In addition, it has been shown that CXCR4 is consistently co-expressed with its ligand CXCL12 in glioblastoma multiforme [30] and that high levels of CXCL12 attract CXCR4-positive vascular and inflammatory cells and promote tumor cytokine secretion [23]. The gene discussed is CXCL12; the disease is glioblastoma.