ERBB2 and breast cancer: BC patients have shown a robust infiltration of lymphoid cells in the tumor after treatment with trastuzumab.19 Indeed, a pilot study of neo-adjuvant trastuzumab with 18 BC patients suggested that the anticancer effects are not only mediated by the direct inhibition of the HER2 signaling pathway but also through the induction of antibody-dependent cellular cytotoxicity (ADCC).