Gut Health Linked to Breast Cancer Spread: New Research
A recent study highlights the impact of gut health on the spread of breast cancer. The research suggests that an unhealthy gut, leading to a buildup of bile acids, may facilitate the metastasis of breast cancer. This discovery from the University of Virginia Comprehensive Cancer Center could pave the way for new prevention methods.
The Role of the Gut Microbiome
Led by Dr. Melanie Rutkowski, the study examines how intestinal microorganisms affect the spread of hormone receptor-positive (HR+) breast cancer. According to Rutkowski, an unhealthy gut microbiome disrupts bile acid levels, leading to metabolic and immune dysfunction. This disruption creates conditions in the body that encourage breast tumors to spread.
HR+ breast cancer is the most common metastatic form of the disease. It involves hormone receptors that, when bound by hormones, may promote cancer growth. Approximately 80% of breast cancer cases are HR+, with around 225,000 new cases diagnosed annually in American women. When the cancer spreads, treatment becomes more challenging, and the risk of mortality increases.
Potential for Treatment
Rutkowski’s research suggests modifying bile acid composition or using FDA-approved bile acid sequestrants as potential treatments. These drugs are already used for metabolic diseases and could reduce breast cancer metastasis.
Previous studies linked gut microbiome imbalance with poor outcomes, pinpointing bile acid buildup as a trigger for inflammation. This inflammation drives breast cancer cells to metastasize. Co-author Dr. Audrey Putelo highlighted the potential to develop new methods to identify and reduce the risk in high-risk patients due to the measurable and modifiable nature of bile acids.
Future Research
Elevated bile acids and insulin resistance correlate with reduced survival rates in HR+ breast cancer patients. However, those receiving bile acid-suppressing medications often lived longer. Further research aims to determine if these medications directly contribute to this benefit.
Rutkowski finds the results promising, expressing interest in exploring whether these drugs can prevent the initial spread of cancer. If successful, these drugs could be used to prevent metastatic breast cancer. Ongoing analyses of additional patient data aim to confirm these findings and explore the immune-related effects of bile acid signaling in tissues vulnerable to tumor spread.
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