CD274 and non-small cell lung carcinoma: Pembrolizumab, for example, is approved for use in metastatic non-small cell lung cancer as first-line treatment in patients with ≥ 50% of tumor cells expressing PD-L1, as determined by a Food and Drug Administration-approved test [11], such as the Dako IHC PD-L1 22C3 pharmDx companion assay used in the trial underlying approval [11, 12].