Oncostatin M (OSM) is a multifunctional cytokine produced by bone microenvironment by cells of both mesenchymal and hematopoietic origin, including osteocytes, osteoblasts, macrophages and T lymphocytes (Brown et al. 1987, Malik et al. 1989). It belongs to the interleukin-6 (IL-6) subfamily and shares properties with all the members of the family but is closely related to leukemia inhibitory factor (LIF) structurally and functionally and it infact utilizes the LIF receptor (LIFR) in addition to its specific receptor OSMR. In humans, there are two types of functional OSM receptor complexes: the type I OSM receptor complex consisting of gp130 and LIF receptor (LIFR) subunits, and the type II OSM receptor complex consisting of gp130 and OSM receptor beta (OSMRbeta) subunits (Chen & Benveniste 2004, Thoma et al. 1994, Gomez-Lechon 1999). Upon association with its specific receptor complexes OSM, then activates two major signaling pathways: Janus Kinase-Signal Transducers and Activators of Transcription (JAK-STAT) and Mitogen-Activated Protein Kinase (MAPK), to regulate downstream events. OSM is involved in the regulation of complex cellular processes such as growth regulation, differentiation, gene expression, and cell survival in humans (Tanaka & Miyajima 2004).