How bad gut bacteria leave DNA fingerprints in colon cancer
Microbiome-Genome Crosstalk in Colorectal Cancer: Colibactin Signatures and Fusobacterium nucleatum in Epidemiology, Driver Selection, and Translation.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Some gut bacteria make chemicals that break DNA in colon cells, causing specific mutations that lead to cancer—especially in young people. Another bacteria makes cancer resistant to chemo but helps it respond to immunotherapy.
Surprising Findings
Fusobacterium nucleatum is linked to both chemoresistance AND improved response to anti-PD-1 immunotherapy.
Most people assume a cancer-linked bacterium is purely harmful—this one does opposite things depending on treatment type, suggesting microbiome effects are context-dependent and complex.
Practical Takeaways
If you're under 50 and have a family history of CRC, ask your doctor about stool metagenomics or ctDNA testing for SBS88 signature and Fusobacterium nucleatum.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Some gut bacteria make chemicals that break DNA in colon cells, causing specific mutations that lead to cancer—especially in young people. Another bacteria makes cancer resistant to chemo but helps it respond to immunotherapy.
Surprising Findings
Fusobacterium nucleatum is linked to both chemoresistance AND improved response to anti-PD-1 immunotherapy.
Most people assume a cancer-linked bacterium is purely harmful—this one does opposite things depending on treatment type, suggesting microbiome effects are context-dependent and complex.
Practical Takeaways
If you're under 50 and have a family history of CRC, ask your doctor about stool metagenomics or ctDNA testing for SBS88 signature and Fusobacterium nucleatum.
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Claims (6)
A bacterial toxin called colibactin can cause DNA damage in children, and this damage can be found as one of the earliest genetic changes in tumors that develop in the colon later in life.
The bacterium Fusobacterium nucleatum is linked to reduced effectiveness of chemotherapy drugs like 5-fluorouracil and oxaliplatin in a subtype of colorectal cancer, due to its activation of specific cellular signaling pathways that promote autophagy and inhibit cell death.
A specific genetic change in the APC gene is found in most tumors that show a unique pattern of DNA damage caused by colibactin, a toxin produced by certain bacteria, and this genetic change is much more common in tumors with that damage pattern than in those without it.
Certain strains of E. coli that produce colibactin are linked to distinct patterns of DNA damage found in colorectal tumors, particularly in younger patients, and these damage patterns are found in a portion of the mutations that drive tumor development.
Colorectal cancers diagnosed before age 50 are three to four times more likely to carry a specific DNA mutation pattern linked to colibactin-producing bacteria than cancers diagnosed after age 50, indicating that exposure to these bacteria earlier in life may be linked to the increase in early-onset colorectal cancer.