Two potential biomarkers have been identified for the diagnosis of early malignant pleural mesothelioma (MPM) in a study that compared the differences in microRNA (miRNA) expression between MPM patients and past asbestos exposure (PAE) subjects.
The study, “Plasmatic extracellular vesicle microRNAs in malignant pleural mesothelioma and asbestos-exposed subjects suggest a 2-miRNA signature as potential biomarker of disease” was published in PlosOne.
By comparing the expression pattern of miRNAs of MPM patients to that of PAE subjects, the authors have distinguished two miRNAs with decreased expression levels in this type of cancer. Because both groups of participants had previously been exposed to asbestos, the changes in miRNA expression are more likely to be related only with the development of cancer.
Commonly used as biomarkers for other diseases, miRNAs are small portions of our genetic material, whose function is to regulate the expression of genes.
Once the expression of specific miRNAs is changed, the regulation of the expression of several genes becomes altered, causing stress to the cells and triggering inflammation.
The two miRNAs present in a lesser amount in MPM patients, miR-103a-3p and mi-R-30e-3p, are known to be involved in cancer development and progression. The targets of these miRNAs include several genes that are important for cancer development, which makes their deregulation a potential important step in the development of cancer in MPM patients.
The study assessed the blood of participants who had been in contact with asbestos. Of these participants, 23 had developed cancer (MPM patients) and 19 had not (PAE subjects).
Their blood samples were then processed to obtain specific miRNAs that were contained in vesicles that transport miRNAs to the exterior of the cells (extracellular vesicles – EVs).
The authors chose to study these enclosed miRNAs due to their increased stability and effective quantification, as well as for their functional meaning of promoting communication between the cells and their surrounding environment.
Once miRNA expression patterns had been obtained, the data was statistically tested and adjusted for age, sex, body mass index, and smoking status to ensure the accuracy, sensitivity and specificity of the results.
The team acknowledged some limitations in their study, including the small number of subjects, and the lack of patients with other thoracic diseases like lung cancer, pleural metastasis, or benign pleural effusion, a condition in which fluid builds up in the thin membranes surrounding the lungs.
Nonetheless, the findings suggest that a simple blood sample could be used to help diagnose MPM patients in the future.
“[O]ur findings suggest an EV-associated miRNA signature able to discriminate MPM from PAE subjects. This signature may be an important non-invasive biomarker for detection of MPM in the future,” they wrote.