CD274 and head and neck squamous cell carcinoma: The coefficients of correlation between the negative or positive status for CD274 and 73 − 10 were 83% for NOM, 50% for SIN, and 100% for HNSCC, with a significant correlation (r = 0.58, 95% CI: 0.148–0.82, p = 0.01, Fig. 3d).