RESUMEN
Objective: To dynamically monitor the expression level of miR-21 in peripheral blood before and after radiotherapy in patients with esophageal carcinoma and explore its clinical implication. Methods: Twenty-four patients who were primarily diagnosed of esophageal carcinoma at Department of Radiation Oncology, Shanghai Sixth People's Hospital between August 2009 and June 2013 were recruited, and simultaneously 19 healthy subjects were also recruited as the healthy controls. The miR-21 level in peripheral blood of patients with esophageal carcinoma before and after radiotherapy as well as the healthy subjects was examined by realtime fluorescence quantitative-PCR. The receiver-operating characteristic (ROC) curve and the area under the curve (AUC) were used to evaluate the accuracy of miR-21 level in peripheral blood predicting esophageal carcinoma. The relationships of change in miR-21 level with the clinicopathological characteristics, short-term response and the survival were analyzed. Results: The expression level of miR-21 before radiotherapy was significantly higher in patients with esophageal carcinoma than that in the healthy controls (P < 0.01), and the AUC value was 0.895 [95% confidence interval (CI): 0.797-0.992]. The sensitivity and specificity of miR-21 in predicting esophageal carcinoma were 91.67% and 73.68%, respectively. The expression level of miR-21 in patients with esophageal carcinoma after radiotherapy was significantly declined (P < 0.01). Furthermore, the expression level of miR-21 was declined significantly after radiotherapy in patients with phase T3-4 esophageal carcinoma as compared with that in patients with phase T1-2 esophageal carcinoma (P < 0.01); the expression levels of miR-21 was also declined significantly in patients with esophageal squamous-cell carcinoma (ESCC) as compared with that in patients with esophageal adenocarcinoma (EAC) (P < 0.01). The expression level of miR-21 in peripheral blood was associated with overall survival (OS) of patients with esophageal carcinoma. The OS of patients whose miR-21 level was not significantly declined after radiotherapy had a relatively short survival time (P < 0.05). Conclusion: The dynamic expression level of miR-21 in peripheral blood is a useful biomarker for diagnosis and prognostic prediction for esophageal carcinoma.