Chimeric antigen receptor (CAR)-T cell therapy in triple-negative breast cancer: current status and future perspectives

Triple-negative breast cancer (TNBC) is the hardest to treat and the most aggressive form of breast cancer. Surgery, radiotherapy, and systemic chemotherapy are currently available, but deficiencies exist, including drug resistance and high frequency of recurrence. The absence of estrogen receptor (ER), progesterone receptor (PR), and HER2 makes conventional targeted therapies unsuitable for TNBC. The immunogenicity of TNBC emphasizes the urgency of introducing chimeric antigen receptor (CAR)-T cell therapy. The success of CAR-T therapy in the management of blood cancers suggests its feasibility. CAR-T therapy is achieved by editing the patient's autologous T cells to attack malignant cells. Currently, more and more CAR-T therapies targeting TNBC are being proposed and researched. In particular, different types of potentially tumor-associated antigens (TAA) offer promising directions. However, many obstacles require overcoming, especially physical or chemical ones in solid tumors. This paper reviews the TAAs currently under study, including their rationale and problems. In addition, the advantages of CAR-T therapies over other TNBC therapies and the current impediments and solutions are discussed to provide an overall view of the latest advances and to stimulate other ideas.