As Pearson’s correlation analysis indicated, among the identified seven CXCR members in HNSCC, five of the CXCR members, including CXCR2 and CXCR4 to CXCR7, were negatively correlated with methylation level (Fig. 2 B–F). Here, CXCR2 is linked to head and neck squamous cell carcinoma.