A new method exploring the links between our microbiome and bowel cancer

29th November 2023

Researchers funded by our Curestarters have developed a new method for analysing and profiling the types of microbes present in patient tumour samples. They hope that this work could one day contribute to the development of a new type of biomarker test that will help doctors understand more about a patient’s cancer.

What were our researchers looking for?

Worldwide Cancer Research scientist Dr Luigi Nezi and his team in Italy are interested in how changes to our ‘microbiome’- the tiny microbes that live in and alongside us- could be connected to cancer growth.  

Research is already uncovering intriguing ways that our microbiome could influence cancer growth, and even how we can treat cancer. But less is known about the types of microbes that actually grow in and around tumours (the ‘tumour microbiome’), and how these different microbe strains are connected to the tumour. So Dr Nezi and his team set out to find out more. 

But first, what is our microbiome? And why do scientists like Dr Nezi think that it could be so important in cancer?

What is the microbiome?

The microbiome is the name given to the trillions of microbes - bacteria, viruses, and other tiny bugs - that live on and within us. The vast majority of these microbes do us no harm. In fact, research increasingly shows that we need these microbes to carry out important functions. Microbes in our digestive system (our gut microbiome) help us to digest our food, and also help to keep our immune system running well. 

But research has also found links between changes to our microbiome and some forms of disease, including cancer. 

For example, studies suggest that some types of gut microbe may be involved in the development of bowel tumours. And intriguingly, there is also growing evidence that the types of microbes that a patient has in their gut microbiome may even influence the effectiveness of some types of cancer treatment. 

Dr Nezi and his team wanted to study these links further. But first, the researchers needed to analyse data from hundreds of cancer samples. So they turned to a huge digital ‘library’ of cancer samples, called The Cancer Genome Atlas. 

Harnessing the power of The Cancer Genome Atlas 

The Atlas contains all sorts of genetic and molecular data extracted from thousands of donated patient tumour samples. Luckily, these datasets also contain the genetic information of any bacteria strains that were present on the cancer sample at the time that it was taken too. 

Finding a way to extract this information is tricky, and takes time. But with the help of Curestarter funding, Dr Nezi and his team were able to develop a reliable way to search for, gather, and analyse the information they wanted. 

A new way to study links between microbes and cancer

With their method, the researchers were able to more accurately “clean“ the type of bacteria found in the tumour sample and ‘cross-check’ them with different characteristics of the tumour. They searched for any common patterns that could link the types of bacteria detected with different tumour properties. 

The team found interesting evidence linking some bacteria species to different tumour characteristics- including certain specific molecular ‘signatures’, and the presence of a certain type of immune cell. Five specific bacterial species also seemed particularly strongly linked to some tumour properties.

The researchers also tested their approach on fresh bowel cancer samples donated by patients from IEO - their Italian hospital - and were still able to detect reliable bacterial signals and patterns- further confirming that their new approach works. 

What does this mean for patients with bowel cancer? 

It is early days, and this is just the beginning. But if further research can establish that certain types of bacteria are linked with some specific tumour characteristics, like aggressiveness, or likelihood to spread, then this could be very useful information for predicting how the tumour is likely to behave.

It could mean that by seeing which bacteria are present in a patient’s tumour microbiome, doctors can know more about how the tumour is growing, and which treatments are likely to be the most effective. 

Ultimately, the researchers hope that their work could help integrating information regarding the disease with those from the surrounding environment that, all together, would provide doctors with a more accurate prognostic tool and patients with more precise and effective therapies. 

In the meantime, the researchers hope their new approach will also help to build up a detailed picture of just how tumours and our microbiome are connected. They particularly want to investigate how the tumour microbiome could change as the cancer begins to spread, and to adapt their new method to be able to detect viruses present in the tumour too. 

This fantastic step forward would not have been possible without our Curestarters.

Dr Luigi Nezi, Worldwide Cancer Research scientist
Thanks to your support, we are making a significant step in advancing cancer research, which will help improve the lives of countless individuals affected by this devastating disease.

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