Tamoxifen, a drug used to treat breast cancer, might benefit from the addition of probiotics.

The microbiomes of many parts of the human body, including the breast, are unique from one another.

The majority of breast cancer tumours test positive for the oestrogen receptor (ER+), which alters the breast microbiome and promotes the formation of cancer.

According to recent research, endocrine-targeted treatment combined with dietary changes can alter the microbiome of the breast, which in turn can slow the progression of breast cancer and stop its recurrence.

Probiotics may increase the anticancer effectiveness of tamoxifen and other drugs that target the endocrine system, according to the findings of researchers at Wake Forest University in North Carolina.

Next most common type of cancer is breast cancer.

In the United States, females are more likely to be diagnosed with Trusted Source than any other type of cancer.

Two thirds of breast cancer tumours are sensitive to hormones such as oestrogen and progesterone, which indicates that the cells that make up the tumour have receptors that allow them to utilise the hormones as a source of fuel to develop.

Estrogen receptor-positive

Trusted Source breast cancer, also known as ER+ breast cancer, is the most prevalent kind of breast cancer.

According to studies from a reliable source, however, the distinctive microbiome of the breast can shift in response to changes in nutrition or the presence of malignancies.

Recent research conducted by scientists at Wake Forest University in Winston-Salem, North Carolina, suggests that the anticancer effect of the breast cancer medicine tamoxifen, which is a common endocrine-targeted therapy, may be amplified by the use of probiotics.

Katherine L. Cook, Ph.D., the team’s lead researcher, presented the group’s results in June at the annual meeting of the Endocrine Society, which was called ENDO 2022. At the Wake Forest University School of Medicine, Dr. Cook serves as an associate professor in both the Department of Surgery and the Department of Cancer Biology.

Estrogen “keyholes”
Dr. Parvin Peddi is a medical oncologist and the director of Breast Medical Oncology for the Margie Petersen Breast Center at Providence Saint John’s Health Center. He is also an Associate Professor of Medical Oncology at Saint John’s Cancer Institute in Santa Monica, California. He discussed this research with Medical News Today. She did not take part in the research in any way.

“Normal breast tissue responds to the shifting hormones in a woman’s body,” Dr. Peddi added, “as any woman knows with periods and menstrual cycles or if someone has been pregnant. This is true whether or not someone has had breast cancer.” […When] there are fluctuations in the hormone level, breast tissue has what are termed receptors for oestrogen inside the cells, and they’re basically just these keyholes.”

According to Dr. Peddi, the majority of breast cancer tumours activate this pathway, which causes the body to produce more oestrogen receptors and develop.

The microbiome of the breast
A microbiome is a collection of microorganisms (such as bacteria, viruses, and fungus) that live in a certain area. These microbes can be found anywhere from the human gut to the ocean floor. There are a variety of distinct microbiomes located in and across the human body.

Although the microbiome of the gut is the most extensive and well-studied of all the microbiomes, the microbiome of the breast is also present.

Dr. Cook was a participant in prior studies that shown the potential of the Mediterranean diet to lower the incidence of breast cancer by modifying the microbiota of the breast. Together with her colleagues Wake Forest researchers, she pondered whether or not endocrine-targeted medicines, which are often employed to stop the recurrence of ER+ breast cancer, may also exhibit a comparable impact.

What exactly is meant by the term “targeted therapy”?
Endocrine-targeted treatment, which is also known as hormone therapy, may be provided in order to assist in lowering oestrogen levels or in inhibiting estrogen’s effects. Tamoxifen is a medicine that is frequently used to lower the chance of developing breast cancer in high-risk patients and to assist in preventing the disease from returning after it has been surgically removed. Other examples are the aromatase inhibitors fulvestrant and exemestane. Fulvestrant is also an example.

Dr. Peddi went on to explain that endocrine therapy is often well tolerated and only causes minimal side effects: “[Endocrine therapy is] not like chemo, where you go with a large hammer and attempt to destroy cancer that way.” “[It’s] a gradual dying option with cancer cells, [a] slow taking away of the oestrogen,”

The procedures of the study
In order to examine how the breast cancer medicine tamoxifen and other endocrine-targeted treatments alter the breast microbiome in the context of the battle against ER+ tumours, Dr. Cook and her colleagues at Wake Forest University carried out three separate experiments.

Lactobacillus’ antitumor potential
A mouse model was administered tamoxifen and either a diet similar to the Mediterranean or a diet typical of the Western world that was heavy in fat for the duration of the first preclinical stage of the trial.

They discovered that the rats who were administered tamoxifen had increased amounts of lactobacillus in their breast tissue. [Citation needed] Lactobacillus is a Gram-positive bacterium that is widely recognised for the probiotic and anti-inflammatory effects it possesses.

The researchers then proceeded to introduce Lactobacillus into the mammary glands of mice that had been genetically modified to produce breast cancers. These mice exhibited a significant reduction in the creation and growth of breast tumours.

Larger animal study
In the next part of this investigation, we focused on bigger creatures. Their ovaries had been surgically removed in order to recreate the effects of menopause.

Tamoxifen treatment lasted for a total of two and a half years with these participants. In addition, the amounts of Lactobacillus that were found in these animals’ breast tissue were enhanced.

The examination of human breast tissue
In the third phase of the investigation, Dr. Cook and her colleagues evaluated tissue from ER+ breast cancers that had been removed from women who had been treated with neoadjuvant endocrine-targeted treatment Trusted Source. Aromatase inhibitors or Faslodex were among the medications that were prescribed as part of this treatment.

The levels of cancer cell proliferation in tumour samples taken from women who had higher concentrations of Gram-positive bacteria in their tumours was shown to be lower.

In conclusion, Dr. Cook stated:

“The fact that we have identified this potential population in the breast tissue that’s regulated by most cancer therapies and that this population does have potential anticancer signalling [indicates] a conclusion that the breast has its own unique bacterial microbiome that can be modified by diet and drug administration and that it could represent a novel targetable factor to prevent breast cancer risk and reoccurrence,” said one of the researchers. “The fact that we have identified this potential population in the breast tissue that’s regulated by most cancer

Considerations for the Conduct of Future Research
This experiment has certain restrictions because it was done as part of a preclinical investigation.

Dr. Cook recognised the need to “examine whether or not [the findings] may be applicable in clinical investigations.” [The findings] could be useful in clinical studies.

In addition, Dr. Peddi pointed out that the study does not provide evidence of causality.

Dr. Cook said that her team is presently investigating the possibility of improving outcomes by combining probiotics that are available without a prescription with hormone-specific drugs.

During this stage of the study, researchers focused only on analysing how Lactobacillus affected the microbiota of breast tissue. Dr. Cook mentioned that her team is investigating whether or not probiotics in general can have an effect on the microbiota of the breast.

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