In addition to traditional therapies such as surgery, chemotherapy, radiation, and hormonal therapy, novel approaches to the management of this disease have recently shown promise. One such approach has been to use the body’s own immune mechanisms to target and kill tumor cells. Trastuzumab (Herceptin), a monoclonal antibody (mAb) that binds the HER2 protein product, is designed to do just that, and recently published reports indicate that it affords a significant disease-free survival (DFS) benefit to high-risk node-negative (NN) and node-positive (NP) breast cancer patients (Piccart-Gebhart et al. 2005, Romond et al.