The Role of Micro-RNAs in Cancer: Review

Micro RNAs (miRNA) are small, non-protein-coding RNA molecules. They have roles in growth, differentiation, proliferation and cell death by suppressing one or more target genes. miRNAs may be located in the introns and exons of protein-coding genes or in intergenic regions. More than 50% of miRNAs are found in cancer-associated;regions of the genome or in fragile sites; this suggests that miRNAs have important roles in the pathogenesis of neoplasias. Many experimental studies have shown that miRNAs may constitute a new class of oncogenes or tumor suppressor genes. miRNAs that may have roles in human cancers can be determined by detecting miRNAs that have different levels of expression in normal and pathologic tissues. Some miRNAs may undergo epigenetic regulation while others may target factors which directly or indirectly have a role in epigenetic mechanisms. The softwares used for the identification of miRNA targets are PicTar, Target-ScanS and miRanda. How the miRNAs bind to their targets and regulate gene expression at different stages should be determined to understand the functional importance of miRNAs and to establish their utility in diagnosis and treatment of diseases.