Ganglioglioma (GGL)

What is a ganglioglioma (GGL) brain tumour? 

Ganglioglioma is a very rare type of glioma brain tumour that contains a mixture of neuronal and glial cells, and hence is part of a group of tumours classified as mixed neuronal-glial tumours. 

Neuronal cells are those that form the neurons in the brain, which primarily carry information. Glial cells are those that form the structure of the brain and interact closely with the neurons, nourishing them and helping them to function correctly.

Where do ganglioglioma tumours appear in the brain?

Gangliogliomas often present in a temporal lobe: we have two temporal lobes, one on each side of the brain around the region of the ear. In this position these tumours tend to cause epilepsy, so a seizure may be the first sign that a ganglioglioma is present.

There are occasional reports of ganglioglioma occurring in the cerebellum, brainstem and spinal cord, which are at the back and base of the brain, running down into the spine.

Is a ganglioglioma cancerous?

Gangliogliomas are usually classified as a grade 1 or 2 glioma brain tumour, which means that they are a form of “low-grade” cancer that grows very slowly and does not spread to other parts of the body. When the tumour is simple to remove completely and does not grow back, it may be referred to as benign or non-cancerous.

What is an anaplastic ganglioglioma?

Unfortunately in rare cases the glial cells within a ganglioglioma can transform to a higher grade. When this happens, they are reclassified as a grade 3 glioma because they have become more aggressive and more difficult to treat. At this stage they would be considered cancerous. This type of tumour tends to recur after surgery, so radiotherapy and chemotherapy would be used to help control the progression, in the same way that it would be for other types of grade 3 gliomas.

What are the symptoms of a ganglioglioma?

A ganglioglioma can cause any of the symptoms usually associated with a brain tumour, listed here, depending on where it occurs in the brain.

However it is common to experience seizures with this tumour type, so anti-seizure medication will be prescribed for the patient to help control these. Surgery to reduce tumour size and ideally remove the tumour usually helps to reduce or completely remove the seizures

What is the treatment for a ganglioglioma?

The first line treatment for a ganglioglioma is surgery, which if successful will be enough to have removed the tumour altogether. In the unlikely event that the tumour recurs, surgery may well be repeated.

If the glial cells within the tumour show signs of progression to a higher grade, then radiotherapy and/or chemotherapy would be offered as well.

What is the prognosis for a ganglioglioma?

More than 95% gangliogliomas are low-grade and usually do not recur after removal, so the prognosis for these tumours that can be completely removed is often a cure.

For the remaining 5% of ganglioglioma patients these tumours will be more challenging to treat, but no definite prognosis can be established due to the rarity of this situation.

Factors such as tumour location, how much of the tumour can be removed using surgery, and the range of genetic alterations and/or epigenetic differences (which affect the way that genes behave) are most likely to influence the variability in symptoms and outcome for patients with ganglioglioma.

Genetic profiling of ganglioglioma brain tumours

Identification of a genetic mutation called BRAF V600E has been found in approximately 10% - 60% of gangliogliomas, but is not specific to this tumour type and is also found in a range of other types of glioma brain tumours. This mutation does not seem to correlate with any particular pattern of ganglioglioma progression or the likelihood of recurrence, but may provide a useful target for treatments. Drugs that focus on influencing this BRAF V600E mutation are currently being developed as potential new treatments for a range of gliomas.

The presence of a tumour protein (tp) p53 mutation may be found in the glial cells of a ganglioglioma. This is also found in other types of gliomas, for example in over 80% of IDH-mutant astrocytoma tumours. Unfortunately this may mean that the tumour is more likely to be aggressive or higher grade than those tumours without this mutation.

Frequently asked questions

Who can be diagnosed a ganglioglioma?

Although gangliogliomas have been reported in people of all ages, they are most commonly diagnosed in children and young adults.

How common are ganglioglioma brain tumours?

Gangliogliomas are rare, accounting for approximately 1% - 2% of all brain tumours.

What are the risk factors for gangliogliomas?

Children with certain genetic syndromes, including neurofibromatosis 1 and tuberous sclerosis, are at higher risk of developing gangliogliomas and other types of gliomas. However, most gangliogliomas tumours develop independently of any genetic syndrome and you will be tested to clarify whether this is the case.

How will we find a cure for ganglioglioma brain tumours?

Research we are funding across all of our Centres of Excellence will help lead towards finding a cure for a range of glioma brain tumours.

Our team at the University of Plymouth Low-Grade Brain Tumour Centre of Excellence are researching a range of mutations in brain tumour cells that initiate tumour progression and drive growth, transforming slow-growing low-grade gliomas into high-grade gliomas. Their discoveries are designed to enable new treatments to be developed and tested in order to halt and hopefully reverse this process. The team are also testing combination therapies for low-grade brain tumours, designed to enhance the effectiveness of existing treatments.

Pioneering research at our Brain Tumour Research Centre of Excellence at Queen Mary University of London is focused on using glioblastoma multiforme (GBM) stem cells to help develop unique, patient-specific treatments. Their new pipeline of research is designed to also deliver benefits for other tumour types in the future.

The team of research and clinical experts at our Centre of Excellence at Imperial College, London are part of a global collaboration looking at how the ketogenic diet can influence glioma metabolism and help in the effective treatment and management of living with this group of brain tumours.

Scientists at our Centre of Excellence in the University of Portsmouth are looking at mitochondria in glioblastomas, exploring ways to ‘shut down’ these ‘batteries’ that supply energy to the brain tumours. Learnings may well cast light on new treatments for other types of glioma as well.

We also fund BRAIN UK at Southampton University, the country’s only national tissue bank registry providing crucial access to brain tumour samples for researchers from all clinical neuroscience centres in the UK, effectively covering about 90% of the UK population, and an essential component in the fight to find a cure for all types of glioma brain tumours.