Identification of serum exosomal miR-148a as a novel prognostic biomarker for breast cancer.

OBJECTIVE Breast cancer (BC) is one of the most common malignanciesD. Li, J. Wang, L.-J. Ma, H.-B. Yang, J.-F. Jing, M.-M. Jia, X.-J. Zhang, F. Guo, J.-N. Gao affecting females. Aberrant expression of microRNAs (miRNAs) has been associated with carcinogenesis of BC. The aim of our study was to investigate the correlation of serum exosomal miR-148a expression and the clinical outcome of patients with BC. PATIENTS AND METHODS Quantitative Real Time-Reverse Transcription Polymerase Chain Reaction (qRT-PCR) was applied to evaluate the expression level of serum exosomal miR-148a in patients with BC, patients with benign breast tumors, and healthy controls. Then, the clinical value of serum exosomal miR-148a in BC was evaluated. RESULTS Serum exosomal miR-148a levels were gradually downregulated from healthy controls patients with benign breast tumors to BC patients. Serum exosomal miR-148a could well distinguish BC patients from healthy volunteers. The expression level of serum exosomal miR-148a in BC patients was significantly upregulated following surgery, while dropped in the cases with disease relapse. A significant association was found between serum exosomal miR-148a levels and the tumor-node-metastasis (TNM) stage, differentiation, and lymph node metastasis in BC. In addition, BC patients with lower expression of serum exosomal miR-148a levels suffered worse overall survival and disease-free survival than those with higher expression of serum exosomal miR-148a levels. Furthermore, serum exosomal miR-148a was an independent risk factor for BC. CONCLUSIONS Our data have demonstrated that serum exosomal miR-148a is significantly reduced in patients with BC and downregulation of serum exosomal miR-148a is closely associated with unfavorable clinical outcome of BC, indicating that serum exosomal miR-148a might serve as a promising diagnostic and prognostic biomarker for BC.