How Does Asbestos Cause Mesothelioma?

Mesothelioma is a highly aggressive form of cancer that is difficult to diagnose and treat.About two to three thousand cases are diagnosed annually in the United States alone and account for about three percent of all diagnosed cancer cases.

The condition affects the mesothelial cells lining the covering of internal organs and body cavities.It is called pleural mesothelioma when it affects the lungs and chest cavity;pericardial mesothelioma when it involves the covering of the heart;peritoneal mesothelioma when it occurs in the peritoneum and testicular mesothelioma when the tunica vaginalis covering the testis is affected.  Mesothelioma is almost exclusively associated with inhalation or ingestion of asbestos fibers  and most victims come down with the disease after some ten to fifty years after exposure though it can progress more rapidly in a few cases.

The question to ask is:how does exposure to asbestos cause mesothelioma?The exact mechanism by which asbestos causes mesothelioma is still being researched into but four different theories have been advanced by medical professionals:

v  Asbstos fibers cause irritation and inflammation of the mesothelium leading to irreversible scarring,damage to cells and eventually cancer.

v  Asbestos fibers enter cells and disrupt the normal function of cellular structures that control cell division,causing changes that lead to cancer.

v  Asbestos causes the production of free radicals which damage the DNA,causing mutations which lead to the cells becoming cancerous.

v  Asbestos enters cells causing them to produce abnormal proteins called oncoproteins.These molecules are thought to cause mesothelial cells to ignore the normal restraint on cell division,thereby leading to uncontrolled cell division and ultimately cancer.

The underlining  factor common to the four theories is the fact that asbestos causes cellular damage which causes cells to lose control over the normal cycles of cell division causing them to divide uncontrollably.In health,cells follow cycles of division that ensure that tissues and organs do not grow beyond their normal sizes.In cancer cells however,all such natural restraints are lost.

In cases of mesothelioma,the membranes(mesothelium) in the affected region begin to thicken with fluid building up between the membrane spaces.As the cancer cells continue to divide and pile on top of one another,tumours begin to form.The uncontrolled division of the cancer cells and increase in the size of the tumours lead to impaired function of the organs and systems involved primarily from pressure caused by the tumours and inadequate nutrition of the normal cells.

Asbestos exposure is as at date the only proven cause of mesothelioma.However,researchers have shown that smoking can aggravate a less serious asbestos-related condition like asbestosis and prompt the formation of tumours and onset ofmesothelioma.Asbestos exposure and smoking have been shown to have a synergistic effect and can greatly increase the risk of developing lung cancer.It is therefore advised that individuals with history of asbestos exposure should abstain from smoking.They should also present themselves for regular screening checks by their doctors so that any histological changes can be detected on time for better management and increased chances of survival.