For further analysis, the expression of A2AR in tumor infiltrated immune cells was detected by immunohistochemical (IHC) staining in our HNSCC tissue microarrays (TMAs), which contains 43 normal oral mucosae, 48 dysplasia (Dys) and 165 primary HNSCC (PH) tissues. The gene discussed is ADORA2A; the disease is head and neck squamous cell carcinoma.