Is Breast Cancer Genetic?

Breast cancer can run in families. This is called hereditary breast cancer. BRCA gene mutations are the most common cause of hereditary breast cancer.

Except for some types of skin cancer, breast cancer is the most common cancer in people assigned female at birth. In this group, the average lifetime risk of developing breast cancer is 13%Trusted Source, according to the American Cancer Society.

Some individuals have a higher chance of breast cancer. This can be due to genetic factors that increase risk.

This article takes a closer look at the genetic and hereditary risk factors for breast cancer and the screening recommendations for those at higher risk.

What are the genetic and hereditary risk factors for breast cancer?

Cancer is a genetic disease. Trusted Source. It’s caused by DNA changes, called mutations, in certain genes that cause cells to grow and divide out of control.

Most genetic changes that contribute to cancer are acquired during your lifetime. These are called somatic mutations. Somatic mutations happen due to things like the natural ageing process or certain lifestyle and environmental factors.

What about hereditary breast cancer?

Hereditary cancer is when cancer runs in families. This means mutations associated with higher cancer risk are passed down to you from one or both of your parents. About 5–10% Trusted Source of breast cancers are hereditary.

The most common hereditary cause of breast cancer is mutations in the BRCA1 or BRCA2 genes. Individuals with BRCA mutations have about a 70% chance (Trusted Source) of developing breast cancer by age 80 years. These mutations also increase the risk of:

• breast cancer at a younger age
• Breast cancer affecting both breasts
• other cancers, including ovarian and pancreatic cancers

You can inherit BRCA mutations from either parent. Trusted Source. If you’re the child of a parent who has a BRCA mutation, you have a 50% chance of inheriting the mutation.

It’s also possible to have breast cancer run in your family, but not be associated with any known mutations that increase breast cancer risk. Scientists continue to work to identify and characterise further inherited risk factors for breast cancer.

What other genes are associated with hereditary breast cancer?

Hereditary breast cancer can also result from inherited mutations in other genes. Though these are much less commonTrusted Source.

Some gene mutations are linked with rare genetic syndromes that increase the risk of breast cancer and other cancer types. Gene mutations involved in these syndromes include:

• PTEN, which causes Cowden syndrome
• TP53, which causes Li-Fraumeni syndrome
• CDH1, which causes hereditary diffuse gastric cancer and also increases the risk of lobular breast cancer
• STK11, which can cause Peutz-Jeghers syndrome

Other inherited gene mutations that boost breast cancer risk are those in:

• PALB2
• ATM
• CHEK2

What are the other risk factors for breast cancer?

In addition to hereditary factors, other known risk factors for breast cancer are:

• being an older age
• being a certain race or ethnicity. White women are more likely to develop breast cancer overall, and Black women are more likely to develop more aggressive breast cancer types
• having a personal history of breast cancer
• having dense breast tissue
• having certain benign changes to your breasts, especially atypical hyperplasia or lobular carcinoma in situ (LCIS)
• having certain factors in your reproductive history, including:
  • starting your period at an early age
  • entering menopause at a later age
  • not having children or having children after age 30
  • not breastfeeding
• using hormonal birth control or menopausal hormone replacement therapy
• Having previously had radiation therapy to your chest
• being overweight or obese
• engaging in low levels of physical activity
• drinking alcohol in excess

What are the screening recommendations for someone with high-risk factors for breast cancer?

The American Cancer Society Trusted Source recommends that people with a high risk of breast cancer begin getting a yearly breast MRI and mammogram at age 30.

You’re considered to be at a high risk for breast cancer if:

• You have a confirmed BRCA mutation
• You have a close relative, including a parent, sibling, or child, with a confirmed BRCA mutation
• You or a close relative has an inherited genetic syndrome that increases breast cancer risk, such as Cowden syndrome or Li-Fraumeni syndrome
• You had previous radiation therapy to your chest when you were between the ages of 10 and 30 years
• Breast cancer risk assessment tools that are based mainly on family history have determined that your lifetime risk of breast cancer is 20–25% or higher [Trusted Source].

Individuals at a high risk of breast cancer should continue screening with a yearly breast MRI and mammogram as long as they’re in good health.

Takeaway

Cancer is a genetic disease in which DNA mutations cause cells to grow uncontrollably. Most of the mutations linked with cancer arise on their own.

But some cancers are hereditary, meaning that they run in families. You may inherit gene mutations in these types of cancers from your parents. BRCA gene mutations are the most common cause of hereditary breast cancer.

Yearly screening with a breast MRI and a mammogram is recommended for people with a higher chance of breast cancer. You may wish to discuss your individual breast cancer risk and screening recommendations with your doctor.