BRCA1 & BRCA2 Mutation Test – Genetic Cancer Risk Explained

What is BRCA1 & BRCA2 Mutation Test?

The BRCA1 and BRCA2 Mutation Test is a genetic test that checks for harmful mutations (changes) in the BRCA1 and BRCA2 genes.
These genes normally play an important role in repairing damaged DNA and controlling cell growth.

If a person inherits a mutation in either of these genes, it increases the risk of developing certain cancers, particularly:

• Breast cancer
• Ovarian cancer
• Prostate cancer
• Pancreatic cancer

Both men and women can carry BRCA gene mutations, and these changes can be passed down from either parent.
The test is most useful for people with a family history of cancer or early-onset cancer.

Where BRCA Genes Are Found in the Body

BRCA1 and BRCA2 are inherited genes that exist in every cell of the human body.
They are not produced by the body but are part of our genetic material (DNA) inherited from our parents.

Genetic Location

• BRCA1 gene – located on chromosome 17
• BRCA2 gene – located on chromosome 13

Each of these genes acts as a tumor suppressor, meaning they help prevent cells from growing uncontrollably.
When one of these genes is mutated, it can no longer repair DNA properly — allowing abnormal cells to multiply, which increases cancer risk.

Main Functions and Importance of BRCA1 & BRCA2 Genes

1. DNA Repair

BRCA1 and BRCA2 help repair breaks in DNA strands, preventing cells from accumulating genetic errors that could lead to cancer.

2. Tumor Suppression

They act as tumor suppressor genes, controlling abnormal cell division and maintaining genetic stability.

3. Early Detection of Genetic Cancer Risk

Identifying mutations in BRCA genes helps find individuals who are genetically predisposed to cancer even before symptoms appear.

4. Helps in Cancer Prevention

If someone tests positive, doctors can recommend preventive actions such as:

• Regular mammograms or MRIs
• Lifestyle modifications (healthy weight, no smoking, limited alcohol)
• Preventive medications (chemoprevention)
• Preventive surgery (mastectomy or removal of ovaries)

5. Guides Cancer Treatment

Patients with BRCA mutations may benefit from targeted therapies like PARP inhibitors, which are especially effective in BRCA-positive cancers.

Causes of Low or Negative Results

A negative BRCA test result means no harmful mutation was detected in either the BRCA1 or BRCA2 gene.

Possible Causes of a Negative Result

• The person does not carry a known pathogenic mutation.
• The cancer in the family may be caused by other genes not tested.
• The person may still develop cancer due to non-genetic causes (age, hormones, environment, lifestyle).

Symptoms or Implications of a Low/Negative Result

A negative result generally indicates no inherited BRCA mutation and a normal risk level similar to the general population.

Key Points:

• Cancer risk is not eliminated, but it’s not genetically increased due to BRCA mutations.
• Regular cancer screening is still recommended.
• If strong family history exists, the doctor may suggest expanded genetic panel testing for other cancer-related genes.

Causes of High or Positive Results

A positive BRCA test means a harmful or pathogenic mutation has been detected in either the BRCA1 or BRCA2 gene.

Implications of a Positive Result

• The mutation disrupts the gene’s DNA repair function, allowing cells to become cancerous over time.
• The person has a significantly increased lifetime risk of certain cancers.

These risks are much higher than the general population, where breast cancer risk is around 12% and ovarian cancer risk around 1–2%.

Symptoms or Implications of High/Positive Result

A BRCA mutation itself does not cause symptoms — it’s a genetic predisposition, not an active disease.
However, people who carry these mutations are more likely to develop cancers earlier and may have multiple relatives with related cancers.

Clinical Implications

• Women: Increased surveillance for breast and ovarian cancer.
• Men: Screening for prostate and breast cancers.
• Family members: Should be offered genetic counseling and testing.

Early identification allows timely preventive care and targeted treatment if cancer develops.

Understanding “Variant of Uncertain Significance (VUS)”

Sometimes the report shows a “Variant of Uncertain Significance (VUS)” — a change in the BRCA gene whose effect is not yet clearly understood.
It doesn’t confirm risk but requires further genetic study or follow-up testing over time.

Reference Ranges

Sample Type and Testing Method

Sample Type

• Blood sample: DNA extracted from white blood cells
• Saliva sample: DNA collected from saliva using a sterile kit

Testing Method

• Genetic sequencing: Detects changes in BRCA1 and BRCA2 genes.
• Next-Generation Sequencing (NGS) is most commonly used.
• Testing can identify both small mutations and large deletions or duplications in these genes.

Testing Steps

1. Sample collection (blood or saliva).
2. DNA extraction in a specialized genetic laboratory.
3. Sequencing and analysis of BRCA1 and BRCA2 genes.
4. Genetic counselor interpretation — to explain results and risks.

Test Preparation

• No fasting or special diet required.
• Inform your doctor about your personal and family history of cancer.
• Genetic counseling before and after testing is highly recommended to understand the implications.

When to Consult a Doctor or Genetic Counselor

You should discuss BRCA testing with your doctor if you have:

• Family history of breast, ovarian, or prostate cancer
• Breast cancer before age 50
• Triple-negative breast cancer
• Multiple relatives with the same or related cancers
• A known BRCA mutation in the family

If you test positive, consult a genetic counselor to discuss:

• Cancer risk management
• Screening schedules
• Preventive medication or surgery options
• Testing for other family members

Important Word Explanations

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