EDN1 and posterior cortical atrophy: PCa cells cause osteoblastic metastasis through release of osteoblast-promoting factors such as bone morphogenic protein, Wnt family ligand, endothelin-1, platelet-derived growth factor, and osteolytic lesions through the release of parathyroid hormone-related protein (PTHrP), which upregulate receptor activator of nuclear factor kappa-B ligand (RANKL) and down-regulate osteoprotegerin to result in osteoclastogenesis and bone resorption [12-13].