What is acute myeloid leukaemia (AML)?

Acute myeloid leukaemia (AML) is a type of blood cancer that starts from young white blood cells called granulocytes or monocytes 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 in the bone marrow. The bone marrow is the soft inner part of your bones. You make blood cells in a controlled way, as your body needs them.

All blood cells start as the same type of cell, called a stem cell. This stem cell then develops into:

  • myeloid stem cells become white blood cells called monocytes and neutrophils (granulocyte), red blood cells and platelets
  • lymphoid stem cells, which become white blood cells called lymphocytes

The 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 white blood cells called granulocytes or monocytes too quickly because they grow and divide too fast. These abnormal cells build up in the blood and bone marrow.

The leukaemic cells can eventually spread to other parts of the body including the lymph nodes and the spleen.

If it wasn't treated the leukaemia would cause death within a few weeks or months. But treatments work very well for most people with AML.

How leukaemia affects you

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.

Too many white blood cells can overcrowd the bone marrow. So there is not enough space for other types of blood cells. Then you might have lower than normal levels of red blood cells and platelets.

Having too few red blood cells makes you tired and breathless (anaemic). And 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 and 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 it?

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

Who gets it?

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.

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