Abstract
Long non-coding RNAs (lncRNAs) are transcripts longer than ~200 nucleotides with little or no protein-coding capacity. Growing evidence shows that lncRNAs present important function in development and are associated with many human diseases such as cancers, Alzheimer disease, and heart diseases. Transcribed ultraconserved region (T-UCR) transcripts are a novel class of lncRNAs transcribed from ultraconserved regions (UCRs). UCRs are absolutely conserved (100%) between the orthologous regions of the human, rat, and mouse genomes. The UCRs are frequently located at fragile sites and at genomic regions involved in cancers. Recent data suggest that T-UCRs are altered at the transcriptional level in human tumorigenesis and the aberrant T-UCRs expression profiles can be used to differentiate human cancer types. The profound understanding of T-UCRs can throw new light on the pathogenesis of human cancers.