IL6 and head and neck squamous cell carcinoma: The p38 MAPK pathway regulates several cellular functions, including cell differentiation, apoptosis, and cell-cycle activity [21,44], while in HNSCC and other tumor types, activation of p38 MAPK is clearly associated with oncogenesis and tumor progression [20,45], contributing to the production of pro-inflammatory cytokines, such as IL-6, and tumor necrosis factor α (TNF-α) [46].