γδ T Cell-Mediated Immune Responses for Cancer Therapy: Special Focus on Breast Cancer.

Triple-negative breast cancer (TNBC) is a type of breast cancer (BC) with high aggressive nature, devoid of receptors for estrogen and progesterone hormones and with overexpression of the HER2/neu protein. It is more aggressive than other types of BC, common occurring in younger women. Recently, preclinical and clinical studies have investigated the use of immune therapies to treat TNBC patients. However, a subset of patients is responding to immunotherapy due to the high level of tumor mutation burden. The bidirectional communication among the tumor microenvironment (TME) cells via signal molecules modulates γδ T cells to support or impair tumor growth. This review emphasizes γδ T cell-mediated immune responses with a special focus on breast cancer. We present the cytotoxic characteristics of γδ T cells. We also present the promising role of γδ T cells in mounting pro-tumor and anti-tumor responses in the TME. Finally, our review focuses on prominent features of γδ T cells as a curse in breast cancer development.