MicroRNA Biomarkers in Primary Brain Malignancies

Despite the concerted efforts within the management of brain malignancies over the past few decades, primary brain cancers remain an obscure challenge with unfavourable outcomes for the patients. Glioblastomas (GBM) and medulloblastomas afford the most prevalent brain tumours and account for markedly high mortality rates within affected patients. The unmet clinical requirements for an early diagnostic biomarker and effective treatment have shed light onto microRNAs (miRNAs). These are small, endogenous noncoding RNAs involved in a wide spectrum of biological processes, such as post-translational modification, tumorigenesis, angiogenesis, invasiveness, and apoptosis. Increased expression of miR-21 has been shown to have devastating effects upon patients with brain tumours, and it could be used as a diagnostic biomarker and an early relapse indicator. miRNAs such as miR-128a, miR-34a, miR-7 and miR-1253 have demonstrated tumour suppressive properties and could serve as putative therapeutic agents. MiRNA signatures, such as miR-21 and miR-10b could be incorporated as potential prognostic indicators for advanced and metastatic brain malignancies, whereas miR-221/222 cluster has a therapeutic potential to sensitise cancerous cells towards radiotherapy. Herein, we summarised current knowledge on how miRNAs with significant role in glioblastomas and medulloblastomas specifically can be effectively used as promising brain cancer diagnostics, prognostics, and therapeutics