Insulin-Like Growth Factor-Binding Protein 5 (IGFBP-5) is a secreted protein that belongs to the insulin-like growth factor (IGF) binding proteins superfamily. Members of this family prolong the half-life of the IGFs. They have been shown to either inhibit or stimulate the growth promoting effects of the IGFs on cell culture. They alter the interaction of IGFs with their cell surface receptors. IGFBP-5 contains one IGFBP N-terminal domain and one thyroglobulin type-1 domain. IGFBP-5 is expressed by fibroblasts, myoblasts and Osteosarcoma. It is also present at lower levels in liver, kidney, and brain.