ERBB2 amplification is well correlated with an aggressive phenotype characterized by reduced response to chemotherapy, high recurrence rate and short survival time and serves as a significant prognostic predictor for breast cancer patients (37, 41) . Trastuzumab (Herceptin), an FDA-approved monoclonal antibody against the ERBB2 protein, has been shown to dramatically increase response rate and extend survival in breast cancer patients with ERBB2 amplification. Given Trastuzumab's proven efficacy and substantial benefit in multiple clinical trials, detection of ERBB2 amplification has become critical (42) (43) (44) (45) .