Understanding Risk and Genetics for Loved Ones
What Loved Ones Need to Know
Because someone close to you has been diagnosed with breast cancer at a young age, you may be wondering why, or whether family history played a role. Family history is the biggest known risk factor for developing breast cancer at a young age, especially when a close relative (like a parent, grandparent, or sibling) was also diagnosed early.
About 5–10% of all breast cancers are hereditary, meaning they’re linked to gene mutations passed down from a parent.
What are genes and why do they matter?
Genes are tiny pieces of information made of DNA that tell your body how to function. You get half of your genes from each parent, and you pass them on to your children.
Think of each gene as a recipe with instructions for your body to make something it needs, like a specific protein. If there’s a change or error in the instructions (called a mutation), it can affect how your body works and may increase your risk of developing certain diseases, including cancer.
You May Have a Higher Chance of Developing Breast or Ovarian Cancer If:
Mutations
You or a family member has a known BRCA1, BRCA2, or other gene mutation
Changes Found
You’ve had a breast biopsy showing certain pre-cancerous changes, like atypical ductal or lobular hyperplasia, or lobular carcinoma in situ (LCIS)
A Relative with Breast Cancer
A close blood relative (parent, sibling, or child) was diagnosed with breast or ovarian cancer, especially before age 50
Relatives with Breast Cancer before 50 yrs
Two or more relatives on the same side of the family (grandparent, aunts, uncles, cousins) had breast cancer before 50 or ovarian cancer at any age
Pre-menopause Diagnosis
You or a family member was diagnosed with breast or ovarian cancer before menopause
Cancer Syndromes
Your family has a known hereditary cancer syndrome like Cowden syndrome or Li-Fraumeni syndrome (both linked to breast cancer and other rare cancers)
Take the Next Step
If any of these apply to you, it doesn’t mean you’ll develop cancer but it’s a good reason to talk to your doctor or a genetic counselor. Understanding your risk is the first step toward managing it. A smart plan may include genetic testing, routine screenings, and other steps to catch cancer early or lower your risk. You don’t have to face this alone. Support and resources are available to help you move forward with confidence.
Assess Your Risk with This Free Tool
This free, online tool can help you assess your personal risk based on your family history and other factors. It’s quick, private, and can give you helpful insight to discuss with your doctor or a genetic counselor.
Understanding Inherited Risk
We all inherit two sets of chromosomes; one from each parent. These chromosomes carry genes that help regulate how cells grow and repair. When certain genes mutate (change), they can increase the risk of diseases like breast and ovarian cancer.
Two specific genes—BRCA1 and BRCA2—are most commonly linked to breast cancer risk. These mutations can be passed through families and are found on chromosomes 17 and 13.
Around 10% of young adults with breast cancer carry a BRCA1 or BRCA2 mutation, which can raise lifetime breast cancer risk to 50–85%.While BRCA1 and BRCA2 are the most well-known genes linked to breast and ovarian cancer, they’re not the only ones that can increase risk. Other genes—such as PALB2, CHEK2, ATM, and several others—may also play a role. Talking with a genetic counselor can help you understand your family history, assess your personal risk, and make informed decisions about screening and prevention.
Who’s more likely to carry a BRCA mutation?
Genetic testing may be especially important if your loved one:
- Was diagnosed with breast cancer before age 50
- Has had breast cancer in both breasts
- Has a personal or family history of ovarian cancer
- Has Ashkenazi Jewish or Dutch ancestry
- Was diagnosed with other related cancers, including male breast cancer, prostate cancer, or pancreatic cancer.
Other Genetic Mutations Linked to Breast Cancer:
While BRCA1 and BRCA2 are the most well-known, they aren’t the only mutations tied to breast cancer. The following genes can also increase your risk:
| BARD1 | CD[H1] | CHEK2 | NF1 | PALB2 |
| PTEN | RAD51C | RAD51D | STK11 | TP53 |
Want to learn more about these genes?
FORCE (Facing Our Risk of Cancer Empowered) is a national nonprofit that helps individuals and families navigate the challenges of hereditary cancer. Through education, advocacy, and a strong support network, FORCE empowers you to make informed decisions about your health.
Explore the Genes by Name page to learn how different genes influence cancer risk and access research-based tools for managing that risk.
Why This Matters to You
If your loved one has a BRCA1, BRCA2, or other inherited gene mutation, it’s not just important for their care; it could be important for yours. Close blood relatives—such as parents, siblings, or children—may also carry the same genetic mutation and have an increased risk of developing cancer. However, when close relatives aren’t available for testing, it’s still important for extended family members, like aunts, uncles, and cousins, to consider genetic testing. Identifying a mutation in any relative can provide valuable information to help protect the entire family.
Genetic testing can help clarify that risk. Talk to your doctor about whether testing is right for you and when it should be considered.
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