Deciding whether to pursue genetic testing for the BRCA genes is a personal decision informed by medical guidelines and an understanding of the implications. These genes are recognized markers for an increased hereditary risk of developing certain cancers. This article provides a framework for understanding the basic biology of these genes, the criteria that suggest testing is appropriate, the steps involved, and the meaning of the results.
What Are the BRCA Genes?
The genes known as BRCA1 and BRCA2 are tumor suppressor genes present in every person’s DNA. These genes normally produce proteins responsible for repairing damaged DNA within cells, maintaining the stability of the cell’s genetic material. This DNA repair function is a natural defense mechanism against the uncontrolled cell growth that leads to cancer.
A person who inherits a harmful change, often called a pathogenic variant or mutation, in one of these genes has a non-functional copy. This mutation impairs the cell’s ability to fix DNA damage effectively. The resulting accumulation of genetic errors significantly elevates the lifetime risk of developing several types of cancer.
Criteria for Recommended Testing
Healthcare providers use clinical guidelines to determine who would benefit most from BRCA gene testing. Eligibility is typically based on an assessment of personal and family history that suggests an increased likelihood of a hereditary cancer syndrome. Testing is not routinely recommended for individuals with an average risk profile.
One major consideration is a person’s individual history of cancer diagnosis. This includes breast cancer diagnosed at a relatively young age (often 50 or younger), or a diagnosis of triple-negative breast cancer at any age. A personal history of ovarian, fallopian tube, peritoneal, or pancreatic cancer also meets the criteria for testing, regardless of the age of diagnosis.
Family history is another major factor, as the pathogenic variants are inherited from a parent. Testing may be recommended if a close blood relative has a known BRCA mutation or if there is a pattern of multiple relatives on the same side of the family with related cancers. This includes cases of male breast cancer or two or more relatives with breast, ovarian, or prostate cancer.
Ancestry can also be a consideration because certain populations have specific founder mutations that occur more frequently. For instance, people with Ashkenazi Jewish heritage have a higher prevalence of specific BRCA1 and BRCA2 mutations compared to the general population.
Understanding the Testing Process
The process of BRCA gene testing begins with pre-test genetic counseling. This consultation involves meeting with a genetic counselor or a trained healthcare professional to review family medical history and confirm testing eligibility. The counselor discusses the potential benefits, limitations, and possible emotional impact of the test results, ensuring the individual is fully informed before proceeding.
The physical collection of the sample is a simple and non-invasive procedure. The test analyzes DNA, which can be obtained from a blood draw or a saliva sample. Genetic testing laboratories then analyze the DNA to look for the known harmful changes in the BRCA1 and BRCA2 genes.
While the BRCA genes are the primary focus, some tests may use a multigene panel that looks for mutations in other cancer-related genes simultaneously. The type of test performed depends on the individual’s specific personal and family history, with results typically becoming available within a few weeks.
Interpreting Test Results and Next Steps
Genetic test results are typically categorized into three main outcomes, and the interpretation is always done in consultation with a genetic counselor. A positive result, or a pathogenic variant, means a harmful mutation in BRCA1 or BRCA2 was found. This finding confirms a significantly increased lifetime risk for certain cancers, but it does not guarantee a cancer diagnosis.
For a positive result, the next steps involve creating a personalized risk management plan with specialists. This may include enhanced cancer surveillance, such as starting screening mammograms and breast magnetic resonance imaging (MRI) at younger ages. Options for proactively reducing cancer risk include chemoprevention drugs or risk-reducing surgeries, such as prophylactic mastectomy or removal of the ovaries and fallopian tubes.
A negative result, or a benign variant, means no known harmful BRCA mutation was detected. It is important to understand that a negative result does not eliminate all cancer risk, as most cancers are not hereditary. Management is then based on the person’s overall medical history and general population screening guidelines.
The third possibility is a Variant of Uncertain Significance (VUS), which indicates a change in the DNA was found, but current scientific evidence is insufficient to classify it as either harmful or harmless. VUS results are often inconclusive, and while they can be common, they typically do not alter medical management decisions and are monitored over time as more data becomes available.