MicroRNAs in the Pathogenesis of Cancer

MicroRNAs (miRs) are small (19–25 nucleotides) non–protein-coding RNAs involved in development, differentiation, and aging; they act by inducing messenger RNA (mRNA) silencing through degradation, and post-transcriptional or decoy activity. miR profiles of human solid and hematologic malignancies have highlighted their potential value as tumor markers in cancer patient management. Different experimental lines of evidence have confirmed that deregulation of miRs not only results as consequence of cancer progression but also directly promotes tumor initiation and progression in a cause–effect manner. These findings reveal a potential and appealing role for miRs as cancer therapeutic targets. This review focuses on the causes and consequences of miR deregulation in carcinogenesis and tumor progression. The work aims at providing the molecular bases for the understanding of the potential role of miRs in the translational and clinical setting.