Bao et al. (2006b) suggested that GSCs are more likely to form in the tumor vasculature than non-tumor stem cell gliomas under the same conditions. In addition, GSCs can also promote tumor angiogenesis through VEGF and stromal-derived factor 1 (SDF-1) (Folkins et al., 2009). The gene discussed is CXCL12; the disease is neoplasm.