US, WASHINGTON (ORDO NEWS) — Israeli scientists conducted the first comprehensive microbial census of the population of tumor cells, and it turned out that bacteria of certain species prefer to live in each of the malignant formations. The discovery will allow the development of new methods of anti-cancer therapy.
Researchers at the Weizmann Institute analyzed the microbial composition of the cells of thousands of tumors that were removed from the bodies of patients with cancer of the breast, bone tissue, brain and ovaries, skin and lungs, pancreas. Samples were collected at nine medical centers in four countries.
It turned out that in almost all types of neoplasms, bacteria are present. In this case, tumors of bone tissue, mammary glands and pancreas showed the content of microorganisms in 60 percent of cases, while with melanoma “settlers” were found in only 14% of samples.
In total, scientists found traces of the presence of 528 species of microorganisms. The variety of bacteria differed and depended on the type of cancer. So, the largest number of microbes was observed in breast cancer.
It also turned out that much more bacteria are collected inside such a tumor than in healthy tissue outside it. In addition, some types of microorganisms clearly preferred to settle precisely within the neoplasm, rather than in healthy tissue.
Let us explain that in such cases, scientists do not recount all microorganisms and do not determine the type of each “tenant” found. To determine the microbial composition, genetic material is studied. According to the unique “fingerprints” of each microorganism, experts determine what species are present in one or another of the studied samples.
Note that the relationship of the microbial population of the tumor and the development of cancer has been identified by scientists before. In addition, experts three years ago found that bacteria prevent laboratory animals from recovering from cancer. It was also shown that microorganisms determine the response of human tumors to immunotherapy.
However, these were studies of certain types of tumors . New, more extensive data, according to Israeli experts, will help develop methods to combat a wide variety of cancers. After all, changing this local mini-microbiome will potentially allow you to overcome neoplasms, including those resistant to existing methods of therapy.
However, it is not yet clear whether microorganisms contribute to the growth of tumors.
It is also not clear how microbes get into neoplasms. So, earlier studies have identified “settlers” in the intestines and in tissues that are somehow exposed to microorganisms. But the Israeli experts, we repeat, have revealed bacteria specific to certain tumors in the bone tissue and in the tissue of the mammary glands. Even the most protected organ from outside invasion, the brain, could not escape such a fate.
Perhaps the microbial composition of tumors is determined by the influence of environmental factors, which also determine the appearance of a particular type of cancer. So, several years ago, doctors discovered magnetic nanoparticles in the human brain , the presence of which was associated with air pollution.
As the head of the current study Ravid Straussman, a study of lung cancer smokers found that they often settle bacteria-destroying chemicals present in tobacco smoke.
Perhaps it’s simply easier for microorganisms to colonize certain types of tumors, Strassman says.
An article by the authors of the study was published in one of the most famous scientific journals Science.
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