It is well known that in osteoblastic metastasis, a vicious circle develops between PCa cells and osteoblasts/osteoclasts, with PCa cells providing growth factors to osteoblasts and osteolytic factors (e.g., BMPs, TGF-β, IGF, FGF, PDGF, ET1, VEGF, and MMPs) that activate these cells and allow them to produce bone-derived growth factors (e.g., PDGF, BMPs, TGFβ, IGFs, and FGFs) that further induce cancer-cell stimulation [94, 95]. This evidence concerns the gene CLN5 and cancer.