Abstract: Objective To investigate the expression levels and clinical significance of serum long chain non coding RNA cancer susceptibility candidate 11(lncRNA CASC11) and Testis-associated highly-conserved oncogenic long non-coding RNA(lncRNA THOR) in esophageal cancer patients.Methods Esophageal cancer patients diagnosed in our hospital from January 2017 to January 2021 were selected as the observation group(n=129),and healthy individuals who underwent physical examination in our hospital(n=129) were as the control group.Serum lncRNA CASC11 and lncRNA THOR expression levels were detected by RT-qPCR;the 3-year survival rate was analyzed by Kaplan-Meier method;and the diagnostic value was analyzed by ROC curve.Results The expression levels of serum lncRNA CASC11(1.48±0.35 vs 1.01±0.20) and lncRNA THOR(1.54±0.28 vs 1.11±0.15) in the observation group were obviously higher than those in the control group(P＜0.05).The proportions of high expression of serum lncRNA CASC11 and lncRNA THOR in patients with infiltration depth of T3~T4,tumor diameter>4cm,TNM staging of Ⅲ-Ⅳ,and lymph node metastasis were obviously higher than those in patients with infiltration depth T1~T2,tumor diameter ≤ 4cm,TNM staging Ⅰ-Ⅱ,and no lymph node metastasis(P＜0.05).After 3-year of follow-up,52 out of 129 esophageal cancer patients died and 77 survived.The 3-year survival rate of patients with high expression of lncRNA CASC11(32.20% vs 82.86%) and lncRNA THOR(36.07% vs 80.88%) was obviously lower than that of patients with low expression of lncRNA CASC11 and lncRNA THOR(P＜0.05).The area under the curve(AUC) of serum lncRNA CASC11 and lncRNA THOR levels for diagnosing esophageal cancer was 0.888 and 0.914,respectively,with cutoff value of 1.29 and 1.32.The AUC of the combined diagnosis of the two was 0.946,and the combined diagnosis of the two was superior to their individual diagnosis(Z_{combination-lncRNA CASC11}=2.410,Z_{combination-lncRNA THOR}=2.167,P=0.010,0.040).Conclusion The serum levels of lncRNA CASC11 and lncRNA THOR in patients with esophageal cancer are upregulated,they are obviously associated with the 3-year survival rate of patients,and the combination of the two has higher efficacy in the diagnosis of esophageal cancer.

Key words: esophageal cancer;survival rate;long chain non coding RNA cancer susceptibility candidate 11;testis-associated highly-conserved oncogenic long non-coding RNA