Breast Cancer: The Breast Microbiome

As many as 1 in 8 women are affected by breast cancer in the U.S.

Breast cancer researchers are having a eureka moment.  New research in the past few years is looking into the breast microbiome and how bacterial populations may influence the development of breast cancer.

But first, what is the breast microbiome?

You are a super organism.

Your human body cells are outnumbered by your microbial cells 10:1.  This makes you an amalgamation of many species, in other words, not only human, super-human.

Most of these microbial species are found in the gut.  However, unique populations of microbes live on your skin, varying from place to place, based on the conditions, moist or dry, etc.  Your mouth has a unique microbial community as do your urogential areas.

New research into the breast is finding the same thing.  The breast skin microbiome may vary dramatically from the breast tissue microbiome, and this may influence the development of breast cancer.

Breast cancer rates and development

Breast cancer is the leading cause of death for women globally [1]. In the US,1 in 8 women will be diagnosed with breast cancer at some point in their lives [2].  We know that factors influencing the development of breast cancer include age, diet and genetics, but there are other factors that may also be important in the development of malignant breast cancer.

As our ability to look closely at a large amount of genetic and other cancer markers increases, researchers have been able to see how virus and bacterial interactions may be related to breast cancer.  Earlier studies focused on viruses like Human Papillomavirus (HPV) and other common viruses found in breast tissue as a potential cause of tumor development [2].  However, more recently, breast microbiome has become of interest as a factor in the development of breast cancer.

Breast Bacterial Community

The breast has a highly diverse bacterial microbiome, irrespective of lactation history [3].  Bacterial load and species makeup varies by patient, but also varies between normal and cancerous tissues in single individuals [2].  There is potential that the presence of particular strains may stimulate an immune response that can prevent cancers, or that a bacterial absence may alter the risk of tumor development [2].

Women with breast cancer have been found to have higher populations of some types of bacteria like Staphylococcus, Enterobacteriaceae and Bacillus [3].  Some types of bacteria have been shown to have a clear pathogenic component related to cancer development. For example, Helicobacter pylori is linked to the development of gastric cancer [3].  

However, some bacteria have a clear beneficial effect, as seen with Bacillus fragilis, which has been shown to have an anti-inflammatory effect in the lining of the gut [2].  The same dynamics may apply to breast tissue although the research has not identified any of these specific types of interactions yet.

What to do about his information?

While no direct benefit between taking oral probiotics and breast health has been made, oral probiotics like Lactobacillus acidophilus (a strain in H2PRO) do make their way to the breast tissue [3].  Additionally, probiotic ingestion has been correlated with decreased numbers of E. coli in the breast, indicating that probiotics may inhibit pathogenic bacterial populations [3].

With this in mind along with all the other benefits of probiotics (gastrointestinal health, increased immunity) why wouldn’t you take them?

#LoveYourGuts, why NOT?


1- Hieken, Tina et al. (2016) The Microbiome of Aseptically Collected Human Breast Tissue in Benign and Malignant Disease. Scientific Reports. 6, 30751. Accessed July, 2017

2- Xuan C, et al. (2014) Microbial Dysbiosis Is Associated with Human Breast Cancer. PLoS ONE 9(1): e83744.

3- Brubaker, Jennifer (July 8, 2017) The Breast Microbiome: A Role for Probiotics in Breast Cancer Prevention. Microbial Sciences. Accessed July, 2017

Further Reading:

There’s a Breast Microbiome, and it’s different in women with cancer, The Washington Post, Erin Blakmore, 2016.


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