Russian scientists have identified three types of bacteria that positively affect the outcome of melanoma. This was reported by the press service of the RNF.
Immunotherapy is one of the most promising ways to treat cancer. It allows you to use the body’s own immune response, which is stimulated with the help of special drugs, to fight cancer. This type of treatment is much less harmful than chemotherapy or radiotherapy, but it is not always effective. In particular, cancer cells can trick the immune system by “faking” immune response checkpoints. This is the name of the molecules on the cell that come into contact with the immune system and “convince” the cell that the target is a “friend”. To solve this problem, doctors can suppress checkpoints with special inhibitors, but these have many side effects. Many are believed to be related to individual characteristics of the human gut microbiome.
Specialists of Yu M. Lopukhin Federal Scientific and Clinical Center for Physical and Chemical Medicine and colleagues from other universities conducted a genetic analysis of stool samples from 449 volunteers undergoing immunotherapy against melanoma. Next, the researchers compared the microbiome data with the treatment outcomes. “We identified three types of bacteria that are associated with successful cancer immunotherapy in 85% of cases. One of them is representative of bifidobacteria found in dairy products and used in probiotics. This suggests that for a more successful treatment of melanoma, patients can be recommended to take probiotics that improve the state of the intestinal microflora,” say the scientists.
In addition, the authors identified biomarkers, that is, biomarkers that can be used to predict how successful immunotherapy will be. These were bacterial genes whose presence in metagenomes was associated with effective therapy. The immunotherapy turned out to be successful in patients that contained genes for metabolism in stool samples, namely the conversion of bacterial polysaccharides, fatty acids, and other compounds vital to microorganisms. Treatment was less effective if stool samples contained genes for pathogenic bacteria that made them resistant to antibiotics.
The authors hope their discovery will make cancer treatment more effective and safer.
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