Acute myeloid leukaemia (AML) is a type of leukaemia and therefore a type of blood cancer. The word ‘acute’ in the name indicates that the disease may progress very quickly. The word myeloid refers to the type of blood cells affected  – the myeloid cells.  AML is the most common form of acute leukaemia. It’s an aggressive type of leukaemia that causes symptoms quickly and progresses rapidly. AML is predominately diagnosed in adults, common in the over 60 years of age. Children can also be diagnosed with AML.

AML develops in white blood cells called myeloid cells in the bone marrow, and often quickly moves into the blood. The bone marrow is the soft inner part of the bones, where new blood cells are produced. Every blood cell grows from a stem cell in the bone marrow. Normally, the stem cells make an early stage of the blood cell called a blast. These blasts should develop into healthy blood cells. In the case of myeloblasts, these derive from myeloid stem cells, and normally develop into fully functioning myeloid cells, platelets or red blood cells. There are several types of myeloid cells which have different functions, such as fighting viral and bacterial infections and preventing the spread of tissue damage.

This type of leukaemia, acute myeloid (AML) develops when immature myeloblasts start multiplying uncontrollably, resulting in increased numbers in the blood and bone marrow. The abnormal/immature myeloblasts could now be considered as leukaemia cells. AML can be described as having too many leukaemia cells in the bone marrow and the blood. The leukaemia cells can sometimes spread to the lymph nodes, spleen, liver, central nervous system (brain and spinal cord) and other organs. In addition, excessive numbers of myeloblasts or leukaemia cells begin to accumulate in the bone marrow, preventing it from producing other healthy blood cells.

In AML, the bone marrow may also make abnormal red blood cells and platelets. The number of these abnormal cells increases rapidly, and the abnormal (leukaemia) cells begin to crowd out the normal white blood cells, red blood cells and platelets that the body needs.

AML occurs when a myeloid cell develops changes (mutations) in its DNA. A cell’s DNA controls how cells develop, function and die. Normally, the DNA tells the cell to grow at a set rate and to die at a set time. In ALL, the mutations result in the leukaemia cells continuing to grow and divide without any of the normal control.