PDGFB and brain stem glioma: In order to identify regional differences in glioma, and in particular unique characteristics of those arising in the brainstem, we generated mouse Brainstem Glioma (BSG) and Cerebral Cortex Glioma (CG) by injecting RCAS-PDGF-B virus-producing cells into the brainstem or cerebral cortex, respectively, of postnatal day 2–4 (P2-4) Nestin-Tv-a(Ntv-a);Ink4aARF−/− mice (Figure 1a) [34,43].