Upregulation of Noggin and Follistatin by ZEB1 in breast cancer cells induced differentiation of osteoclasts in vitro, suggesting an osteolytic influence in the bone microenvironment (Mock et al. 2015), however the role BMP antagonists play in coordinating the osteoblastic and osteolytic activities in bone metastatic lesions are far from being clear. This evidence concerns the gene ZEB1 and breast cancer.