ERBB2 and neoplasm: These indicated that Arg9 could possibly enhance the bio-functional effect of cargo protein in vitro and in vivo. The single chain antibody against HER2 could hardly play a parallel role of the whole antibody; however, with the help of Arg9, the fusion protein might be able to assert a satisfactory inhibitory effect of tumour cell proliferation or survival through the HER2-Akt signalling pathway.