The bacteria that live in your gut seems to have far more influence over our health than we ever could have imagined even a decade ago. Now, researchers from the University of Texas have looked into how the microorganisms living within us are altering how cancer drugs work and, in turn, how we may be able to tailor the bacterial diversity to benefit patients going through treatment.
By studying over 200 bacteria found in the mouth and 100 in the gut, the researchers then looked at how patients undergoing treatment for malignant melanoma responded to the immunotherapy treatment. While the type of bacteria in the mouth had little impact on the outcome, those patients with the greatest diversity of gut bacteria were found to be the ones who responded most positively to the cancer therapy. They also found significant differences in the types of bacteria between those responding and those who were not.
“Our research shows a really interesting link that may mean the immune system is aided by gut bacteria when responding to these drugs,” explains Dr Jennifer Wargo, who is presenting her team's work at the NCRI Cancer Conference this week. “Not all patients respond to immunotherapy drugs and it’s hard to know who will benefit from the treatment prior to it being given. The gut microbiome can be changed through a number of different strategies, so there is real potential here to modify the gut microbiome to boost an immunotherapy response.”
By altering the diversity of bacteria in a patient, it may in turn change how they respond to certain cancer treatments. This could be achieved in a number of ways, either by supressing some types with antibiotics, boosting others with probiotics, or even giving people fecal transplants, which repopulates the bacteria living in the patient with the microbiome of another person’s gut.
This isn’t actually the first time that the bacteria living in the gut of patients, known as the microbiome, has been found to influence cancer treatments. Early studies have found that chemotherapy can be impacted in both positive, and negative ways. For example, in some instances the microbiome has been found to reduce inflammation, meaning that certain cancer drugs that work by boosting inflammation as a way of fighting cancer may become less efficient.
It adds to a body of work that is slowly uncovering the role that the trillions of bacteria living both on and within us have in influencing how our bodies respond to infection. Bacteria have been found to influence our immune system, as well as being linked to certain allergies. Perhaps by harnessing this, it could lead to novel treatments not just for cancer, but a whole host of other conditions to boot.
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