BLM Gene Mutation Increases Mesothelioma Risk, Study Finds

New research suggests an inherited mutation on the BLM gene increases susceptibility to deadly malignant mesothelioma.

The research comes from the University of Hawaii, one of the world’s top locations for mesothelioma research. 

Researcher Michele Carbone and his team sequenced the DNA of 155 mesothelioma patients. They found that people who are missing one BLM gene are much more likely to contract mesothelioma – especially if they are exposed to asbestos. 

If people know they have the BLM gene mutation, they could potentially cut their risk for mesothelioma by being especially mindful of asbestos exposure. 

Genetic Susceptibility to Mesothelioma

Asbestos exposure is the primary cause of malignant mesothelioma. Some people who live or work around asbestos develop mesothelioma years later. But scientists are still trying to understand why some asbestos-exposed people get cancer and others do not. 

They know that genetics plays an important role. Dr. Carbone previously discovered that a mutation on the BAP1 gene increases the risk of getting mesothelioma and several other cancers. According to the University of Hawaii, this “led to the investigation of other genetic mutations with similar functions—including those of the BLM gene.”

People who have two mutated BLM genes (from both mother and father) develop a condition called Bloom Syndrome. It is much more common to have only one mutated BLM gene. About one in 900 people has this mutation. People with this mutation are unlikely to know it unless they are tested. 

Asbestos exposure is dangerous for anyone, but it could be especially deadly for these people. 

Testing for the BLM Gene Mutation

Having too little of the protein encoded by the BLM gene may promote mesothelioma in several ways. It appears to trigger inflammation. It causes “genetic instability”. And it keeps mesothelioma cells from dying like normal cells do.  

Researchers used mice with the BLM genetic mutation to test its role in mesothelioma.  

“Blm+/− mice exposed to asbestos had a significantly shorter survival and higher incidence of mesothelioma compared to controls,” the researchers write in Proceedings of the National Academy of Sciences. 

Lab tests on mutated human cells showed the same thing. Next, researchers sequenced the DNA of 155 mesothelioma patients.  Thirty-three of the patients had multiple mesothelioma cases in their families. 

Two of the 33 familial cases of mesothelioma had the BLM genetic mutation. Some of their relatives with a mutated BLM gene also developed mesothelioma. None of their relatives with a non-mutated BLM gene were affected. 

Among the 122 non-familial mesothelioma cases, five people also had the mutation.

“Therefore, 7 of 155 apparently unrelated mesothelioma patients carried BLM+/− mutations, significantly higher than the expected frequency in a general, unrelated population from the gnomAD database,” write the researchers. 

The NIH has awarded a grant to Dr. Carbone to continue researching the BLM gene. 

Sources:

Bononi, A, et al, “Heterozygous germline BLM mutations increase susceptibility to asbestos and mesothelioma”, December 14, 2020, Proceedings of the National Academy of Sciences, https://www.pnas.org/content/early/2020/12/09/2019652117

“Genetic mutation increases one’s susceptibility to mesothelioma”, December 17, 2020, University of Hawaii website, https://www.hawaii.edu/news/2020/12/17/gene-susceptibility-mesothelioma/