What Are the Risk Factors for Breast Cancer?
Breast Cancer & Genetics:
What you need to know
Most people think they won't get breast cancer if it doesn't run in their family.
But that's not how it usually works.
In fact, most breast cancers, about 85 to 90 out of 100 cases, happen by chance. These are called "sporadic" cancers. They occur as we age or due to lifestyle and environmental factors, not because of an inherited gene.
Only about 5 to 10 percent of breast cancers are inherited. That means a damaged gene has been passed down from a parent. These damaged genes can come from either the father or mother.
The most well-known genes are BRCA1 and BRCA2.
Everyone has BRCA genes. Their normal job is to help repair damaged DNA and prevent cancer. But when someone inherits a mutated (damaged) version of BRCA1 or BRCA2, their cells can't fix DNA errors as well. This raises the risk of breast, ovarian, and other cancers. Having a mutation does not mean cancer is guaranteed. It means the risk is higher. For example, women with a harmful BRCA mutation have a 45 to 85 percent chance of developing breast cancer by age 70.
Other inherited genes. BRCA isn't the only player. Other genes linked to higher breast cancer risk include PALB2, CHEK2, ATM, and TP53. Some are rare, but together they help explain more inherited cases.
Should you get genetic testing?
Testing is not for everyone. Doctors typically suggest it if you have:
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Multiple family members with breast or ovarian cancer
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Cancer diagnosed at a young age (under 50)
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A known gene mutation in your family
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Male breast cancer in your family
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Ashkenazi Jewish ancestry (BRCA mutations are more common)
Genetic testing is a simple blood or saliva sample done at your doctor's office. A genetic counselor can help you understand the results.
What if you have a mutation?
Knowing can empower you. Options include more frequent screening (MRI plus mammogram), risk reducing medications, preventive surgery, or lifestyle changes.
The bottom line
Most breast cancers are not inherited. But if cancer runs strongly in your family, genetic testing can give you answers and options. Either way, regular screening matters for everyone, not just those with a family history.
