Given the previously established link between granulocytic CD11b+Ly6GhiLy6Cint MDSC expansion and cancer metastasis (70, 71), our studies suggest a role for STAT4 in inhibiting immunosuppressive myeloid cell differentiation to prevent HNSCC establishment at lymph node metastatic sites. This evidence concerns the gene ITGAM and head and neck squamous cell carcinoma.