Further Understanding of the Immune Microenvironment in Head and Neck Squamous Cell Carcinoma: Implications for Prognosis

Purpose We aimed to review the literature on the tumor microenvironment as a key player in tumor growth and anti-cancer treatment responses in head and neck cancer. Patients and methods We reviewed the recent literature on this topic, using the following research words: "tumor microenvironment" and "head and neck cancer or neoplasm or head and neck squamous cell carcinoma" and "immune cells" and "stromal cells". A search was conducted on the PubMed website and reports from international meetings, presentations and abstracts. Results The tumor microenvironment is a complex network in which myeloid cells, tumoral cells, growth factors and cytokines are involved in angiogenesis, the extracellular matrix and epithelial-to-mesenchymal transition. Conclusion Immune resistance and rapid tumor growth depend on immunosuppressive and pro-tumoral environments. Further investigations to classify and adequately treat patients with head and neck cancer are required.