As shown, PD-L1_1 selectively binds to PD-L1-positive tumor cells with affinities comparable to those previously observed on lymphocytes9, whereas only a poor binding was observed on MCF-7 cells, thus confirming its binding specificity for the target cells with a positive correlation between the level of expression of PD-L1 on the cells and the extent of binding of PD-L1_1 to those cells. This evidence concerns the gene CD274 and neoplasm.