If breast cancer runs in your family, you might wonder if you're also at risk. In certain families, breast cancer shows a pattern that can be detected through genetic testing long before any symptoms appear.
About 5 to 10% of all breast cancers are caused by an inherited gene mutation passed down through the family. That means the risk was present from birth, in every cell of the body, and inherited from one parent. More than 60% of women who carry a mutation in BRCA1 or BRCA2 will develop breast cancer during their lifetime, compared with about 13% of women in the general population (NCI BRCA Gene Changes Fact Sheet).
This article explains what inherited breast cancer risk means, which family history patterns matter most, who should consider genetic testing, and what your options are if testing reveals an elevated risk.
13%
average woman’s lifetime breast cancer risk
60%+
lifetime breast cancer risk for women with a mutation in BRCA1 or BRCA2
A single inherited gene mutation may change your hereditary cancer risk. Knowing about it early could change what you can do about it.
Source: NCI BRCA Gene Changes Fact Sheet
Can Breast Cancer Be Inherited?
Yes, but most breast cancers are not hereditary. About 90 to 95% of breast cancers are sporadic, meaning they develop over time due to a combination of age, hormonal changes, lifestyle factors, and gradually accumulating DNA damage. These cases do not follow a hereditary pattern. (American Cancer Society)
The remaining 5 to 10% are hereditary, caused by a gene mutation you were born with. This mutation is present in every cell of your body, inherited from one of your parents, and can be passed to your children.
Why the Difference Matters
A confirmed hereditary gene mutation may elevate your lifetime hereditary cancer risk and open specific monitoring and prevention options that simply are not available to people who do not know they carry it. Knowing earlier may provide more opportunities for surveillance and prevention.
Which Gene Mutations Are Linked to Inherited Breast Cancer Risk?
Several genes are associated with elevated hereditary breast cancer risk.
BRCA1 and BRCA2
BRCA1 and BRCA2 are genes that, when working normally, help your body repair damaged DNA. Think of them as part of your body's built-in cancer defense system. When either gene has an inherited mutation, that protection is significantly weakened:
A mutation in BRCA1: May raise a woman’s lifetime breast cancer risk to 72%. Cancers in people with a mutation in BRCA1 tend to develop earlier and may be more aggressive, a subtype called triple-negative breast cancer. Also raises lifetime ovarian cancer risk to 44%. (NCI BRCA Gene Changes Fact Sheet)
A mutation in BRCA2: May raise a woman’s lifetime breast cancer risk to approximately 69%. Also associated with male breast cancer, ovarian cancer, pancreatic cancer, and prostate cancer. (NCI BRCA Gene Changes Fact Sheet)
Importantly, BRCA mutations can be inherited from either parent. A father who carries a BRCA mutation has a 50% chance of passing it to each child, regardless of the child's sex. If your father's mother had breast cancer, that history matters for you.
Other Genes Worth Knowing About
BRCA1 and BRCA2 are not the only hereditary breast cancer genes. Several others can elevate risk meaningfully:
PALB2: A mutation in PALB2 may raise lifetime breast cancer risk to approximately 33 to 58%, approaching BRCA2 levels in some studies. PALB2 is increasingly recognized as a high-priority gene in hereditary breast cancer risk assessment. (New England Journal of Medicine, Antoniou et al., 2014)
ATM and CHEK2: These are considered moderate-risk genes, raising breast cancer risk by approximately 2 to 4 times above average. Both are commonly included in comprehensive hereditary cancer panels.
TP53: Mutations in TP53 cause Li-Fraumeni syndrome, a rare hereditary condition with a very high lifetime risk for several cancer types, including breast cancer.
A comprehensive hereditary cancer panel tests all of these genes from a single sample simultaneously, which is why panel testing has replaced older approaches that tested one gene at a time.
What Family History Patterns Suggest Inherited Breast Cancer Risk?
Family history is often the first clue that inherited breast cancer risk may be present. Not every case of breast cancer in your family means a hereditary mutation is present, but certain patterns make it significantly more likely.
Does Your Family History Suggest Inherited Breast Cancer Risk?
Any one of these patterns is worth discussing with a physician. Two or more together may significantly increase the probability that an inherited mutation may be present in the family.
A mother, sister, or daughter diagnosed with breast cancer, especially before age 50
Two or more close relatives on the same side of the family with breast cancer
Any family member with both breast cancer and ovarian cancer
A male relative diagnosed with breast cancer
Ovarian cancer in any first- or second-degree relative
A relative with bilateral breast cancer (both breasts affected)
Ashkenazi Jewish ancestry combined with any personal or family breast or ovarian cancer history
A family pattern that includes breast, ovarian, pancreatic, or prostate cancer across generations — this may suggest a BRCA carrier family
Source: American Cancer Society, NCCN.
Should You Get Genetic Testing for Inherited Breast Cancer Risk?
