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IGHV, TP53 and del(17p): the gene tests in CLL | CION Cancer Clinics
IGHV, TP53 and del(17p) tests look at the genes inside CLL cells to guide treatment. A TP53 change or del(17p) means some older treatments are unlikely to work, while targeted treatments often still do. Unmutated IGHV suggests CLL may need treatment sooner. These changes are not inherited. This page explains each test, when it is done or repeated, and what a result cannot tell you. At CION Cancer Clinics, every leukaemia, MDS and MPN case is reviewed by our haematologist and discussed at a tumour board before a plan is agreed.
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Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
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On this page
- Why test for IGHV, TP53 and del(17p) in CLL?
- What does each test look for?
- What is the difference between mutated and unmutated IGHV?
- When in your CLL journey are these tests done?
- What do people get wrong about these gene results?
- What do the words on a CLL gene report mean?
- What can a gene result not tell you?
- Common questions about IGHV and TP53 testing
The short answer
Why test for IGHV, TP53 and del(17p) in CLL?
These tests look at the genes inside your CLL cells. They help your haematologist understand how the CLL is likely to behave and, most importantly, which treatment is likely to work for you. They are usually done before treatment starts, not always at diagnosis.
They are tests on the cancer, not on your family
The changes these tests find are in the CLL cells only. They are not inherited, and they are not passed on to your children. Your family members do not need to be tested because of your result.
Why the result changes treatment
Some older treatments, including combinations of chemotherapy and antibody drugs, work poorly when the CLL has a TP53 change. Newer targeted tablets and other targeted treatments often still work in that situation. Knowing the result first means you are not given a treatment unlikely to help.
Who may not need them yet
If you are on watch and wait with no triggers, your doctor may not order all of these straight away. A TP53 result from years ago may no longer be accurate, so it is usually repeated when treatment is being planned. IGHV does not change, so it is done once.
How to read the result without panic
Gene reports are written for doctors, and the wording can sound alarming. Words such as "unfavourable" or "high risk" describe groups of patients in studies, many of whom were treated before today's targeted medicines existed. Keep the report safe, do not search each line late at night, and go through it with your haematologist, who can place it beside your stage, your counts and your general health.
The tests
What does each test look for?
These are usually done on a blood sample at a specialised laboratory. Results can take longer than a routine blood test.
IGHV mutation status
Looks at the antibody gene in the CLL cells. The result is either "mutated" or "unmutated". It tells your doctor about the CLL's likely pace and which treatments suit it.
Done once. The result does not change over time.del(17p) by FISH
FISH, a test that uses glowing markers to see pieces of chromosomes, checks whether part of chromosome 17 is missing. That part carries the TP53 gene.
TP53 mutation
A gene sequencing test that looks for changes inside the TP53 gene itself. It can find problems that FISH misses, so both are often done.
Usually repeated
- Before first treatment
- Before any later treatment
The wider FISH panel
The same FISH test often reports other changes too, such as del(13q), trisomy 12 and del(11q). Each carries different information about the CLL.
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What is the difference between mutated and unmutated IGHV?
Mutated IGHV
Unmutated IGHV
CLL tends to grow more slowly
CLL tends to need treatment sooner
Often the more favourable result
Often the less favourable result, though targeted treatment works well
A wider range of treatment choices may suit
Targeted treatment is usually preferred over chemotherapy combinations
Does not mean treatment is never needed
Does not mean treatment must start now
Timing
When in your CLL journey are these tests done?
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At or soon after diagnosis
Some haematologists order IGHV and FISH early, to understand the CLL from the start. Others wait. Both approaches are reasonable if you are well and on watch and wait.
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When a treatment trigger appears
This is when the tests matter most. TP53 and del(17p) are checked, or checked again, because the answer shapes the treatment choice.
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If the CLL comes back or stops responding
CLL cells can gain new changes over time, especially after treatment. TP53 and del(17p) are usually repeated before the next treatment is chosen.
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When the picture suddenly changes
If glands grow quickly or new symptoms appear, your doctor may look for a change in the disease and repeat tests as part of that check.
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Commonly believed
What do people get wrong about these gene results?
"A TP53 change means nothing will work."
It means some older treatments are unlikely to help. Targeted treatments often still work well in CLL with a TP53 change, which is exactly why the test is done before choosing.
"We should test our children for the same gene."
These changes happen only in the CLL cells during your life. They are not inherited, and testing family members for them is not useful.
"Unmutated IGHV is the bad kind of mutation."
