Families with a history of breast or ovarian cancer often face difficult questions about their future health.
Many people choose genetic testing to learn whether they have inherited mutations that increase their risk of developing cancer.
However, these tests do not always provide clear answers. In many cases, doctors find genetic changes whose effects are unknown, leaving patients uncertain about what the results mean and whether they should take action. Now, a new study offers hope that this uncertainty may soon be reduced.
Researchers from the University of Copenhagen and Denmark’s Rigshospitalet have developed a new way to determine whether certain inherited genetic mutations are harmful or harmless.
Their findings, published in the Journal of Clinical Investigation, could help doctors identify cancer risks earlier and make better decisions about prevention and treatment.
The research focuses on the BRCA2 gene, one of the most important genes linked to hereditary cancer. Mutations in BRCA2 can greatly increase a person’s risk of developing breast cancer, ovarian cancer, prostate cancer, and pancreatic cancer.
Public awareness of BRCA genes has grown over the years because genetic testing can identify people who may benefit from increased cancer screening or preventive treatments.
Although genetic testing has become much more common, it still has an important limitation. Scientists understand the effects of many BRCA2 mutations, but there are also many genetic variants whose impact remains unclear.
These are known as variants of unknown significance. When one of these variants appears in a test result, doctors cannot confidently tell patients whether it increases their cancer risk or not.
This uncertainty can be stressful for patients and their families. Some people may worry unnecessarily about developing cancer, while others may miss opportunities for early prevention because doctors do not have enough information about the mutation.
To solve this problem, the Danish research team created a new testing approach using advanced gene-editing technology known as CRISPR-Select. This technology allows scientists to study specific genetic changes in a highly controlled way and observe how they affect cells.
The researchers tested 54 different BRCA2 variants that had previously been classified as uncertain. Their method was able to determine whether each variant was likely to be harmful or harmless with much greater confidence than before.
Dr. Maria Rossing, the lead researcher and a clinical professor at the University of Copenhagen, said the ability to classify these mutations is extremely important. If doctors know that a person carries a dangerous mutation, they can take steps before cancer develops.
These steps may include earlier and more frequent cancer screening, preventive surgery, lifestyle recommendations, and faster treatment if cancer is detected.
The new method was tested in a real clinical environment using samples from patients around the world. Researchers introduced specific genetic variants into cells and then exposed those cells to chemotherapy drugs.
By carefully studying how the cells responded, they could determine whether the mutation interfered with the cell’s normal ability to repair DNA damage. Problems with DNA repair are one of the main reasons BRCA2 mutations can increase cancer risk.
The scientists then compared their results with internationally accepted classification standards to ensure the findings were reliable and clinically useful.
One of the most important aspects of the project is that the results are being shared with the global medical community. The researchers are updating international genetic databases with information about the 54 tested variants. As a result, doctors and genetic counselors around the world will be able to access the findings when evaluating patients.
This means that the benefits of the study extend far beyond Denmark. A family undergoing genetic testing in Australia, the United States, the United Kingdom, or anywhere else may now receive clearer answers if one of these variants appears in their test results.
The researchers believe this work demonstrates that advanced laboratory methods can successfully be integrated into everyday clinical care. Their collaboration between the University of Copenhagen’s Biotech Research and Innovation Centre and Rigshospitalet showed that the approach is practical and effective in a hospital setting.
While more work is needed to evaluate additional genetic variants, the study represents an important step toward reducing uncertainty in genetic testing. Thousands of people every year receive test results that contain variants of unknown significance. New tools like this could help transform those uncertain findings into useful medical information.
In the future, wider adoption of this testing approach could help doctors identify high-risk individuals earlier, provide more personalized care, and improve cancer prevention strategies. It may also reduce anxiety for patients who are waiting for answers about their inherited cancer risk.
For families affected by hereditary breast and ovarian cancer, the research offers something that has often been difficult to obtain: clearer information. By helping doctors distinguish harmful mutations from harmless ones, this new method could support earlier prevention, better treatment decisions, and ultimately save lives.
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