TGFB1 and breast cancer: Interestingly, in breast cancer cells both HIF-1α and TGF-β regulate a common set of genes including VEGF and CXCR4, toward the activation of the metastatic program, whereas the combined use of small molecule inhibitors of HIF-1α and TGF-β, targeting cancer cells and the microenvironment, reduces bone metastasis by decreasing osteoclastic bone resorption and increasing osteoblast activity [148].