miR-26a suppresses tumour proliferation and metastasis by targeting metadherin in triple negative breast cancer.

It has been reported that miR-26a plays an important role in various cancers. In this study, we found that miR-26a was downregulated in triple-negative breast cancer (TNBC), and its expression levels were associated with lymph node metastasis and overall survival in TNBC. We also found that the ectopic expression of miR-26a inhibited TNBC cell proliferation and metastasis in vitro and in vivo by downregulating MTDH (a miR-26a' target gene) mRNA and protein and that the overexpression of MTDH could partially abrogate miR-26a-mediated suppression. Our data suggest that miR-26a functions as a tumour suppressor in TNBC development and serves as a prognostic marker for breast cancer.