Circulating miR-200c levels significantly predict response to chemotherapy and prognosis of patients undergoing neoadjuvant chemotherapy for esophageal cancer

Background. There is increasing evidence that microRNA expression in cancer tissue is useful for predicting the prognosis of patients with cancer. However, the relationship between the levels of circulating microRNAs and response to chemotherapy and prognosis remains unclear in esophageal cancer. Methods. We measured the serum levels of miR-21, miR- 145, miR-200c, and let-7c by quantitative RT-PCR in 64 patients with esophageal cancer who underwent neoadjuvant chemotherapy. Results. The serum levels of miR-21, miR-145, miR-200c, and let-7c in esophageal cancer patients were significantly higher than those in healthy volunteers. High expression of miR-200c correlated significantly with poor response to chemotherapy (p = 0.0211). There was no significant relationship between chemosensitivity and the levels of miR-21, miR-145, and let-7c. High expression of miR- 200c was associated with shortened progression-free survival (p = 0.0076), but there was no significant relationship between prognosis and the expression of miR- 21, miR-145, and let-7c. Multivariate analysis identified miR-200c expression as the most valuable prognostic factor for patients with esophageal cancer who receive neoadjuvant chemotherapy. Conclusions. The serum level of miR-200c can be useful for predicting the response to chemotherapy and the prognosis of patients with esophageal cancer who receive neoadjuvant chemotherapy.