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Breast Microbiome Different in Women With Breast Cancer

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There's a breast microbiome, and it's different in women with breast cancer

By Erin Blakemore October 19, 2016 (Washington Post)

"In one of the most recent studies, researchers from the Mayo Clinic have identified significant differences in the breast bacteria of women with and without breast cancer.

The paper, published in the journal Scientific Reports, reveals that inside the breast is a complex
microscopic world much different from that of the skin tissue just outside. Researchers used DNA
sequencing to analyze sterile breast tissue removed from 33 women in the operating room and
compared the results to breast skin and cheek swabs taken from the same patients.
The tiny organisms contained within the breast of women who had benign breast disease — lesions and
abnormalities that ended up not being cancerous — were dramatically different from those in samples
taken from the same locations in women who did have cancer. Women with breast cancer had more
abundance of a variety of bacteria such as Fusobacterium, Atopobium and Lactobacillus. And their skin
microbiome just inches away seemed completely distinct.

"There were really striking differences between skin tissue and breast tissue," said Tina J. Hieken, a
Mayo Clinic breast surgical oncologist who led the study. Not only did breast skin have a different mix
of bacteria, but the bacteria that lived there also were more abundant."

"Fusobacterium, for example, has been associated with colorectal cancers, but Hieken said more

research is needed to determine exactly how the two might be linked. "These bacteria might act by
secreting virulence factors or by creating a pro-inflammatory environment," she said. "We'd like to
look at what's really going on in the microenvironment of the tissue."

Fusobacterium is a genus of anaerobic, Gram-negative, non-sporeforming, bacteria, similar to Bacteroides. Individual cells are slender' rod-shaped bacilli with pointed ends.[2][3] Strains of Fusobacterium cause several human diseases, including periodontal diseases, Lemierre's syndrome, and topical skin ulcers.

In 2011, researchers discovered that Fusobacterium flourishes in colon cancer cells, and is often also associated with ulcerative colitis, although researchers have not determined if the organism actually causes these diseases or if it simply flourishes in the environment these diseases create.[5] The bacterium is a big anchor for biofilms.[6][7] It is suseptible to clindamycin.[8] In contrast to Bacteroidesspp., Fusobacterium has a potent lipopolysaccharide. Fusobacterium spp. are part of normal, healthy placental microbiome.[9][10]


Lactobacillus is a genus of Gram-positive, facultative anaerobic or microaerophilic, rod-shaped, non-spore-forming bacteria.[1] They are a major part of the lactic acid bacteria group (i.e. they convert sugars to lactic acid). In humans, they constitute a significant component of the microbiota at a number of body sites. In women of European ancestry, Lactobacillus species are normally a major part of the vaginal microbiota.[2][3][4]

Interactions with other pathogens[edit]

Lactobacillus species produce hydrogen peroxide which inhibits the growth and virulence of the fungal pathogen Candida albicans in vitro and in vivo.[9][10] Following antibiotic therapy, certain Candida species can suppress the regrowth of Lactobacillus species at body sites where they cohabitate, such as in the gastrointestinal tract.[9][10]


Atopobium is a genus of Actinobacteria, in the family Coriobacteriaceae.Atopobium species are anaerobic bacteria, Gram-positive rod-shaped or elliptical found as single elements or in pairs or short chains.This is an facultative anaerobic bacteria, Gram-positive rod-shaped or elliptical cocobacilli, which form small colonies on blood agar at 37 °C is also positive for acid phosphatase. It can be identified by 16S ribosomal RNA sequencing,[3] and is associated with bacterial vaginosis.
Actinobacteria (Atopobium is an actinobacteria)The Actinobacteria are a phylum of Gram-positive bacteria. They can be terrestrial or aquatic.[1] They are of great economic importance to humans because agriculture and forests depend on their contributions to soil systems. In soil, they behave much like fungi, helping to decompose the organic matter of dead organisms so the molecules can be taken up anew by plants. In this role the coloniesoften grow extensive mycelia, like a fungus would, and the name of an important order of the phylum, Actinomycetales (the actinomycetes), reflects that they were long believed to be fungi. Some soil actinobacteria (such as Frankia) live symbiotically with the plants whose roots pervade the soil, fixing nitrogen for the plants in exchange for access to some of the plant's saccharides. to repost; trouble with copying it)Beneficial bacteria may protect breasts from cancerJune 24, 2016
Source:American Society for Microbiology"Women with breast cancer had elevated levels of Escherichia coli and Staphylococcus epidermidis, are known to induce double-stranded breaks in DNA in HeLa cells, which are cultured human cells. "Double-strand breaks are the most detrimental type of DNA damage and are caused by genotoxins, reactive oxygen species, and ionizing radiation," the investigators write. The repair mechanism for double-stranded breaks is highly error prone, and such errors can lead to cancer's development.

