ERBB2 and cancer: We initially focused on human epidermal growth factor receptor 2 (HER2), which is commonly overexpressed in cancer cells and closely associated with tumor invasion and progression.[28] We engineered MedTACHER2 by fusing an engineered scFv(HER2) derived from trastuzumab (Herceptin)[29] with scFv(sortilin) (Figure S6a, Supporting Information).