CXCL8 and head and neck squamous cell carcinoma: Regulatory cytokines relevant to MΦ polarization such as IL-1α, IL-4, IL-6, IL-8, IL-10, IL-23, M-CSF, GM-CSF, EGF, PGE2 and TGF-β are typically expressed in HNSCC [25, 39, 40].