Circ-SLC7A5, a potential prognostic circulating biomarker for detection of ESCC.

Circular RNAs (circRNAs), resulting from the non-canonical splicing of linear pre-mRNAs, have permanently altered our perspectives toward cancer recently, especially in carcinogenesis and cancer progression. However, the roles of circRNAs in esophageal squamous cell carcinoma (ESCC) remain largely unknown. In the current study, circRNAs expression profiles are screened in ESCC, using plasma samples from 10 ESCC patients, including different TNM stages and 5 normal controls. Characteristics of circRNAs including length, types, and the possibility of binding to proteins are analyzed. Candidate tumor-related circRNAs are then quantitated in ESCC tissues, plasmas and cell lines. ESCC tissues can secret circRNAs into plasma and patients with high plasma circ-SLC7A5 are associated with high TNM stage, tending to have shorter overall survival than those with high levels. In addition, the biological characteristics of circ-SLC7A5 including location, miRNAs binding, m6A modification were analyzed. Our study reveals a novel prognosis biomarker of circ-SLC7A5, providing a preliminary landscape of circRNA expression for detection of ESCC.