New evidence of lncRNA role in tumor progression and metastasis

Intensive studies about non-coding RNAs (ncRNAs) in past decade show that ncRNAs are involved in many biological processes including development, differentiation and metabolism. ncRNAs are classified into small ncRNAs and long ncRNAs (lncRNAs). Small ncRNAs including siRNAs, piRNAs and miRNAs play roles in transcriptional gene silencing. Although the definition is crude, lncRNAs are defined as transcribed RNA molecules that are longer than 200 nucleotides (1,2). After the first recognition of lncRNA as having a transcriptional function in mouse by Okazaki et al., there have been increasing numbers of articles regarding the roles and function of lncRNA in chromatin modification, transcriptional regulation post-transcriptional regulation, and human diseases (2-4). However much is still unknown regarding the functions of lncRNA in human diseases including cancer.