Immunoglobulin G Fragment C Receptor Polymorphisms and Clinical Efficacy of Trastuzumab-Based Therapy in Patients With HER-2/ <i>neu</i> –Positive Metastatic Breast Cancer

These data support for the first time the hypothesis that Fc gamma R-mediated ADCC plays an important role in the clinical effect of trastuzumab. Prospective studies are needed to confirm the role of Fc gamma R polymorphisms in predicting clinical outcome of patients with breast cancer treated with trastuzumab-based therapy.