CD274 and head and neck squamous cell carcinoma: To examine the ability of Pam3CSK4 and S. aureus to regulate PDL1 in other HNSCC models, we chose to advance models from our panel of 43 cell lines based on relative expression of the Toll-like receptors as determined by RNAseq, as TLR2 is thought to heterodimerize with TLR1 or TLR6, and because these TLRs are thought to be largely responsible for recognition of bacterial cell wall components [25].