CXCR4 and central nervous system cancer: For these reasons, we investigated the role of CD133+ glioma stem cell, defined by the formation of GBM neurospheres, aiming to narrow down a possible chemotactic relationship with MSCs, through research into specific binding of MCP-1/CCL2 and SDF-1/CXCL12 in CD133+ cells, considering the presence of their receptor CCR2/CXCR4 in MSCs.