CXCR4 and glioblastoma: Recently, glioblastoma stem cell invasion in an orthotopic xenograft model was promoted via an Orphan Receptor 1/HER2-CREB signalling axis17, and an ABCF1-CXCL12-CXCR4 axis was recently shown to promote GBM invasion by activating the PI3K-Akt signalling pathway18.