EGFR and glioblastoma: Verhaak et al. has previously described different clinical genetic GBM subtypes (proneural, neural, mesenchymal, and classical) based on the gene expression of different markers, such as platelet-derived growth factor-receptor alpha (PDGF-Rα), neurofilament light (NEFL), CD44, and epidermal growth factor-receptor (EGF-R), respectively2.