For this purpose we selected three unique primary patient-derived xenograft models previously established and molecularly characterized at Gustave Roussy, which harbor amplifications of the PDGFRA gene, IGRG93 glioma derived from an adult glioblastoma and IGRM57 from a childhood medulloblastoma, or a normal copy number of the PDGFRA gene, NEM14 pediatric glioma. The gene discussed is PDGFRA; the disease is glioma.