Noncoding RNA activated by DNA damage (NORAD): Biologic function and mechanisms in human cancers.

Noncoding RNA activated by DNA damage (NORAD) is a newly identified long non-coding RNA (lncRNA) comprising one exon located on Chr20q11.23. NORAD is unique among lncRNAs because it is highly conserved, abundantly expressed, upregulated upon DNA damage, and maintains chromosomal stability in human cells. NORAD is dysregulated in different types of cancers and has been implicated in several processes correlated with carcinogenesis, such as cell proliferation, invasion, metastasis, and apoptosis. The mechanisms underlying the effects of NORAD are complex and involve multiple factors and signaling pathways. The biologic function and mechanisms of NORAD in human cancers are systematically reviewed here to provide new directions for future research.