Fig. 1

miR-26a-5p is downregulated in TNBC. A Downregulated miRNAs in breast cancer tissue especially in TNBC were obtained from TCGA-BRCA database. B Heatmap of different downregulated miRNAs expression between TNBC and normal breast tissue from TCGA-BRCA database. C MirPath v.3 GO Reverse Search was used to find DNA damage-related miRNAs. Four candidate miRNAs were chosen from overlapping the above four gene sets and we chose miR-26a-5p as a preferred target. D The expression of miR-26a-5p in breast cancer (red bar) was downregulated compared with normal tissues (blue bar) from TCGA-BRCA database. Its expression in TNBC (red bar) was downregulated compared with NTNBC (blue bar). E The expression of miR-26a-5p in breast cancer tissues (red bar) and matched normal tissues (blue bar) was measured by RT-qPCR. Its expression in TNBC (red bar) was downregulated compared with NTNBC (blue bar) in clinical tissues. F The expression of miR-26a-5p in breast cancer cell lines and human normal breast epithelial cell line MCF10A was measured by RT-qPCR. ***P < 0.001, ****P < 0.0001