MicroRNAs Regulate the Epithelial to Mesenchymal Transition (EMT) in Cancer Progression

MicroRNAs (miRNAs) are a class of small noncoding RNAs that regulate gene expression by targeting mRNAs and leading to either translation repression or RNA degradation. miRNAs have fundamental effects in the regulation of intracellular processes, and their importance during malignant transformation and metastasis is becoming increasingly well understood. The epithelial-mesenchymal transition (EMT), which reprograms tumor cells transcription, has been highlighted as a powerful process in tumor invasion, metastasis and tumorigenicity. In recent years, many studies have significantly enhanced our knowledge of EMT by the characterization of miRNAs that influence the signaling pathways and downstream events that define EMT on a molecular level. In this review, we detail the miRNAs and signal transduction pathways involved in the EMT process and demonstrate their importance in the study of cancer progression. We believe that this information will improve prognostication and reveal new opportunities for therapeutic intervention.