Differentially expressed microRNAs in exosomes of patients with breast cancer revealed by next-generation sequencing

MicroRNAs (miRNAs/miRs) in exosomes play crucial roles in the onset, progression and metastasis of cancer by regulating the stability of target mRNAs or by inhibiting translation. In the present study, differentially expressed miRNAs were identified in exosomes of 27 breast cancer patients and 3 healthy controls using RNA sequencing. The differentially expressed microRNAs were selected by bioinformatic analysis. Subjects were followed up for 2 years and exosomal miRNA profiles were compared between patients with and without recurrence of breast cancer. A total of 30 complementary DNA libraries were constructed and sequenced and 1,835 miRNAs were detected. There were no significant differences in the expression of miRNAs between the basal-like, human epidermal growth factor receptor-2(+), luminal A, luminal B and healthy control (HC) groups. A total of 54 differentially expressed miRNAs were identified in triple-negative breast cancer (TNBC) patients vs. HCs, including 20 upregulated and 34 downregulated miRNAs. The results of the reverse transcription-quantitative PCR were consistent with this. Receiver operating characteristic curve analyses indicated that miR-150-5p [area under the curve (AUC)=0.705, upregulated], miR-576-3p (AUC=0.691, upregulated), miR-4665-5p (AUC=0.681, upregulated) were able to distinguish breast cancer patients with recurrence from those without recurrence. In conclusion, the present results indicated differences in miRNA expression profiles between patients with TNBC and healthy controls. Certain exosomal miRNAs were indicated to have promising predictive value as biomarkers for distinguishing breast cancer with recurrence from non-recurrence, which may be utilized for preventive strategies.