RESUMEN
<p><b>OBJECTIVE</b>This article aims to review recent studies on the biological characteristics of long non-coding RNAs (lncRNAs), transcription regulation by lncRNAs, and the results of recent studies on the mechanism of action of lncRNAs in tumor development.</p><p><b>DATA SOURCES</b>The data cited in this review were mainly obtained from the articles listed in PubMed and HighWire that were published from January 2002 to June 2010. The search terms were "long non-coding RNA", "gene regulation", and "tumor".</p><p><b>STUDY SELECTION</b>The mechanism of lncRNAs in gene expression regulation, and tumors concerned with lncRNAs and the role of lncRNAs in oncogenesis.</p><p><b>RESULTS</b>lncRNAs play an important role in transcription regulation by controlling chromatin remodeling, transcriptional control, and post-transcriptional controlling. lncRNAs are involved in many kinds of tumors and play key roles as both suppressing and promoting factors.</p><p><b>CONCLUSION</b>lncRNAs could perfectly regulate the balance of gene expression system and play important roles in oncogenic cellular transformation.</p>