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Medical glossary

Mutation

A mutation is a change in the DNA sequence. Some mutations are harmless; others can lead to a cell growing out of control.

Last updated: ~1 min read
A laboratory scientist loading a DNA sequencer
Figure 1.Mutations are found by DNA sequencing

01Short answer

In leukaemia, mutations mostly arise in blood cells during life (acquired or somatic). They matter for diagnosis, risk group and targeted treatment, for example FLT3, IDH1/2, NPM1 and TP53. A result may list a “VAF” (variant allele fraction), which shows what share of cells carry the change. Some mutations cause resistance to a medicine.

02Simple explanation

A change in DNA.

Mostly acquired.

Affects treatment.

Resistance is possible.

03Scientific explanation

NCI: a mutation is any change in the DNA sequence of a cell.

The NCI Dictionary explains cancer terms in plain language; check the exact meaning for your situation with your doctor.

04What happens in the body?

In the report

Gene name, change, VAF and comment.

A copying error
Figure 2.A copying error — Mutation

Resistance

Some mutations make a medicine ineffective.

A matching key
Figure 3.A matching key — Mutation

Where you will see this word

In test results, discharge letters and conversations with your doctor. Write the word down and ask what it means.

Ask your doctor

The general meaning and the meaning of your own result can differ. The most important question is “What does this mean for me?”

05From an unfamiliar word to a clear answer: four steps

Write it down, look it up, prepare a question, ask.

Write it down — From a result or a conversation.1Write it downFrom a result or a conversation.
Look it up — Learn the plain meaning.2Look it upLearn the plain meaning.
Prepare a question — What does this mean for me?3Prepare a questionWhat does this mean for me?
Ask — Your doctor gives the personal explanation.4AskYour doctor gives the personal explanation.
UnderstandingResults feel less frightening.
ConversationA shared language with your doctor.
SafetyNot drawing conclusions alone.

06Key points at a glance

TopicIn brief
In the reportGene name, change, VAF and comment.
ResistanceSome mutations make a medicine ineffective.
Where you will see this wordIn test results, discharge letters and conversations with your doctor. Write the word down and ask what it means.
Ask your doctorThe general meaning and the meaning of your own result can differ. The most important question is “What does this mean for me?”

07Key terms

Somatic mutation
A change acquired during life.
VAF
The fraction carrying the change.
Term
A word with a precise medical meaning.
Reference range
The range a laboratory considers normal.

08Key points

  • Learn.
  • Ask your doctor.
  • Write it down.
  • Write the word down.
  • Ask what it means.

09Frequently asked questions

I have a mutation: is that bad?

It depends on the mutation; some open the way to targeted treatment.

Should my family be tested?

Only if an inherited mutation is suspected.

This word is in my results: should I worry?

The word itself does not mean a serious or mild condition; get the explanation from your doctor.

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. I have a mutation: is that bad?

  2. Should my family be tested?

  3. This word is in my results: should I worry?

My questions

12Sources

  1. National Cancer Institute. NCI Dictionary of Cancer Terms: mutation
  2. MedlinePlus Genetics. Help Me Understand Genetics: The basics
  3. National Cancer Institute. Biomarker Testing for Cancer Treatment
  4. National Cancer Institute. NCI Dictionary of Cancer Terms
  5. National Cancer Institute. Leukemia
  6. National Cancer Institute. NCI Dictionary of Cancer Terms: chromosome
  7. National Cancer Institute. NCI Dictionary of Cancer Terms: cytogenetics
  8. National Cancer Institute. NCI Dictionary of Cancer Terms: thrombocytopenia
  9. National Cancer Institute. NCI Dictionary of Cancer Terms: leukopenia
  10. National Cancer Institute. NCI Dictionary of Cancer Terms: anemia
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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