Serum microRNA-193b as a promising biomarker for prediction of chemoradiation sensitivity in esophageal squamous cell carcinoma patients

Esophageal squamous cell carcinoma (ESCC) is the most predominantly occurring type of esophageal cancer worldwide. Locally advanced ESCC patients are treated by neoadjuvant chemoradiation for tumor downstaging prior to tumor resection. Patients receiving this treatment have an increased expectation of cure via the following tumor resection and have better survival outcomes. However, not all patients respond well to chemoradiation and poor responders suffer from treatment-associated toxicity and complications without benefits. No method is currently available to predict patient chemoradiation response and to exclude poor responders from ineffective treatment. To address this clinical limitation, the present study aimed to identify non-invasive biomarkers for predicting patient chemoradiation response. Due to the features of microRNA (miRNA) in cancer diagnosis, prognosis and treatment response prediction, serum miRNA arrays were performed to identify potential miRNA(s) that may be used for chemoradiation response prediction in ESCC. Using an miRNA array to compare pre-treatment serum sample pools from 10 good responders and 10 poor responders, the present study identified miR-193b, miR-942 and miR-629* as candidate miRNAs for predicting chemoradiation response. Subsequent validation using reverse transcription-quantitative polymerase chain reaction confirmed that miR-193b, however not miR-942 and miR-629*, were significantly increased in sera from 24 good responders, compared with 23 poor responders. Further analyses using the receiver operating characteristic curve revealed a strong predictive power of serum miR-193b on discriminating good responders from poor responders to chemoradiation. In addition, a high serum level of miR-193b was significantly associated with better survival outcomes. Therefore, serum miR-193b may be considered a promising biomarker for predicting chemoradiation response and post-therapy survival of ESCC patients.