New research to investigate role gut bacteria plays in breast cancer

Researchers are investigating the function of gut bacteria in breast cancer and how we could use it to fight against the disease, thanks to new funding from Breast Cancer Now.

Bacteria living in our gut can affect our immune system and previous research in other cancers has shown a connection between healthier gut bacteria and better overall outcomes for patients.

Cancerous cells can spread in many different ways, including by manipulating the immune system to prevent being killed. When breast cancer spreads to other parts of the body, it becomes incurable.

Breast Cancer Now has awarded £249,065 to Dr Stephen Robinson at the Quadram Institute to study the composition and function of the gut bacteria in oestrogen receptor (ER) positive breast cancer. 

Up to 80% of women with the disease are diagnosed with ER-positive breast cancer, making it the most common type of breast cancer.

Stool samples will be taken from women who have recently been diagnosed with ER-positive breast cancer and are yet to begin treatment. Further samples will then be taken from the same women at various stages during and after treatment to see how gut bacteria changes during the course of the disease.

The team will compare samples from people who respond well to treatment to people who don’t, to analyse any differences in their gut bacteria and see if it’s possible to predict the outcome of treatment based on this information.

Using mice, the researchers will also investigate how gut bacteria influence the immune system. The team will test specific bacteria species that have been linked with better treatment outcomes alongside bacteria linked with poorer outcomes, to see how the bacteria affect the progression of breast cancer. 

Dr Stephen Robinson at the Quadram Institute said: “Evidence shows that certain bacteria living in our gut can help slow the growth and spread of cancers, including breast cancer. These findings are particularly important given that breast cancer treatment may disturb normal gut bacteria.

“We’re looking into how exactly the bacteria help our bodies prevent cancer from progressing, and whether standard treatments are affecting this.”

Dr Simon Vincent, Breast Cancer Now’s director of research, support and influencing, said: “This project will provide crucial insights into the role gut bacteria play in breast cancer. It could help us develop new approaches to treatment that use gut bacteria to activate the immune system and reduce the chance of breast cancer spreading and becoming incurable.

“With around 11,500 women tragically dying from breast cancer each year in the UK, we urgently need to find new ways to prevent the disease spreading, and treat it effectively when it does.”

Kerry Blake, 34, from Hertfordshire found a small lump in her left breast a month before her wedding.

Kerry said: “A few days before the wedding I felt a pain in my breast so booked a doctor’s appointment to get it checked out. During the examination, the doctor confirmed I had a small pea-sized lump and referred me to the breast clinic.”

After an ultrasound, mammogram and needle biopsy, Kerry was given the devastating news that she had grade 2, ER-positive breast cancer.

Kerry said: “The doctor sat down next to me to give me the results. I burst into tears and was trying hard to listen and make sense of what he was saying but all I could think was I’m 28, how can I have breast cancer?”

In the following months, Kerry had CT scans, MRI scans, fertility appointments, chemotherapy and radiotherapy, followed by a single mastectomy. She also had the 6cm tumour in her left breast removed.

It’s now been five years since Kerry’s diagnosis, and she believes it’s due to advances in research that’s she’s living a full and active life today.

Kerry said: “Receiving a breast cancer diagnosis is terrifying, but thanks to research, I'm here today. For me and countless others, breast cancer research isn't just about finding a cure; it's about finding kinder, more effective treatments and inspiring hope. With every research breakthrough, we're closer to a world where no more lives are lost to this terrible disease.”

Breast Cancer Now is the research and support charity here for anyone affected by breast cancer. Call their free helpline on 0808 800 6000 to speak to their expert nurses or find out more and donate at breastcancernow.org

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