Abstract: Objective To investigate the difference in the expression of long non-coding RNA NORAD(LncRNA NORAD) and microRNA-199a-3p(miR-199a-3p) in the serum of patients with esophageal squamous cell carcinoma and healthy people,and analyze their diagnostic value for esophageal squamous cell carcinoma. Methods A total of 286 patients with esophageal squamous cell carcinoma admitted to our hospital from January 2018 to December 22 were included in the esophageal squamous cell carcinoma group,the clinicopathological characteristics were recorded,in the same period,204 healthy people excluding esophageal squamous cell carcinoma and other systemic diseases were included as the healthy control group.The expression levels of serum LncRNA NORAD and miR-199a-3p were detected by real-time fluorescence quantitative PCR(qRT-PCR);Pearson correlation was applied to analyze the correlation between serum LncRNA NORAD and miR-199a-3p expression levels;the diagnostic value of serum LncRNA NORAD and miR-199a-3p expression levels in esophageal squamous cell carcinoma was analyzed by the ROC curve. Results The expression level of serum LncRNA NORAD in esophageal squamous cell carcinoma group was higher than that in healthy control group,the expression level of miR-199a-3p was obviously lower than that in the healthy control group(P<0.05).There was a negative correlation between serum LncRNA NORAD and miR-199a-3p expression in patients with esophageal squamous cell carcinoma(r=-0.649,P<0.05).The proportions of high expression of LncRNA NORAD and low expression of miR-199a-3p in patients with lymph node metastasis,TNM stage T3+T4 and poorly differentiated esophageal squamous cell carcinoma were higher than those in patients with no lymph node metastasis,TNM stage T1+T2 and moderately/highly differentiated esophageal squamous cell carcinoma,with statistically obvious difference(P<0.05).The AUC of LncRNA NORAD and miR-199a-3p in the diagnosis of esophageal squamous cell carcinoma was 0.817,0.796 and 0.854,respectively. Conclusion The serum level of LncRNA NORAD is high and miR-199a-3p is low in patients with esophageal squamous cell carcinoma.LncRNA NORAD and miR-199a-3p can both be used as an auxiliary diagnostic index for esophageal squamous cell carcinoma.

Key words: esophageal squamous cell carcinoma, serum, long non-coding RNA NORAD, micro RNA-199a-3p