Decreased expression of microRNA-124 is an independent unfavorable prognostic factor for patients with breast cancer

BACKGROUND MicroRNA-124 (miR-124) has been reported to be downregulated in breast cancer. However, its clinical significance and prognostic value in breast cancer have not been extensively studied. METHODS The tissue expression levels of miR-124 were measured using quantitative real-time PCR in 133 breast cancer patients. The correlation between the miR-124 levels and the clinicopathological factors of the patients was also analyzed. Survival and Cox proportional-hazards regression analyses were performed to determine the correlation between miR-124 expression levels and prognosis in the patients. RESULTS Quantitative real-time PCR analysis showed that miR-124 had lower expression in breast cancer specimens than that in matched adjacent normal breast tissues (0.39 ± 0.16 vs. 1.00 ± 0.39; P < 0.05). Low miR-124 expression level was significantly associated with advanced TNM stage (P = 0.011), lymph node metastasis (P = 0.012), and poorer pathological differentiation (P = 0.023). A significant difference was found that breast cancer patients with low miR-124 expression level had distinctly shorter overall survival than patients with high miR-124 expression level (63.8% vs. 35.2%, P = 0.03). Furthermore, multivariate analysis of the prognosis factors with a Cox proportional hazards model confirmed that low miR-124 expression was a significant independent predictor of poor survival in breast cancer (HR = 3.16, 95% CI: 1.79-9.13, P = 0.017). CONCLUSION These findings proved that the decreased expression of miR-124 might be associated with tumor progression and poor prognosis in patients with breast cancer. VIRTUAL SLIDES The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3752603721493544.