CD274 and neoplasm: IHC for PD-L1 and PD-1 was performed with 5H1 and M3 mAbs, respectively; samples were considered “positive” if cell surface PD-L1 and PD-L2 expression by tumor cells and tumor-infiltrating immune cells, including tumor-infiltrating lymphocytes (TILs) and histiocytes, was ≥5%.