TGF-β(transforming growth factor-beta) is a family of multifunctional proteins. TGF-β was originally identified for its ability to induce the growth of normal rodent fibroblast in soft agar. It is now known that TGF-β is a potent growth inhibitor of many normal and transformed cell lines. It regulates normal cell growth, development and tissue remodeling following injury. TGF-β is produced as latent high molecular weight complexes. The activation of latent TGF-β is an important step in the regulation of its action.