PD-L1 together with PD-L2 are binding and functional partners of PD-1, expressed on the surface of many organ cells and in various tissues (Freeman et al., 2000; Latchman et al., 2001) playing a dominant role in the suppression of T cell responses, especially in the tumor microenvironment (Zou and Chen, 2008), thereby preventing effector immune cells from killing cancer cells (Azuma et al., 2008). This evidence concerns the gene CD274 and neoplasm.