Diagnosing brain tumours associated with epilepsy in children

Glioneuronal tumours are a rare type of tumour in the brain that are strongly associated with epilepsy and seizures in young children.

There are currently no tailored treatment options for GNTs, with management focussed on controlling symptoms or surgery to remove the affected tissue, which is invasive and associated with risks.

One of the reasons for the lack of targeted treatments for these tumours may be due to their complex characteristics, which can lead to difficulties in diagnosing them accurately.

Dr Tom Stone, Research Associate at UCL GOS ICH and lead scientist on this project, describes the complications associated with this:

"One of the reasons that we don’t have targeted treatments for these tumours is partially because, in order to develop new treatments for disease, you first have to be able to properly and accurately separate the tumours into their biological groups, so that they can be studied."

Traditionally, GNTs are diagnosed by what pathologists see under the microscope – which is a sample of the brain tissue that was removed during surgery. There appear to be different subtypes of tumours falling under the umbrella of GNTs – but separating them can be challenging as many are similar in appearance and lack any prominent features that enable researchers to tell them apart.

The rarity of these tumours also means that it is difficult to get a large enough sample together to study the tumour types in more detail – which adds to the lack of guidance in achieving an accurate diagnosis. Altogether, interpretation of these tumours can often be subjective across different researchers and centres.

“If you give two pathologists the same slide and give them the same criteria or features to look for to try and diagnose the tumour, a lot of the time they will disagree. I would say the rate of agreement is somewhere around 50%,” Dr Stone says.

To try and create a more objective diagnostic tool, researchers at the UCL GOS ICH have used a modern genetic technology called methylation profiling.

Methylation profiling can identify the unique DNA profile of tumours, which can make it possible to tell the difference between brain tumours that may look similar under the microscope.

Dr Stone and his team found that by using this approach alongside tissue analysis and routine imaging that patients receive before their surgery, they were able to confidently identify different types of tumours at a higher rate than the traditional method of looking down the microscope.

“By using this integrated approach, we now face a possibility where almost all GNTs can be accurately identified," Dr Stone says. "Once properly diagnosed, targeted treatment plans for children with GNTs can be developed, giving hope to children with these tumours and associated epilepsy."

The team are now excited to explore the potential of this new diagnostic approach, and how it may be translated into the clinic to benefit patients with GNTs.

This study was run by The Everest Centre for Low-Grade Paediatric Brain Tumours, funded by The Brain Tumour Charity.

The research team have also received funding from us here at GOSH Charity, to support their work in understanding and diagnosing epilepsy-related brain tumours in children. 

"Funding such as that provided by GOSH Charity allows us to explore ideas that may not necessarily generate profit - but that might just help to improve peoples’ diagnoses and move towards better treatments, and by extension, survival and quality of life naturally improve as an ongoing effect of that," Dr Stone says.

By funding novel research like this into rare diseases, GOSH Charity hopes to lead to the development of new diagnostic approaches and therapies to build a brighter future for children with rare or complex diseases.

Read the published paper on the Wiley Online Library: DNA methylation‐based classification of glioneuronal tumours synergises with histology and radiology to refine accurate molecular stratification - Stone - 2023 - Neuropathology and Applied Neurobiology - Wiley Online Library.