ERBB2 and breast cancer: Trastuzumab, a humanized monoclonal antibody against the extracellular domain of Her-2, has been shown to be very effective in combination with chemotherapy for the treatment of early stages [5,6] or metastatic breast cancer [7,8] and even as a single-agent for the later group [9] with substantial decrease in breast cancer recurrence and mortality [10,11,12,13].