EGFR and glioblastoma: In particular, the EGFR variant III (EGFRvIII) with a deletion of exons 2–7 in glioblastoma, which is frequently co-expressed with the wild-type receptor (wtEGFR) in association with STAT-3, plays a key role in the resistance of cancer cells to chemotherapy and radiotherapy [14,15,16,17,18].