Criteria to define CSCs
Percentage (n)
Pathological subtype
(Ignatova et al., 2002) Isolation of clonogenic cells 80 % (n=10) Anaplastic astrocytoma and recurrent malignant GBM
(Brehar et al., 2009) Expression of stem cell markers (nestin, CD133) 100 % (n=1) Glioblastoma (1)
(Galli et al., 2004) capacity for long-term proliferation, self-renewal, multipotency and their tumorigenicity 100 % (n=10) Glioblastoma (6), Medulloblastoma (4),
(Singh et al., 2003) Self-renewal, proliferation, and lineage restricted differentiation 100% (n=14) Medulloblastoma (8), Pilocytic astrocytoma (3), Grade 2 astrocytoma (1), Ependymoma (1), Ganglioglioma (1)
(Yuan et al., 2004 ) Formation of tumor spheres, self-renewal capacitiy, expression of NSC markers as well as lineage markers,  multipotentiality, capability  of forming tumors in vivo 100 % (n=6) Glioblastomas
(Bao et al., 2006) Neurosphere formation and tumorigencity 100 % (n=3) Primary gliomas
(Yi et al., 2007) Formation of tumor spheres,  Tumorigenicity 100 % (n=3) anaplastic oligoastrocytoma
(Kelly et al., 2009) Formation of tumor spheres, self-renewal capacitiy, multilineage Differentiation 73 % (n=11) Glioblastomas
Table 3: Isolation of cancer stem cells from human brain tumors. With few exceptions, cancer stem cells has been isolated from 100% of all tumors.