Microbiota: A key factor affecting and regulating the efficacy of immunotherapy

BackgroundImmunotherapy has made significant progress in cancer treatment; however, the responsiveness to immunotherapy varies widely among patients. Growing evidence has demonstrated the role of the gut microbiota in the efficacy of immunotherapy.Main bodyHerein, we summarise the changes in the microbiota in different cancers under various immunotherapies. The microbial-host signal transmission on immunotherapeutic responses and mechanisms associated with microbial translocation to tumours in the context of immunotherapy are also discussed. In addition, we have highlighted the clinical application value of methods for regulating the microbiota. Finally, we elaborate on the relationship between the microbiota, host and immunotherapy, and provide potential directions for future research.ConclusionDifferent microbiota cause changes in the tumour microenvironment through microbial signals thereby affecting immunotherapy efficacy. Translocation of gut microbiota and the role of extraintestinal microbiota in immunotherapy deserve attention. Microbiota regulation is a novel strategy for combination therapy with immunotherapy. Although there are several aspects that deserve further refinement and exploration with regard to administration and clinical translation. Nevertheless, it is foreseeable that the microbiota will become an integral part of cancer treatment. The changes of microbiota in different cancers under various immunotherapies are summarised.The mechanisms of bacterial translocation and by which microbiota influence efficacy of immunotherapy are discussed.The strategies of regulating immunotherapy by gut microbiota modification are elaborated.The interactions between immunotherapy, host and gut microbiota are illustrated.image