CD274 and Ewing sarcoma: Moreover, the PD-L1 gene level was increased considerably in recurrent (1.17 ± 0.12) compared to non-recurrent (0.82 ± 0.08) osteosarcoma tumors (P = 0.008), also recurrent Ewing sarcoma (1.28 ± 0.08) compared to non-recurrent Ewing sarcoma tumors (0.57 ± 0.06) (P < 0.0001) (Fig. 1F).