A microbe found in the colon and commonly associated with the development of colitis and colon cancer also may play a role in the development of some breast cancers, according to new research.
Breast tissue cells exposed to this toxin retain a long term memory, increasing the risk for disease.
In a series of laboratory experiments, researchers discovered that when Enterotoxigenic Bacteroides fragilis (ETBF) was introduced to the guts or breast ducts of mice, it always induced growth and metastatic progression of tumour cells.
While microbes are known to be present in body sites such as the gastrointestinal tract, nasal passages and skin, breast tissue was considered sterile until recently, says senior study author Dipali Sharma, Ph.D., a professor of oncology at Johns Hopkins Medicine.
The study is the first step to show the involvement of ETBF in breast cancer development, Sharma says.
Additional studies are needed to clarify how ETBF moves throughout the body, whether ETBF can be a sole driver to directly trigger the transformation of breast cells in humans, and/or if other microbiotas also have cancer-causing activity for breast tissue.
In clinical studies, the investigators have started looking for microbiome changes among breast cancer patients to see how this impacts tumour progression and response to therapy
