2021 Volume 35 Issue 3 Pages 143-154
In 1981, neoplasms became the primary cause of death in Japan, and the upward trend as a cause of death remains intact even now. In 2018, approximately 374,000 Japanese were killed by cancers, the proportion of total deaths being 27.4%. This means that approximately one out of 3.5 deaths in Japan were caused by neoplasms. In recent years, immunotherapies have rapidly developed and been now recognized as the “fourth” standard therapy against cancer, after surgery, chemotherapy, and radiotherapy. In particular, immune checkpoint inhibitor therapies have been attracting attention because of their potent clinical efficacies against advanced cancers. Several antibodies for immune checkpoint blockade have been approved as clinical drugs in many countries, including Japan, and a large number of clinical trials are currently proceeding to further expand their applications. However, there remain several critical issues in the present immune checkpoint blockade therapy, one of which is the identification of biomarkers correlating with either clinical benefits or adverse events. In this review, we discuss recent findings concerning the relationships between enteric microbiota and the clinical efficacy/inefficacy of immune checkpoint blockade therapies.
