A recent study suggests that issues with gut health may contribute to the spread of breast cancer to other body parts. An unhealthy gut might lead to increased bile acids, potentially causing breast cancer to metastasize. This new discovery could pave the way for preventing metastasis and saving lives.
Research Findings
The study, conducted by the University of Virginia Comprehensive Cancer Center under the leadership of Melanie Rutkowski, Ph.D., highlights the role of gut microorganisms in the metastasis of hormone receptor-positive (HR+) breast cancer. Rutkowski explained to Newsweek, “An unbalanced gut microbiome disrupts bile acid regulation. This loss of control affects metabolism and immune function, creating conditions that facilitate the spread of breast tumors.”
HR+ breast cancer is the most prevalent form of metastatic breast cancer. Hormone receptors in cells activate when hormones bind to them. If these hormones bind to receptors in breast cancer cells, they may promote cancer growth. The Breast Cancer Research Foundation reports that approximately 80% of breast cancers are hormone receptor-positive. In the United States, 225,000 HR+ breast cancer diagnoses are expected annually among women. Once the cancer spreads, treating it becomes more difficult, increasing the patient’s mortality risk.
Potential Solutions
Rutkowski further stated via EurekAlert! that an unhealthy gut microbiome may lead to improper bile acid regulation. This malfunction can have adverse effects on health, metabolism, and the immune system, promoting breast tumor metastasis. Modifying bile acid composition or treating patients with bile acid sequestrants—already FDA-approved for metabolic diseases—could reduce breast cancer metastasis.
Audrey Putelo, Ph.D., a co-author of the study, commented on the potential of measuring and modifying bile acids. “This finding allows the development of new strategies to identify high-risk patients and minimize the risk of metastatic disease,” she stated. Connections exist between high bile acid levels and insulin resistance, both linked to lower survival rates in HR+ breast cancer patients. Those with metastatic disease who received bile acid-suppressing medications had extended survival times. More research is necessary to confirm if these drugs directly influence patient outcomes.
Ongoing Research
Rutkowski called the findings “extremely encouraging.” The research team is now analyzing more patient data to see if long-term medication use can prevent tumor spread. The current challenge is the underdevelopment of stable microbiome modification methods. Therefore, the team is studying how bile acid signaling affects tissues where breast tumors typically spread. They aim to identify additional targets for intervention to limit tumor dissemination.
Reference: Putelo, A. M., Bajgai, S., Poblete, M. K., Guido G., Lanfranca, M. P., Rutkowski. M. R., et al., “Commensal Dysbiosis Alters Primary Bile Acid Signaling to Drive Mammary Gland Inflammation and Breast Tumor Dissemination,” Cancer Res 2026. https://doi.org/10.1158/0008-5472.CAN-25-4466
Contact Newsweek editors for this story: Kara Dolman and James Debens.
Leave a Reply