant mesothelioma, such as erionite and taconite.
• Simian Virus 40: Originating in the rhesus monkey and contaminating millions of polio vaccines administered in the 1950s and ’60s, simian virus 40 has been linked to malignant mesothelioma and several other malignancies.

Additional risk factors that are not as well-researched in medical literature include chronic inflammation, chest injuries, genetics and organic chemicals. For further information on the other potential causes of mesothelioma, please see the Mesothelioma Etiology page.

It should be noted that cancer doctors and research scientists know that smoking does not cause mesothelioma, but it can aggravate other asbestos-related conditions (such as asbestosis) and compromises the body’s ability to fight the biological effects of asbestos fibers. Additionally, asbestos exposure and smoking has a synergistic affect that can increase a person's risk of developing lung cancer by as much as 84 times or more. For this reason, those who have been exposed to asbestos are highly advised not to smoke.

For those who would like to learn more, extensive information about mesothelioma and treatment options are available to patients and their family members by filling out this form or calling 800-615-2270 and speaking with an educated patient and family advocate.

How Asbestos Exposure Causes Mesothelioma

The exact method by which asbestos causes mesothelioma is still being researched, but medical professionals have a number of theories:

• Asbestos causes irritation and inflammation of mesothelial cells, which results in irreversible scarring, cellular damage, and eventually cancer.
• Asbestos fibers enter cells and disrupt the function of cellular structures that are essential for normal cell division, causing cellular changes that lead to cancer.
• Asbestos causes the production of free radicals. These molecules damage DNA, and cause cells to mutate and become cancerous.
• The presence of asbestos causes cells to produce oncoproteins. These molecules cause mesothelial cells to ignore normal cellular division restraints, and this can lead to the development of cancer.

The element that ties each theory together is the fact that asbestos results in cellular damage. This causes cells to lose control over normal cell cycles and results in uncontrollable division. Healthy cells follow cycles of cell division that ensure tissues do not grow and duplicate beyond normal conditions - in cancerous cells, these restraints are lost.

In cases of mesothelioma , the result of the cellular damage is that membranes in the affected location begin to thicken, and fluid builds up in the spaces between membrane layers. As cancer cells continue to divide and pile on top of one another, tumors begin to form. The uncontrolled division of cancer cells results in the impaired function of the body's organs and systems (primarily due to factors such as internal pressure caused by the growth of tumors, and the reduction of essential nutrients for organs), resulting in a number of symptoms.

For further information on available treatment options to reduce the severity of symptoms, please see the Mesothelioma Treatments page.

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Definition: Asbestos

Asbestos is a naturally-occurring fibrous mineral that was widely used in industrial, commercial and domestic products throughout the 20th century. Asbestos was touted for its durability, fire resistance and excellent insulating properties, and was used in several thousand different manufactured "asbestos products," including construction materials, household appliances and brake linings. Because asbestos use was so widespread, millions of Americans have been exposed to the toxic material, which has led to the development of malignant mesothelioma among thousands of Americans.

Definition: Mesothelioma

Mesothelioma develops in the linings of organs and body cavities, typically in the pleura, pericardium, or peritoneum. In very rare cases, mesothelioma may develop in the lining of the testicles, known as the tunica vaginalis. Internal organs and body cavities are covered by a thin tissue membrane called the mesothelium. This lining covers the thoracic cavity (where it is called the pleura), the heart sac (where it is known as the pericardium), and the abdominal cavity (where it is called the peritoneum). The mesothelium offers both support and protection for organs and body cavities and provides a source of lubrication that helps organ function and health.