CD274 and neoplasm: Positive tumor PD-L1 expression was significantly associated with shorter OS (P = 0.001): 78% (7/9) of patients with positive tumor PD-L1 expression had a median OS of 17 months (95% CI, 12.1–21.9), whereas only 15% (4/27) of those with negative tumor PD-L1 expression died of the disease within the study period (median OS, not reached; Fig. 4).