CCL2 and glioblastoma: This tropism may be related to the monocyte chemoattractant protein 1 (MCP-1)/CC motif chemokine ligand 2 (CCL2) and stromal cell-derived factor-1 (SDF-1)/CXC motif chemokine ligand 12 (CXCL12) chemokines, which mediate MSC migration to CD133+ glioblastoma cells in vitro [9].