NORAD Expression Is Associated with Adverse Prognosis in Esophageal Squamous Cell Carcinoma.

BACKGROUND: NORAD (non-coding RNA-activated by DNA damage) is a conserved, abundant, and broadly expressed long non-coding RNA, which functions to preserve genome stability. However, its prognostic significance in esophageal squamous cell carcinoma (ESCC) remains unclear.

MATERIAL AND METHODS: The expression of NORAD was detected by quantitative real-time polymerase chain reaction in pairs of tumorous and adjacent normal tissues derived from 106 ESCC patients. We analyzed the potential relationship between NORAD expression levels in tumor tissues and clinicopathological features of ESCC patients and clinical outcome.

RESULTS: The relative expression levels of NORAD were significantly upregulated in tumor tissues (p < 0.001) compared to adjacent normal tissues. In addition, high expression of NORAD was correlated with larger tumor size (p = 0.021) and T stage (p = 0.045). Kaplan-Meier analysis indicated that patients with high NORAD expression had poor overall and disease-free survival (p < 0.001). Moreover, multivariate analysis showed that increased expression of NORAD was an independent predictor of overall survival (p = 0.001).

CONCLUSION: Our data indicate that increased NORAD expression might serve as a novel molecular predictor of poor prognosis in ESCC patients and maybe a potential target for diagnosis and gene therapy.