Mutant KRAS favors a microbe that signals back.

Mutant KRAS in colorectal tumors favors Bacteroides acidifaciens, which signals back to reinforce RAS-MAPK signaling.

• Why it matters: Understanding the reciprocal interaction between tumor genetics and the microbiome could reveal new mechanisms driving colorectal cancer progression and potential therapeutic targets.
• What they did: Jiao et al. analyzed the relationship between mutant KRAS and the microbiome, identifying Bacteroides acidifaciens as favored by mutant KRAS and elucidating its signaling pathway involving SusF-ARHGEF2.
• The result: The findings suggest that mutant KRAS promotes specific microbiome composition that, in turn, enhances RAS-MAPK signaling, potentially creating a feedback loop influencing tumor behavior.