ERBB2 and triple-negative breast carcinoma: First, we investigated the expression of BRD4 in different subtypes of BRCA cell lines using the Cancer Cell Line Encyclopedia (CCLE) database (Fig. 3a) and found that the expression of BRD4 is higher in triple-negative breast cancer (TNBC) cell lines than in cell lines of the luminal and HER-2 subtypes.