The metastaic cells of primary cancers, in particular cells of prostate cancer which have the potential to induce osteoblastic activity, express a number of factors that mediate bone deposition: platelet derive growth factor (PDGF), ligands of the Wnt signalling pathway, insulin-like growth factor (IGF), transforming growth factor-β (TGF-β), bone morphogenic proteins (BMPs), and fibroblast growth factors (FGFs). Here, IGF1 is linked to prostate cancer.