Original title: A gut microbiome-derived risk score is associated with future cancer development
Emily Oosterhout, Rose Leijdesdorff, Oleg Kambur, Bert van der Vegt +14 · September 2026
Cancer is a leading cause of illness and death worldwide, and new cases are rising. Known lifestyle factors like smoking, obesity, and diet increase this danger, but gut bacteria also play a role. Most past research only looked at people who already had cancer. Researchers wanted to see if gut bacteria could warn us about future cancer years before diagnosis. They examined stool samples to analyze the mix of microbes living in the gut. By tracking which specific bacteria were present, they built a risk score using 28 microbial species. People with higher scores faced a higher risk of getting a cancer diagnosis over up to 10 years of follow-up. This remained true even after accounting for established lifestyle risks. The score also worked in separate groups of patients and showed signs of predicting future cancer in another population. Gut bacteria can show warning signs years in advance.
Imagine trying to guess which houses on your street will need a new roof within the next ten years. The usual clues—age, weather, shingles—only get you so far, because the roof looks fine today. Now suppose the bird nests on each roof gave an early hint: certain species and patterns today predict trouble later, long before any water gets in. In this paper, the houses are people, the bird nests are the bacteria living in their gut, and the hint is a score computed from a stool sample. That score is then checked against cancer diagnoses over the following ten years.
Cancer risk is often assessed through lifestyle factors like smoking, obesity, and diet. This study adds a new kind of signal: the bacteria in a stool sample can carry a warning of cancer years before a diagnosis, even after those factors are taken into account. If it holds up, it could help screen people earlier.
The abstract doesn't say whether the microbiome changes cause cancer or are just an early marker. It also doesn't report how well the score would perform as a screening test in a real clinic, and the FINRISK result is only described as a consistent trend rather than a strong validation. Since the main score was built and validated in European cohorts, generalizing to other populations is not established.
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A gut microbiome-derived risk score is associated with future cancer development — Emily Oosterhout, Rose Leijdesdorff, Oleg Kambur et al. — medRxiv — doi:10.64898/2026.09.09.26362619
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.