Patient-derived glioma stem cells (GSCs) from histologically confirmed GBM less than 7 days post dissociation in serum-free media demonstrating a wide range of phenotypes which all resulted in intracranial tumor growth in NOD scid gamma (NSG) mice. (A) Patient-derived cells from case 2025, a newly-diagnosed GBM; (B) patient-derived cells from case 2033, a multifocal GBM; (C) patient-derived cells from case 2188, a recurrent GBM; and (D) patient-derived cells from case 2216 from a newly-diagnosed GBM. All four have distinguishing characteristics of adherent neurospheres (A), large 3-dimensional neurospheres (B), and small clumps of cells with adherent cell populations (C,D) However, all form orthotopic xenografts which grow at increasing rates in successive generations. (Scale bar = 100 μm).