RUNX2 and breast cancer: Overall, our data indicated the oncogenic effect and concomitant mechanism of the RUNX2-MMP1 axis in the modulation of the proliferation, migration, invasion and drug resistance in triple negative breast cancer drug-resistant cells in vitro, together with tumor growth of breast cancer cells in vivo, which would supply overwhelming new references for dissecting the pathogenesis of TNBC and facilitating the development of clinical remedies and novel therapeutic targets for triple negative breast cancer.