The heightened importance of the microbiome in cancer immunotherapy

Abstract

The human microbiome is recognized as a key factor in health and disease. This has been further corroborated by identifying changes in microbiome composition and function as a novel hallmark in cancer. These effects are exerted through microbiome interactions with host cells, impacting a wide variety of developmental and physiological processes. In this review, we discuss some of the latest findings on how the bacterial component of the microbiome can influence outcomes for different cancer immunotherapy modalities, highlighting identified mechanisms of action. We also address the clinical efforts to utilize this knowledge to achieve better responses to immunotherapy. A refined understanding of microbiome variations in patients and microbiome-host interactions with cancer therapies is essential to realize optimal clinical responses.

Trial registration: ClinicalTrials.gov NCT03353402 NCT03341143 NCT03829111.

Keywords: cancer immunotherapy; immune checkpoint inhibitors; live biotherapeutic products; microbiome; tumor microenvironment.