Bacteria in the Gut Increases Success Rates of Cancer Therapy

Humans are infected with billions of bacteria, which is higher than the number of cells in the body. However, it's not all bad news due to the variability of microbiomes. Microbiomes have a huge impact on individual diagnosis since it is essential for overall health. The microbiome consists of all the symbiotic, commensal and pathogenic bacteria present within us. It is involved in digestion, protection from infection and immune system regulation. An individual's microbiome is a risk factor, modifiable by diet, exercise and use of antibiotics.

An article released in Science earlier this month named 'Gut microbiome modulates response to anti–PD–1 immunotherapy in melanoma patients' specified how the diversity and composition of gut microbiomes affects response to immunotherapy drugs. Bacteria in the human digestive tract can impact upon the response of melanoma to immunotherapy.

A richer, more diverse microbiome correlates with positive response to therapy. For example, bacteria such as Faecalibacterium and Clostridiales seemed to be beneficial, in comparison to species such as Bacteroidales, which were not. Patients with metastatic melanoma treated with anti–PD1 checkpoint blockade have better disease control when a more diverse population of bacteria in the gut is present or when there is an abundance of specific types of bacteria. Doctors have stated that disrupting a patient's microbiome may lead to the impairment of their ability to respond to cancer treatment.

However, it is important to remember that this approach does not work in every patient: only 25% of cancer patients respond to treatment via PD-1 blockers. This means that much more work needs to be carried out in order to be able to treat these difficult diseases in the remaining 75% of patients. Also, those taking antibiotics, had a significantly reduced success rate and relapsed due to a disrupted gut microbiome. Therefore, if more research is undertaken, findings from this new study could provide a new way in which to improve the treatment of cancer.

Article: http://science.sciencemag.org/content/early/2017/11/01/science.aan4236

Extra reading: http://science.sciencemag.org/content/358/6363/573/tab-pdf and https://www.theguardian.com/lifeandstyle/2017/nov/06/microbiome-gut-health-digestive-system-genes-happiness