In the context of breast cancer brain metastasis, we also found BRD4 silencing caused downregulation of two downstream target molecules, Shh and Gli, while BRD4 overexpression improved their expression (Figure 7A and 7B), suggesting that BRD4 may promote MMP9 expression through SHH signaling pathway in 231-BR cells. This evidence concerns the gene GLI1 and breast cancer.