What Is Cancer? 4 Cancer Immunology

Tumor immunotherapy, which began with Coley’s toxin, has long been tried by various therapeutic methods based on the concept of “immune surveillance” and has now become the fourth standard tumor therapy due to the success of “immune checkpoint inhibitors (ICI).” Some fundamental problems with tumor immunotherapy have been overcome by a new strategy improving the immunosuppressive state around the tumor, where inhibitory cytokines and negative receptor-ligand pairs suppress tumor immune responses in the so-called “tumor microenvironment.” Immune checkpoint inhibitor therapy is also based on many advances in physicochemical research, such as antibody engineering technology and the evolution of drug delivery systems. Furthermore, new adoptive immunotherapies such as chimeric antigen receptor T (CAR-T) cells and bispecific antibodies have also been ready for use (Bargou R, et al. Science 321(5891):974–977, 2008). Tumor immunotherapy is being developed into a new stage, which is “combination therapy” with conventional golden standards: surgery, chemotherapy, and radiotherapy.