Family history of breast cancer and inherited genes
Some people have a higher risk of developing breast cancer than the general population because other members of their family have had particular cancers. This is called a family history of cancer.
Having a mother, sister or daughter (first degree relative) diagnosed with breast cancer approximately doubles the risk of breast cancer. This risk is higher when more close relatives have breast cancer, or 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.
UK guidelines help GPs to identify people who might have an increased risk of cancer due to their family history.
Referral to a specialist
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 diagnosed with breast cancer aged younger than 40 (a first degree relative is your parent, brother or sister, or your child)
- one first degree male relative diagnosed with breast cancer at any age
- one first degree relative with cancer in both breasts where the first cancer was diagnosed aged younger than 50
- two first degree relatives, or one first degree and one second degree relative, diagnosed with breast cancer at any age (second degree relatives are aunts, uncles, nephews, nieces, grandparents, and grandchildren)
- one first degree or second degree relative diagnosed with breast cancer at any age and one first degree or second degree relative diagnosed with ovarian cancer at any age (one of these should be a first degree relative)
- three first degree or second degree relatives diagnosed with breast cancer at any age
Your GP should also refer you if you have one first degree or second degree relative diagnosed with breast cancer when they were older than 40 years and one of the following:
- the cancer was in both breasts (bilateral)
- the cancer was in a man
- ovarian cancer
- Jewish ancestry
- sarcoma (cancer of the bone or soft tissue) in a relative younger than age 45 years
- a type of brain tumour called glioma or childhood adrenal cortical carcinomas
- complicated patterns of multiple cancers diagnosed at a young age
- two or more relatives with breast cancer on your father's side of the family
Breast cancer genes
If you have a very strong family history of certain cancers, there might be a faulty 
in your family that increases your risk of breast cancer. We know about several gene faults that can increase breast cancer risk and 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. These genes stop cells in our body from growing and dividing out of control. If there is a in these genes, it means that cells can grow out of control. This can lead to developing several cancers including breast cancer.
Other genes that could increase your risk of developing breast cancer if they have a fault include:
- TP53 gene
- PALB2 gene
- ATM gene
- CHEK2 gene
- STK11 gene
- PTEN gene
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.
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.
