BRCA1, BRCA2 Gene Tests

What does BRCA stand for?

BRCA stands for "Breast Cancer Susceptibility" in English. It is thought that 5% to 10% of breast cancer cases are hereditary, that is, caused by abnormal genes passed from parent to child.

Mutations that predispose to breast cancer are primarily found in the BRCA1 and BRCA2 genes. In normal cells, these genes help stabilize DNA and prevent uncontrolled cell growth. They are therefore tumor suppressor genes.

If a woman carries a dangerous mutation in the BRCA1 or BRCA2 gene, her lifetime risk of developing breast and/or ovarian cancer is greatly increased. In addition, some BRCA1 mutations are associated with cancers of the cervix, uterus, pancreas and colon, as well as some BRCA2 mutations in the pancreas, stomach, etc. It also poses additional risks for gallbladder, biliary tract cancer and melanoma.

Is It Enough to Look for BRCA1 and BRCA2 Genes?

In patients with a family history of stomach, colon, pancreatic and bone cancer, genes such as TP53, PALB2, PTEN, CHEK2, BRIP1, STK11, RAD50 and ATM may also play a role in predisposition to breast and ovarian cancer.

In studies conducted in Turkey and abroad, BRCA1 and BRCA2 genes were found in all genetic cases. Therefore, it is recommended to screen genes other than BRCA1 and BRCA2 genes in breast and ovarian cancer patients who are thought to be hereditary.

Who Should Have BRCA1 and BRCA2 Gene Tests?

• Diagnosis of ovarian or primary peritoneal cancer (regardless of age)
• Diagnosed with breast cancer before the age of 45
• Diagnosed with breast cancer between the ages of 46-50 and have a family history
• Breast cancer in both breasts or breast cancer in two or more lesions in the same breast
• If a first-degree relative (mother, sister, daughter) was diagnosed with breast cancer before the age of 50
• Both breast and ovarian cancer in first and second degree relatives in the family
• If there is a family history of ovarian cancer in a first-degree relative, regardless of age
• If a family member has mutations in BRCA 1 and BRCA 2 genes
• If the male member of the family has a history of breast cancer
• Diagnosed with triple negative breast cancer before the age of 60

Since BRCA-related disorders are associated with adult disease, testing is not recommended for people under the age of 18. In families with BRCA-associated cancer, genetic testing of affected individuals should be performed first, if possible, and then BRCA screening should be performed in unaffected individuals in the family who are considered to be at risk according to possible test results.

What does it mean if BRCA1 and BRCA2 gene mutations are positive?

Genetic counseling should be done. A positive test does not mean a cancer diagnosis. People with these mutations have an increased risk of developing cancer associated with these genes. However, this does not mean that the person will definitely develop cancer. Patients should be informed that most cases do not develop cancer.

Whether or not cancer develops, there is a 50% risk of passing the mutation to the next generation. Individuals with the mutation should also be informed that other members of the family may also carry the mutation. Since BRCA-related cancers occur at a younger age, early screening is recommended.

What should be done for breast cancer?

• From the age of 18, monthly breast examinations (by the individual)
• Clinical breast examination every 6 months from the age of 25
• Annual breast MRI between 25-29 years of age
• Annual mammography and breast MRI after age 30
• Patients should be informed about risk-reducing mastectomy.