The word 'biomarker' is short for 'biological marker', or indicator. It could be a change in a gene in the tumour's DNA, or it could be a molecule produced by the tumour. The presence or absence of particular gene changes or molecules (biomarkers) can give your health team more information about your tumour.
As a result, if you have a brain tumour, a biomarker test may be used to look at genes associated with your type of tumour. Biomarker tests are only suitable for some brain tumour types.
These tests may be helpful in:
It is very important to know that biomarkers are not treatments and that research is still in early stages.
At the moment, there are two main biomarker tests for brain tumours. These are the MGMT methylation test and the 1p/19q test - however not all hospitals offer these tests. There are also the IDH-1 and the BRAF tests for a few selected types of tumour.
The Brain Tumour Charity's research funding has contributed to the development of these tests.
The MGMT methylation test can be useful in predicting how effective chemotherapy treatment is likely to be for you and can be used to help plan a suitable, individualised treatment plan.
Your tumour may be suitable for this test if it is one of the following:
- Anaplastic astrocytoma
- Anaplastic oligodendroglia
- Anaplastic oligoastrocytoma
MGMT is a gene that is responsible for the coding of a protein involved in DNA repair. The MGMT test is used to determine the levels of activity of the MGMT protein. Because it is involved in DNA repair, the MGMT protein can disturb the action of some chemotherapy drugs (such as Temozolomide). It does this by taking away the point at which the chemotherapy attacks most effectively. Higher levels of the MGMT protein can therefore lower the effectiveness of some chemotherapy drugs.
The 1p/19q test may predict long-term survival in people who have some types of brain tumour. The test can also be useful in diagnosing some types of brain tumours, and in making decisions about appropriate treatment types.
Your tumour may be suitable for this test if it is one of the following:
Our bodies are made up of cells. Each cell has 23 pairs of chromosomes, which carry genes that you inherit from your mother and father. The 1p/19q test looks at genetic changes to chromosome numbers 1 and 19 in tumour cells and whether these genes are complete or have a section missing (which is known as 'loss of heterozygosity'). Loss of sections 1p/19q in tumour cells are associated with improved outcomes in people with some types of brain tumour.
The IDH-1 test may predict long-term survival in people who have some types of brain tumour. It may also be useful in predicting how effective a particular treatment is likely to be.
If you have a glioma, you may be suitable for IDH-1 testing but please speak to your neuro-oncologist for information and advice.
IDH-1 is a gene. A mutation (change) in the IDH-1 gene has been found in a large number of astrocytomas, oligodendrogliomas and secondary glioblastomas. For people with high grade glioma, mutations to the IDH-1 gene are often linked with longer-term survival rates. It is not yet clear, however, how mutations to the IDH-1 gene link to outcomes for people with low-grade brain tumours. In addition to long-term survival rates, scientists have looked at whether the IDH-1 gene mutation predicts treatment outcomes.
Further research needs to be carried out before clear conclusions can be drawn, but it looks possible that chemoradiotherapy (a combination of chemotherapy and radiotherapy) may be more effective for people who have the IDH-1 mutation than those who do not.
The BRAF test (along with other investigations) can sometimes help to determine whether a tumour is a pilocytic astrocytoma (a type of grade 1 tumour) rather than another type of (nonpilocytic) astrocytoma if there is uncertainty.
BRAF testing is only clinically useful in a few selected tumour types and is most commonly used to determine whether a tumour is a pilocytic astrocytoma. If you are interested in BRAF testing, please speak to your neuro-oncologist for information and advice.
BRAF is a gene that makes a protein called B-raf. The B-raf protein is important because it sends signals to help direct the growth of cells within our body. Signals sent from the BRAF gene to the cells is known as the 'BRAF pathway'.
Research has found that some brain tumours (some types of grade 1 and 2 astrocytoma, including grade 1 pilocytic astrocytoma) sometimes have a fault with their BRAF gene.
The fault leads to the BRAF gene permanently sending signals that make cells divide and create copies of themselves. This uncontrolled growth of cells forms a tumour. Can I have BRAF testing? BRAF testing is only clinically useful in a few selected tumour types and is most commonly used to determine whether a tumour is a pilocytic astrocytoma. If you are interested in BRAF testing, please speak to your neuro-oncologist for information and advice.
In some hospitals biomarker testing is now done routinely (where appropriate to the tumour type), it is not suitable for everyone with a brain tumour.
If your hospital does not do this and you are interested in having a test, speak to your neuro-oncologist, who will be able to tell if it is suitable for you and, if so, may be able to arrange for a test at another hospital. It is important to note that the tests will not necessarily influence your treatment plan at the hospital you attend.
The tests can only be carried out once you have had a biopsy and the biopsy material has been analysed. It does not matter how long ago the biopsy was performed, so old samples can be used.
Before you have the test or ask for the result, it is worth thinking about what the results might reveal and whether you want to know the result.
If you have further questions, need to clarify any of the information on this page, or want to find out more about research and clinical trials, please contact our team:
0808 800 0004 (free from landlines and mobiles)
support@thebraintumourcharity.org
Phone lines open Mon-Fri, 09:00-17:00
clinicaltrials@thebraintumourcharity.org
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Our free Brain Tumour Information Pack has been designed to help you feel confident when discussing treatment and care options with your medical team.