Therapeutic Potential of Lymphoid Infiltrates in Breast Cancer

Despite diagnostic and therapeutic advances in breast cancer, it remains the most frequently diagnosed malignancy in females, with the highest cancer-related mortality rate in women globally. With an improved understanding of the complex interactions between breast cancer and the immune system, immunotherapy has shown great potential in clinical management, potentially adding to current treatment modalities. These immunotherapeutic approaches include adoptive cell transfer therapy, cancer vaccination, monoclonal antibody therapy, and oncolytic virus therapy. Depending on the immune cells and cytokines present, the tumour microenvironment (TME) can be immunosuppressive or favourable for mounting an immune response. Effector lymphocytes play an essential role during an anticancer immune response, but their activities can be suppressed by the hostile TME. Many studies have made good progress in the modulation of the immune response to allow the identification and elimination of tumour cells. However, the efficacy of these immunotherapies is patient-specific and highly dependent on the immunological profile of the tumour and its TME. This review will give an overview of breast cancer, the immune system as well as their complex relationship. Strategies and approaches that can harness the potential of immunotherapy that engages lymphocytes in the treatment of breast cancer, along with their current challenges, will also be discussed.