The history and basics of tumor immunity

Abstract

According to the cancer immunoediting hypothesis, cancer cells select low immunogenicity cancer cells that are less likely to be attacked by the immune system （immune selection） and develop various immunosuppressive mechanisms in the host to escape from the immune system （immune escape） during cancer development. It has become clear that the balance between immune selection and immune escape in each cancer patient results in differences in the tumor microenvironment （TME）, which are immunologically referred to as hot and cold. While immune checkpoint inhibitors （ICIs） have been successfully introduced into the clinic for various types of cancer, more than half of patients treated with ICIs fail to respond, even in combination, due to multiple immunosuppressive mechanisms in the TME. It is therefore necessary to develop more effective cancer immunotherapeutic strategies and define biomarkers for stratifying responders and non-responders via a detailed analysis of the immune responses in each cancer patient. We propose that elucidating the various immunosuppressive mechanisms involved in cancer may lead to the development of appropriate cancer immunotherapy, and thus to immune precision medicine for cancer.