Table of ContentsView AllTable of ContentsGene MutationsHigh-Penetrance GenesLow-Penetrance GenesAssessing Genetic RiskGenetic TestingFrequently Asked Questions

Table of ContentsView All

View All

Table of Contents

Gene Mutations

High-Penetrance Genes

Low-Penetrance Genes

Assessing Genetic Risk

Genetic Testing

Frequently Asked Questions

Many women want to understand theirbreast cancerrisk, especially if someone in their family has or has had the disease.

Geneticssignificantly affects about 5% to 10% of breast cancers.Having a sister or mother with breast cancer roughly doubles your risk, but most people who get breast cancer don’t have a close relative with it.

This article discusses the role of genetics in breast cancer, key genes, testing, and nongenetic risk factors.

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Mother with breast cancer with her daughters

Breast canceris the most common cancer in women, affecting as many as 1 in 10.

Breast Cancer Facts and Statistics: What You Need to Know

Gene Mutations: A Risk for Breast Cancer

Genesare made from DNA (deoxyribonucleicacid), the heritable information you get from your parents. Inheriting certain (mutated) versions of specific genes, such as theBRCA1 gene(breast cancer susceptibility 1 gene), may increase yourrisk of breast cancer.

Normal BRCA1 FunctionsThe same genes that increase your risk of cancer also perform normal functions. For example, the BRCA1 gene usually works to help repair your DNA if damaged.But specific mutated versionsof BRCA1 don’t work very well and increase your cancer risk.

Normal BRCA1 Functions

The same genes that increase your risk of cancer also perform normal functions. For example, the BRCA1 gene usually works to help repair your DNA if damaged.But specific mutated versionsof BRCA1 don’t work very well and increase your cancer risk.

High-penetrance genes increase your risk of breast cancer more than other types of genes. People with these genes are more likely to get cancer earlier than those with nongenetic breast cancer. They are also more likely to have cancer in both breasts and to have other cancers, such as ovarian cancer.

BRCA Genes

BRCA1 and BRCA2 genes are among the most important in assessing breast cancer risk. Females carrying one of these genes have a 50% to 85% chance of getting breast cancer in their lifetime.Additionally, they have a 10% to 40% risk of ovarian cancer and an elevatedrisk of other cancers.Men with BRCA mutations might be more likely to have prostate or pancreatic cancer.

You can inherit a mutated BRCA gene from either parent, and having only one BRCA gene still significantly increases your risk.While having a BRCA mutation gives you agenetic predispositionfor breast cancer, it does not mean you will certainly get it.

Prevalence of BRCA MutationsBetween 1 in 300 and 1 in 500 women in the United States have a BRCA mutation that significantly increases their risk of breast cancer.In the United States, BRCA mutations are more common in people of Eastern European (Ashkenazi) Jewish descent.

Prevalence of BRCA Mutations

Between 1 in 300 and 1 in 500 women in the United States have a BRCA mutation that significantly increases their risk of breast cancer.In the United States, BRCA mutations are more common in people of Eastern European (Ashkenazi) Jewish descent.

Other Moderate to High-Penetrant Genes

Scientists have studied other, less common genes thought to increase cancer risk, but much less so than BRCA genes.

Many other genes also occur as part of broader medical conditions. They might increase your risk of breast cancer and multiple other medical problems, including different types of cancer. Some of these genes are:

Non-BRCA Gene Mutations That Raise Breast Cancer Risk

These genes are not a standard part of genetic testing.Scientists are still researching these genes. It’s believed that more low-penetrance genes are yet to be identified based on the number of family-linked breast cancer cases.However, it could also be due to other shared risk factors within a family.

Having a family history of breast cancer increases your risk, but the specifics of this can vary.

For example, a history of breast cancer in a parent or full sibling (first-degree relatives) increases your risk more than breast cancer in further-removed relatives such as a cousin, aunt, or grandmother.

