An unhealthy intestinal microbiome could make breast cancer more aggressive, study finds

A new study by researchers at the University of Virginia Cancer Center links an intestinal microbiome with bad cancer that can become invasive and spread faster to other organs. The results of the study were published in the last issue of the journal Research against cancer. The study titled "Pre-existing commensal dysbiosis is an intrinsic regulator of tissue inflammation and tumor cell dissemination in hormone-receptor positive bad cancer" was funded by a grant from Susan G Komen.

Microbiome in the human intestine. New research from the Faculty of Medicine at the University of Virginia suggests that an unhealthy microbiome can promote the spread of bad cancer. – illustration Credit: Alpha Tauri 3D Graphics / Shutterstock

Principal investigator, Melanie Rutkowski, of the Department of Microbiology, Immunology and Cancer Biology, found in her study that if the intestinal microbiome or microbial contents of the intestine of laboratory mice were altered, their bad cancer to Hormonal-positive receptors became more favorable. aggressive. This change in normal health flora of bacteria in the gut of mice has altered the nature of cancer and spread it to spread to other organs, write researchers.

The team writes that until now, it was unclear why some of the hormone receptor positive cancers were more aggressive and invasive than others. They examined intrinsic host factors such as an altered intestinal microbiome called "commensal dysbiosis" and its badociation with the aggressive nature of cancer.

Rutkowski explained, "When we disrupted the balance of the microbiome in mice by chronically treating them with antibiotics, this caused systemic inflammation and within the bad tissue. In this inflamed environment, tumor cells were much more able to spread tissue to the blood and lungs, a major site for metastasis-positive hormone receptor bad cancer. She said that as a result of her study they transplanted the unhealthy microbiome from their mice tested to other mice with positively positive bad cancer through fecal transplantation. The results were similar in the recipient mice, she explained. This proves the direct effect of the microbiome on the conversion to aggressiveness of bad cancer.

Experts say that hormone receptor positive cancers or bad cancers that develop under the influence of female hormones, estrogen and progesterone make up about 65% of all bad cancers. These cancers are more sensitive to hormone therapy and often give good results. Rutkowski explained that the spread and growth of these cancers depends on several factors observed at the time of diagnosis. She said: "One of them has a high level of [immune] cells called macrophages are present in the tissues. She added: "Studies have also shown that an increase in collagen structural protein levels in tissues and tumors also resulted in an increase in bad cancer metastasis. "

She then explained that people with an intestinal microbiome in poor health had increased inflammation of the intestine. This effect is often sustained and powerful, she said. She added, "The disturbance of the microbiome has resulted in long-term inflammation in the tissues and in the tumor environment. These results suggest that having an unhealthy microbiome and the changes that occur in the tissues and that are related to an unhealthy microbiome may be an early predictor of invasive or metastatic bad cancer. In the end, based on these findings, we would think that an unhealthy microbiome contributes to increased invasion and a higher incidence of metastatic disease. "

Experts warn that there is a study in the animal and that it is impossible to extrapolate it in humans. Rutkowski warned that the team had used antibiotics to kill healthy intestinal microbes, but not all antibiotics are bad and should, if necessary, be taken by women with bad cancer . This study should not encourage women with bad cancer to flee all antibiotics, warn experts. The team adds that it is necessary to continue research to prove the link between the continued use of antibiotics and the spread of bad cancer. This study was conducted in genetically modified laboratory mice with a positive HR bad cancer. The real situation in humans may be different, says the team.

Doctors and the team of researchers add that this study shows that if the intestinal microbiome could be maintained, the results could be positive in women with bad cancer. Rutkowski said this study highlights the importance of a healthy gut microbiome. She added that many aspects of health are badociated with the health of the intestines. This study reveals another reason to maintain a healthy microbiome.

Rutkowski concluded: "A healthy diet, high in fiber, accompanied by exercise, sleep – all of which contribute to overall positive health. In theory, if you do all of this, you should have a healthy microbiome. And that, we think, is very much badociated with a long-term favorable outcome for bad cancer. "