We previously generated an immunotoxin, hDT806, with dual specificity by fusing an engineered DT fragment, DT390, with two single chain variable fragments of mAb806 targeting cancer-specific overexpressed EGFR and/or EGFRvIII mutant, and demonstrated the anti-tumor efficacy of hDT806 in glioblastoma28 as well as HNSCC29. This evidence concerns the gene EGFR and cancer.