Tumor cells produce factors, including FGFs, urokinase-type plasminogen activator (uPA), endothelin-1 (ET-1), prostate-specific antigen (PSA), insulin-like growth factors (IGFs), bone morphogenic proteins (BMPs), and vascular endothelial growth factor (VEGF), which stimulate osteoblast proliferation and differentiation (68, 69). The gene discussed is CLN5; the disease is neoplasm.