Macrophage colony-stimulating factor (M-CSF) is a homodimeric cytokine that belongs to receptor tyrosine kinase subclass III of the receptor tyrosine kinase (RTK) family. M-CSF acts on a CSF-1 receptor tyrosine kinase, which initiates signaling cascades to support cell proliferation and differentiation (Hamilton). M-CSF is produced by endothelial cells, osteoblasts, and during pregnancy by the uterine epithelial cells (Ryan). M-CSF synergizes with other factors to support proliferation and differentiation of multipotent hematopoietic progenitor cells, and regulates proliferation and differentiation of the mononuclear phagocyte progenitor cells to monocytes and macrophages. It also supports survival, proliferation, and function of the differentiated macrophages and regulates differentiation of mononuclear phagocytes to osteoclasts (Pixley & Stanley). M-CSF plays an important role in the implantation of the embryo and early development (Makrigiannakis et al.).