Findings from the US study reveal healthy breast tissue contains more of the bacterial species Methylobacterium, a species known to produce phytohormones that exert an anti-cancer effect.
“To my knowledge, this is the first study to examine both breast tissue and distant sites of the body for bacterial differences in breast cancer," said Dr Charis Eng co-senior author and chair of Cleveland Clinic's Genomic Medicine Institute
"Our hope is to find a biomarker that would help us diagnose breast cancer quickly and easily. In our wildest dreams, we hope we can use microbiomics right before breast cancer forms and then prevent cancer with probiotics."
While it may be some way off, the prospect of probiotic use in breast cancer is making some interesting headway.
Lactobacillus acidophilus, a probiotic found in yogurt and kimchi, has shown anti-cancer properties as its ingestion has found its way to the mammary gland.
The species are found in abundance in healthy breast tissues compared to cancerous tissues. Its presence in fermented milk products may also exert protective antioxidant effects.
Published online in the journal Oncotarget, the study examined the tissues of 57 patients who underwent mastectomy for breast cancer or cosmetic breast surgery.
The team from the Cleveland Clinic in Ohio also looked at patients’ oral rinse and urine to assess bacterial composition of these sites.
In addition to the Methylobacterium finding, cancer patients' urine samples were found to have increased levels of gram-positive bacteria such as Staphylococcus and Actinomyces.
“If we can target specific pro-cancer bacteria, we may be able to make the environment less hospitable to cancer and enhance existing treatments,” said co-senior author Dr Stephen Grobymer, section head of surgical oncology at Cleveland Clinic.
“Larger studies are needed but this work is a solid first step in better understanding the significant role of bacterial imbalances in breast cancer."
Probiotics and the breast
For women undergoing breast surgery, the role of probiotics may provide some much-needed benefit in postsurgical infections.
According to an article published last month, their use “would be of great interest and importance to examine the precise mechanisms and correlate the reported alterations of the microbiome with the infectious complications in the surgical and/or critically ill patient.”
Additionally, the microbiome’s role in breastfeeding is well established, with the interplay between gut and breast microbiota crucial breastfeeding and infant development.
A breastfeeding mother’s gut microbiome has a crucial role in her offspring’s immune development.
In addition, distinct sites in and around the breast such as breast skin tissue, swabs, and cheek swabs are known to have unique microbiome signatures.
These microbes reside within breast tissue irrespective of a history of infection or lactation.
Published online ahead of print: doi.org/10.18632/oncotarget.21490
“Breast tissue, oral and urinary microbiomes in breast cancer.”
Authors: Charis Eng et al.