← Back
After treatment and remission

Genetic monitoring

Changes in the chromosomes and genes of leukaemia cells give important information both at diagnosis and in the years after. This topic explains when and why genetic tests — karyotype, FISH and gene panels — are done during remission.

Last updated: ~3 min read
Glowing chromosome pairs in rows on a dark glass plate.
Figure 1.A karyotype shows all the chromosomes.

01Short answer

Genetic monitoring means re-checking the chromosome and gene changes of leukaemia cells during remission when needed. There are three main methods: karyotype (looking at all chromosomes under a microscope), FISH (searching for specific genes with glowing probes) and next-generation sequencing (NGS), which reads many genes at once. The genetic profile at diagnosis becomes the “starting point”. In remission these tests are usually not done every time but when there is a specific question: when blood counts change, during a bone marrow test, after a transplant or when a treatment decision is needed. Finding a new change does not always mean relapse; only your doctor interprets the result together with all the other information.

02Simple explanation

Leukaemia cells have a genetic “passport”.

The result at diagnosis is the starting point.

The main tests are karyotype, FISH and NGS.

In remission they are done when there is a specific question.

Only your doctor interprets the result.

03Scientific explanation

Karyotype: according to MedlinePlus, the number and structure of a cell’s chromosomes are assessed under a microscope; dividing cells are needed.

FISH: according to the NCI, fluorescent probes attach to specific genes or chromosome regions and show their number and location.

NGS: the 2022 ELN recommendations for AML advise testing a set of genes at diagnosis (for example NPM1, FLT3, TP53); these results define the risk group.

Clonal evolution: over time, new changes can appear in leukaemia cells; if relapse is suspected, repeating the genetic test can change the choice of treatment.

04What happens in the body?

An overall look at chromosomes

A karyotype is a “photograph” of all the chromosomes in a cell. A change found at diagnosis (for example t(8;21) or inv(16)) can be looked for again in a bone marrow test during remission. Its absence is a good sign.

A targeted search: FISH

FISH looks for one specific change. It also works on cells that are not dividing and can be more sensitive than a karyotype. After a transplant it is sometimes used to tell donor and recipient cells apart.

A clear cell nucleus with a few bright dots inside.
Figure 2.FISH marks specific genes with glowing dots.

Many genes at once: NGS

Next-generation sequencing reads dozens of genes at the same time. At diagnosis this defines the risk group and sometimes the choice of a targeted medicine. In remission some centres also use it to track residual disease.

Many thin glowing DNA strands passing in parallel through a glowing gate.
Figure 3.NGS reads many genes at once.

When is it repeated in remission?

Usually: at a planned bone marrow test, when blood results change unexpectedly, before and after a transplant, and when relapse is suspected. It is not done routinely at every visit.

If a new change is found

Sometimes small age-related changes that are not linked to the leukaemia are seen. Your doctor assesses the result together with blood tests, marrow findings and how you are, and repeats the test if needed.

Inherited predisposition

Rarely, a genetic test shows an inborn predisposition (for example changes in DDX41 or RUNX1). This matters for relatives and for choosing a possible donor, and is discussed with a genetic counsellor.

05From starting point to decision

The steps of genetic monitoring.

Baseline profile — The genetic result at diagnosis is kept.1Baseline profileThe genetic result at diagnosis is kept.
Sample — Marrow or blood is taken when needed.2SampleMarrow or blood is taken when needed.
Comparison — The new result is compared with the earlier one.3ComparisonThe new result is compared with the earlier one.
Decision — The doctor explains the result and sets the plan.4DecisionThe doctor explains the result and sets the plan.
A precise profileThe leukaemia’s own features.
ComparisonChange is seen in time.
The right decisionThe plan is adjusted to the result.

06Comparing genetic tests (simplified)

TestWhat it showsIn remission
KaryotypeNumber and structure of all chromosomesDuring a bone marrow test
FISHA specific gene or chromosome changeWhen there is a targeted question
NGS panelMutations in many genesAs your doctor decides
Quantitative PCRThe amount of one markerPlanned molecular monitoring (“Molecular monitoring”)

* Your doctor decides which test is needed according to the type of leukaemia.

07Key terms

Karyotype
A picture of all of a cell’s chromosomes.
FISH
Searching for a specific gene with glowing probes.
NGS
Reading many genes at once.
Mutation
A change in a gene.
Clonal evolution
New changes appearing in leukaemia cells over time.
Inherited predisposition
A gene change passed on from a parent that raises risk.

08Key points

  • The genetic profile at diagnosis is the starting point.
  • Karyotype, FISH and NGS answer different questions.
  • In remission, tests are done for a specific question.
  • A new change does not always mean relapse.
  • Inherited predisposition matters for the family too.
  • Keep copies of your reports.

09Frequently asked questions

Do I need a genetic test at every visit?

No. Blood tests are usually enough, and genetic tests are done for a specific reason.

Can a genetic test be done on blood?

Some tests can, but for a karyotype and in many cases FISH, bone marrow is more informative.

My result says “normal karyotype” — is that good?

It means no chromosome changes visible under the microscope were found. Your doctor gives the overall assessment.

Can leukaemia be passed to my children?

Most leukaemias are not inherited. If a rare inherited predisposition is suspected, a genetic counsellor will explain.

How long do results take?

It depends on the test: FISH a few days, karyotype and NGS usually 1–3 weeks.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Do I need a genetic test at every visit?

  2. Can a genetic test be done on blood?

  3. My result says “normal karyotype” — is that good?

  4. Can leukaemia be passed to my children?

  5. How long do results take?

My questions

12Sources

  1. MedlinePlus (U.S. National Library of Medicine). Karyotype Genetic Test
  2. National Cancer Institute (NCI). Definition: fluorescence in situ hybridization (FISH)
  3. American Cancer Society. Tests for Acute Myeloid Leukemia (AML)
  4. National Cancer Institute (NCI). Biomarker Testing for Cancer Treatment
  5. Blood, 2022. Doehner H et al. Diagnosis and management of AML in adults: 2022 ELN recommendations
  6. Blood, 2021. Heuser M et al. 2021 update on MRD in AML: a consensus document from the ELN MRD Working Party
  7. MedlinePlus (U.S. National Library of Medicine). Genetic Testing
  8. Leukemia & Lymphoma Society (LLS). Minimal/Measurable Residual Disease
  9. National Cancer Institute. Facing Forward: Life After Cancer Treatment
  10. National Cancer Institute. Coping: survivorship
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
Last updated: ← Back to the list

Open the interactive site →