Feasibility of predicting the evolution of cerebral gliomas based on study of microRNA expression levels in blood plasma and saliva

The management of cerebral glioma (CG) remains challenging. Recently, methods based on the study of the expression levels of miRNAs in blood plasma have proven to be promising. The volume of tumor tissue is known to correlate with increased expression levels of microRNA-21 and -210. MicroRNA-15, -16, -34, -126 and -342 are involved in the regulation of tumor proliferative potential, and microRNA-128 is involved in the regulation of metabolic activity. The aim of the study was to evaluate the extended protocol for assessing the expression of microRNA-15, -16, -21, -34, -126, -128, -210, and -342 in the plasma and saliva of CG patients. Material and Methods. The study group consisted of 24 patients with supratentorial glioma (8 men and 16 women aged 41 to 71 years, mean age: 56 years). The control group consisted of 30 volunteers. MicroRNA expression was studied in plasma and saliva according to the StemLoop-RealTime protocol, using fluorescently labeled samples with small miRNA U6 as a reference gene. Statistical analysis was carried out using nonparametric methods. Results. The lack of CG stabilization and the most probable progression of the tumor with a poor prognosis was related to an increase in microRNA-21 and -210 expression levels and decrease in microRNA-128 expression and at least four of microRNA 15, -16, -34, -126, and -342. Stabilization of CG with a high probability of progression was associated with an increase in microRNA-21 or microRNA-210 expression levels, decrease in no more than three of microRNA-15, -16, -34, -126, -342 expression levels as well as decrease in microRNA-128 expression. Stabilization of the tumor with a low probability ofprogression was associated with a decrease in the expression of microRNA-21 and -210 and in no more than one of miRNA-15, -16, -34, -126, -342 below the reference level, with a simultaneous increase in miRNA-128 expression. Conclusion. The determination of microRNA expression in blood plasma and saliva can be one of the important criteria for assessing the prognosis of CG.