IL6 and head and neck squamous cell carcinoma: While our gene expression results remain only correlative, the elevated expression of IL6R, STAT3 and its downstream target CD274 in PBMCs from HNSCC patients, together with results of immunophenotyping of myeloid suppressor cells and the elevated arginase activity strongly suggest that CMT transiently stimulates immunosuppressive IL-6/STAT3 signaling.