EGFR and glioblastoma: In GBM, EGFR amplification is mostly associated with gene rearrangements associated to deletion of particular exons, or portions of exon, and leading to the generation of EGFR variants, that include deletion at N-terminal regional (EGFRvI), deletion at exons 14-15 (EGFRvII), deletion at exons 2–7 (EGFRvIII), deletion at exons 25–27 (EGFRvIV), deletion at exons 25–28 (EGFRvV).