Therefore, we compared the extreme cases of PDGF-induced gliomagenesis from NSCs (as defined by GFAP positivity in the SVZ) versus reactive astrocytes (GFAP expression in the cortex, induced in response to injury by delivery of RCAS-PDGF) in order to determine if, when engineered into the mouse brain, it is possible to initiate cancer from a non-self renewing cell. This evidence concerns the gene GFAP and cancer.