(Ivanhoe Newswire) – People who carry a mutation in a gene called BAP1 are susceptible to developing two forms of cancer- mesothelioma and melanoma of the eye. In addition, when these individuals are exposed to asbestos or similar mineral fibers their risk of developing mesothelioma, an aggressive cancer of the lining of the chest and abdomen, may be substantially increased.

The study describes two U.S. families with a high incidence of mesothelioma, as well as other cancers, associated with mutations of the BAP1 gene. Mesothelioma tumors are typically associated with asbestos and erionite exposure. Erionite, a naturally occurring mineral fiber similar to asbestos, is found in rock formations and volcanic ash. Deposits have been located in at least 12 states.

Only a small fraction of individuals exposed to erionite or asbestos actually develop mesothelioma, one of the deadliest forms of cancer that kills about 3,000 people each year in the United States, with half of those diagnosed dying within one year.

"This discovery is a first step in understanding the role of the BAP1 gene and its potential utility when screening for mutations in those at high risk," Michele Carbone, M.D., Ph.D., study co-leader and director of the University of Hawaii Cancer Center, was quoted as saying. "Identifying people at greatest risk for developing mesothelioma, especially those exposed to dangerous levels of asbestos and erionite worldwide, is a task made easier by virtue of this discovery."

Joseph R. Testa, Ph.D., study co-leader and Carol and Kenneth E. Weg chair in Human Genetics at Fox Chase Cancer Center, was quoted as saying, "This is the first study to demonstrate that individual genetic makeup can greatly influence susceptibility to mesothelioma. People exposed to dangerous levels of asbestos or erionite, those with a strong family history of mesothelioma, or those who have been previously diagnosed with a rare tumor of the eye known as uveal melanoma, may benefit from this new discovery."

The study found evidence that some people with BAP1 gene mutations also developed breast, ovarian, pancreatic or renal cancers, suggesting the gene mutation may be involved in multiple cancer types.

The researchers first suspected that mutations in the BAP1 gene might underlie mesothelioma in people with a strong family history of the disease after noticing genetic changes in or near other stretches of DNA where the BAP1 gene is located. Looking more closely at two families with unusually high rates of mesothelioma, they saw that every person who had provided a sample and had developed mesothelioma or melanoma of the eye also carried mutations in the BAP1 gene. Further investigation led to sequencing the gene in 26 individuals who had developed mesothelioma but did not have a family history of the disease. Tumors from about 25 percent of this group carried mutations in the BAP1 gene, and in two cases the mutations were inherited. Both of the individuals with inherited mutations had previously developed melanoma of the eye.

SOURCE: Nature Genetics, published online August 28, 2011