To determine if SX-682 could be efficacious in a syngeneic, immunocompetent murine model of HPV-negative HNSCC, MOC1 tumors implanted s.c. in the flank of mice were evaluated via RNA in situ hybridization for expression of CXCR2 and the murine CXCL chemokines, CXCL1 and CXCL2, as mice lack the IL-8 gene (Fig. 5a). This evidence concerns the gene CXCR2 and head and neck squamous cell carcinoma.