The PDGF-A;PDGFRα;p53−/− tumors displayed histopathological features that are observed in high-grade gliomas, i.e., tumors were densely packed, containing poorly differentiated cells with marked nuclear atypia, numerous giant multinucleated cells, and characteristic areas of pseudopalisading necrosis (Fig 3D). The gene discussed is TP53; the disease is glioma.