IGFBPs control the distribution, function and activity of IGFs in various cell tissues and body fluids. IGFBP-6, which specifically inhibits IGF-II actions, is produced by bone cells and is the major IGFBP present in cerebrospinal fluid. IGFBP-6 has been shown to inhibit IGF-II-dependent cancers such as neuroblastoma, colon cancer and rhabdomyosarcoma.