MicroRNA-21 contributes to the discrimination of chemoresistance in metastatic gastric cancer

Background: Multidrug resistance in gastric cancer greatly impedes the efficacy of chemotherapy.

Objective: To explore the efficacy of microRNA-21 (mir-21) in distinguishing metastatic gastric cancer (MGC) with chemoresistance.

Methods: From April 2012 to May 2015, 92 MGC patients were enrolled. Cisplatin and fluorouracil-based systemic chemotherapy was given, and patients' characteristics and follow-up data were collected. In addition, miR-21 expression was determined in tumor tissue and plasma.

Results: Sixty-seven patients responded to chemotherapy, and chemotherapy resistance was observed in 25 patients. miR-21 expression in tumor tissue and plasma was significantly elevated in the chemotherapy-resistant group (CRG) compared to the chemotherapy-sensitive group (CSG) (p< 0.001). miR-21 expression in tissue was associated with tumor differentiation (p= 0.042), and plasma miR-21 was correlated with gender (p= 0.016), tumor differentiation (p= 0.003), and number of metastatic sites (p< 0.001). Receiver operating characteristic (ROC) analysis indicated that miR-21 in tissue yielded an area under the ROC curve (AUC) of 0.830 (95%CI: 0.737-0.900, sensitivity: 88.0%, specificity: 68.7%) in distinguishing CRG from CSG; and plasma miR-21 yielded an AUC of 0.759 (95%CI: 0.658-0.842, sensitivity: 52.0%, specificity: 88.1%) in distinguishing CRG form CSG. Log-rank test and Cox proportional hazard regression analysis indicated that patients with higher miR-21 expression in tissue and plasma experienced shorter overall survival (P< 0.001).

Conclusion: miR-21 could serve as a potential biomarker to identify MGC with chemoresistance.