Roles of Gut Microbiota in Cancers of the Gastrointestinal Tract

The gut microbiota, comprised of a large population of microorganisms including bacteria, bacteriophages, fungi, and archaea interacting closely with the host, plays a major role in gut inflammation and tumorigenesis through direct cell-cell contact or secretion of bioactive substances. Shotgun metagenomic sequencing studies conducted in the last decade have revealed the widespread alterations of the microbial landscape in tumors of the gastrointestinal (GI) tract and, together with functional experiments, pinpointed specific microbes that functionally contribute to tumorigenesis.

Altered gut microbiota is casually linked to GI cancers. In light of the increasingly appreciated association, specific fecal microbes have been promulgated as non-invasive diagnostic markers for early GI cancer detection. Moreover, modulation of the gut microbiota has been proposed as a new strategy to prevent GI cancers and enhance the efficacy of GI cancer therapies. This Research Topic will cover issues in these interconnected areas that help transform discoveries in basic science into clinical applications.

This Research Topic seeks to capture the state-of-the-art development in the field of GI cancer microbiota to consolidate our understanding of the functional roles of gut microbes in GI tumorigenesis and their exploitation in GI cancer diagnosis and prevention. This Research Topic also welcomes contributions that shed new light on the roles and mechanisms of gut microbes in modulating the efficacy of GI cancer therapies, including chemotherapy and immunotherapy. Both original articles and reviews are welcome.