Breast Cancer and Genetic Testing
Breast cancer is the most common invasive cancer in women in the developed and developing world. About 5 to 10% of breast cancer cases are inherited.
Inherited breast cancer results from changes or mutations in certain genes that are passed on from a parent. Breast cancer prognosis is better when the cancer is detected in the early stages.
The BRCA Genes
BRCA stands for BReast CAncer gene. More than 1000 different mutations or changes in these genes have been identified to increase breast cancer risk. The role of BRCA genes in breast cancer was first identified in the 1990s. Clinical testing for BRCA mutations gained popularity when Angelina Jolie, who was tested positive for BRCA mutations, underwent preventive surgery to decrease her risk of developing breast and ovarian cancer.
FDA Approved BRCA Markers
In 2018, the Food and Drug Administration (FDA)approved the reporting of three specific mutations in the BRCA1/BRCA2 genes for breast cancer screening. The FDA-approved markers can be used to identify the risk for breast and ovarian cancer in women, and breast and prostate cancer in men.
In the US, these mutations are found in 2% of people of Ashkenazi (Eastern European) Jewish descent and less than 0.1% of the population overall.
Testing positive for any one of these markers indicates an increased risk of developing breast and ovarian cancers in women and breast and prostate cancers in men. On the other hand, an absence of the three tested mutations does not rule out the chances of developing any of the conditions mentioned above. These three mutations are not very common in the general population.
The BRCA Genes and Breast Cancer Risk
Changes in the BRCA genes have been linked to an increased risk of breast cancer. Genetic changes can accumulate over time as cells divide. Some of these changes lead to uncontrolled cell division, increasing a person’s risk of developing cancer.
Not all cancers are inherited, but a parent carrying a change in the BRCA genes can pass it on to their children and increase their lifetime risk of developing cancer.
The BRCA1 gene or BReast CAncer 1 gene carries instructions for producing a tumor suppressor protein that helps prevent uncontrolled cell growth and division. This protein also plays a role in repairing damaged DNA, which is crucial for maintaining genome stability.
The BRCA2 gene or BReast CAncer 2 gene is also a tumor suppressor gene.
Reducing Your Risk For Breast Cancer
- A breast cancer genetic test is recommended for anyone with a family history of breast, ovarian, or prostate cancer.
- A genetic counselor can help you understand the pros and cons of the test and your testing options. They can also help you interpret and understand the implications of your test results.
- If any risk markers are identified through the test, you would require further screening. Based on the results of the screening test, your doctor may recommend preventive methods.
- Mammography is the most common screening test for breast cancer. Other screening tools include breast exams and tissue sampling.
Summary
- Breast cancer develops in the breast tissue. Advanced age, dense breast tissues, genetics, and extended exposure to estrogen are a few risk factors for breast cancer.
- About 5 to 10% of breast cancer cases are due to changes in certain genes like BRCA1 and BRCA2.
Learn About Your Genetic Risk For Breast Cancer - Over 1000 mutations in the BRCA genes influence breast, ovarian, and prostate cancer risk.
- The FDA approved three markers in the BRCA genes that can identify the risk for breast cancer in both men and women.
- A genetic test can help people with a family history of breast, ovarian, or prostate cancer identify their risk for these conditions.
- A healthcare provider or genetic counselor can help you understand the pros and cons of the test, interpret the results, and suggest a further course of action.
References
https://www.cancer.org/latest-news/fda-approves-consumer-test-for-certain-brca-mutations.html
https://www.fda.gov/news-events/press-announcements/fda-authorizes-special-controls-direct-consumer-test-reports-three-mutations-brca-breast-cancer
https://www.23andme.com/brca/
https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet
https://medlineplus.gov/genetics/gene/brca1/
https://medlineplus.gov/genetics/gene/brca2/
