Virtual Medical Centre

Childhood Leukaemia

• What is Childhood Leukaemia?
• Who gets Childhood Leukaemia?
• Predisposing Factors
• Progression
• Probable Outcomes
• How is Childhood Leukaemia Diagnosed?
• How is Childhood Leukaemia treated?
• Childhood Leukaemia References
• Drugs/Products Associated with Childhood Leukaemia

What is Childhood Leukaemia?

Childhood leukaemias arise from cells located in the bone marrow. The bone marrow is the soft, spongy tissue located in the centre of most long bones and is responsible for the production of the cellular components of blood; namely white cells, red cells and platelets.

Lymphoblasts and myeloblasts are found in the bone marrow and are normal precursor cells of white and red blood cells. These lymphoblasts are influenced by many endogenous factors such as proteins and cytokines to differentiate into mature white and red blood cells.

Leukaemia occurs when there is abnormal proliferation of lymphoblasts and myeloblasts in the bone marrow.

It may secondarily affect the blood, lymph nodes, liver, spleen, bones, joints, central nervous system, testes and skin.

Who gets Childhood Leukaemia?

In children, 80% of leukaemias are Acute Lymphoblastic Leukaemia (ALL), 20% are Acute Myeloid Leukaemia (AML) and 1% are Chronic Myeloid Leukaemia (CML).

Leukaemia makes up approximately 35% of childhood malignancies and is the most common form of cancer in children. It is more common in males, caucasians and in the 2-5 year age group.

Predisposing Factors

Childhood leukaemia results from abnormal gene function, commonly the result of mutations or inactivation of tumour suppressor genes (e.g. RB1, p53 ) or the activation of proto-oncogenes (e.g. MYC, ABL).

There is strong suggestion that inherited predisposition is a very important factor. Siblings of affected individuals can have up to a 4 four fold increase in risk. Twin studies have also established a genetic link.

Although irradiation, chemical carcinogens and oncogenetic viruses have been shown to induce leukaemia in animal models, the exact cause in children remains unknown and is probably multifactorial.

There is an increased incidence of leukaemia in children with Down syndrome and in children with some rare genetic diseases such as ataxia telangiectasia, Wiskott-Aldrich syndrome and Fanconi anaemia

Progression

Childhood leukaemias usually present with widespread involvement of the bone marrow which may accompanied by the presence of large numbers of tumour cells in the peripheral blood. It may spread haematologically.