The Dual Roles Of Human Gamma Delta T Cells: Anti-Tumor Or Tumor-Promoting

gamma delta T cells are the unique T cell subgroup with their T cell receptors composed of gamma chain and delta chain. Unlike alpha beta T cells, gamma delta T cells are non-MHC-restricted in recognizing tumor antigens, and therefore defined as innate immune cells. Activated gamma delta T cells can promote the anti-tumor function of adaptive immune cells. They are considered as a bridge between adaptive immunity and innate immunity. However, several other studies have shown that gamma delta T cells can also promote tumor progression by inhibiting anti-tumor response. Therefore, gamma delta T cells may have both anti-tumor and tumor-promoting effects. In order to clarify this contradiction, in this review, we summarized the functions of the main subsets of human gamma delta T cells in how they exhibit their respective anti-tumor or pro-tumor effects in cancer. Then, we reviewed recent gamma delta T cell-based anti-tumor immunotherapy. Finally, we summarized the existing problems and prospect of this immunotherapy.