CD274 and head and neck squamous cell carcinoma: Thirty-four cultured human tumor lines derived from 18 melanomas (MEL), 12 renal cell carcinomas (RCC), and 4 squamous cell carcinomas of the head and neck (SCCHN), and normal donor peripheral blood monocytes (Monos), were treated with cytokines that we found expressed in the PD-L1+ TME by gene expression profiling (GEP), including IFN-g, IL-1a, IL-10, IL-27 and IL-32g.