IGF-BPs control the distribution, function and activity of IGFs in various cell tissues and body fluids. Currently, there are seven named IGF-BPs that form high affinity complexes with both IGF-I and IGF-II. IGF-BP7 is expressed in a wide range of normal human tissues, and it generally shows reduced expression in cancer cell lines of prostate, breast, colon, and lung origin. It plays a role in skeletal myogenesis by binding to IGF in a manner that inhibits IGF-induced differentiation of skeletal myoblasts, without affecting IGF-induced proliferation. Additionally, IGF-BP7 suppresses growth and colony formation of prostate and breast cancer cell lines through an IGF-independent mechanism, which causes a delay in the G1 phase of the cell cycle and increased apoptosis. Recombinant Human IGF-BP7 is a 26.4 kDa protein consisting of 256 amino acid residues.