Conversely, Lactobacillus and Streptococcus, considered to be health-promoting bacteria, were more prevalent in healthy breasts than in cancerous ones. Both groups have anticarcinogenic properties. For example, natural killer cells are critical to controlling growth of tumors, and a low level of these immune cells is associated with increased incidence of breast cancer. Streptococcus thermophilus produces anti-oxidants that neutralize reactive oxygen species, which can cause DNA damage, and thus, cancer.

The motivation for the research was the knowledge that breast cancer decreases with breast feeding, said Reid. "Since human milk contains beneficial bacteria, we wondered if they might be playing a role in lowering the risk of cancer. Or, could other bacterial types influence cancer formation in the mammary gland in women who had never lactated? To even explore the question, we needed first to show that bacteria are indeed present in breast tissue." (They had showed that in earlier research.)

But lactation might not even be necessary to improve the bacterial flora of breasts. "Colleagues in Spain have shown that probiotic lactobacilli ingested by women can reach the mammary gland," said Reid. "Combined with our work, this raises the question, should women, especially those at risk for breast cancer, take probiotic lactobacilli to increase the proportion of beneficial bacteria in the breast? To date, researchers have not even considered such questions, and indeed some have balked at there being any link between bacteria and breast cancer or health."

Besides fighting cancer directly, it might be possible to increase the abundance of beneficial bacteria at the expense of harmful ones, through probiotics, said Reid. Antibiotics targeting bacteria that abet cancer might be another option for improving breast cancer management, said Reid.

In any case, something keeps bacteria in check on and in the breasts, as it does throughout the rest of the body, said Reid. "What if that something was other bacteria--in conjunction with the host immune system? We haven't answered this question, but it behooves experts in the field to now consider the potential.""

Lactobacillales or lactic acid bacteria (LAB) are an order of Gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod- or coccus-shaped bacteria that share common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and milk products, produce lactic acid as the major metabolic end product of carbohydrate fermentation.

Was the late scientist/chemist Jane Plant (who passed away after having breast cancer several times) somewhat right about avoiding milk and milk products because of the lactic acid in milk products?

Lactic Acid Found To Fuel Tumors

A team of researchers at Duke University Medical Center and the Université catholique de Louvain (UCL) has found that lactic acid is an important energy source for tumor cells. In further experiments, they discovered a new way to destroy the most hard-to-kill, dangerous tumor cells by preventing them from delivering lactic acid.

"We have known for more than 50 years that low-oxygen, or hypoxic, cells cause resistance to radiation therapy," said senior co-author Mark Dewhirst, DVM, Ph.D., professor of radiation oncology and pathology at Duke. "Over the past 10 years, scientists have found that hypoxic cells are also more aggressive and hard to treat with chemotherapy. The work we have done presents an entirely new way for us to go after them."

Many tumors have cells that burn fuel for activities in different ways. Tumor cells near blood vessels have adequate oxygen sources and can either burn glucose like normal cells, or lactic acid (lactate). Tumor cells further from vessels are hypoxic and inefficiently burn a lot of glucose to keep going. In turn, they produce lactate as a waste product.

Tumor cells with good oxygen supply actually prefer to burn lactate, which frees up glucose to be used by the less-oxygenated cells. But when the researchers cut off the cells' ability to use lactate, the hypoxic cells didn't get as much glucose.

For the dangerous hypoxic cells, "it is glucose or death," said Pierre Sonveaux, professor in the UCL Unit of Pharmacology & Therapeutics and lead author of the study, published in the Nov. 20 online edition of the Journal of Clinical Investigation. He formerly worked with Dr. Dewhirst at Duke.

Decades ago the scientist Otto Warburg noted a relationship between lactic acid fermentation and tissue hypoxia and the formation and progression of cancer. Maybe some types of bacteria, maybe particularly the ones that act like fungus and spread out with hyphae or branches, can initiate cancers in the breast?

Fusobacterium nucleatum

Fusobacterium nucleatum is an oral bacterium, indigenous to the human oral cavity, that plays a role in periodontal disease. This organism is commonly recovered from different monomicrobial and mixed infections in humans and animals. It is a key component of periodontal plaque due to its abundance and its ability to coaggregate with other species in the oral cavity.[1][2]Fusobacterium nucleatum is part of normal, healthy placental microbiome.[3][4]

F. nucleatum has a demonstrated association with colon cancer; in addition, a mechanism has been described by which F. nucleatum induces tumor growth without the more general mechanism of inducing inflammation or otherwise irritating the colon tissue. This suggests direct and specific carcinogenesis.[6]

Periodontal Disease is Associated With Increased Breast Cancer Risk in Postmenopausal Women

Among women who had quit smoking within the past 20 years, those with periodontal disease had a 36 percent higher risk of breast cancer. Women who were smoking at the time of this study had a 32 percent higher risk if they had periodontal disease, but the association was not statistically significant. Those who had never smoked or had quit more than 20 years ago had a 6 percent and 8 percent increased risk, respectively, if they had periodontal disease.

Oral health links breast cancer