Osteoclast cells express the RANK receptor (receptor activator of nuclear factor Kappa B) and in effect serve as ideal molecular targets. RANK is expressed on osteoclast precursors as well as mature osteoclasts. RANK is the essential signaling receptor for osteoclast differentiation during the process of osteoclastogenesis, as triggered by the osteoclast differentiation factor known as RANK-ligand (RANKL) (6, 7) . RANK signaling, with additional signaling through c-Fms, the receptor for macrophage-colony-stimulating factor (M-CSF), triggers the proliferation and fusion of mononuclear cells and the formation of multinucleated, mature osteoclasts (7, 8) .