Figure 24. A vicious cycle, interaction between the tumor cells and bone cells.Osteoclastic resorption and osteoblast deposition of bone during mineralization causes stimulation of Bone derived Growth Factors which in turn stimulate the cancer cells which have capability to stimulate both osteoblast and osteoclast through osteoblatic and osteolytic chemokines and thus causing a vicious cycle. TGFβ: Tissue growth factor beta, PTHrP: Parathyroid hormone-related protein, IL: Interleukin, TNF: Tumor necrosis factor, ET: endothelin -1, PDGF: Platelet derived growth factor.