Cancer: a new method to weaken the defenses of malignant tumors

In 2018, 8.1 million people were diagnosed with cancer worldwide, according to estimates from the World Cancer Report 2018. That same year, 9.6 million deaths from cancer were recorded. Today, a new study marks a major step in research against this scourge.

According to an article published in the journal EBioMedicine on August 26, scientists reportedly found a way to tear down the protective wall that surrounds tumors, potentially re-exposing them to the killing power of the immune system and immunotherapeutic treatments. While they are still in their first lab trials, this approach could help boost the effects of innovative cancer treatments such as CAR-T therapy which have so far failed to overcome severe tumors.

Doctors Francis Mussai and Carmela De Santo from the University of Birmingham (UK) studied the immune cells, called myeloid suppressor cells or MDSCs, from 200 adults and children who had been diagnosed with cancer. These cells send a barrage of chemical signals that protect tumor cells and prevent the activation of T cells capable of killing them. Also, the more they are present, the more the cancer can become resistant and spread to other parts of the body, explain the researchers. By using an antibody already available to treat leukemia, the researchers succeeded in destroying these immune cells.

This approach could “improve the treatment of many types of cancer”

“Treatments that work with the immune system to kill cancer often fail because it can make it difficult for our body’s defenses to gain access to tumor cells. Our research indicates that administering this antibody at the same time as immunotherapies could dramatically increase the number of patients benefiting from the latest treatment innovations,” says Dr. Mussai.

In the past, researchers had already discovered a way to break the protective layer of tumors in mice, using antibodies that attach to the surface of the MDSC. But they had failed to apply their theory in clinical trials on humans.

“This is the first time that we have been able to effectively target the immune cells that form a barrier around solid tumors,” says Mussai. And to add: “If this approach works in patients, it could improve treatments for many types of cancer, both in adults and children. We believe that our approach will have the greatest impact in CAR- T, which, although showing great promise in blood cancer, has so far had only limited success in solid tumors.”

“Although this is preliminary research, it has given us a better understanding of how tumors interact with the immune system and has given us a tantalizing idea of ​​how we might make immunotherapies work for a larger number of patients in the future. But we are still a long way from getting this treatment. The next step will be to find out more about the side effects of the antibody, and how it works in the body,” comments the Dr Emily Farthing, Research Information Manager at Cancer Research UK.

Findings applicable to hemophagocytic lymphohistiocytosis

In addition to treating cancers, these findings could also be applicable to treating hemophagocytic lymphohistiocytosis or macrophage activation syndrome. This disease involves a defect in the mechanisms of targeted cytotoxicity and the inhibitory controls of natural killer and cytotoxic T cells. It is so rare that very few treatments are currently available, especially for young children.

This is why the researchers are now planning a clinical trial to test the safety and activity of their antibody on patients who have it. The trial will also include patients with advanced tumors.

In France, since 2004, cancer has been the leading cause of premature death ahead of cardiovascular disease. According to the Inca, in 2018, 204,600 men and 177,400 women were diagnosed with cancer. In men, prostate cancer comes first, followed by those of the lung and colon-rectum. In women, breast cancer is the most common followed by colon-rectum and lung.