In the process of bone metastasis in lung, breast, and prostate cancer, tumor-driven osteoclastogenic factors, such as TGFβ1, PTHLH (parathyroid hormone-like hormone), and MMP-2 (Matrix metalloproteinase-2), facilitate osteolysis and homing of cancer cells to bone [55,56]. This evidence concerns the gene MMP2 and prostate carcinoma.