Leukaemia is a cancer of the white blood cells. These cells are produced by the bone marrow.
There are a number of different types of leukaemia. Leukaemia is named according to the type of white blood cell which is affected and whether it is chronic or acute. Acute leukemias come on suddenly, often within days or weeks, progressing quickly and need to be treated urgently. Chronic leukemias develop more slowly, often over many months or years.
The four main types of leukaemia are:
Another type of leukaemia is the less common hairy cell leukaemia.
Each disease has its own characteristics and treatment.