Hematogenously disseminated PCa cells home to the red bone marrow through interactions mediated by the CXCL12–C-X-C motif chemokine receptor (CXCR)4 axis derived from bone marrow stromal cells, as well as integrins, supported by in vivo and in vivo studies [55,56]. The gene discussed is CXCL12; the disease is posterior cortical atrophy.