The Role of the Microbiome in Modulating Response and Adverse Events in Solid Tumor Immunotherapy Treated Patients

The role of the host and tumoral microbiome has been initially described through purely observational and correlative studies by a number of groups and across cancer histologies. As further preclinical and early clinical studies are performed to quantify this interaction, mechanistic insights have been increasingly noted. With gut and tumoral microbes being shown to affect host systemic immune responses both to tumors themselves as well as off target effects leading to immune related adverse events (irAE). As sequencing technologies continue to improve and our understanding of the mechanisms of these interactions deepen these insights have begun to make their way into the clinical setting through pilot trials of microbial modulation to optimize outcomes. In this work we will review microbial associations with response and irAE, proposed mechanisms behind these observations, and initial clinical trials to improve modulate these microbes.

Through this Research Topic collection, we propose to demonstrate the progression of the interface of microbiome research and immunology outlining the path it has taken from observational, to mechanistic study, to early preclinical trials. To date our improved understanding has garnered insights into the mechanisms behind these observed differences in patient outcome but the quantification of the interaction of two complex systems requires future and in-depth study. This work will highlight areas of ongoing and necessary investigation as well as areas of future study to begin to understand the microbiome:host immune interface and begin to leverage this understanding to improve outcomes for our patients.

For this Research Topic, we welcome all types of articles dealing with:

• Gut microbial associations with response to therapy
• Gut microbial associations with immune related adverse events
• Microbial interactions with the tumor immune environment
• Proposed and demonstrated mechanisms of microbial interactions with host immunity
• Microbial modulation and immunotherapy outcomes
• The effect of antibiotics on the gut microbiome and response to immunotherapy
• Preclinical studies of fecal transplantation and immunotherapy response
• Pilot trials of fecal transplantation and immunotherapy response
• Overview of previous and ongoing trials
• Optimizing fecal transplantation algorithms and selection
• Next generation therapeutics modulating the gut and tumoral microbiome

Manuscripts consisting solely of bioinformatics or computational analysis of public genomic or transcriptomic databases which are not accompanied by robust and relevant validation (clinical cohort or biological validation in vitro or in vivo) are out of scope for this topic.