Discovery could lead to kinder and better treatments

Researchers have shown how some brain tumours grow without being challenged by the immune system – a discovery which could lead to kinder and more effective treatments.

Childhood brain tumours like ependymoma are serious and hard to treat types of cancer. The immune system is not able to fight these cancers properly, and immunotherapy treatments that have had so much success for other cancer types often do not work.

For the first time, researchers with funding from The Little Princess Trust and the Brain Tumour Charity have shown how some childhood brain tumours are able to trick the immune system into believing that the cancer is a normal part of the brain.

These findings, published recently in Nature Genetics, could help scientists design new treatments that reawaken the immune system and encourage it to recognise and attack cancer cells.

Prof Richard Gilbertson’s group at the Cancer Research UK Cambridge Institute showed that the fluid around the brain (cerebrospinal fluid) is key.

They discovered that, when the brain is still developing before birth, special stem cells collect molecules from the fluid and present them to the immune system.

This helps the immune system learn not to attack healthy brain cells – however, brain tumours release chemicals into the fluid that forces the immune system to see them as ‘safe’. Through this process, the cancer can grow unchecked.

This creates an exciting opportunity to bring immunotherapies into paediatric brain tumour patients.

Working in the lab, LPT-funded researcher Dr Elizabeth Cooper tested whether this process could be blocked. She was able to show, in lab models, that preventing brain tumour chemicals from reaching the stem cells allowed the immune system to recognise and fight the cancer.

While this research is in its early stages, it is a big step forward for ependymoma research. Dr Cooper said: "This creates an exciting opportunity to bring immunotherapies into paediatric brain tumour patients, with the potential to target a number of different layers of communication” 

The team are now hoping to move this work towards early clinical trials. If successful, this research could help bring immunotherapy to children with a range of brain tumours.

Prof Richard Gilbertson said: “It is incredibly exciting to have identified a potential new route to treating childhood brain tumours.

"Early signs suggest this approach could come with very few side effects – something that is especially important for children and their families.”