Bromodomain inhibitors including JQ1 represent a promising class of targeted therapies for breast cancer through disrupting the function of BET proteins (BRD2, BRD3, and BRD4) by preventing their binding to acetylated lysines on histones, leading to a transcriptional downregulation of key oncogenic genes driving tumor growth, cell survival, and metastasis [22]. Here, BRD4 is linked to breast cancer.