Family history of breast cancer and inherited genes

What does family history mean?

Having a mother, sister or daughter diagnosed with breast cancer increases your risk of breast cancer. This risk is higher:

• when more close relatives have breast cancer

• if a relative developed breast cancer under the age of 50

But most women who have a close relative with breast cancer will never develop it.

Speak to your GP if you are worried about your family history of breast cancer. They might refer you for a family history risk assessment. This happens at a specialist breast clinic or a genetic clinic.

The specialists who assess you at the clinic can tell you more about your risk of developing breast cancer.

Referral to a specialist clinic

UK guidelines help GPs to identify people who might have an increased risk of cancer due to their family history.

Your GP will refer you to a specialist breast clinic or genetics clinic for assessment if you have any of the following:

• One first degree female relative has had breast cancer before the age of 40.

• One first degree male relative has had breast cancer at any age.

• One first degree relative has had cancer in both breasts. And the first cancer was before the age of 50.

• Two first degree relatives, or one first degree and one second degree relative, have had breast cancer at any age.

• One first degree or second degree relative has had breast cancer at any age. And one first degree or second degree relative has had ovarian cancer at any age. One of these relatives should be a first degree relative.

• Three first or second degree relatives have had breast cancer at any age.

Your GP should also refer you if you have one first degree or second degree relative who has had breast cancer after the age of 40, and one of the following:

• The cancer was in both breasts.

• The cancer was in a man.

• Ovarian cancer.

• Jewish ancestry.

• Sarcoma in a relative younger than age 45 years.

• A type of brain tumour called glioma or childhood adrenal cortical carcinoma.

• A number of cancers have been diagnosed in your family at a young age.

• Two or more relatives with breast cancer on your father's side of the family.

Read NICE guidance about increased risk due to family history

Breast cancer genes

If you have a very strong family history of certain cancers, there might be a gene change (mutation) in your family that increases your risk of breast cancer. We know about several gene changes that can increase breast cancer risk. There are tests for some of them.

Genes that increase the risk of breast cancer are BRCA1 and BRCA2. BRCA stands for BReast CAncer gene. Everyone has BRCA1 and BRCA2 genes.

These genes stop cells in our body from growing and dividing out of control. A gene change in the BRCA1 or BRCA2 gene means that the cells can grow out of control. This can lead to cancer developing.

Other genes that could increase your risk of developing breast cancer if they have a change include:

• TP53 gene

• PALB2 gene

• ATM gene

• CHEK2 gene

• STK11 gene

• PTEN gene

• RAD51C gene

Find out more about breast cancer genes

Having one of these faulty genes means that you are more likely to get breast cancer than someone who doesn’t. But it is not a certainty.

Remember that most breast cancers happen by chance. Researchers estimate that only around 5 to 10 out of 100 breast cancers (5 to 10%) are caused by an inherited faulty gene.

Read about testing for inherited cancer genes

Do I need extra screening?

Cancer screening is a test that looks for early signs of cancer in healthy people.

Staff at the breast or genetics clinic can work out your risk of developing breast cancer. They can then tell you whether you might need extra screening.

Find out more about breast screening