Susceptibility to Mesothelioma

By Medical Discovery News

May 26, 2012

Susceptibility to Mesothelioma

Today a simple blood test can tell whether someone carries the genetic mutation for breast, colon, and possibly even lung cancer. This is possible because years of research have allowed scientists to identify genes responsible for tumor development.

Among the most recent discoveries is the genetic mutation behind mesothelioma, an aggressive cancer that forms in the lining of the chest and abdomen. About 3,000 people die of mesothelioma every year, nearly half within one year of diagnosis.

The main cause of this cancer is asbestos, a fibrous material that gets inhaled into the lungs. The National Institutes of Health estimate 11 million people were exposed to asbestos between 1940 and 1978, but symptoms typically don’t show up for 25 to 50 years, so the number of mesothelioma cases won’t peak until about 2020.

Yet for years scientists have been puzzled as to why only a small fraction of people exposed to asbestos develops mesothelioma. Scientists at the NIH may have just discovered the reason. They’ve identified a gene that, if mutated, predisposes people to mesothelioma and melanoma of the eye.

The study focused on two American families with a high incidence of mesothelioma and other cancers. Every family member who developed mesothelioma or melanoma of the eye had mutations in a gene called BAP1. In another 26 mesothelioma patients with no family history of cancer, a quarter of them also had BAP1 mutations.

Some of these same patients developed additional cancers such as breast, ovarian, pancreatic or renal cancers. This suggests BAP1 gene mutations may contribute to multiple types of cancer. Since the gene is responsible for repairing DNA damage and suppressing tumor activity, a mutation of BAP1 explains why those who carry it face higher cancer risks.

While some genetic mutations are inherited, the vast majority are likely due to random mutations in healthy cells. However, for cancer to actually develop, different genes that cause cells to grow out of control and spread must also accumulate mutations.

These random mutations can occur from exposure to carcinogenic substances such as asbestos, but another fibrous mineral called erionite can also cause cancer. The federal government recently issued a health warning to workers in gravel pits or on road projects in 12 western states where erionite has been used. Early studies indicate erionite is much more potent than asbestos when inhaled.

Since new tools have made DNA sequencing cheaper and easier, more scientists are now studying and identifying an increasing number of genetic mutations associated with cancer. And as more genetic testing becomes available, people who learn of their predisposition for cancer can avoid being exposed to erionite, asbestos, UV light, cigarette smoke, and other DNA damaging mechanisms.

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