EGFR and glioblastoma: At a cut-off value of >10% of tumour cells with staining, they found that 22% of 103 patients were EGFR positive, with EGFR expression being significantly associated with worse overall survival [53] In another study, Chakravarti and colleagues investigated the expression of EGFR using anti-EGFR antibody Zymed (clone 31G7), which detected both the wtEGFR and EGFRvIII, in 155 tissue microarrays from patients with glioblastoma multiforme.