The role of microRNA in the pathogenesis of glial brain tumors.

Gliomas are the most common and fatal primary brain tumor in adults. Gliomas are highly invasive tumors with the highest mortality among all primary malignant brain tumors. Until now, the molecular mechanism that is responsible for glioma tumorigenesis and progression remains unclear. MicroRNAs (miRNAs) are short non-coding RNAs with 18-22 nucleotides in length which function as key regulators of various biological processes through negative control over gene expression at the post-transcriptional level. MiRNA dysregulation plays a key role in cancer oncogenesis, including the development and progression of gliomas. MiRNAs regulate a wide range of tumor processes including cell proliferation, differentiation, angiogenesis, invasion and apoptosis. In addition, microRNAs can be selectively packaged, secreted, and transported between cells in exosomes that are able to cross the blood-brain barrier (BBB) and are readily available in almost all types of human body fluids, making them promising biomarkers for gliomas. Increasing evidence has shown that miRNAs play an important role in glioma. For example, a large number studies indicated that this miRNA-21could affect on a variety of cellular and molecular pathways such as insulin-like growth factor (IGF)-binding protein-3 (IGFBP3), RECK, and TIMP3. Exosomal miR-21 may has key roles in gliomas pathogenesis. These findings indicated that miR-21 has critical roles in gliomas pathogenesis and could be used as diagnostic and therapeutic biomarkers for glioma patients. Profiling miRNAs expression in various human pathological conditions is a rapidly growing field, and it is likely that the knowledge gained from these studies regarding the genesis of gliomas will have the potential in the field of minimally invasive therapy with miRNA to improve the prognosis of patients with this pathology.