Not surprisingly, having two first-degree relatives with breast cancer increases your risk even more. Having one first-degree relative with breast cancer doubles your risk, while having two almost triples it.

Family History That Increases Your Genetic Risk

Having family members with the following history might also put you at an increased risk for breast cancer:

Other Risk Factors

Factors other than genetics and family history that may influence your breast cancer risk include:

Breast Cancer Genetic Tests

Genetic testingis an important part of assessing breast cancer risk. These tests often look for the BRCA1 or BRCA2 mutations, but other genes might be tested in certain circumstances.

Testing is typically recommended for those predisposed to a BRCA1 or BRCA2 mutation. Your healthcare provider may suggest testing if:

Getting a Genetic Test for Breast CancerThere isn’t one right answer as to whether to get tested. Your other risk factors, insurance coverage options, and personal preferences may all play a role. Talk to your healthcare provider about your concerns to determine what’s best for you.

Getting a Genetic Test for Breast Cancer

There isn’t one right answer as to whether to get tested. Your other risk factors, insurance coverage options, and personal preferences may all play a role. Talk to your healthcare provider about your concerns to determine what’s best for you.

Summary

About 5% to 10% of breast cancer is genetic, often from the inheritance of a BRCA mutated gene. While the BRCA mutation puts you at a genetic predisposition and increases your risk for breast cancer, it doesn’t mean you will get it.

Your medical history, family history, and lifestyle factors play a role in breast cancer risk. If you’re concerned about your risk for breast cancer, speak to your healthcare provider about genetic testing, most likely for the BRCA gene.

A Word From Verywell

If someone in your family has had breast cancer, it’s only natural to wonder about your own risk. Unfortunately, clear-cut answers aren’t always available. Speak with your healthcare provider about your questions and concerns. Together, you can decide on the best ways to manage your risk.

Frequently Asked QuestionsNo. Most people who get breast cancer don’t have the mutated BRCA gene known to significantly increase their risk of breast cancer. Moreover, most people who get breast cancer don’t have a close relative who has already had the disease.Learn MoreStudy Identifies Most Important Factors in Breast Cancer RiskNot necessarily. You have an increased risk of getting breast cancer if your mother or grandmother has had it compared to someone who doesn’t have such a relative. Work with your healthcare provider to assess your overall risk.Learn MoreYour Risk of Breast Cancer If Your Mother Had Breast CancerPeople who know they have the BRCA gene mutation have a higher risk. Having multiple relatives with the disease also increases your risk, especially if they were diagnosed with breast cancer at a young age (under 45). But risk also increases with other factors, like age and late-onset menopause.

No. Most people who get breast cancer don’t have the mutated BRCA gene known to significantly increase their risk of breast cancer. Moreover, most people who get breast cancer don’t have a close relative who has already had the disease.Learn MoreStudy Identifies Most Important Factors in Breast Cancer Risk

No. Most people who get breast cancer don’t have the mutated BRCA gene known to significantly increase their risk of breast cancer. Moreover, most people who get breast cancer don’t have a close relative who has already had the disease.

Learn MoreStudy Identifies Most Important Factors in Breast Cancer Risk

Not necessarily. You have an increased risk of getting breast cancer if your mother or grandmother has had it compared to someone who doesn’t have such a relative. Work with your healthcare provider to assess your overall risk.Learn MoreYour Risk of Breast Cancer If Your Mother Had Breast Cancer

Not necessarily. You have an increased risk of getting breast cancer if your mother or grandmother has had it compared to someone who doesn’t have such a relative. Work with your healthcare provider to assess your overall risk.

Learn MoreYour Risk of Breast Cancer If Your Mother Had Breast Cancer

People who know they have the BRCA gene mutation have a higher risk. Having multiple relatives with the disease also increases your risk, especially if they were diagnosed with breast cancer at a young age (under 45). But risk also increases with other factors, like age and late-onset menopause.

