Why Mesothelioma Strikes Only Some Asbestos Exposure Victims

Just about everyone stricken by mesothelioma was at some point in the past exposed to asbestos. But not everyone exposed to asbestos develops mesothelioma.

In fact, only about 10 percent of asbestos-exposure victims fall prey to mesothelioma. Scientists haven’t yet been able to satisfactorily explain why this is so.

Increasingly, though, they believe it’s because asbestos interacts with particular genes in such a way as to elevate the risk of mesothelioma for some asbestos-exposure victims and not others.

Writing in the online edition of the journal Carcinogenesis, one team of European researchers described their own progress in establishing the connection between asbestos exposure and the particular genes the mineral fibers need to interact with in order to set the stage for mesothelioma.

Mesothelioma Risk Shown Higher for Variant SNPs

The researchers started their report by describing the steps they took to conduct a gene-environment interaction analysis.

This analysis included asbestos exposure and 15 single nucleotide polymorphisms — or SNPs. A SNP is what genetic scientists call a DNA sequence that contains a barely noticeable change.

For example, say you have DNA molecule X containing a DNA sequence that looks like this in the majority of people: AAAAAAAA. Then you have the same DNA molecule X containing a DNA sequence that looks like this in only a few people: AAAAAATA.

Same DNA molecule, yet that minor variation may cause the molecule to perform differently from one group of people to the next.

The SNPs the mesothelioma researchers investigated were previously identified through a genome-wide association study on Italian subjects.

They also assessed gene-asbestos interaction risk using a variety of methods so as to ensure the reliability of their eventual findings.

Among the 15 SNPs examined by the researchers, they found that 10 of them contained DNA sequence variations significant enough to suggest a mesothelioma-risk connection.

Indeed, their analysis “suggested a possible synergistic effect between asbestos exposure and [SNPs] rs1508805, rs2501618, and rs5756444,” they wrote.

Earlier Mesothelioma Study Indicated Possible Genetic Component

The authors of this study were mainly based at research centers in the city of Turin, Italy — namely, the City of Health and Science Hospital, University of Turin, and the Human Genetics Foundation.

The remaining members of the author team came from the University of Genoa, Rome’s IRCCS San Raffaele Pisana, and the city of Novara’s University of Piemonte Orientale.

Several of the researchers participated in a 2013 study that laid the groundwork for this current investigation.

The aim of the 2013 study — published in April of that year in the online journal PLoS One — was to identify genetic risk factors that might contribute to the development of mesothelioma.

The researchers looked at 407 mesothelioma cases from Italy and compared them to 428 mesothelioma cases from Australia.

The genes were examined using a genome-wide association study that turned up 370,000 genotyped SNPs and 5-million imputed SNPs.

The genome-wide association study identified no single marker significant enough to cause anyone to shout “Eureka!” However, the process did uncover several interesting gene associations the researchers thought were interesting.

The researchers came away from the study convinced there must be a genetic component to mesothelioma. In addition to their study observations, they pointed to reports of familial clustering and candidate-gene association studies that also support this view.

The takeaway from the 2013 study was that asbestos fibers in the lung appear to exert a carcinogenic effect but may also interfere with the chromosome segregation and mitosis processes of healthy cells.