The role of cytokines in head and neck squamous cell carcinoma: a review

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide, accounting for approximately 6% of all cancer cases and responsible for an estimated 1-2% of all cancer deaths. Much research evidence has accumulated in the recent years on the changes in the expression of pro-inflammatory and, to a lesser extent, anti-inflammatory cytokines, that (i) may have a role in the malignant transformation of HNSCC, (ii) may be used as diagnostic markers in the sera of patients because of their excessive production by the tumor cells and (iii) may act as possible immunotherapeutic targets. Among pro-inflammatory cytokines, interleukin-8 (IL-8) has been reported to have an important role in cancer invasion, angiogenesis and metastasis. Recent studies have shown an increased concentration of IL-8 in patients with HNSCC and a positive association with lymph node metastasis and tumor classification, although IL-8 was not significantly associated with shorter overall survival and cancer progression-free survival. Additional evidence on the pathological mechanism of origin, invasion, and metastasis of HNSCC, as well as a better understanding of the implications of cytokines, chemokines and growth factors, are of paramount importance for the advancement of research in head and neck oncology.