ESR2 and neoplasm: We observed that trastuzumab inhibited tumour growth in vivo, most likely because of ADCC, as previously reported (Barok et al, 2007), but we also showed that trastuzumab did not inhibit the expression of signalling protein, whereas Erb-hcAb and Erb-hRNase were able to inhibit not only tumour growth but also signal transducers.