In the recent study where pembrolizumab monotherapy did not improve progression-free survival, except in the sub-group of SCLC patients with high PD-L1 expression at the stromal interface, only 1 PD-L1+ case out of 35 was found when using DAKO 22C3, which was assessed on tumor cells [52]. The gene discussed is CD274; the disease is small cell lung carcinoma.