CXCL12 and central nervous system cancer: Among these factors, stromal cell-derived factor-1 (SDF-1/CXCL12) is known to be involved in glioma invasion by recruiting macrophage or T-regulatory cell migration to the peritumoral area [13], by cross-talking with endothelial cells [14], or by mobilizing hematopoietic stem cells and progenitor cells [15].