SP cells from proneural/PDGFB-driven GBM express higher levels of stem cell markers, display increased self-renewal, increased chemo-resistance, and are more tumorigenic when compared to the sorted main population (MP) cells7, but with the exception of chemo-resistance, the contribution of ABCG2 to this phenotype is unclear. This evidence concerns the gene ABCG2 and glioblastoma.