Not quietly consistent with our speculation, confocal microscopy immunofluorescence of glioma tumorsphere displayed that contrasting to Notch1 positive glioma cells which comprised a large proportion in the CD133+ glioma cell spheres, CXCR4 positive glioma cells only represent a small subset of CD133+ glioma cell spheres. This evidence concerns the gene PROM1 and central nervous system cancer.