SPP1 and posterior cortical atrophy: Advanced PCa cells express high levels of Integrin α3, α6, and β1 (ITGA3/A6/B1) [37, 38], EphA2 [39, 40], and connexins (Cx) such as Cx43/45 [41] at their surface, and also increase levels of extracellular matrix (ECM) components including fibronectin (FN) [42], osteopontin (OPN) [43], and hyaluronan [44] in tumor stroma.