A recent study indeed showed that 55.5% of tumor-free SVZ tissue contains low-level mutations, such as TP53, EGFR, RB1, PDGFR, or TERT variations shared by matching tumor tissue in IDH-wildtype GBM patients, but not in IDH-mutant GBM patients (23). The gene discussed is EGFR; the disease is glioblastoma.