CXCL12 and astrocytoma (excluding glioblastoma): The significance of the expression and function of the CXCL12/CXCR4 axis in brain tumors has been intensely investigated in adult and children GBM, astrocytoma, medulloblastoma, oligodendroglioma, and oligodendroastrocytoma (Domanska et al., 2011).