An overview of BRCA gene test
The BRCA gene test is a blood test that analyzes a person's DNA to identify harmful mutations in either the BRCA1 or BRCA2 genes. These mutations significantly increase the risk of developing breast cancer, ovarian cancer, male breast cancer, prostate cancer, pancreatic cancer, and melanoma. The test is typically offered to individuals with a personal or family history of breast or ovarian cancer and is not routinely performed for those at average risk. The test sample may be blood or saliva, and it may take a few weeks to receive the results. A genetic counselor is often involved in interpreting the test results and discussing the implications for an individual's health and cancer risk management.
What is BRCA gene test used for?
The BRCA gene test is used to determine if an individual has changes (mutations) in their DNA that increase the risk of breast and ovarian cancers. The test analyzes the BRCA1 and BRCA2 genes, which are associated with a higher risk of these cancers. If a gene mutation is detected, the individual and their doctor can work together to manage the risk. The test is typically offered to those with a personal or family history of breast or ovarian cancer.
How to prepare for BRCA gene test?
To prepare for an BRCA gene test, you should:
- Gather information about your family's medical history, especially that of close relatives.
- Document your personal medical history, including collecting records from specialists or results of previous genetic testing, if available.
- Write down questions for the counselor.
- Consider having a friend or family member accompany you to help ask questions or take notes.
On the day of the test, the BRCA gene test is most often a blood test. A doctor, nurse, or medical technician will insert a needle into a vein, usually in your arm, to draw the blood sample needed for testing. The sample will be sent to a lab for DNA analysis. In some cases, other sample types, such as saliva, may be collected for DNA analysis.
Results may take a few weeks before they are available. You will meet with your genetic counselor to learn your test results, discuss their implications, and go over your options. Your test results may be positive, negative, or uncertain.
It is essential to discuss any concerns or questions about the BRCA gene test with your healthcare provider or genetic counselor before the test to ensure you are well-informed and prepared for the process.
How is BRCA gene test conducted?
An BRCA gene test is most often conducted as a blood test. A healthcare professional inserts a needle into a vein, usually in your arm, to draw a blood sample that is then sent to a lab for DNA analysis. In some cases, a saliva sample may be collected for DNA analysis instead. Discuss your preferred sample type with your doctor or genetic counselor.
How are BRCA gene test results reported?
BRCA gene test results are typically reported as positive, negative, or uncertain. A positive result indicates the presence of a gene mutation associated with increased risk of breast and ovarian cancers. A negative result means that no harmful mutations were found in the BRCA1 or BRCA2 genes, although this doesn't guarantee a zero percent risk of developing cancer. An uncertain result may occur when a gene variant is detected that hasn't been well-studied or is of unknown significance in terms of cancer risk. In these cases, a genetic counselor will help interpret the results and discuss their implications for your health.
Understanding the report
The interpretation of BRCA gene test results can be complex. A positive result indicates that you carry a gene mutation that increases your risk of developing breast and ovarian cancers. In such cases, you and your doctor can work together to manage your risk. A negative result can be less clear. It doesn't necessarily mean that you don't have a gene mutation; it might mean that the test didn't detect the specific mutation you have or that there are yet-to-be-discovered mutations. An ambiguous or variant of uncertain significance result occurs when the analysis finds a genetic variant that may or may not be associated with an increased cancer risk. In these situations, it's recommended to consult a genetic counselor to help interpret the finding and decide on appropriate follow-up. It's important to note that genetic counseling can help you understand the potential implications of the test results for your health and guide you through the decision-making process.
Limitations and Considerations
Limitations of the BRCA gene test include:
- No detection of all mutations: Although the BRCA gene test can detect the majority of mutations in the BRCA1 and BRCA2 genes, it may not detect all mutations. There is a possibility of having a gene mutation that the test wasn't able to detect.
- Limited to specific genes: The BRCA gene test specifically screens for mutations in the BRCA1 and BRCA2 genes, which are associated with increased risks of breast and ovarian cancers. It may not detect gene mutations in other genes that can also contribute to cancer risk.
- Results may not apply to everyone: Since genetic mutations can vary among individuals, the implications of the test results may not be the same for everyone. Some people may have different outcomes or risks based on their unique genetic makeup.
- False-negative results: In rare cases, the BRCA gene test may produce false-negative results, meaning that it doesn't detect an existing gene mutation. This can occur if the test misses the mutation or if the mutation is located in a part of the gene that isn't analyzed by the test.
- Emotional and social implications: Undergoing genetic testing can have emotional, financial, medical, and social implications. Some people may experience anxiety, sadness, or depression upon receiving test results, and there may be concerns about insurance discrimination or strained family relationships.
- New variants of uncertain significance: The test may identify genetic variants of uncertain significance, which means that their impact on cancer risk is not well understood. As new research emerges, these variants may be reclassified as either positive or negative results. It is important to stay in touch with the healthcare provider or genetic counselor who ordered the test for updates.
- Other genetic tests may be necessary: Depending on individual circumstances, other genetic tests may be needed to fully assess the risk of hereditary cancer. Some families may carry gene mutations in other genes that are not screened by the BRCA gene test.