MicroRNA blood test may help cement mesothelioma diagnosisCurrently, diagnosing malignant pleural mesothelioma (MPM) is rarely a simple process. It typically involves chest X-rays, CT scans, biopsies, fluid sampling and blood tests, the results from which are combined to get a complex (and occasionally confusing) picture of a patient's respiratory health.
By themselves, blood tests have never been used as the primary tool for diagnosing mesothelioma. Rather, they usually just confirm or contradict what appears on medical scans. However, all that may soon change, since scientists have shown that testing blood for tiny bits of genetic material - called microRNA - can spot MPM with more than 80 percent accuracy.
Bloodborne biomarkers aren't always reliable
The American Cancer Society states that bloodborne biomarkers for MPM are not terribly accurate. Currently, most blood screens test for the presence of either osteopontin or soluble mesothelin-related peptides, two forms of protein that appear in slightly elevated levels in patients with MPM. However, these levels are rarely significant enough to warrant an initial diagnosis based only on them.
Hence, blood tests are used post-diagnostically, usually to track the course of MPM once it has been established.
This may not be true for much longer, though. According to Australian researcher Michaela Kirschner of the group Asbestos Diseases Research, a new test developed by her team in Sydney may be able to detect mesothelioma quite accurately based on the microRNA found floating in a patient's blood.
Small bits of genetic matter point to big disease
Kirschner and her colleagues began their study by testing blood samples from eight patients, five of whom had MPM. The group found that between the two patient cohorts, those with mesothelioma had unusual microRNA levels in their blood.
MicroRNA is any short strand of free floating genetic material - usually around 22 base pairs long - that helps regulate a person's genes. The Australian team determined that MPM patients had four times the normal amount of one particular form of microRNA, called miR-625-3p, in their blood.
Could blood tests for miR-625-3p spot mesothelioma? The team tried as much, and it worked. Molecular tests for miR-625-3p spotted MPM with 82 percent accuracy. Such screens could reduce diagnostic ambiguity.
"This test would then represent a relatively simple way to circumvent the problems associated with obtaining a tissue biopsy," Kirschner explained. "For a patient, this would mean that appropriate treatment could be instituted at an earlier stage."
She and her team presented their full results at this year's European Lung Cancer Conference in Geneva, Switzerland.
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