If your personal or family history includes any of the patterns above, hereditary breast cancer risk genetic testing may be worth discussing with a physician or counselor. The goal is not simply to confirm that cancer “runs in the family.” It is to find out whether there is a specific inherited gene mutation that could change your screening, prevention, or treatment options.
You do not need to have been diagnosed with cancer to ask about testing. Many people pursue hereditary cancer risk testing proactively because of family history, ancestry, or a known mutation in a relative.
A genetic counselor or qualified clinician can help you understand:
Whether your history meets testing guidelines
Which hereditary cancer panel is appropriate
What a positive, negative, or uncertain result would mean
How results could affect screening recommendations
Whether relatives may also need testing
If a known mutation is already present in your family, testing can be more targeted. If no one in the family has been tested before, a broader hereditary cancer panel may help clarify whether inherited risk is part of the picture.
What Happens If You Test Positive for an Inherited Breast Cancer Gene Mutation?
A positive result indicates that an inherited gene mutation was identified. This is an actionablefinding. Knowing you carry an inherited mutation gives you access to clinical options that may not be available to people who do not know their status. These options, always discussed with and managed by a physician, may include:
Enhanced surveillance: Annual breast MRI in addition to mammography, often starting as early as ages 25 to 30 for people with a mutation in BRCA1 or BRCA2. Combining MRI and mammography may significantly improve early-stage breast cancer detection compared with mammography alone.
Risk-reducing medications: Tamoxifen and raloxifene are FDA-approved medications that may reduce breast cancer risk in high-risk women. These decisions are highly individual and made in consultation with a physician.
Risk-reducing surgery: A preventive bilateral mastectomy may reduce breast cancer risk by more than 90% for people with a mutation in BRCA1 or BRCA2. This is a major decision that requires extensive counseling and is not appropriate or necessary for everyone.
Family communication: A positive result has implications for your biological relatives. All first-degree relatives (sisters, brothers, sons, and daughters) each have a 50% chance of carrying the same mutation. A genetic counselor helps you navigate when and how to share this information.
Monitoring for related cancers: People with a mutation in BRCA1 or BRCA2 also need to be monitored for ovarian cancer. A positive result can lead to a broader conversation about your full inherited cancer risk, not just breast cancer.
FAQ: Breast Cancer Inherited Risk
Does breast cancer always run in families?
No. Around 90 to 95% of breast cancers are sporadic, meaning they develop over time and are not caused by inherited gene mutations. Many women diagnosed with breast cancer have no strong family history. That said, for the 5 to 10% of cases that are hereditary, family history is a critical signal worth taking seriously. (American Cancer Society)
If my mother had breast cancer, what is my risk?
One first-degree relative with breast cancer roughly doubles your lifetime risk compared to the general population average of about 13%. Two first-degree relatives with breast cancer raise your risk to approximately 4 times the average. Age at diagnosis matters significantly: a mother diagnosed before 50 is a stronger signal of potential hereditary risk than one diagnosed in her 70s. Genetic testing can clarify whether an inherited gene mutation is responsible. (American Cancer Society)
Can men inherit breast cancer gene mutations?
Yes. Men can carry BRCA1 and BRCA2 mutations and pass them to their children. Men with a mutation in BRCA2 face approximately 6 to 8% lifetime breast cancer risk, low compared to female carriers, but significantly elevated compared to the general male population. Male carriers also face elevated prostate and pancreatic cancer risk. A father with a mutation in BRCA1 or BRCA2 has a 50% chance of passing it to each child, regardless of the child's sex. (NCI BRCA Gene Changes Fact Sheet)
What is the difference between inherited breast cancer risk and a mammogram?
A mammogram is an imaging test that looks for signs of breast cancer that may already be present. It is a monitoring tool used on an ongoing, repeated basis. Genetic testing analyzes the DNA you were born with to identify inherited mutations that may elevate your lifetime cancer risk. It is done once, and the results are relevant for life. Genetic testing informs whether mammography should be supplemented with MRI and at what age monitoring should begin. The two tools complement each other.
If Breast Cancer Runs in Your Family, There is Something You Can Do About It
If there's a history of breast cancer in your family, genetic testing can clarify your inherited risk and guide your next steps. Knowing whether you carry an inherited mutation can help you and your physician make more informed decisions.
Kadance members receive access to hereditary cancer risk testing across 26 clinically actionable genes, genetic counseling to interpret results, and a documented plan their physician can act on. Visit www.kadance.com to learn about current membership options.
The information in this article is intended for educational purposes only and does not constitute medical advice. It may not fully reflect the current scope of Kadance services, testing panels, or program offerings. For the most accurate and up-to-date information about what Kadance includes, please visit kadance.com or speak with a member of our team.
Kadance is a membership program, not insurance. Kadance does not provide or pay for medical treatment. All medical decisions should be made with a licensed physician.
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