Previously we demonstrated that rat C6 glioma cells contain a small population of Hoechst 33342 dye-effluxing SP cells7, which was confirmed to fit the criteria of glioma CSCs (GSCs): These SP cells possess higher self-renewal ability, for instance, they could produce both SP and non-SP cells, and also form spheres in the serum-free media with bFGF and PDGF. This evidence concerns the gene FGF2 and central nervous system cancer.