HLA class II expression on tumor cells and low numbers of tumor‐associated macrophages predict clinical outcome in oropharyngeal cancer

BACKGROUND: Human papillomavirus (HPV)‐positive oropharyngeal squamous cell carcinoma (OPSCC) is a highly immunogenic tumor and differences in tumor microenvironment might contribute to the improved survival of HPV‐positive OPSCC patient. METHODS: A comprehensive multivariate analysis with clinical and immune variables (human leukocyte antigen [HLA] I/II, programmed death ligand 1 (PD‐L1), programmed death receptor 1 (PD1), T cells, and macrophages) was performed in 142 OPSCC patients. RESULTS: We found an inverse correlation between the expression of HLA class II molecules on tumor cells and CD68+ CD163+ tumor‐associated macrophages (TAMs). High HLA‐DP/DQ/DR expression and low number of TAMs were associated with longer disease‐specific survival and disease‐free survival (DFS). Furthermore, a new population of CD8+ FoxP3+ T cells was correlated with shorter DFS in multivariate analysis. CONCLUSIONS: \We identified new prognostic markers for patients with oropharyngeal cancer, which can be used for selecting patients that can benefit from immunotherapy.