Figure 2.

Glioblastoma stem cell characterization. (a) Phase contrast and fluorescent microscopy of GSC-1-GFP+ growing into tumor spheres in neurosphere medium (magnification ×10). (b) Comparative genomic hybridization array (CGHa) of GSC-1 demonstrating tumor genomic alterations. Each BAC (bacterial artificial chromosome) spotted on the comparative genomic hybridization array is represented by a dot. BACs are ordered on the x-axis according to their position in the genome. For each chromosome, the telomere of the short arm is on the left and the telomere of the long arm is on the right. The y-axis corresponds to fluorescence ratio. Yellow, green, and red indicate, respectively, genomic copy number normal, loss, and gain. Genetic alteration includes complete chromosome 10 loss (green) and gain of chromosome 7 with EGFR amplification (arrow). (c) RT-PCR analysis showing specific expression of endothelial markers CD31 and VE-cadherin by hCMEC and not by GSC-1, GSC-2, and GSC-3 after differentiation in EGM-2 medium. ALAS is used as control. (d) Immunostaining of tumor sphere cells for neural stem cell marker (nestin) at the beginning of the differentiation assay, then astrocytic (GFAP) and neuronal (TUJ-1) markers by the differentiated cells around a tumor sphere at day 7 (magnification ×10).