CCL2 and head and neck squamous cell carcinoma: Overall, most cytokines were either suppressed (e.g., IFN-γ, CCL3, CCL20, CXCL1, TWEAK, TGF-β, SCF, LIF) in PB from HNSCC patients compared to controls or showed an elevated trend (e.g., CCL2, IL-16, IL-15) at specific time points.