CXCL12 and Familial prostate cancer: Prostate cancer cells are attracted to skeletal tissue by chemotactic cytokines, which normally regulate the migration of Hematopoietic Stem Cells (HSCs) into the hematopoietic stem cell niche: in fact, osteoblastic-induced stromal-derivedfactor-1 (SDF-1 or CXCL12) binds the CXCR4 receptor expressed both by HSCs and PCa cells.