The lack of colocalization between YFP and GFAP was similar to that observed in tumors of another glioma mouse model in which PDGF stimulation was combined with deletion of another tumor suppressor, Pten (Lei et al., 2011), and implies that the majority of GFAP+ cells are reactive astrocytes that have infiltrated the YFP+ tumor bulk in our model. Here, GFAP is linked to glioma.