HER2/neu Vaccines in Breast Cancer

Recently, the role of immunotherapy has been expanded in the management of breast cancer. The human epidermal growth factor receptor (HER)2/neu protein is overexpressed in many breast cancers, and is the target of documented endogenous immune responses. To exploit these responses, several immunotherapies have been developed, such as trastuzumab, a monoclonal antibody targeting this protein, as well as several HER2/neu-based vaccines. Clinical studies in metastatic patients have shown these vaccines to be safe and to produce vaccine-specific immune responses; unfortunately, little evidence of clinical effectiveness has been reported. The authors' group has evaluated a HER2/neu vaccine as a preventive adjunct in breast cancer patients who are disease free but at a high risk of recurrence. Preliminary results suggest a decrease in recurrence and imply that vaccinating earlier in the disease process may hold promise. In the future, vaccine therapy, alone or in combination, could be a valuable preventive modality in the management of breast cancer.