Circulating microRNA-103a-3p could be a diagnostic and prognostic biomarker for breast cancer.

Breast cancer (BC) is the most frequent cancer for women worldwide. Recently, a spectrum of cell-free circulating microRNAs (miR) has been recognized as promising biomarkers for BC diagnosis and prognosis, among which miR-103a-3p has been reported in several types of human cancer. However, the role of miR-103a-3p in BC remains unknown. A total of 112 patients with BC and 59 healthy controls were recruited into the present study. The expression level of serum miR-103a-3p was evaluated using reverse transcription-quantitative PCR. Receiver operating characteristic curves were utilized to calculate diagnostic accuracy. Survival curves were generated to analyze survival outcomes. It was found that circulating miR-103a-3p level was upregulated in patients with BC compared with that in healthy controls, and its expression was decreased following surgery. In addition, miR-103a-3p expression level was also associated with advanced clinicopathological features, including positive epidermal growth factor receptor 2 status, metastasis and an advanced TNM stage. The circulating serum miR-103a-3p level could be used to discriminate between patients with BC and the healthy controls prior to surgery using an area under curve [(AUC), 0.697; 95% confidence intervals (CI), 0.615-0.778], and distinguish patients with BC and metastasis from those without metastasis (AUC, 0.936; 95% CI, 0.892-0.980). In addition, high expression level of miR-103a-3p was associated with worse survival outcomes in patients with BC. In conclusion, the present study suggests that miR-103a-3p could be a potential non-invasive diagnostic and prognostic biomarker for BC.