While breast cancer has not historically been considered an immunogenic cancer, recent data demonstrating the powerful anti-cancer effects of immune checkpoints in many cancers, including breast cancer, has reinvigorated the field. Although the responses are generally low with single agents, some patients experience disease control for a long period of time. Selecting appropriate patients for immunotherapy is an important area of research, and many biomarkers are under investigation. Although immunotherapies are still in their early stages of development, learning how to use them in combination with other agents that can alter antigen presentation or other immune elements will be crucial. This review aims to summarize efforts in immune-related biomarker and drug development, particularly as it pertains to breast cancer.
Keywords: biomarkers; breast cancer; checkpoint inhibitors; drug development; immunotherapy.