Expanded understanding of the genome’s normal function has led to recognition that large portions of it are transcriptionally active, and that perhaps a minority of transcribed RNA is translated into protein.20 Most non-translated RNAs fall into a diversity of families that vary by length, stranded-ness (double versus single), and function.21 Developing an understanding of the abundance and diversity of such RNAs remains an area of active investigation, but these RNA species are clearly important contributors to genome regulation. RNA molecules are also increasingly recognized as having roles in a variety of disease processes, including cancers. 22 For example, small non-coding RNA molecules known as microRNA’s have been shown to have an active role in the pathogenesis of Ewing’s sarcoma and may eventually provide both therapeutic targets and prognostic biomarkers for this condition.23
