A number of signalling pathways that include autocrine components, such as TGFalpha/EGF/EGFR, PDGF/PDGFR, HGF/SF and CXCL12/CXCR4 ligand/receptor systems, have been identified in glioma and glioblastoma [32]. Here, CXCR4 is linked to glioblastoma.