IGF1 and prostate cancer: The resulting osteolysis makes available factors (which lie in the bone matrix, e.g., TGF-β, insulin-like growth factor-1 [IGF-1], matrix metalloproteinases [MMPs], fibroblast growth factor [FGF], bone morphogenetic proteins [BMPs], and platelet-derived growth factor [PDGF]) to stimulate prostate cancer cell proliferation.