The term leukaemia refers to a group of cancers of the white blood cells.
If you have leukaemia, some of your white blood cells don't grow properly. They stay in your bone marrow
and reproduce in an uncontrolled way. These abnormal white blood cells fill up your bone marrow and prevent it from making the normal blood cells (white blood cells, red blood cells and platelets
). This means your body may be less able to fight off infections and you may develop anaemia or bruise and bleed abnormally.