In a study, funded by Breast Cancer Now, researchers found a gene that may help breast cancer spread to the brain.

Researcher Clare Isacke and her team

New findings

Scientists found that a gene called ID2 could be driving breast cancer to spread to the brain, where it becomes incurable.

The team at the Breast Cancer Now Toby Robins Research Centre at The Institute of Cancer Research, London observed that patients whose tumours had a more active ID2 gene were more likely to develop secondary breast cancer in the brain.

Researchers think that in future these findings could lead to a test to identify who is at higher risk of breast cancer spreading to the brain and help to develop new ways to prevent it or treat it.

Addressing an unmet need

When cancer spreads from the tumour in the breast to other parts of the body, known as secondary or metastatic breast cancer, it is incurable.

Around 15-30% of people with secondary breast cancer develop tumours in the brain. These tumours can severely affect their quality of life.

Dr Simon Vincent, Director of Research, Support and Influencing at Breast Cancer Now, explained why breast cancer in the brain is particularly hard to treat:

‘The brain has a unique barrier protecting it from anything harmful, called the blood-brain barrier. It stops many existing cancer drugs from reaching the brain, making treatment options for secondary breast cancer there very limited.’

‘Stopping breast cancer from spreading to the brain and finding better ways to treat it if it does, is one of the greatest areas of unmet need in breast cancer.’

In this study, researchers led by Professor Clare Isacke, studied the spread of breast cancer in mice, to find what could be driving the disease to move to the brain and verified their findings by analysing data from breast cancer patients.

What helps breast cancer grow in the brain

Investigating differences in gene activity between tumours in the breast and tumours that spread to the brain and lungs in mice, researchers found two genes, Id2 and Aldh3a1 that may help breast cancer spread.

Breast cancer cells found in the brain had high activity of these two genes. It means these genes could play a key role in helping breast cancer cells survive in this new environment.

Scientists also confirmed the relevance of these genes in breast cancer patients. They found that people with oestrogen receptor negative (ER-) breast cancer whose tumours had more active ID2 and ALDH3A1 genes, were at higher risk of breast cancer spreading.

But only patients with high ID2 activity levels were more likely to develop secondary tumours in the brain.

Breast Cancer Now researcher

Future direction

Researchers will further investigate the role of ID2 to understand if targeting it could help to prevent breast cancer from spreading to the brain or to treat it if it does.

‘Understanding the mechanisms by which breast cancer cells invade different parts of the body is very important. It provides information about how we could develop ways to specifically target, in this case, the development of breast cancer in the brain,’ Simon added.

Researchers also think that measuring the levels of ID2 activity could help to find breast cancer patients who are more likely to develop secondary breast cancer the brain. While more research is needed to understand if it could be developed into a useful and reliable test, a test like this could indicate who may need a more intensive treatment to stop people developing secondary breast cancer in the brain.

The study is published in journal Breast Cancer Research.

Find out more about secondary breast cancer in the brain. 

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