Osteosarcoma, the most common malignant bone tumor in children and adolescents, remains a complicated disease to treat; no new treatments have been developed in more than three decades. Due to the importance of the immune system in osteosarcoma disease progression, immunotherapeutic strategies have been explored to potentially improve long-term survival. However, most immunotherapeutics have not reached the level of success hoped would occur in this disease. Understanding the immune system in osteosarcoma will be key to optimizing treatments and improving patient outcomes. Therefore, immunophenotyping can be used as a very powerful tool to help better understand the complexity of the immune response seen in osteosarcoma and in the use of immunotherapy in this malignancy. This book chapter will provide an overview of the known immune responses seen in this disease and potential developments for the future of immunophenotyping. Indeed, it appears that being able to track the immune system throughout the disease and treatment of patients with osteosarcoma could allow for a personalized approach to immunotherapy.
Keywords: Cytokine; Granulocyte; Immunology; Immunopathology; Immunotherapy; Lymphocyte; Lymphoid; Myeloid.