 The receptor activator of NF-kB ligand RANKL system is considered important for bone homeostasis . RANKL exist in three isoforms and the effects of all isoforms are mediated through binding to a specific receptor receptor activator of NF-KB RANK. RANKL is predominantly found as a transmembrane protein and signalling is therefore dependent on cell-cell interaction to a neighbouring cell expressing RANK that subsequently activates NFKB and regulates cellular activation through regulation of cell cycle i.e proliferation, differentiation and apoptosis. RANKL-RANK interaction is modified by osteoprotegerin OPG, which is an endogenous secreted protein that binds RANKL and inhibits its signalling. 