EGFR and glioblastoma: These enhancer elements impacted regulatory elements and chromatin structure within glioblastoma.67 Extrachromosomal DNA is present in almost half of human cancers due to uneven segregation of chromosomes without a centromere.68 Mutant EGFR extrachromosomal DNA is eliminated during anti-EGFR treatment, causing resistance, yet reappears after drug cessation.63