EGFR and glioblastoma: Yet, the expression of EGFRvIII varies across time, where its expression decreases after initial resection,56,61,62 and can be lost as mechanism of resistance to therapy, reappearing again when therapy is stopped.63 EGFRvIII expressing cells can retain their EGFR-wild-type status via paracrine mechanisms and IL-6-driven signalling.64 This raises questions over the presumed role of EGFRvIII as a driver mutation for glioblastoma and makes it harder for targeted therapies to be effective.