Down-regulated microRNA-124 expression as predictive biomarker and its prognostic significance with clinicopathological features in breast cancer patients

Background: MicroRNAs (miRNAs) have been documented as playing important roles in cancer development. In this study, we investigated to clarify the clinicopathological significance and prognostic value of miR-124 in breast cancer. Methods: Quantitative Real-time PCR method was used to assess the expression levels of miR-124 in breast cancer patients and the association of miR-124 expression levels with the clinicopathological characteristics in breast cancer patients. Survival and Multivariate Cox proportional hazards model analysis was used to evaluate whether the miR-124 expression level and various clinicopathological characteristics were independent prognostic marker for breast cancer patients. Results: We found that the lower expression of miR-124 in breast cancer specimens compared with corresponding adjacent normal breast tissues P < 0.05. Results showed that decreased expression of miR-124 was significantly related to advanced clinical stage (stage III and IV) (P = 0.021) and positive lymph node-metastasis (P = 0.011). Patients with low expression of miR-124 had significantly shorter overall survival (70.2 %) than patients who had cancers with high miR-124 expression (29.8), (logrank test P = 0.021). Moreover, Multivariate Cox proportional hazards model analysis indicated that lowr miR-124 expression was found to be independently linked to poor survival of patients with breast cancer and other factors were not significantly associated with survival of patients. Conclusion: Our data suggested that decreased expression of miR-124 has prognostic value in breast cancer and may serve as a prognostic marker for breast cancer, and also downregulation of miR-124 was inversely associated with the lymph node metastasis in breast cancer.