In total, 12 studies had estimated in tumor cells expression of PD-L1[9,10,12,18–26] and 5 studies evaluated expression of PD-L1 in both tumor and immune cells.[19,22–24,26] Also, different study owns different criteria for PD-L1 cut-off values which were summarized in Table 1. This evidence concerns the gene CD274 and neoplasm.