Unique MicroRNA signature and clinical outcome of cancers.

MicroRNAs (miRNAs) are endogenous small non-protein-coding RNAs (18-25 nucleotides) that conduct the post-transcriptional repression of hundreds of their target proteins. They regulate many kinds of basic cellular processes including proliferation, differentiation, stress response, and cell death. Recent evidence has shown that deregulation of miRNAs correlates with certain features of diverse cancers (such as tumorigenesis, differentiation status, and outcome of tumor patients), and indicates that miRNAs can act as oncogenes or tumor suppressors. Here, we summarize these recent studies and provide a new perspective on understanding the role of miRNAs in initiation and progression of cancers. We also discuss the future applications of miRNAs in diagnostic and prognostic implications of cancers.