Other growth factor receptors, like Egfr, and proteins commonly deregulated in glioma including Rb, Pten, Cyclin D2, Junc, and Cdk4 (Wang et al., 2009) remained unaltered in p53ΔNcells and tumors (Figure 3—figure supplements 2 and 3), as did the closely related Pdgf receptor Pdgfrb and the receptor ligands Pdgfa and Pdgfb (Figure 3—figure supplement 4). This evidence concerns the gene CDK4 and central nervous system cancer.