A small RNA molecule called miR-132-3p was found to be downregulated in blood samples of mesothelioma patients. In combination with other biomarkers, this microRNA could improve the early detection and outcome of mesothelioma.
The study with the findings, “Circulating miR-132-3p as a Candidate Diagnostic Biomarker for Malignant Mesothelioma,” was recently published in Disease Markers.
microRNAs, or miRNAs, are small molecules of RNA that do not code for any protein, but have an essential role regulating the expression of proteins and maintaining their balance.
Abnormal levels of miRNAs are often associated with diseased cells, and many studies have demonstrated that miRNAs can be used as biomarkers for several diseases, including mesothelioma. Detecting miRNAs circulating in the blood can help diagnosing diseases without the use of aggressive and invasive tissue collection protocols.
To identify miRNAs that could be used to diagnose malignant mesothelioma, researchers at the Institute of Prevention and Occupational Medicine, in Germany, evaluated the levels of 377 microRNAs in blood samples collected from 21 mesothelioma patients and 21 asbestos-exposed controls.
They identified 15 candidate miRNAs that were differently expressed between mesothelioma patients and cancer-free control subjects.
But further analysis of these 15 candidate miRNAs in a second cohort, which included 22 mesothelioma patients and 44 asbestos-exposed controls, only confirmed the previous results for one miRNA.
Known as miR-132-3p, the miRNA was found at significantly lower levels in mesothelioma patients compared to cancer-free controls. Additionally, miR-132-3p expression levels were not affecting by degradation of the blood samples, suggesting that this is a robust and stable biomarker candidate to be measured in the blood of suspected mesothelioma patients.
A detailed analysis showed that miR-132-3p had a sensitivity of 86 percent and specificity of 61 percent to identify mesothelioma cases. This meant that it could identify 86 out of 100 mesothelioma patients, and 61 out of 100 subjects who did not have the disease.
Based on these results, miR-132-3p did not have the desired diagnostic performance. But in combination with another miRNA known to be a biomarker for mesothelioma, miR-126, the researchers reported an improved specificity of 86 percent. Still, biomarkers in cancer should have a specificity of at least 95 percent to avoid false positives.
The authors, however, consider that miR-132-3p, in combination with other microRNAs or proteins, could be a potential biomarker for mesothelioma and improve early diagnosis of the disease.
“To evaluate the use of the miR-132-3p/miR-126 combination for the detection of malignant mesothelioma at early stages, studies with a prospective design are urgently needed,” the researchers wrote.