We have previously shown that both antibodies inhibit NRG1 binding, NRG1-induced pHER3 stimulation, ligand-induced signaling and ligand-induced melanoma cell proliferation through binding to different epitopes [29, 30], one of which (A3) has been mapped to the ErbB3 heterodimerization loop with other ErbBs. This evidence concerns the gene NRG1 and melanoma.