Abstract:Objective To investigate the expression of miRNA in breast cancer (BC) patients and potential as diagnostic biomarkers. Methods Totally 48 BC patients as well as healthy volunteers were involved in this study. The levels of serum miRNA-21, miRNA-210 and miRNA-1246 were detected by RT-PCR. Diagnostic capability of miRNA were analyzed. Results Compared with normal subjects, levels of serum miRNA-21, miRNA-210 and miRNA-1246 were increased significantly in BC patients (P = 0.000), especially in patients on stage III or patients with lymph node metastasis (P < 0.05). ROC curve analyses indicated that AUC value of miRNA-21, miRNA-210 and miRNA-1246 was 0.936 (95% CI: 0.866, 0.976), 0.980 (95% CI: 0.928, 0.998) and 0.737 (95% CI: 0.638, 0.822), respectively. The specificity of miRNA-21, miRNA-210 and miRNA-1246 was 0.854 (95% CI: 0.722, 0.939), 0.917 (95% CI: 0.800, 0.977) and 0.583 (95% CI: 0.432, 0.724), respectively. Further analyses showed that, in terms of diagnostic capability, combination of miRNA-210 and miRNA-1246 or combination of miRNA-21, miRNA-210, and miRNA-1246 is not superior to miRNA-210 only. Fisher discriminant analysis established the best diagnostic model for BC, whose specificity is 100.0%. Conclusion miRNA-21, miRNA-210 and miRNA-1246 are highly expressed in breast cancer patients. Serum miR-210 may be an ideal diagnostic biomarker for BC.