Childhood cancer and heredity
Genetic testing
At the Máxima Center, you may encounter genetic testing at three different moments:
- Genetic testing at diagnosisTo give your child the best possible treatment, we need to know exactly what type of cancer it is.
- Genetic testing after referral to a geneticistDo you or your child’s pediatric oncologist have questions about heredity? That may be a reason to carry out genetic testing.
- Genetic testing as part of scientific researchWe still don’t know everything about heredity and childhood cancer. That’s why we study hereditary predisposition.
What is heredity?
Everyone inherits certain traits from their parents — for example, your eye colour, or whether your hair is curly or straight. You can also inherit a change in your DNA that increases the chance of developing a disease. This DNA change can run in families. It doesn’t mean that every family member will become ill, but it does mean there’s a higher risk.
A DNA change can also appear for the first time in someone. This often happens in childhood cancer — the child is then the first in the family with a genetic predisposition to cancer.
When we talk about heredity, we mean genes and DNA. Below you can see what DNA and genes are.%2520%257B%2520%255Bnative%2520code%255D%2520%257D&w=1080&q=100)
Our bodies are made up of countless cells. Inside each cell are chromosomes - long strands of DNA. DNA contains a kind of code that helps determine what you look like and how your body works. A gene is a small piece of DNA that contains the code for an inherited trait.
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- How can a hereditary predisposition be identified?
DNA is found inside cells. To find out whether there is a hereditary predisposition, we examine the DNA from healthy cells. For this, we usually use a blood sample and sometimes a small piece of skin. In the laboratory, the DNA is extracted from the blood or skin sample and examined for changes.
The information in DNA is stored in the body as a kind of code made up of specific substances. The names of these substances are represented by four letters: A, T, G and C. In DNA testing, we look to see whether there is a change in this DNA code.
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- DNA changes in tumour cells and in normal cellsTumour DNA
Tumour DNA is the DNA found in tumour cells. Tumour DNA contains many changes that cause these cells to behave like cancer cells. These DNA changes develop during life and are not passed on to your children, so they are not hereditary.
Germline DNAThe DNA in the healthy cells of your body is called germline DNA. This is the DNA you inherited from your parents. When a change is found in the DNA of healthy cells, it means there is a hereditary predisposition. This means you have a higher chance of developing cancer.
Sperm and egg cells also contain germline DNA, so a hereditary predisposition can be passed on to your children.
At the Máxima Center, we perform different types of DNA testing. We can look at a single gene (a small piece of DNA), at many pieces of DNA at once, or at the chromosomes.
Deciding whether to take part in DNA testing
At the Máxima Center, every child has a limited DNA test at diagnosis to help us choose the best possible treatment. If the pediatric oncologist considers it necessary, they will refer you to a geneticist. You decide for yourself whether to take part in scientific DNA research. The pediatric oncologist, nurse practitioner, or geneticist will explain the possible advantages and disadvantages for your family.
Possible advantages
If a hereditary predisposition is found in your child, you, your partner, your other children, or other family members may have the same predisposition. The geneticist may then advise you to have regular check-ups now or in the future. If cancer is detected at an early stage, treatment is usually less intensive.
If you are thinking about having more children, there are options to prevent passing on the predisposition to a next child. You can find general information about hereditary conditions and having children [here].
Possible disadvantages
Knowing that there is a hereditary predisposition can be emotionally challenging and may cause stress. For example, when you need to inform your family, during extra medical check-ups, or while waiting for test results. Some parents and children feel that this outweighs the possible advantages.
A hereditary predisposition can sometimes mean that you have to pay a higher premium for a life or disability insurance. You can read more about insurance and hereditary predisposition [here].
Support during DNA testing
If you find it difficult to decide, or if you are anxious about the DNA test results, the geneticist or your child’s pediatric oncologist can support you and, if needed, arrange additional help. This support is also available after you receive the results. They can also explain the findings to your family members.
If faith plays a role in your decision, it may help to talk with family, friends, or a pastor or imam. You can also contact a medical social worker or a spiritual counsellor at the Máxima Center. Our team includes people from different religious backgrounds.
Sometimes it’s not the right time to think about DNA testing. In that case, the geneticist will discuss whether the decision can be postponed until later.
Helping others through scientific research
By taking part in scientific research on hereditary predisposition, you help us improve care for children with cancer in the future. Thanks to this kind of research, we can better identify hereditary predispositions.
If we find a hereditary predisposition in your child during scientific research that is important for your child’s health, and possibly for your own and your family’s, we will always inform you. This is why it’s important to think carefully in advance about whether you want to receive such information.
You can also contribute to scientific research by donating to the Biobank, without taking part in studies on hereditary predisposition.
- Hereditary conditions in childhood cancer
Here you can find more information about three hereditary conditions:
Li-Fraumeni syndromeDICER1 syndrome(Fanconi anemie (FA)) - More information
Please note that most of this information is only available in Dutch.
Erfelijkheid.nlTalking to family about hereditary predispositionInformation about insurancesTalking to children about hereditary predispositionInformation about the Biobank of the Máxima CenterDutch Childhood Cancer Association (VKKN)