Clinical evaluation of 4 types of microRNA in serum as biomarkers of esophageal squamous cell carcinoma.

To the best of our knowledge, there is currently no specific biomarker for esophageal cancer used in clinical practice. However, studies consider that microRNAs (miRNAs/miRs) could have useful implications in clinical practice. The present study aimed to investigate the feasibility of using serum microRNAs as biomarkers for esophageal squamous cell carcinoma (ESCC). Using reverse transcription-quantitative polymerase chain reaction, the expression levels of serum miR-21, miR-25, miR-145 and miR-203 were detected in 31 untreated patients with ESCC (EC-UT), 35 inactive period patients with ESCC following treatment (EC-T), 33 patients with esophageal benign disease (benign) and 32 healthy donors (healthy). Furthermore, the ability of these microRNAs to function as biomarkers of ESCC alone and in combination were investigated. The expression levels of serum miR-21, miR-25 and miR-145 in EC-UT were significantly higher than in the other groups (P<0.001). High sensitivity and specificity were shown when miRNAs were used as biomarkers for ESCC, particularly miR-21 and the combination of miR-21 with miR-145. Comparing EC-UT with healthy, benign and EC-T groups, and a combined group (3 groups set as 1 negative control), the sensitivity and specificity of miR-21 were 71.0 and 96.9, 74.2 and 87.9, 77.4 and 82.9, and 74.2 and 88.0%, respectively. The combined sensitivity and specificity of miR-21 and miR-145 were 71.0 and 96.9, 90.9 and 72.7, 97.1 and 82.9, and 80.6 and 80.0%, respectively. In conclusion, 3 types of miRNA (miR-21, miR-25 and miR-145) in serum could serve as potential biomarkers for ESCC. Furthermore, the expression level of miR-145 in serum was upregulated, compared with the downregulation reported in previous studies in ESCC tissues and cells.