Circulating plasma microRNAs in the detection of esophageal squamous cell carcinoma

Circulating microRNAs (miRNAs/miRs) have been reported as diagnostic biomarkers for esophageal cancer (EC) diagnosis. However, contrasting results have been achieved in different studies. In the present study, a meta-analysis was performed, based on the systematic search of PubMed and Web of Science, to evaluate the diagnostic value of circulating miRNAs in the peripheral blood in EC. The top 5 most-studied miRNAs were selected for confirmation by reverse transcription quantitative-polymerase chain reaction using the blood plasma of 125 patients with esophageal squamous cell carcinoma (ESCC) and 125 healthy individuals from Henan, China. A total of 45 studies from 22 articles, regarding 33 miRNAs were considered in the meta-analysis. The pooled sensitivity and specificity were both 0.79 (95% confidence interval, 0.76-0.82 for both). Among the 5 miRNAs considered (miR-21, miR-223, miR-375, miR-25 and miR-100), miR-21 and miR-223 were significantly overexpressed whereas miR-375 expression was reduced in patients with ESCC compared with healthy individuals (all P<0.001). The areas under the curves (AUCs) were 0.80, 0.73, and 0.69 for miR-21, miR-223, and miR-375, respectively. The AUCs increased when discriminating between patients with early ESCC in stage 0-I and the non-invasive carcinoma stage Tis-T1 stage from controls. Thus, it was concluded that plasma miR-21, miR-223 and miR-375 may serve as non-invasive diagnostic biomarkers in patients with ESCC, especially early ESCC in stages 0-I and Tis-T1.