The characteristics in which differences by PD-L1 expression were observed included initial diagnosis of ES-SCLC, which was identified in 84% of patients with PD-L1–negative tumors and 60% with PD-L1–positive tumors, and elevated lactate dehydrogenase levels in 16% and 42%, respectively (Table S1). Here, CD274 is linked to small cell lung carcinoma.