TOWARDS SEARCH FOR GLIOBLASTOMA MULTIFORME BIOMARKERS: MIRNA IN FOCUS

Abstract

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor characterized by poor prognosis and limited tools for diagnostics. This study evaluates the diagnostic potential of circulating microRNAs in GBM through a meta-analysis and experimental validation using real time quantitative PCR. The meta-analysis demonstrated strong diagnostic accuracy of circulating miRNAs with Summary Receiver Operator Characteristic curve showing an Area Under the Curve value of 0.93. However, high heterogeneity across studies prompted meta-regression analysis that demonstrated statistically significant differences by region, method of detection, expression mode, miRNA profile, sample type and sample size. Fagan’s nomogram has shown that a positive miRNA test raised the probability of GBM diagnosis to 90%, while a negative result reduced it to 19%. In the experimental part, miR-221 and miR-222 were selected based on their substantial upregulation in GBM. Stem-loop reverse transcription and qPCR have shown statistically significant dCt differences for miR-221, but not for miR-222 that has shown high Ct values and unreliable amplification. Similar Ct values in cDNA and No Reverse Transcriptase controls indicated possible non-specific binding or primer carryover from reverse transcription reaction to qPCR. These findings highlight the potential of circulating miRNAs as diagnostic biomarkers for GBM. However, technical challenges in RT-qPCR and methodological variability highlight the need for standardized protocols, improved primer design, and need for neutral internal reference. With further optimization, miRNA-based liquid biopsies may enhance early detection and personalized GBM diagnostics.