Bacteria living inside the digestive system may alter how cancer drugs work, a study suggests, and could improve cancer immunotherapy response.
The human body is home to a vast number of micro-organisms. Indeed, estimates suggest that tissues are so heavily outnumbered by microbes that the body is in fact only 10% human. A growing body of research has shown that these microbes can influence the immune system and they have been implicated in auto-immune diseases and allergies.
Immunotherapies are one of the most exciting breakthroughs in treating cancer. They work by allowing the immune system to help it to attack tumours more easily. However, not everyone responds to these treatments, and researchers are trying to understand why.
Now a small study by the University of Texas has found that people harbouring a more diverse community of gut bugs are more likely to benefit.
Scientists studied over 200 mouth and over 100 gut microbiome samples from people who had advanced melanoma. They discovered that people whose cancer responded to immunotherapy treatment had more diversity in the types of bacteria found in their gut. They also found significant differences in the type of bacteria found in the gut of people whose cancer responded versus those who didn't.
This research suggests that adapting people's gut bacteria, such as by giving antibiotics, probiotics or a faecal transplant before immunotherapy, could increase the benefits already achieved with the new immunotherapy drugs already being used to treat several different types of cancer.
Understanding role of microbes has great potential
The study was presented at the National Cancer Reserach Institute's Cancer Conference in Liverpool.
Dr Jennifer Wargo, lead researcher at the University of Texas, said: "Our research shows a really interesting link that may mean the immune system is aided by gut bacteria when responding to these drugs. 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."
Sir Harpal Kumar, Chief Executive of Cancer Research UK, said: "Our bodies are filled with trillions of bacteria, and we are just beginning to scratch the surface of understanding their great potential."
"It's really interesting and exciting to see new evidence emerge on the close connection between the immune system and the bacteria living in our guts. As this, and several other studies, have shown, manipulating these bacteria could be exploited in future to help patients respond better to treatment."