The low expression of miR-1976 in plasma samples indicating its biological functions in the progression of breast cancer

Background The incidence of breast cancer (BC) is the highest among women. Identification of miRNAs as biomarkers may help to improve the diagnosis of BC. The purpose of this study was to assess the expression levels of miR-1976 in plasma samples and the biological functions in the progression of BC. Methods The expression levels of miR-1976 in plasma samples and tissues were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The associations between the expression levels and clinicopathological features were studied. Cell supernatants were used to simulate circulation. The biological functions of miR-1976 were assessed in vitro and in vivo. Results The expression levels of miR-1976 in plasma samples were found significantly lower in patients with BC than those in healthy controls, and were associated with Ki-67. The expression levels in BC tissues were lower than those in adjacent normal tissues, and were correlated with the number of lymph nodes and Ki-67. The expression levels in BC cell supernatants and cell lines were lower than that in normal human breast epithelial cell line HBL-100. miR-1976 knockdown promoted proliferation in vitro and in vivo. Conclusion miR-1976 may serve as a promising non-invasive biomarker for the diagnosis of BC in the future.