Taken together, our data showed a novel potential therapeutic strategy by combined inhibition of BRD4-RAC1 oncogenic signaling pathways which decrease tumorigenesis and development of breast cancer by targeting c-MYC/G9a/FTH1 axis and HDCA1/Ac-H3K9 axis in different molecular subtypes in a context-dependent manner. Here, BRD4 is linked to breast cancer.