Severalstudies have found that 60–84% of GBM cancers overexpress epidermalgrowth factor receptors.54,55 Therefore, a cocktailof WT-PEG engagerEGFR and pH-PEG engagerTfR couldbe simply utilized for brain delivery of PEGylated drugs followedby specific targeting of EGFR-overexpressing GBM. This evidence concerns the gene EGFR and glioblastoma.