[Current status and prognosis of immune checkpoint inhibitors for esophageal cancer]

Programmed cell death protein 1 (PD-1/CD279) and cytotoxic T Lymphocyte Antigen-4 (CTLA-4) are important immune checkpoints, through the role of the corresponding ligands and inhibit T cell activation and production of cytokines, in maintaining the body's vital role in peripheral tolerance. The use of anti-CTLA-4/PD-1 /PD-L1 monoclonal antibodies to block the tumor signaling pathway has shown excellent anti-tumor efficacy in a variety of solid tumors, and it is expected that immunotherapy will be available for the treatment of 60% advanced tumors in the next decade. Esophageal cancer is one of the major causes of cancer-related deaths worldwide, and its 5-year survival rate is generally low. Currently, radiotherapy, chemotherapy, and surgery are the standard treatments for esophageal cancer, and there is no effective treatment scheme for patients with esophageal cancer who fail to respond to standard treatment. Due to the diversity of somatic cell gene mutations and the generation of neo-antigens in esophageal cancer, immunotherapy has become a feasible treatment scheme to improve the prognosis of esophageal cancer. In this situation, the application of immunotherapy for esophageal cancer or more specific immune checkpoint inhibitors has gradually become the focus of the treatment of esophageal cancer. Nowadays, the research of immune checkpoint inhibitors, such as ipilimumab, tremelimumab, pembrolizumab, nivolumab and avelumab on esophageal cancer is proceeding at an amazing speed. The phase Ⅰ b clinical study of immunotherapy for esophageal cancer, which previously attracted great interest, has been replaced by the phase Ⅲ clinical study, and the results of the relevant studies also show a good prospect for the application of immune checkpoint inhibitors for esophageal cancer. However, the prediction of therapeutic effect and the selection of the best candidates still need to be further studied.