ERBB2 and neoplasm: For example, an IgG-like anti-human epidermal growth factor receptor 2 (aHer2)/aCD3 bispecific molecule was engineered to include two low-affinity Her2 binding domains, thereby increasing the selectivity of the BsAb for cells overexpressing Her2 and increasing selective killing of tumor cells over Her2-expressing bystander cells [11].