Therapeutic Vaccination Strategies for Breast Cancer

Abstract Even though the impact of the immune system on the clinical course of cancer has been known for decades, its role in the treatment of various tumor entities has often been given little consideration. In recent years, the treatment landscape for breast cancer has undergone significant changes. Routine treatment has been revolutionized, in particular, by the use of T cell-based immunotherapies in the form of immune checkpoint inhibitors (ICIs). While this underscores the importance of the immune system in the treatment of breast cancer, other T cell-based immunotherapies, such as therapeutic vaccines, do still not play a significant role in clinical practice. In recent years, numerous studies on various vaccine candidates have been conducted, some of which have demonstrated a successful induction of an immune response. The selection of antigens and routes of administration/adjuvants capable of inducing long-lasting and clinically effective T cell responses remains a key challenge. The combination of ICIs with therapeutic vaccines could also hold promise for the future, by enhancing the specificity of the T cell response and thus augmenting the anti-tumor effect.