More importantly, we found that purified CD133+ GSC cells, not CD133+ glioblastoma spheres (containing mostly CD133- progeny), express a tumor-suppressor phenotype, which is characterized by the expression of a series of genes associated with a slow-growing, undifferentiated, polarized, migrating, anti-inflammatory, and anti-angiogenic phenotype [1]. This evidence concerns the gene PROM1 and glioblastoma.