All the cells in our body carry genetic material which determines how each cell will function. This genetic material is made up of genes which are stored on 23 pairs of chromosomes. Each pair of chromosomes is numbered, 1 to 22, with the last two chromosomes being the sex chromosomes X and Y.

In about 6 out of 10 cases of acute myeloid leukaemia (AML) doctors can recognise abnormal changes in the chromosomes of the leukaemic white blood cells.

One such change is the T eight twenty-one, which is written t(8;21). Here a piece of chromosome number 8 has been swapped or “translocated” with a piece of chromosome number 21. Because of this, a very important gene that is involved in the development of white cells, AML1, is disrupted and can't work properly any more. This results leads to the uncontrolled growth of the leukaemia and also prevents the cells growing into normal healthy white cells.

Between 1 in 10 to 1 in 20 people with AML have t(8;21). make up about 5 to 10% of cases of AML.

People with an t(8;21) tend to respond better to chemotherapy. Their remission rates are higher and their survival rates are also higher. Because of this people who have the t(8;21) change on their chromosomes are a 'good risk' group. So if you have AML then having t(8;21) means that you have a subtype of AML which usually responds well to treatment.