Stimulating the immune system to distinguish tumor cells from healthy cells and selectively attack them has revolutionized the way some cancers are treated. This revolution began with personalized medicines called CAR-T(from the English Chimeric Antigen Receptor T-cells), a therapy in which the patient is their own donor. In this strategy, the patient's T lymphocytes (which are natural defenses) are extracted, genetically reprogrammed in the laboratory to kill cancer cells, and then reintroduced into the bloodstream so that they can attack the tumor. Now, scientists at the University of California are proposing a reprogramming method that avoids having to manufacture the cells outside the human body and has allowed for the successful treatment of aggressive leukemia, multiple myeloma, and even a solid tumor, so far in mice transplanted with human cells.

Finding therapies to control the progression of cancer is a race against time. Stimulating the immune system to distinguish tumor cells from healthy cells and selectively attack them has been a game-changer. In leukemias, the disease disappears and there are no signs of recurrence after a few years. This revolution would not be understood without the CAR-T (from the English Chimeric Antigen Receptor T-cells), a type of personalized drug. However, in 85% of diseases, cell therapy is not adept at recognizing and attacking tumor cells. So, is it possible to design a similar, but more sensitive, treatment that targets less visible cancers?

The most aggressive colorectal tumors have learned to evade the immune system and go undetected by its defenses. Although immunotherapies have revolutionized the fight against many types of cancer, colorectal cancer is still one of the leading causes of death worldwide. In most metastatic cases, patients do not respond to these drugs because their immune system does not recognize the malignant cells as a threat. But there is hopeful news. A study led by the Institute for Research in Biomedicine (IRB Barcelona) and the National Center for Genomic Analysis (CNAG) has discovered how these tumors manage to block the immune system and, therefore, limit the effectiveness of immunotherapy, the treatment that reactivates the body's defense cells to attack. The key: the hormone TGF-β. The researchers have found that, through a hormone known as TGF-β, colorectal tumors generate a double barrier that protects them from immune attack. "The issue is that the tumor microenvironment of more metastatic colon cancers is different from that of more benign ones and is characterized by the presence of TGF-β, an immunosuppressive hormone," Dr. Eduard Batlle, ICREA researcher and head of the colorectal cancer laboratory at IRB Barcelona, explained to ARA. "Malignant cells use this hormone to evade detection by T lymphocytes, the cells on which our immune system is based," he clarified.

In 2018, the Nobel Prize in Medicine was awarded to Japanese scientist Tasuku Honjo and American James P. Allison for their studies on cancer immunotherapy. Their research began in the late 1980s and 1990s, but that basic research has borne fruit, and today immunotherapy is a fundamental therapy in the fight against this disease—or diseases, because there are many types of cancer—which caused nearly 17,000 deaths in Catalonia last year.

The first thing Carla Borrell thought about when she was diagnosed with cancer was her family. She says that, along with friends and doctors, they were the driving force that kept her from giving up when she was told she had a lung tumor, one of those with the worst prognosis. Her only option was to undergo surgery to have half of her severely damaged right lung removed. The operation left her devastated, requiring more than 120 stitches and nearly a month of hospitalization to drain all the fluid accumulated in her respiratory system, but the tumor disappeared and initial checkups showed a favorable outcome. However, as the weeks passed, they detected metastases in her head, and she had to undergo further surgery.

Every week, new scientific literature on cancer is published, leaving patients and their families dreaming of possible care. But the revolution against this disease began more than a decade ago, with the approval of the first immunotherapies, which stimulate our body's defenses to attack malignant cells. Patient survival has changed radically thanks to these drugs, which have demonstrated success that was unthinkable a few years ago with traditional treatments. There is still a long way to go: some patients respond very well to treatment, but others relapse over the years, and some with very aggressive tumors continue to have a very poor prognosis. However, the emergence of immunotherapy has marked a paradigm shift in the fight against cancer, and experts maintain that we must continue exploring new forms of treatment to fully exploit its potential.

A woman who was diagnosed with neuroblastoma, a brain cancer, as a child has been tumor-free for 18 years thanks to treatmentCAR-T cell immunotherapyThe case is covered in a study published in the journal Nature Medicine and it is assumed that the woman is the patient with this type of cancer who has lived the longest without the presence of the tumor until now, which makes the researchers think that she has been completely cured.