Disparities in the gut microbiome between healthy people and women with estrogen-driven breast cancer may indicate possible biomarkers based on the microbiome that could help to mitigate the risk of certain cancers.1

The estrobolome is the gut bacterial genes that are capable of metabolizing estrogens in gut bacteria. Residential microbes, whose population includes bacteria, viruses, Archaea, and Eukaryotes, are increasingly recognized for playing important roles in health and disease. The human gastrointestinal tract has up to 1011 bacterial cells per gram of luminal content. Their collective genome, the gut metagenome, has vastly more individual genes than the human genome. The function of the microbiome affects the host, both locally and distantly. Disequilibrium can contribute to disease, including malignancy.

To determine the effects that estrobolome may have on estrogen levels and human breast cancers, Sylvia Adams, MD, from the Laura and Isaac Perlmutter Cancer Center, New York University Langone Medical Center in New York City, and colleagues are currently conducting a study comparing microbiota between postmenopausal healthy women and patients who have developed estrogen-driven cancers.

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“If the estrogen metabolism-gut microbiome axis is functional with underlying individual variations in estrogen levels, it is plausible that the estrobolome could contribute to the risk of hormone-driven malignancies including breast cancer and as such could serve as a potential biomarker,” stated the researchers.

“Interventions that may include use of prebiotics, probiotics, or antimicrobial agents could be designed specifically to target gut bacterial species with b-glucuronidase activity to decrease estrogen-related cancer risk or become components of future therapies. In conclusion, links between the microbiome and estrogen-driven breast cancer are growing, and we hope that research will identify specific characteristics of the gut microbiome that can be used to develop novel approaches for breast cancer risk assessment, prevention, and treatment.”


1. Kwa M, Plottel CS, Blaser MJ, Adams S. The intestinal microbiome and estrogen receptor-positive female breast cancer [published online ahead of print April 22 2016]. JNCI. doi:10.1093/jnci/djw029.