CD8A and cancer: Therefore, the importance of the MHC-I modulation in cancer immune evasion has been emphasized in recent years and a range of studies have reported that the loss or downregulation of MHC-I is a major mechanism of cancer immune evasion by blocking the surface presentation of tumor-associated antigens, thus suppressing the cytotoxicity of CD8+ T cells and impairing the adaptive immune response [7, 8].