What is acute myeloid leukaemia (AML)?

Acute myeloid leukaemia (AML) is a type of blood cancer. AML starts from the fast and uncontrolled growth of early myeloid blood cells in the bone marrow. The bone marrow is the soft inner part of the bones, where new blood cells are made.

Blood cells and leukaemia

To understand how and why leukaemia affects you as it does, it helps to know how you make blood cells.

Your body makes blood cells Open a glossary item in the bone marrow. The bone marrow is the soft, spongy tissue in the inner part of your bones. You make blood cells in a controlled way, as your body needs them. This continuous supply keeps your blood healthy and your body functioning properly.

All blood cells start as the same type of cell, called a stem cell. This stem cells can turn into any type of blood cell. The stem cells can develop into:

  • myeloid stem cells 
  • lymphoid stem cells

Myeloid stems cells become monocytes, red blood cells, platelets and white blood cells called granulocytes. Neutrophils are one type of granulocyte.

Lymphoid stem cells develop into white blood cells called lymphocytes. Examples include B lymphocytes and T lymphocytes.

The simplified diagram below helps to explain this.

A simplified diagram showing how blood cells are made

In acute myeloid leukaemia, the bone marrow makes too many monocytes or granulocytes. These cells are not fully developed and are not able to work normally.

Diagram showing the cells in which AML starts

What happens in AML?

The word acute means that the leukaemia can develop fairly quickly. The bone marrow produces early myeloid cells too quickly because they grow and divide too fast. These abnormal cells build up in the bone marrow and block healthy blood cells from developing. They can also spill out into the blood.

The leukaemic cells can eventually spread to other parts of the body including the lymph nodes Open a glossary item, liver and the spleen Open a glossary item. You might also find AML in the gums, skin, muscle, and central nervous system (CNS) Open a glossary item, but this is less common.

If it wasn't treated the leukaemia would cause death within a few weeks or months. Survival depends on many factors including:

  • age at diagnosis
  • genetic changes in the leukaemia cells
  • how advanced the AML is

Improvement in treatment now makes it possible to tailor treatment based on your individual situation and health.

How does leukaemia affect the body?

Too many white blood cells can overcrowd the bone marrow. So there is not enough space for other types of healthy blood cells. You are more likely to get infections and to find it hard to get over the infections. This is because healthy white blood cells help fight infection. But when you have leukaemia, your body makes abnormal white blood cells and they don’t work properly.

You also have lower than normal levels of red blood cells and platelets due to the overcrowding in the bone marrow.

Red blood cells carry oxygen from your lungs to the rest of your body. Having too few red blood cells can make you tired and breathless (anaemic). Platelets help your blood to clot when you get a cut or wound. If you don’t have enough platelets, you can have bleeding problems such as bruising or nosebleeds.

Abnormal white blood cells can also build up in other parts of the body, such as the spleen, lymph nodes or the liver. This can make your tummy (abdomen) swell and feel uncomfortable. The leukaemia cells can also spread to the brain in some people.

How common is AML?

AML is rare. Around 3,100 people are diagnosed with AML in the UK every year. 

Who can get AML?

Adults or children can get AML. It is most common in older people. More than 40 out of 100 (more than 40%) of new cases are in people aged 75 and over.

  • Cancer Incidence from Cancer Intelligence Statistical Information Team at Cancer Research UK  (2016 - 2018 UK average) 
    Accessed September 2023

  • Acute myeloid leukaemia in adult patients: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up
    M Heuser and others
    Annals of Oncology, March 2020. Volume 31, Issue 6, Pages 697 to 712

  • Acute Myeloid Leukaemia
    C D DiNardo and others
    The Lancet, June 2023. Volume 401, Pages 2073 to 2086

  • Hoffbrand’s Essential Haematology (8th Edition)
    AV Hoffbrand and D A Steensma
    Wiley Blackwell, 2020

  • Leukaemia: a model metastatic disease
    A E Whiteley and others
    Nature Reviews Cancer, May 2021. Volume 21, Issue 7, Pages 461 to 475

  • Cancer: Principles and Practice of Oncology (12th edition)
    VT DeVita, TS Lawrence, SA Rosenberg
    Wolters Kluwer, 2023

Last reviewed: 
25 Sep 2023
Next review due: 
25 Sep 2026

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