Medical Oncologist
CION Cancer Clinics
When a childhood cancer suggests an inherited cause | CION Cancer Clinics
Most childhood cancers are not inherited. They come from chance changes in one growing cell. A minority do have an inherited fault behind them, and certain clues make that more likely: some rare tumour types, tumours on both sides, signs on the body and a family pattern. This page explains those clues, what testing involves, and why finding an inherited cause matters for the whole family. At CION Cancer Clinics, our oncologists plan screening and care for families with an inherited cancer syndrome, explained in plain words.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- Could my child's cancer have been inherited?
- Which signs point towards an inherited cause?
- What happens when an inherited cause is suspected
- The words you will meet, in plain language
- Stronger clues and weaker clues
- What this page cannot tell you
- Four things parents fear, and what is actually true
- Common questions about inherited causes of childhood cancer
The short answer
Could my child's cancer have been inherited?
Usually not. Most childhood cancers come from changes that happened by chance in one growing cell, and nothing the parents did or passed on caused them. A minority, often estimated at around one child in ten, have an inherited fault behind the cancer. Certain signs make that more likely.
Why doctors ask this at all
Finding an inherited cause can change the child's treatment, because a few syndromes make some treatments riskier. It also means the child needs checks for new tumours later. And it tells brothers, sisters and parents whether they share the same risk.
What makes a doctor suspicious
Some tumour types are strongly linked to inherited faults. So are tumours in both eyes or both kidneys, more than one separate cancer, and certain marks or growth patterns on the body. A family history of cancer at young ages adds weight.
Why marriages within the family matter
When parents are related by blood, as in many Telangana and Andhra families, some rare conditions become more likely. These need a faulty copy of a gene from both parents. Tell the doctor honestly, without shame. It is medical information, not a judgement.
Four kinds of clue
Which signs point towards an inherited cause?
No single sign proves it. Doctors look at the whole picture, and one strong clue is enough to ask for a referral.
The type of tumour
A handful of rare childhood tumours are so often inherited that testing is offered to every child who has one, whatever the family history.
Examples
- Retinoblastoma, a cancer of the eye
- Adrenocortical carcinoma, of the adrenal gland
- Pleuropulmonary blastoma, a rare lung tumour
- Choroid plexus carcinoma, of the brain
More than one tumour
Tumours in both eyes, both kidneys or several places in one organ suggest every cell started with a fault. So does a second, separate cancer later in childhood.
Signs on the body
Some syndromes leave visible clues. A doctor may notice these during an ordinary examination.
Things doctors look for
- Several flat coffee-coloured patches on the skin
- An unusually large head or one side growing faster
- Birth differences or developmental delay
The family pattern
Cancer in young parents, aunts, uncles or cousins, rare cancers in relatives, or parents who are related by blood. Remember to ask about both sides of the family, including the father's.
Not sure whether this applies to you?
Ask an oncologistStep by step
What happens when an inherited cause is suspected
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The oncologist notes the clue
This often happens at diagnosis, but it can come later, when a second tumour appears or a relative is diagnosed.
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A detailed family history is taken
Who had cancer, what kind and at what age, across three generations on both sides. The counsellor also asks whether the parents are related.
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A genetic counsellor explains the test
Parents hear what the test looks for, what a result could mean for the child and the family, and what it cannot tell them.
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A sample is taken
Usually blood. In a child with leukaemia the blood contains cancer cells, so a small skin sample or another tissue may be used instead.
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The result shapes the plan
A positive result can adjust treatment, start a surveillance plan and open testing for relatives. A negative result is reassuring but does not rule out every possibility.
On the report
The words you will meet, in plain language
- Predisposition
- A raised tendency to develop cancer, present from birth. It is a risk, not a diagnosis.
- Germline
- Present in every cell from birth, and so able to be passed on. This is what an inherited-cause test looks for.
- Somatic
- A change found only in the tumour. Tumour testing is a different test, covered on our targeted therapy pages.
- De novo
- A fault that appeared for the first time in the child. Neither parent carries it, which is why a clear family history does not rule it out.
- Consanguinity
- Parents who are related by blood, such as cousins or uncle and niece. It raises the chance of some rare recessive conditions.
- Café-au-lait spots
- Flat, light-brown skin patches. One or two are common. Many of them can point to neurofibromatosis.
