Role of Gut Microbe in Cancer Immunotherapy

Gut microbes have become more and more popular as their balance is closely related to human health and immunity. The gut has its own mucosal structure which helps prevent pathogenic bacteria from invasion and working with gut microbes to deal with diseases. The gut microbe can affect human immunity through its metabolite and its connection with the mucosal system. They can also help build barriers to prevent hosts from the pathogens. While the dysregulation of gut microbe will cause inflammation, diseases, and tumor growth. The growth of pathogens and the drop of probiotics destroy the function of the host’s immunity and thus result in some gut diseases, such as autoimmune diseases and colorectal cancer. Also, clinical trials have shown that the gut microbe has a great effect on cancer immunotherapy, especially immune checkpoint inhibitors. Research has proved many kinds of bacteria in the human gut can help regulate and promote the blocking of common immune checkpoints like CATL-4. They can take part in cancer immunotherapy by their secretion to trigger the human immune system and help patients deal with tumors as well. Here the structure of the gut immune system, the common gut diseases, and the roles played by gut microbes in them are discussed. Also, the link between gut microbe and cancer immunotherapy will be included. Finally, the challenges and future development of the gut microbe in cancer treatment are briefly mentioned.