Abstract

Breast cancer, a heterogeneous disease, is the frequently diagnosed cancer and the leading cause of cancer-related deaths among women globally. Today, even if the survival rate of breast cancer patients is increased with combination therapies including chemotherapy, monoclonal antibodies, tyrosine kinase inhibitors or immune checkpoint blockade in the patients resistant to the therapies, the disease progression continues. Moreover, the clinical activity of the therapies is limited only to subsets of patients. These difficulties highlight the necessitate for the development of alternative treatment approaches. Vaccines that have protected humans against infectious diseases for centuries are increasingly being developed due to the cost-effective approach related to prevention, treatment, and eradication of cancer. In addition, vaccines confer long-term immune memory critical to prevent tumor recurrence. Breast cancer vaccines have been extensively tested in clinical trials, but no vaccine has been approved for either breast cancer treatment or prevention yet. In the past years, tumor self-antigens have been used in vaccine development. Tumor-specific antigens are not only present in the tumor cell but also in normal cells. Such developed vaccines cause immunological tolerance and cannot provide effective treatment. Currently, neoantigens are popular during vaccine development against breast cancer. Neoantigens formed by somatic mutations differ from self-tumor antigens and are specific to each individual patient. Another important vaccine target is the cancer stem cell that plays a key role in tumor development, dissemination, and resistance to therapy. Breast cancer vaccines targeting cancer stem cell and neoantigen can be used either single or combined with chemotherapy and immune checkpoint blockade and are also considered as an effective therapeutic strategy in breast cancer. In this chapter, the vaccination strategies in current clinical trials and possible future directions for vaccine development against breast cancer are portrayed and intensely discussed.