IGFBP5 and osteosarcoma: For example, IGFBP-5 was reported to inhibit IGF1-stimulated proliferation in the U2 human osteosarcoma cell line (100), and transgenic mice overexpressing IGFBP-5 from the osteocalcin promoter showed decreased trabecular bone formation and reduced rates of mineral deposition during the first few weeks of post-natal life (15).