Moreover, about 80–90% of CRPC patients develop bone metastasis, since the PCa cells expressing the E-selectin ligand CD44, αvβ3 integrin, and CXCR4 bind to bone marrow endothelial cells, bone marrow stromal cells and mesenchymal stem cells to promote bone homing of PCa [33, 34]. This evidence concerns the gene CD44 and posterior cortical atrophy.