6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Wendt C, Margolin S.Identifying breast cancer susceptibility genes - a review of the genetic background in familial breast cancer.Acta Oncol. 2019;58(2):135-146. doi:10.1080/0284186X.2018.1529428American Cancer Society.Breast cancer risk and prevention.Naik R, Veldore VH, Gopinath KS.Genetics and breast cancer - oncologists perspectives.Indian J Surg Oncol. 2015;6(4):415-419. doi:10.1007/s13193-016-0491-7Shiovitz S, Korde LA.Genetics of breast cancer: a topic in evolution.Ann Oncol. 2015;26(7):1291-1299. doi:10.1093/annonc/mdv022Force UPST, Owens DK, Davidson KW, et al.Risk assessment, genetic counseling, and genetic testing for brca-related cancer: us preventive services task force recommendation statement.JAMA. 2019;322(7):652-665. doi:10.1001/jama.2019.10987Centers for Disease Control and Prevention.What are the risk factors for breast cancer?

6 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Wendt C, Margolin S.Identifying breast cancer susceptibility genes - a review of the genetic background in familial breast cancer.Acta Oncol. 2019;58(2):135-146. doi:10.1080/0284186X.2018.1529428American Cancer Society.Breast cancer risk and prevention.Naik R, Veldore VH, Gopinath KS.Genetics and breast cancer - oncologists perspectives.Indian J Surg Oncol. 2015;6(4):415-419. doi:10.1007/s13193-016-0491-7Shiovitz S, Korde LA.Genetics of breast cancer: a topic in evolution.Ann Oncol. 2015;26(7):1291-1299. doi:10.1093/annonc/mdv022Force UPST, Owens DK, Davidson KW, et al.Risk assessment, genetic counseling, and genetic testing for brca-related cancer: us preventive services task force recommendation statement.JAMA. 2019;322(7):652-665. doi:10.1001/jama.2019.10987Centers for Disease Control and Prevention.What are the risk factors for breast cancer?

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Wendt C, Margolin S.Identifying breast cancer susceptibility genes - a review of the genetic background in familial breast cancer.Acta Oncol. 2019;58(2):135-146. doi:10.1080/0284186X.2018.1529428American Cancer Society.Breast cancer risk and prevention.Naik R, Veldore VH, Gopinath KS.Genetics and breast cancer - oncologists perspectives.Indian J Surg Oncol. 2015;6(4):415-419. doi:10.1007/s13193-016-0491-7Shiovitz S, Korde LA.Genetics of breast cancer: a topic in evolution.Ann Oncol. 2015;26(7):1291-1299. doi:10.1093/annonc/mdv022Force UPST, Owens DK, Davidson KW, et al.Risk assessment, genetic counseling, and genetic testing for brca-related cancer: us preventive services task force recommendation statement.JAMA. 2019;322(7):652-665. doi:10.1001/jama.2019.10987Centers for Disease Control and Prevention.What are the risk factors for breast cancer?

Wendt C, Margolin S.Identifying breast cancer susceptibility genes - a review of the genetic background in familial breast cancer.Acta Oncol. 2019;58(2):135-146. doi:10.1080/0284186X.2018.1529428

American Cancer Society.Breast cancer risk and prevention.

Naik R, Veldore VH, Gopinath KS.Genetics and breast cancer - oncologists perspectives.Indian J Surg Oncol. 2015;6(4):415-419. doi:10.1007/s13193-016-0491-7

Shiovitz S, Korde LA.Genetics of breast cancer: a topic in evolution.Ann Oncol. 2015;26(7):1291-1299. doi:10.1093/annonc/mdv022

Force UPST, Owens DK, Davidson KW, et al.Risk assessment, genetic counseling, and genetic testing for brca-related cancer: us preventive services task force recommendation statement.JAMA. 2019;322(7):652-665. doi:10.1001/jama.2019.10987

Centers for Disease Control and Prevention.What are the risk factors for breast cancer?

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