Serum miRNA expression in patients with esophageal squamous cell carcinoma

The aim of the present study was to investigate the feasibility and value of serum microRNAs (miRNAs/miRs) as biological markers for the prediction of the behavior and prognosis of esophageal squamous cell cancer (ESCC). The differential expression of serum miRNA was detected by an miRNA microarray of 9 patients with ESCC and 9 healthy volunteers. The result of the miRNA microarray was validated in serum samples of 69 patients with ESCC and 14 healthy volunteers by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The association between serum miRNA expression and tumor-node-metastasis (TNM) stage was analyzed. A total of 10 serum-specific miRNAs were identified from the patients with ESCC. Through PCR verification, the expression levels of miR-129, miR-451 and miR-365 were consistent with the microarray results validated by RT-qPCR, and the difference was statistically significant compared with the healthy volunteers (P=0.007, P=0.007 and P<0.001, respectively). Multivariate logistic regression analysis showed that miR-365 could serve as potential diagnostic marker for ESCC; the area under the receiver operating characteristic curve was 0.831, with a sensitivity of 80.56% and a specificity of 86.7%, but its expression did not differ significantly among the different TNM stages (stage I-II vs. III, P=0.052; stage III vs. IV, P=0.069). The expression level of miRNA-129 differed significantly among the different stages (stage I-II vs. III, P=0.002; stage III vs. IV, P=0.042), while the expression level of miR-451 did not differ significantly between stage III and IV (P=0.308). In conclusion, serum microRNAs are novel biomarkers for ESCC, and miRNA-365 and miRNA-129 can be used for the early prediction of cancer and the prediction of clinical stage, respectively.