CD274 and neoplasm: Results of Blueprint phase 1, a feasibility study evaluating the analytical comparability of four assays (22C3, 28–8, SP263, and SP142) assessed independently by three experts, indicated that PD-L1 tumor expression (cell staining) was concordant for the 22C3, 28–8, and SP263 assays, while the SP142 assay consistently showed fewer stained tumor cells [10].