Noncoding RNAs: Identification of Cancer-Associated MicroRNAs

Abstract

Naturally occurring microRNAs (miRNAs) are small noncoding RNAs 19–24 nucleotides (nt) long, typically cleaved from 60- to 110-nt hairpin precursors (pre-miRNAs) that are produced from large precursors (pri-miRNAs) and are encoded in the genomes of invertebrates, vertebrates, and plants. miRNAs act as regulators of gene expression during development and differentiation at the transcriptional, posttranscriptional, and/or translational level, although most target genes have yet to be identified. Many miRNAs are conserved in sequence between distantly related organisms, suggesting that these molecules participate in essential processes. In this chapter, we present principles related to the basic and translational research that has emerged in the last decade, a period that can be truly considered the “miRNA revolution” in molecular oncology. Furthermore, we present a compendium of information about the main miRNAs that have been identified in the last several years as playing important roles in cancer. Also, we alert the reader to several additional reviews that may provide a deeper understanding of this new and exciting field of research.