“…As CD133 was originally described as the NSC (Uchida et al, 2000) and BTIC (Singh et al, 2004) marker, its ability to exclusively isolate tumor-initiating cells has been debated in the literature, especially in adult glioblastoma. In this heterogeneous tumor, CD133À cells in long-term culture were found to be capable of tumor initiation in mice (Chen et al, 2010), although many recent publications maintain that not only is the CD133 þ fraction enriched in BTIC capacity Yan et al, 2011), but the features of 'stemness' marked by CD133 are associated with increasing malignancy and poor patient outcome (Bao et al, 2006;Thon et al, 2008;McCord et al, 2009;Pallini et al, 2010). In medulloblastoma, evidence more uniformly supports the application of CD133 as a BTIC marker, as CD133 þ multipotent NSCs were described in the postnatal cerebellum (Lee et al, 2005), and further studies showed that CD133 enriched for brain tumor-initiating capacity and radioresistance in primary and Daoy medulloblastoma-derived tumors (Fan et al, 2006;Blazek et al, 2007;Annabi et al, 2008Annabi et al, , 2010Pistollato et al, 2010;Yu et al, 2010).…”