Tagliabue et al. treated FVB mice that bore HER2+ mammary carcinoma cells (MI6) with trastuzumab with or without a CCL2-blocking monoclonal antibody and found that treatment with anti-CCL2 significantly enhanced the activities of trastuzumab [58], indicating that the therapeutic activity of trastuzumab is dependent on the CCL2 level. The gene discussed is ERBB2; the disease is breast carcinoma.