The advantage of these genetic models is that they permit the study of discrete GBM subtype pathophysiology and therapy response—for example, RCAS-TVA-PDGFRa (proneural subtype) [78,104] and Cre-Lox expression of EGFRvIII or RCAS-TVA-EGFR (classical subtypes) [102,105]. The gene discussed is EGFR; the disease is glioblastoma.