CD274 and head and neck squamous cell carcinoma: Results were validated on two cohorts of 102 HNSCC patients and 139 HNSCC patients under treatment with PD-L1 inhibitors, respectively, and a cohort of 108 HNSCC HPV negative patients and by in vitro experiments in HNSCC cell lines.<h4>Results</h4>We observed a significant association between the gene set and TP53 gene status and OS and PFS of HNSCC patients.