Among the most common mutations found in gliomas both at the tumor biopsy level and at the ctDNA level in the patient’s CSF were mutations within the telomerase reverse transcriptase promoter (TERT), the protein-coding regions of TP53 and the catalytic domain of isocitrate dehydrogenase 1 (IDH1), CDKN2A/CDKN2B deletions, and epidermal growth factor receptor (EGFR) amplifications [78]. The gene discussed is EGFR; the disease is glioma.