ERBB2 and cancer: To determine whether targeted liposomes DARP-Lip(Bn) and fusion toxin EC1-LoPE possess synergistic cytotoxic effect on HER2/EpCAM-positive cancer cells, we incubated BT-474 and MDA-MB-231 cells with different concentrations of DARP-Lip(Bn) and EC1-LoPE and assessed cytotoxicity after 72 h by MTT.