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The Microbiome and Cancer

The microbiome, a collection of all microbes that naturally live in our bodies, contributes to a range of activities from breaking down food to fighting illness. It’s no surprise that changes in the gut microbiome have been implicated in a range of chronic diseases from gastrointestinal inflammation to neurological and cardiovascular illness. With the role of inflammation and the immune system playing a huge role in cancer, researchers have started to uncover that the microbiome may hold the key to understanding cancer.

What is the microbiome?

All the bacteria, fungi, viruses and gene that live in and on our bodies make up the microbiome. It is responsible for protecting us against pathogens, helping our immune system develop, and producing energy through food digestion. Each site of the body, including the gut, the skin, the oral and nasal cavities, have their own set of microbes which are formed early in development but can be alerted due to factors such as diet, medications, and environmental exposures.

Advances in next-generation and high-throughput sequencing have made discoveries relating the microbiome to cancer treatment, detection and causation possible. With these tools, more information about how the microbiome affects disease can be uncovered.

How does the microbiome affect cancer?

The microbiome has many implications for cancer. From development, to treatment, to the discovery of biomarkers of response, many different avenues have been explored in regard to the microbiome and cancer.

While the role of H. pylori in stomach cancer and HPV for cervical cancer have been known for some time, studying the interaction of cancer and the microbiome had largely been ignored for years. In recent years it has been discovered that the microbiome can affect tumor initiation and proliferation by acting on the tumor cells and by manipulating the immune system.

Recent studies of the microbiome and cancer have found that cancer is often associated with an imbalance of the microbiota which leads to a decrease in microbial diversity and community stability. These observations, however, can vary and are sometime relativity small in quantifiable differences. Due to the complexity of each individual’s microbiome, it is hypothesized that this type of research approach will become more personalized medicine than a one-size fits all treatment.

Researchers at Harvard Medical School have an excellent review of “The Potential of the Gut Microbiome to Reshape the Cancer Therapy Paradigm.”

How does MEDSIR study the microbiome?

At MEDSIR we are immensely interested in the interaction of the microbiome and cancer. We believe that fecal and oral microbiome samples are an important addition to any protocol and can give valuable insights. Additionally, understanding the microbiome’s role could led to personalized medicine approaches for each patient, ensuring that they receive the most appropriate treatment option.

MEDSIR specifically has an ongoing project, CALADRIO, which is an exploratory sub-study from samples collect from the KELLY trial that evaluated pembrolizumab and eribulin for hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer previously treated with anthracyclines and taxanes. This microbiome study utilized shotgun metagenomic and 16S rRNA gene sequencing to characterize fecal and saliva microbiota profiles, respectively, and microbiota data were analyzed using MEGAHIT, LEfSe, Wilcoxon ranked sum, and PERMANOVA methods. For more information about this, take a look at the results shared at ESMO Breast 2022!

And of course, contact us if you are interested in any of our trials or starting your own microbiome related study! We’ll be happy to assist.



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