TGF-β1 is a member of transforming growth factor β（TGF-β） family. Transforming growth factor-β polypeptide　family is involved in the regulation of cell processes, including cell division, differentiation, movement, adhesion and death. TGF-β1 regulates many other growth factors positively and negatively. It inhibits the secretion and activity of many other　cytokines, including interferon-γ, tumor necrosis factor-α and various interleukins. It can also reduce the expression level of　cytokine receptor. TGF-β1 is a multifunctional protein that controls proliferation, differentiation and other functions in many cell　types. It plays an important role in bone remodeling, because it is an effective stimulator of osteoblast bone formation, causing　the chemotaxis, proliferation and differentiation of directional osteoblasts. Once cells lose their sensitivity to TGF-β1-mediated　growth inhibition, autocrine TGF-β signal will promote tumor occurrence.