IMMUNOLOGY2026™ Conference Recordings For Attendees-Tumor-infiltrating microbes and their impact on the tumor immune microenvironment

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Video Summary

Christopher Johnson of MD Anderson discussed how tumor-infiltrating microbes, especially Fusobacterium nucleatum, interact with the tumor microenvironment in gastrointestinal cancers. He explained that microbes are enriched in CRC tumors, often in spatially distinct “microbial microniches,” and can influence immune and epithelial behavior. Using RNA-scope, spatial profiling, and digital spatial proteomics, his team found that bacteria localize to focal regions associated with myeloid-cell enrichment, increased immune checkpoint signals, and immunosuppressive niches.<br /><br />In vitro studies showed Fusobacterium can immobilize neutrophils and drive cancer cell dispersal, supporting a role in progression. He also highlighted therapeutic implications: metronidazole reduced tumor growth in Fusobacterium-colonized mouse models, and 5-fluorouracil unexpectedly inhibited Fusobacterium directly but could also be metabolized by some co-occurring microbes into an inactive form, potentially reducing chemotherapy efficacy.<br /><br />Johnson’s group further identified a high-risk Fusobacterium lineage, F. nucleatum animalis clade II, enriched in colorectal tumors and capable of surviving gastric acid via the GAD/GABA system, suggesting descent from the oral cavity to the gut. He concluded that human tumor-colonizing bacteria could be harnessed as a platform for future microbial cancer therapies, while emphasizing the need for human-relevant strains and spatially informed studies.

Meta Tag

Date April 16, 2026 8:00 AM - 8:33 AM

Room Ballroom

Session Major Symposium B: Microbiome Influence on Epithelial-immune Crosstalk

Speaker Christopher Johnston

Track Mucosal And Regional Immunology (MUC)

Year 2026

Keywords

Fusobacterium nucleatum

colorectal cancer

tumor microenvironment

microbial microniches

immune checkpoint

metronidazole

5-fluorouracil

April 16, 2026 8:00 AM - 8:33 AM

Ballroom

Major Symposium B: Microbiome Influence on Epithelial-immune Crosstalk

Christopher Johnston

Mucosal And Regional Immunology (MUC)

2026