There is no consensus on the details regarding the exact mechanisms by which asbestos causes mesothelioma. There is, however, a general knowledge about the processes involved.
The lungs, heart, and some abdominal organs are each surrounded by a mesothelium. The one that surrounds the lungs is called the pleural mesothelium, the one that surrounds the abdominal organs is called the peritoneal mesothelium, and the one that surrounds the heart is called the pericardial mesothelium. It is these linings (but most commonly the pleural one) that are affected by mesothelioma.
How Asbestos Enters the Body
As asbestos crumbles, tiny asbestos fibers are released. The inhalation of these fibers is far and away the most common cause of mesothelioma. When asbestos fibers are inhaled, they can work their way through the smallest of the lungs’ passages and become imbedded in the pleural mesothelium.
What Happens Then?
The body’s natural reaction to asbestos fibers is to release a fluid intended to loosen the fibers so that they can be expelled by coughing. But the fibers are tenacious, and the body’s attempts to expel them are usually ineffective.
The area around the asbestos fibers becomes irritated and inflamed. The fluid continues to be secreted, and over time, it builds up in the pleural cavity - the space between the pleural mesothelium, and the lining around the chest cavity. These effects cause the typical mesothelioma symptoms, such as coughing, wheezing, shortness of breath, and chest pain.
What about the cancer?
It is not well understood how exactly asbestos triggers malignant cell production. We do know however, that the cancer is likely either caused by direct interaction with the asbestos fibers, or by prolonged exposure to toxins that may develop in the mesothelium in the presence of asbestos. Either way, the production of cytokines - substances that control various body processes - is induced, which triggers mesothelial cell production. It is this process that is altered by the above-mentioned toxins or the asbestos fibers themselves. This alteration results in the development of malignant cells.
What about peritoneal and pericardial mesothelioma?
No one is sure how these other more rare forms of mesothelioma are caused, though many suspect it is transported from the pleural mesothelium to the peritoneal mesothelium by the lymphatic system, or ingestion, and to the pericardial mesothelium by the lymphatic system, or proximity.
