ERBB2 and cancer: scFv2(FRP5/225)-ETA is a bispecific LTT, composed of two scFv domains that target EGFR and ErbB-2 linked to modified PE, which demonstrated more potent anti-cancer activity in vitro and in vivo than its monospecific counterparts, scFv(FRP5)-ETA and scFv(225)-ETA.