Gut bacteria living in the digestive system appears to have an influence on whether or not tumors grow smaller during cancer treatments, researchers say.
Scientists from France and the US tested the microbiome, or the microscopic species that live in the human body, in cancer patients. Their studies linked some specific species and the overall diversity of the microbiome in how effective immunotherapy treatments work, the BBC reports.
The human body carries trillions of microorganisms, many of which are involved in digestion, protection from infections and immune system regulation. Immunotherapy works to boost the body’s natural defenses in fighting off cancerous tumors. It works successfully in some patients, but has been known to clear even fatal cancers in others.
One study from the Gustave Roussy Cancer Campus in Paris examined 249 patients suffering from lung or kidney cancer. The researchers found that the patients who had taken antibiotics, such as for dental problems, had some damage to their microbiome and were more likely to have aggressive tumors while undergoing immunotherapy.
Scientists at the University of Texas MD Anderson Cancer Center looked at 112 patients who had advanced melanoma. The results showed that those who responded to immunotherapy had a richer, more diverse microbiome than those who did not.
Tissue samples showed that there were more cells that could kill cancer in the tumors of people with the good bacteria. To further test, the scientists transplanted fecal matter from people to mice with melanoma.
The mice who received bacteria from patients with the good kind of bacteria saw slower growing tumors, compared to the mice who had bad bacteria transplanted.
Jennifer Wargo from Texas said, “If you disrupt a patient’s microbiome you may impair their ability to respond to cancer treatment. Our hypothesis is if we change to a more favorable microbiome, you just may be able to make patients respond better.” She added,
The microbiome is game-changing, not just cancer but for overall health, it’s definitely going to be a major player.
Mark Fielder, president of the Society for Applied Microbiology and professor of medical biology at Kingston University, said, “It’s really interesting and holds a lot of promise, we need to do more work but there are exciting glimmers here in treating some difficult diseases.”
The study was published in the journal Science.