The wording is confusing. Here, "mutated" is usually the more favourable result and "unmutated" the less favourable one. Ask your doctor to explain your own result in plain words.
"The test was done years ago, so it does not need repeating."
IGHV does not change. TP53 and del(17p) can, so they are usually rechecked before each new treatment.
On your report
What do the words on a CLL gene report mean?
- FISH
- Fluorescence in situ hybridisation. A test that uses glowing markers to find missing or extra pieces of chromosomes.
- del(17p) or 17p deletion
- Part of the short arm of chromosome 17, which holds TP53, is missing in the CLL cells.
- Variant allele frequency (VAF)
- On a TP53 sequencing report, roughly how many of the tested cells carry the change. Your doctor interprets it.
- del(13q)
- A missing piece of chromosome 13. When it is the only change, it is often linked with slower-growing CLL.
- Complex karyotype
- Several chromosome changes at once. It can affect treatment choice and is discussed with your haematologist.
Being straight with you
What can a gene result not tell you?
A gene result cannot tell you how long you will live or exactly when you will need treatment. It describes the biology of the CLL cells. Your outlook also depends on stage, fitness, other illnesses and how the CLL responds.
Where these tests are done
IGHV, FISH and TP53 sequencing need a specialised laboratory. CION's haematology team evaluates your case, presents it at a tumour board, and coordinates the tests with qualified laboratories. Ask which tests are being sent, where, and when the results are expected.
What to ask about the cost
These tests are not cheap, and cover varies. Aarogyasri, PM-JAY, CGHS, ECHS, EHS and cashless insurance each have their own rules, and entitlements change, so check your current cover before the sample is sent. Ask for a written estimate if you are paying yourself.
Do not start or stop any medicine based on a gene report. The treating team decides treatment with you.Questions we are asked
Common questions about IGHV and TP53 testing
Is a TP53 change inherited? Should my children be tested?
No. The TP53 change found on a CLL report is in the CLL cells only and developed during your life. It is not the same as inherited TP53 conditions, and it is not passed to your children. They do not need testing because of your result.
Do I need a bone marrow sample for these tests?
Usually not. IGHV, FISH and TP53 tests can normally be done on a blood sample when the CLL count in the blood is high enough. A bone marrow sample is only needed in some situations, and your haematologist will explain why if it is advised.
How long do the results take?
Longer than a routine blood count, because the sample goes to a specialised laboratory and the tests are complex. Ask your doctor when to expect them. If treatment is urgent, your haematologist will explain how the plan works while results are awaited.
My IGHV is unmutated. Does that mean I need treatment now?
No. Unmutated IGHV means the CLL may need treatment sooner than average, but treatment starts only when a trigger appears, such as falling counts or symptoms. Until then, watch and wait usually continues. The result mainly helps choose treatment when the time comes.
Why was FISH normal but TP53 sequencing abnormal?
The two tests look for different things. FISH looks for a missing piece of chromosome 17. Sequencing looks for small changes inside the TP53 gene. A person can have one without the other, which is why guidelines advise both before treatment.
Can the treatment be chosen without these tests?
It is possible but not ideal. Without a TP53 result, a treatment unlikely to work could be chosen. If cost is a concern, talk to your haematologist about which tests matter most in your situation and what your scheme or insurance covers.
Will my result change over time?
IGHV stays the same for life. TP53 and FISH results can change as CLL cells gain new changes, especially after treatment. That is why these are rechecked before a new treatment is chosen, even if an earlier report was normal.
Who explains the report to us?
Your haematologist. At CION, Dr. Basudev Pokhrel and the haematology team go through gene reports with patients and families in plain language. Bring the original reports, not just photos, and write down your questions before the appointment.
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Dr. Basudev Pokhrel reviews blood counts, transfusion needs and blood disorders, and works with the CION tumour board on blood cancers.
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Sources
- National Cancer Institute — Chronic Lymphocytic Leukemia Treatment (PDQ) - Health Professional Version
- American Cancer Society — Chronic lymphocytic leukemia
- Leukaemia & Lymphoma Society — Chronic lymphocytic leukemia
- Blood Cancer UK — Chronic lymphocytic leukaemia (CLL)
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
What Triggers Treatment in CLLWhen these tests become most importantFixed-Duration vs Continuous Treatment in CLLHow gene results feed into the treatment choiceRai and Binet Staging in CLLThe other half of the CLL pictureRichter Transformation: When CLL ChangesWhen a sudden change leads to more tests
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