The study of De Mattos-Arruda and collaborators also found mutations in IDH1/2, EGFR, PTEN, FGFR2 and ERBB2 genes in CSF samples, and showed that CSF ctDNA is longitudinally modulated throughout treatments after the observation of dynamic changes in CSF ctDNA, which recapitulates the treatment courses of patients with glioblastoma [17]. This evidence concerns the gene EGFR and glioblastoma.