EGFR and glioblastoma: To test this hypothesis, we synchronously conducted a preclinical imaging study to investigate target inhibition, 18F-FDG uptake, and survival in patient-derived orthotopic EGFRvIII mutant GBM preclinical models as well as a phase II clinical study of osimertinib in recurrent GBM patients harboring EGFR amplification or mutation, and quantified the metabolic and radiographic changes.