EGFR and cancer: In conclusion, among the diabodies constructed from the anti-cancer cell and anti-T-lymphocyte Fvs, the diabody group with the highest cytotoxicity against TFK-1 cancer cells follows the following rules: 1) the target on the T-lymphocyte is CD3, 2) the domain order is LH-type, 3) the target on the TFK-1 cancer cells is EGFR, 4) the anti-EGFR domains are derived from DL11 or 11F8 Fv.