Abstract
Immunotherapies are set to become part of the therapeutic repertoire for breast cancer in the near future. Active vaccination is a promising strategy, especially in tumors that have a specific tumor-associated antigen. Although cellular immunotherapies have not yet shown efficacy, new technologies are on the way to improve this approach. Given the recent Food and Drug Administration approval of chimeric antigen receptor (CAR) T cells for leukemia, it is only a question of time before solid tumors will follow. However, not all breast cancer patients will respond to cellular or other immunotherapy. Hence, we must define subpopulations of breast cancer patients who benefit from this new approach.