Thanks to a genetic mutation, tumor cells manage to resist treatment.
- 14 to 18% of ovarian cancers are linked to mutations in the BRCA1 and BRCA2 genes.
- In France, approximately 5,000 ovarian cancers are detected each year.
- Surgery and chemotherapy are the two main treatments.
Several strategies have been proven against cancer. In recent years, immunotherapy has developed, in particular to treat ovarian cancer. But some people don’t respond to these drugs, and the disease continues to progress. Researchers at the University of Helsinki have managed to find an explanation for this resistance to treatment. Their findings are published in the specialist journal Nature Communications.
Cells that evade the immune system
“Cancer develops when tumor cells are able to evade the immune system“, recall the authors. Anticancer immunotherapies precisely aim to strengthen the body’s immune defenses so that it can act against cancer. To understand why certain cancer cells manage to escape it, the researchers looked at the links between immune cells and tumor cells. Using new medical imaging technology, they characterized more than 110,000 individual cells from clinical ovarian tumor samples. The scientists studied the genetic characteristics of ovarian cancer and its interactions with the immune system, then they observed the communication between tumor and immune cells.
A genetic mutation in question
“By studying individual cells directly in the tissues, we observed the different ways cancer cells use to hide, depending on specific genetic mutations, says the lead author of the study, Inga-Maria Launonen. We found that the body’s immune system is more effective against tumors when the BRCA1/2 genes are mutated.” In its absence, tumors have tissues that block interactions with immune cells. These BRCA1/2 mutations occur in approximately 20% of poorly differentiated serous carcinomas, the most common form of ovarian cancer. Killer T cells act on aggressive tumor cells, particularly in tumors with BRCA1/2 mutations, improving patient prognosis.
Future precision therapies
“By improving our understanding of how tumor genes trick the immune system, we will be able to develop more effective ways to activate the body’s own immune defenses to kill cancer cells.“, continues Inga-Maria Launonen. With her team, she hopes to be able to use these results to develop precision therapies, adapted to each patient, and to improve the survival rate of ovarian cancer. Survival depends on various factors, including the stage of the cancer, its aggressiveness and the effectiveness of the surgery.
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