Immunotherapy in head and neck cancer

The physiological immune response to malignant cells is based on the interaction of antigen-presenting cells, such as dendritic cells and macrophages, with T and B lymphocytes. CD8(+) effector and natural killer cells are primarily responsible for tumor cell lysis. Tumor cells exploit several mechanisms to influence the body's immune system and promote development and progress of solid head and neck malignancies. Via regulatory T cells, myeloid-derived suppressor cells, tumor-associated macrophages, and cancer-associated fibroblasts, tumor cells promote development of suppressive signaling pathways that enable tumor progression. Novel immune therapeutics aim to influence these signaling pathways. Current studies are investigating agents which influence immune-stimulating or immune-suppressive cytokines, as well as drug-based Toll-like receptor activation and vaccination in head and neck cancer. Development of monoclonal antibodies allows for direct and highly specific binding of therapeutics to cell receptors recently discovered immune checkpoint receptors are particularly intriguing targets. Monoclonal antibodies directed specifically toward T cell-stimulating receptors such as CD28 and CD134, or immunosuppressive receptors CTLA-4 and PD-1, are currently under investigation and have shown promising results.