MDX-H210, constructed by crosslinking antigen binding fragments (F(ab′) fragments) of monoclonal antibody (mAb) H22 to Fc gamma receptor I (FcγRI), and mAb 520C9 to HER-2/neu, respectively, mediates the lysis of tumour cells in vitro, and in human FcγRI transgenic mouse models. The gene discussed is ERBB2; the disease is neoplasm.