Abstract
Manipulation of defined costimulatory pathways may provide a means to direct the immune response against head and neck cancer. Three broad hurdles serve as relative obstacles to effective clinical translation of reagents designed to alter costimulatory function. First is an expanding, but still limited, understanding of the biological function of each individual costimulatory pathway. Second is the paucity of reagents suitable for clinical application. Third is the limited number of valid model systems to evaluate the utility of these novel reagents prior to clinical intervention. This review focuses on the role of a recently discovered costimulatory molecule, B7-H1, as a model for the development of novel strategies for immunotherapy of head and neck cancer.