Oncogenic role of microRNAs in brain tumors.

MicroRNAs (miRNAs) are short non-protein-coding RNAs that function as key regulators of diverse biological processes through negative control on gene expression at the post-transcriptional level. Emerging evidence indicates that miRNAs play an important role in the development of human cancers, with their deregulation resulting in altered activity of downstream tumor suppressors, oncogenes and other signaling molecules. Recent years have seen considerable progress in miRNA research in brain tumors, particularly in glioblastomas and medulloblastomas, providing novel insights into the pathogenesis of these malignant lesions. Expression profiling has unveiled miRNA signatures that not only distinguish brain tumors from normal tissues, but can also differentiate histotypes or molecular subtypes with altered genetic pathways. Moreover, specific miRNA subsets may have potential diagnostic and prognostic values in some brain tumors. Several deregulated miRNAs uncovered in glioblastomas and medulloblastomas have their gene targets and the associated genetic pathways identified. This review summarizes recent findings of miRNA study in brain tumors.