BRD2, a member of the bromodomain and extra-terminal (BET) family including mammalian BRD3, BRD4 and BRDT [9], is remarkably over-expressed in breast cancer [30], gastric cancer (GC) [31], malignant pleural mesothelioma (MPM) [32] and castration-resistant prostate cancer (CRPC) [33]. Here, BRD3 is linked to breast cancer.