Tumor suppression of osteoblasts is seen in vitro and may be due to production by breast cancer cells of IL-1 and IL-11, tumor necrosis factor-alpha, platelet-derived growth factor, or Fas ligand or indirectly due to osteoclastic activation of transforming growth factor-beta (TGFβ) [8],[9]. Here, TGFB1 is linked to breast cancer.