Recognizing the unique specificity of mAb806 to overexpressed EGFR and EGFRvIII mutant [18,19], to steer the potent cytotoxicity of DT specifically to cancer cells while sparing normal cells, we previously generated hDT806 by fusing an engineered DT fragment, DT390, with two single chain variable fragments of mAb806 targeting overexpressed EGFR and/or EGFRvIII, and demonstrated the efficacy of hDT806 in glioblastoma, especially those with EGFRvIII expression [15]. Here, EGFR is linked to glioblastoma.