Decoding Breast Cancer Genes: Your Guide to Therapeutic Testing
"Understanding BRCA and beyond: A European consensus on genetic counselling and therapeutic decision-making in breast cancer."
Breast cancer affects a significant number of women globally, with a lifetime risk varying across different regions. For those with a family history or genetic predispositions, such as carrying a BRCA1 or BRCA2 mutation, the risk is even higher. Understanding your individual risk is crucial, and genetic testing plays a vital role in assessing this risk and guiding preventative measures.
Traditionally, knowing your BRCA1/2 status has been important for assessing cancer risks and making decisions about early detection and preventative surgeries. But now, genetic information is also impacting treatment strategies. Women with BRCA mutations may choose more aggressive surgical options or benefit from targeted therapies like PARP inhibitors.
Next-generation sequencing (NGS) allows for faster and more comprehensive genetic testing, analyzing BRCA1/2 and other genes linked to breast cancer risk. This opens doors for personalized treatment plans. However, the increasing demand for testing raises questions about infrastructure, resources, and how to effectively integrate genetic information into breast cancer care. To address these concerns, a panel of European experts convened to develop consensus recommendations for genetic counseling and testing in the context of metastatic breast cancer.
BRCA Testing and Inherited Risk
The National Cancer Institute describes BRCA1 and BRCA2, what a positive result may mean, and the consequences of genetic testing. Its expert-reviewed summary covers cancer risks associated with these genes, along with screening, risk reduction, treatment, and prognosis. Susan G. Komen reports that the International Breast Cancer Linkage Consortium has collected data on more than 200 families worldwide, each with at least four family members with breast cancer. Komen also says that NCCN recommends BRCA1/2 or hereditary cancer panel testing for people at high risk of an inherited mutation or when results could help guide treatment.
From BRCA Tests to Multigene Panels
A 2021 guideline article says BRCA1 and BRCA2 pathogenic variants account for most hereditary breast cancer and are increasingly used to determine eligibility for PARP inhibitor therapy in BRCA-related cancer. A 2026 narrative review describes multigene panel testing as the current standard for patients deemed to be at high genetic risk, replacing earlier approaches that commonly focused on BRCA1 and BRCA2 alone. However, a 2015 review estimates that BRCA1/2 mutations account for only 20%–30% of familial clustering of breast cancer. It recommends specialist assessment and risk-management advice for patients who test negative for BRCA but have a strong family history.
Why Genetic Counseling and Testing Are More Important Than Ever
An international panel of experts from 17 European countries and Israel gathered to discuss the increasing need for BRCA testing and counseling. The group recognized that as high-throughput testing platforms become more accessible and PARP inhibitors gain traction, there will be a surge in the demand for genetic services. The experts voiced concerns that the existing shortage of genetic counselors could worsen, potentially affecting the quality of care for individuals and families with a history of breast or ovarian cancer.
- Therapeutic Setting: For patients with a suspected genetic predisposition, BRCA1/2 testing should be done after a breast cancer diagnosis, regardless of hormone receptor or HER2 status, especially if the results will influence treatment decisions.
- Predictive and Therapeutic Setting: Genetic testing should focus on individuals with a personal or family history suggestive of BRCA1/2 mutations, and should consider other high-risk genes.
- Reporting of Variants: Pathological variants (class IV and V) in high-risk genes should always be reported. Class III variants (variants of unknown significance) should also be reported, clearly stating the current lack of clinical utility.
- Re-Contacting: Genetic counseling should inform patients that they may be contacted in the future if new information changes the classification of a variant.
Research Beyond BRCA1/2
A 2024 overview of homologous recombination repair deficiency (HRD) screening and testing reports ongoing research into HRD beyond BRCA1/2 as a potential therapeutic target in breast cancer. A separate review says most cases it discusses are associated with BRCA1 and BRCA2 mutations. A case report concerning a 29-year-old woman with triple-negative breast cancer notes that therapeutic germline testing has been recommended for triple-negative cases and for all patients with metastatic breast cancer, regardless of age or family history.
Choosing a Genetic Test
Genetic testing may be recommended after reviewing personal and family cancer history, ancestry, and whether a family member has a genetic mutation; results may help inform risk management for breast, ovarian, and other cancers. Breastcancer.org says panel testing, which checks for many genetic mutations, is generally the most common test used to assess breast cancer risk. Cancer Treatment Centers of America describes testing options that include BRCA1, BRCA2, CHEK2, and other genes. These sources frame test choice around a person’s history and the range of genes being considered.
The Future of Genetic Testing in Breast Cancer
The experts envision a future where genetic testing is seamlessly integrated into breast cancer care, guiding both preventative and therapeutic strategies. While challenges remain in terms of resources and infrastructure, these consensus recommendations provide a roadmap for optimizing genetic services and ensuring that patients receive the best possible care. Prioritizing BRCA1/2 testing for a larger number of potential carriers, rather than using large gene panels on a smaller number of individuals, will help in this goal.
Access and Ethical Questions
A 2024 review reports that BRCA1/2 mutations are found in about 5% of unselected patients with breast cancer. A 2022 ethics review describes BRCA1/2 testing as a precedent in genetic testing and management of inherited cancer risk, and examines ethical challenges related to testing. A 2026 targeted literature review focuses on real-world germline BRCA testing patterns in the United States, noting that not all eligible patients undergo testing and that misconceptions, beliefs, attitudes, and barriers are part of the evidence it surveys.
Testing in Practice and in People’s Lives
A case report drawn from a larger study of 32 BRCA1/2 mutation-positive women describes three women who completed or considered genetic testing before age 25. It highlights developmental, relational, and timing-related influences and challenges as these young women began cancer risk management. In a multi-country study of adult women with HER2-negative advanced breast cancer, BRCA1/2 testing rates were low, with significantly lower rates in five European countries than in the United States. A 2025 report notes that germline BRCA testing is recommended for patients with HER2-negative breast cancer to guide PARP inhibitor treatment selection, while real-world testing and treatment-pattern data in metastatic disease remain limited.