Roles of intestinal microbiota in response to cancer immunotherapy.

Cancer immunotherapy has been significantly effective on multiple cancers; however, there are still a distinct number of non-responding patients and various immune-related adverse events in responding patients. It is known that heterogeneity of intestinal microbiota may lead to different outcomes of therapy. Previous studies have reported that intestinal microbiota is probably attributed to influence the efficacy of cancer immunotherapy. Some intestinal bacteria could synergize with immune checkpoint blockade agents and optimize the immune response against multiple cancers. Therefore, understanding the roles of intestinal microbiota could help to improve the clinical efficacy of cancer immunotherapy. In this review, we first introduced the close relationships between intestinal microbiota and intestinal immune system. Then, we described the emerging evidences that intestinal microbiota responses to cancer immunotherapy. Finally, we briefly reviewed the technical development on intestinal microbiota research.