Current status and future prospective of breast cancer immunotherapy.

The immune system is complicated, interconnected, and offers a powerful defense system that protects its host from foreign pathogens. Immunotherapy involves boosting the immune system to kill cancer cells, and nowadays, is a major emerging treatment for cancer. With the advances in our understanding of the immunology of cancer, there has been an explosion of studies to develop and evaluate therapies that engage the immune system in the fight against cancer. Nevertheless, conventional therapies have been effective in reducing tumor burden and prolonging patient life, but the overall efficacy of these treatment regimens has been somewhat mixed and often with severe side effects. A common reason for this is the activation of molecular mechanisms that lead to apoptosis of anti-tumor effector cells. The competency to block tumor escape entirely depends on our understanding of the cellular and molecular pathways which operate in the tumor microenvironment. Numerous strategies have been developed for activating the immune system to kill tumor cells. Breast cancer is one of the major causes of cancer death in women, and is characterized by complex molecular and cellular events that closely intertwine with the host immune system. In this regard, predictive biomarkers of immunotherapy, use of nanotechnology, personalized cancer vaccines, antibodies to checkpoint inhibitors, engineered chimeric antigen receptor-T cells, and the combination with other therapeutic modalities have transformed cancer therapy and optimized the therapeutic effect. In this chapter, we will offer a holistic view of the different therapeutic modalities and recent advances in immunotherapy. Additionally, we will summarize the recent advances and future prospective of breast cancer immunotherapies, as a case study.