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Side by side
Stronger clues and weaker clues
Points towards an inherited cause
Common, and usually not inherited
Tumours in both eyes or both kidneys
One tumour in one organ
A rare tumour type linked to a known syndrome
A common childhood leukaemia with no other clues
Several close relatives with cancer at young ages
A grandparent who had cancer in old age
Unusual skin marks, growth or birth differences
A child who was otherwise well and growing normally
Being straight with you
What this page cannot tell you
It cannot tell you whether your child's cancer was inherited. That needs a doctor who knows the tumour type, has examined your child and has drawn out the family tree. Some inherited causes are found in children with no warning signs at all, and many children with one clue turn out to have no inherited fault.
It cannot interpret a result
If your child has already been tested, what the specific variant means is a question for the counsellor who ordered the test. A result called a variant of uncertain significance is not a positive result and should not change treatment on its own.
Who this does not apply to
Most families of a child with cancer will never need genetic testing. A single common childhood cancer, with no other clues and no family pattern, is very rarely inherited. If you are unsure, ask your child's oncologist directly whether a referral is worth it.
Commonly believed
Four things parents fear, and what is actually true
"Something I did in pregnancy caused this."
For the vast majority of childhood cancers, no action by either parent caused the illness. Even when a fault is inherited, nobody chooses the genes they pass on.
"No one in our family has had cancer, so it cannot be inherited."
A fault can arise for the first time in the child, and some faults cause illness only when a copy comes from each parent. A clear family history lowers the chance but does not remove it.
"If it is inherited, all our children will get cancer."
Each brother or sister may or may not carry the fault, and carrying it raises risk without making cancer certain. Siblings can be tested for the exact fault once it is known.
"Testing now will delay my child's treatment."
Treatment starts on its usual schedule. Genetic testing runs alongside it, and in the few cases where the result matters for treatment, the team plans around it.
Questions we are asked
Common questions about inherited causes of childhood cancer
How common is an inherited cause in childhood cancer?
Uncommon. Large studies suggest it is a minority, often estimated at around one child in ten, though the share is much higher for a few rare tumour types. For the common childhood leukaemias without other clues, an inherited cause is found much less often.
Should every child with cancer be tested?
Not routinely in most centres. Testing is offered when there is a clue, such as a strongly linked tumour type, more than one tumour, body signs or a family pattern. Some centres abroad now test more widely, and practice is changing as costs fall.
Does a positive result change my child's treatment?
Sometimes. In a few syndromes, doctors try to limit radiation or certain drugs because they raise the chance of a second cancer. More often the treatment stays the same and the result shapes follow-up care. Ask the oncologist what it means for your child's plan.
Do both parents need to be tested too?
If a fault is found in the child, testing the parents shows whether it was inherited or new. That matters for a parent's own health and for brothers and sisters. The counsellor will explain the order in which relatives should be tested.
We are cousins by marriage. Is our child's cancer our fault?
No. Related parents do have a higher chance of some rare conditions, but most children of cousin marriages are healthy, and most childhood cancers have nothing to do with it. Sharing this with the doctor simply helps them choose the right test.
What sample will my child need to give?
Usually a small blood sample. If your child has a blood cancer, the blood carries cancer cells, so the team may ask for a small skin sample or another tissue instead. Your counsellor will explain why and how it is collected.
Is this the same as testing the tumour?
No. Tumour testing looks at changes inside the cancer to guide treatment. Inherited testing looks at the child's own cells for a fault present from birth. Sometimes a tumour result hints at an inherited fault, and then the blood test is used to confirm it.
Who do we ask about this?
Start with your child's oncologist, who knows the tumour type and your child's history. They can refer you to a genetic counsellor. If you are not sure whom to approach, call the CION helpline and describe the diagnosis. Someone will guide you.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
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Sources
- National Cancer Institute — Cancer in Children and Adolescents
- GeneReviews (NCBI) — Li-Fraumeni Syndrome
- GeneReviews (NCBI) — Retinoblastoma
- MedlinePlus Genetics — What does it mean to have a genetic predisposition to a disease?
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Genetic testing after a child's cancer diagnosisWhat the test involves once a referral is madeTesting parents after a child tests positiveFinding out whether the fault was inherited or newParental guilt after an inherited diagnosisFor the parent who blames themselvesShould healthy siblings be tested?What a result means for brothers and sisters
Talk to us
Wondering whether your child's cancer could be inherited?
Tell us your child's diagnosis and any cancers in the family. We will explain whether a genetic referral makes sense and arrange counselling if it does. One helpline serves every CION centre.