CD274 and head and neck squamous cell carcinoma: In recent studies, we predicted that PD-L1 induction stimuli in HNSCC cell lines SCC4, SCC15, and SCC25 were processed via ERK signaling pathways (via EGFR, BRAF-V600E (BRAF), MEK1/2 (MAP2K1, MAP2K2), ERK1/2 (MAPK3, MAPK1), and c-Jun (JUN)) [18,19].