Immunoglobulin G fragment C receptor polymorphisms and clinical efficacy of trastuzumab-based therapy in patients with HER-2/neu-positive metastatic breast cancer.

The anti-HER-2/neu monoclonal antibody trastuzumab has been shown to engage both activatory (fragment C receptor [Fc gamma R]IIIa; Fc gamma RIIa) and inhibitory (Fc gamma RIIb) antibody receptors and Fc gamma R polymorphisms have been identified that may affect the antibody-dependent cell-mediated cytotoxicity (ADCC) of natural-killer cells/monocytes. In this study, we tested whether Fc gamma R polymorphisms are associated with clinical outcome of patients with breast cancer who received trastuzumab.