In this light, the VENTANA PD-L1 (SP263) Assay was developed to address many of these complexities and was validated to reliably detect PD-L1 protein in FFPE NSCLC and HNSCC tissue samples using a rabbit monoclonal antibody optimized for use with the OptiView DAB IHC Detection Kit. This evidence concerns the gene CD274 and non-small cell lung carcinoma.