EGFR and glioblastoma: This heterogeneous EGFR expression is related to amplification of the EGFR locus prior to the deletion of exons [20], although non-malignant cells in the glioblastoma specimens may also express EGFR. Of the fourteen glioblastoma samples used in this study, six expressed EGFRvIII (a total of 36 skipped exons) of which five also expressed significant levels of wild-type EGFR transcripts as determined by quantitative Real-Time PCR (qPCR) (Fig. 3B) (insufficient RNA remained of the sixth sample with EGFRvIII expression to perform qPCR).