Circulating microRNAs in esophageal squamous cell carcinoma: association with locoregional staging and survival.

Locoregional staging and prognostic information play a critical role in esophageal squamous cell carcinoma (ESCC) treatment strategies. Although microRNA (miRNA) is a promising marker for cancer detection, the relationship between circulating plasma miRNAs and ESCC remains unclear. Our study aims to investigate the association between circulating plasma miRNAs and tumor diagnosis or prognosis in ESCC patients. Plasma levels of miR-16, miR-21, miR-22, miR-126, miR-148b, miR-185, miR-221, miR-223, and miR-375 were evaluated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assays from 38 ESCC patients prior to treatment and 19 healthy subjects. Differences in selected miRNAs and their diagnostic and prognostic value were examined. Levels of four of the selected miRNAs were found to be significantly higher in ESCC patients than in controls; namely, miR-16, miR-21, miR-185, and miR-375 (P < 0.050). In addition, the area under the receiver operating characteristic (ROC) curve (AUC) for miR-375 was 0.921 (95% confidence interval [CI] 0.817-0.976). Moreover, the expression levels of miR-16 were higher in patients with T3-4 tumors than in patients with T1-2 tumors (P = 0.020). Kaplan-Meier survival analysis showed that high expression levels of miR-16 and miR-21 in the plasma correlated significantly with shortened progression-free survival (PFS; P = 0.031 and P = 0.038, respectively) and overall survival (OS; P = 0.022 and P = 0.041, respectively) in ESCC patients. Four plasma miRNAs were identified that could potentially serve as novel diagnostic biomarkers for ESCC. Moreover, specific miRNAs, such as miR-16 and miR-21, can predict poor survival in ESCC.