Insights from research and an interview with Dr Jennifer Wargo, MD, University of Texas M.D. Anderson Cancer Center, as featured in a recent JAMA interview.
The human body is home to trillions of microbes – bacteria, viruses, fungi, and other microorganisms – that live in and on us, especially in the gut. Collectively known as the microbiome, these microbes outnumber our human cells and play a crucial role in our health. In recent years, research has started to uncover the connection between the microbiome and how the body responds to cancer and its treatment.
In a recent interview with JAMA, Dr. Jennifer Wargo shared expert insights into this rapidly evolving area of research. Her comments highlight both what we know, and what we are only beginning to uncover, about the links between the microbiome and cancer.
What does a healthy microbiome look like?
According to Dr. Jennifer Wargo, a healthy microbiome is typically diverse and well balanced. This means there is a wide variety of microbial species, and many of them contribute positively to our immune system and overall well-being. In particular, microbes that help ferment dietary fibre are thought to play a protective role, helping the immune system respond effectively while reducing systemic inflammation. On the other hand, an imbalanced microbiome can drive chronic inflammation and increase the risk of disease.
Can we change the microbiome?
The good news is that our microbiome is not fixed. As Dr. Jennifer Wargo explained, it can be influenced by a range of factors, including diet, lifestyle, and medical treatments. In cancer patients, the use of broad-spectrum antibiotics has been linked to worse outcomes – especially when used just before treatments like immunotherapy or CAR-T cell therapy. These antibiotics can significantly reduce microbiome diversity, limiting the presence of helpful microbes that support the immune response.
There are ongoing studies looking at how we can shift the microbiome in a more favourable direction. One example is faecal microbiota transplantation, where stool from a healthy donor is transplanted into a patient. Some clinical trials suggest this may help patients who initially do not respond to immunotherapy begin to benefit from it. While this approach is still experimental, it opens new doors for personalised treatment strategies.
The microbiome’s role in cancer development and progression
Certain microbes have also been directly linked to cancer. As Dr. Jennifer Wargo noted, Helicobacter pylori is known to contribute to the development of gastric cancer and can be treated to reduce risk. Similarly, Fusobacterium nucleatum has been found in colorectal cancer tumours and is associated with more aggressive disease and poorer response to chemotherapy. These findings highlight the possibility of targeting specific microbes to improve outcomes.
Can the microbiome guide treatment?
Although still in the research phase, scientists are exploring whether the microbiome can serve as a biomarker to predict how a patient might respond to cancer therapies. This would involve profiling a patient’s gut microbes and potentially adapting treatment strategies based on the results. While this isn’t yet routine in clinical care, the potential is promising.
What can individuals do?
Although much of the science is still developing, there are simple, evidence-backed actions individuals can take. Diet is a key one. A high-fibre diet that includes a range of whole foods and fewer processed items can support a healthier microbiome. Other factors such as regular exercise, good sleep, and reducing unnecessary antibiotic use – especially broad-spectrum types – may also help maintain microbial balance.
Looking ahead
The connection between the microbiome and cancer treatment is a growing area of interest. While we’re not yet at the point of integrating microbiome profiling into standard cancer care, the potential is clear. For now, awareness around diet and lifestyle remains one of the most actionable ways individuals can support their health and, potentially, their response to treatment.
Listen to the full interview here.
