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Family history and genetic factors

In a small number cases, breast cancer runs in the family. This is known as familial or hereditary breast cancer.
A family history of breast cancer is identified as an unusually high number of close relatives with breast or other types of cancer, cancers at a young age, or in men as well as women.

If you do have a family history of breast cancer then your risk of developing breast cancer is increased. However, having one relative who was diagnosed over the age of 50 would probably not count as a family history. Very broadly speaking a strong family history means having:

  • 2 close family members (mother, daughter, sister, grandmother, aunt) diagnosed with breast cancer under the age of 50.
  • 3 close family members under 60.
  • 4 close family members of any age.


The risk of having hereditary breast cancer is low. In fact it is believed that only around 5% of all breast cancers are due to inherited faults in breast cancer genes (such as BRCA1 or BRCA2) that lead to a high risk of developing the disease.

If you have concerns about any cancers in your family then you should see your GP. They can work out if your family history suggests that you have an increased risk of breast cancer and help you to work out the best option for you.

Breakthrough has developed a dedicated section to this website for women who are concerned about their family history and are looking for more information about hereditary breast cancer.

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