Upregulated expression of serum exosomal hsa_circ_0026611 is associated with lymph node metastasis and poor prognosis of esophageal squamous cell carcinoma

Background: To identify the diagnostic and prognostic values of serum exosomal hsa_circ_0026611 in esophageal squamous cell carcinoma (ESCC). Methods: ESCC serum exosome global circRNA expression was detected using a circRNA microarray. The expression levels of candidate serum exosome circRNAs were detected by quantitative polymerase chain reaction (qRT-PCR). A receiver operating characteristic curve (ROC) was generated to confirm the diagnostic value. Survival data and their differences were observed by the Kaplan-Meier method and log-rank tests. The Cox regression analysis was employed to identify prognostic factors. Results: The expression levels of serum exosomal has_circ_0026611 in ESCC with lymph node metastasis were significantly higher than those in ESCC without lymph node metastasis (P =0.001). In addition, serum exosomal hsa_circ_0026611 expression could be used as a significant parameter to discriminate between non-lymph node-metastatic and lymph node-metastatic ESCC with an area under curve (AUC) of 0.724 (95% CI: 0.604~0.865). The multivariate Cox regression analysis indicated that survival was poor in patients with high serum exosomal hsa_circ_0026611 expression levels compared to those with low serum exosomal hsa_circ_0026611 levels (for OS, HR [95% CI]: 3.79 [1.27, 11.29], for DFS, HR [95% CI]: 2.77 [1.06, 7.22]). Conclusion: Serum exosomal hsa_circ_0026611 expression is significantly upregulated in ESCC with lymph node metastasis and is a predictor of ESCC prognosis.