1G5D2 is a bsAb targeting HER2 and HER3, and it can specifically bind to HER2 and HER3 expressed on tumor cells, thereby inhibiting AKT and ERK downstream signaling pathways and tumor cell proliferation in vitro (120), indicating that it may act as a HER2/HER3 transducer. This evidence concerns the gene ERBB3 and neoplasm.