Gut Bacteria Key to Early Pancreatic Cancer Detection

Whether you had breakfast this morning or not, your pancreas is working quietly behind the scenes. This vital organ produces the enzymes that help digest your food and the hormones that regulate your metabolism. But when something goes wrong with your pancreas, the consequences can be devastating.

Pancreatic cancer has earned the grim nickname "the silent killer" for good reason. By the time most patients experience symptoms, the disease has often progressed to an advanced stage where treatment options become severely limited. In the UK alone , over 10,700 new cases and 9,500 deaths from pancreatic cancer were recorded between 2017 and 2019, with incidence rates continuing to rise.

The most common form, pancreatic ductal adenocarcinoma (PDAC), develops in the pancreatic duct - a tube connecting the pancreas to the small intestine. When tumours form here, they can block the flow of digestive enzymes, causing energy metabolism problems that leave patients feeling chronically tired and unwell. Yet these symptoms are often so subtle that they're easily dismissed or attributed to other causes.

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Now researchers are turning to an unexpected source for early PDAC detection: faecal samples. While analysing poo might seem an unlikely approach to cancer diagnosis, scientists are discovering that our waste contains a treasure trove of information about our health.

This is because your gut is home to trillions of bacteria - in fact, bacterial cells in your body outnumber human cells by roughly 40 trillion to 30 trillion. These microscopic residents form complex communities that can reflect the state of your health, including the presence of disease.

Since PDAC typically develops in the part of the pancreas that connects to the gut, and most people have regular bowel movements, stool samples provide a practical, non-invasive window into what is happening inside the body.

Global evidence builds

This innovative approach has been validated in studies across several countries, including Japan , China and Spain . The latest breakthrough comes from a 2025 international study involving researchers in Finland and Iran, which set out to examine the relationship between gut bacteria and pancreatic cancer onset across different populations.

The researchers collected stool samples and analysed bacterial DNA using a technique called 16S rRNA gene amplicon sequencing. Despite the complex name, the principle is straightforward: scientists sequence and compare a genetic region found in every bacterium's genome, allowing them to both identify and count different bacterial species simultaneously.

The findings from the Finnish-Iranian study were striking. Patients with PDAC exhibited reduced bacterial diversity in their gut, with certain species either enriched or depleted compared with healthy people. More importantly, the team developed an artificial intelligence model that could accurately distinguish between cancer patients and healthy people based solely on their gut bacterial profiles.

The field of microbiome research is evolving rapidly. While this study used amplicon sequencing, newer methods like "shotgun metagenomic sequencing" are providing even more detailed insights. This advanced technique captures the entire bacterial genome content rather than focusing on a single gene, offering an unprecedented resolution that can even detect whether bacteria have recently transferred between individuals.

These technological advances are driving a fundamental shift in how we think about health and disease. We're moving from a purely human-centred view to understanding ourselves as "human plus microbiome" - complex ecosystems where our bacterial partners play crucial roles in our wellbeing.

Beyond pancreatic cancer

The possibilities go well beyond pancreatic cancer. At Quadram, we're applying similar methods to study colorectal cancer. We've already analysed over a thousand stool samples using advanced computational tools that piece together bacterial genomes and their functions from fragmented DNA. This ongoing work aims to reveal how gut microbes behave in colorectal cancer, much like other scientists have done for PDAC.

The bidirectional interactions between cancer and bacteria are particularly fascinating - not only can certain bacterial profiles indicate disease presence, but the disease itself can alter the gut microbiome, as we previously showed in Parkinson's disease , creating a complex web of cause and effect that researchers are still unravelling.

Nonetheless, by understanding how our microbial partners respond to and influence disease, we're gaining insights that could revolutionise both diagnosis and treatment. Our past research has shown this to be incredibly complex and sometimes difficult to understand, but developments in biotechnology and artificial intelligence are increasingly helping us to make sense of this microscopic world .

For cancer patients and their families, this and other advancements in microbiome research offer hope for earlier detection. While we're still in the early stages of translating these findings into clinical practice, the potential to catch this silent killer before it becomes deadly could transform outcomes for thousands of patients, but will require more careful and fundamental research.

The microbial perspective on health is no longer a distant scientific curiosity - it's rapidly becoming a practical reality that could save lives. As researchers continue to explore this inner frontier, we're learning that the answer to some of our most challenging medical questions might be hiding in plain sight - in the waste we flush away each day.

Falk Hildebrand receives funding from the UKRI, BBSRC, NERC and ERC.

Daisuke Suzuki receives funding from Japan Society for the Promotion of Science.