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French researchers have identified previously unsuspected immune cells as culprits in the appearance of certain tumors. A discovery that could change the treatment and prevention of many cancers.
Cancer research has just reached a new decisive milestone. French scientists from the Léon Bérard Center in Lyon and Inserm have discovered immune cells that are potentially the cause of several cancers. This discovery could really improve prevention and pave the way for new therapeutic strategies.
Cells that are supposed to defend us and which change sides
At the heart of this breakthrough are certain white blood cells, specifically a subpopulation of lymphocytes. Some of these cells, normally responsible for spotting pathogens and activating the immune response, have been identified as responsible for the malignant transformation of healthy cells.
Researchers from Inserm, CNRS, Claude-Bernard Lyon 1 University and the Léon Bérard Center at the Lyon Cancer Research Center have been interested in TH17 lymphocytes. These cells are already known to be involved in many inflammatory diseases, such as multiple sclerosis and Crohn’s disease.
30% of cancers potentially affected
The researchers observed that TH17 lymphocytes do not constitute a homogeneous population, but can in fact be divided into several subgroups, one of which appears to promote the development of cancers.More specifically, in this study, we show for the first time that there are actually eight subtypes of TH17 lymphocytes with distinct roles. One of them has a tumorigenic role, that is to say that when certain activation brakes are lifted, it will contribute to the development of cancers. When in contact with these TH17 cells, the cells of the intestine that were healthy until then will become cancerous.“, explains Julien Marie, research director at Inserm.
And the stakes are high because around 30% of cancers appear as a result of localized chronic inflammation. This is particularly the case for certain colorectal, small intestinal, liver and pancreatic cancers.
Major implications for prevention and treatment
This discovery, the result of several years of research, has profound repercussions on the understanding of cancer. It highlights a mechanism previously ignored in the genesis of tumors, making it possible to consider new therapeutic targets.
Scientists have in fact identified that a protein, the cytokine TGF-β, is capable of inhibiting the formation of tumorigenic TH17.
A key step towards better prevention
In addition to offering avenues for improving treatments, this discovery could also transform preventive approaches. The researchers showed that this tumorigenic population is increased in patients at high risk of cancer. By implementing more extensive monitoring in them, this would make it possible to implement preventive treatment and/or intervene much earlier, before the cancer develops. This study therefore appears promising for the development of new preventive therapies.
An implication regarding the use of immunotherapies
“This study may question clinicians about the long-term use of immunotherapies in cancer patients, a treatment that aims to stimulate lymphocytes.“, underlines Julien Marie.
Indeed, while these therapies have revolutionized the management of certain cancers, they are also known to cause chronic intestinal inflammation. It could therefore be important tomorrow to question, for a given patient, the risks that immunotherapy is accompanied by the emergence of tumorigenic TH17 lymphocytes that could ultimately give rise to the development of another cancer.
Researchers are now looking to the future, with clinical studies planned to test new strategies based on these promising results.