Gut microbiome in modulating immune checkpoint inhibitors

Gut microbiome has been increasingly recognized for its influence on a diverse array of human diseases including cancer, and may also influence the outcome of cancer therapies. A prime example is seen in immunotherapy, for which gut microbes determine the therapeutic responses associated with immune checkpoint inhibitors (ICIs) in preclinical models and patient cohorts. This evidence hints that inter-individual variations in the gut microbiota may account for the significant heterogeneity in immunotherapeutic responses to ICIs. Understanding the functional role of gut microbiome in regulating not only mucosal but also systemic immunity and cancer is critical to move forward in this era of precision medicine. What's more, microbiota can be modified via several different strategies that are essential for the efforts in expanding immunotherapy efficacy. This review summarizes latest knowledge about the interactions between microbiome, host immunity and cancer, and strategies to modulate the microbiome with implications to be translated into clinic. FUNDING: This study was supported by National Key R&D Program of China (No. 2020YFA0509200/2020YFA0509203), RGC Theme-based Res Scheme Hong Kong (T21-705/20-N).