Childhood Leukemia

About 3 out of 4 childhood leukemias are ALL. These leukemias start in early forms of white blood cells, called lymphoblasts. Normally they would mature into certain cells that help our bodies fight infections, called lymphocytes. There are several subtypes of ALL, which are based mainly on:

• The type of cell the leukemia looks most like (often B cell or T cell) and how far the cells matured before becoming cancer, known as the immunophenotype of the leukemia
• If the cancer cells have certain gene or chromosome changes

B-cell ALL

The most common form of ALL in children starts in early forms of B cells, which normally mature into cells that make antibodies to fight infections. When these cells develop gene changes or an abnormal number of chromosomes, they can become cancer. These B cells lose the ability to fight infections and can multiply very quickly.

B cells travel to the spleen (an immune organ in the belly, usually under the left ribcage) and lymph nodes to grow and mature. When B cells become leukemia, the spleen and lymph nodes may enlarge. This can result in a large spleen or large lymph nodes, commonly felt as lumps in the neck, underarm, or groin areas.

T-cell ALL

T-cell ALL is a less common form of ALL. T cells are lymphocytes that help fight infections. When these cells develop gene changes or an abnormal number of chromosomes, they can become cancer. These T cells lose the ability to fight infection and can multiply very quickly. This type of leukemia is more common in older children.

T-cell ALL, like B-cell ALL, can cause a large spleen or lymph nodes. Unlike B cells, T cells mature in a small immune organ located in front of the windpipe, called the thymus. When T cells develop into leukemia, the thymus can also enlarge, which can sometimes lead to breathing problems.

For more detailed information, see Prognostic Factors and Survival Rates for Childhood Leukemia.

For more detailed information on the treatment of ALL, see Childhood Acute Lymphoblastic Leukemia (ALL) Treatment.

AML is typically a fast-growing cancer that starts in one of the following types of early (immature) bone marrow cells:

• Myeloblasts: These cells normally become white blood cells called granulocytes (neutrophils, eosinophils, and basophils).
• Monoblasts: These cells normally become white blood cells called monocytes and macrophages.
• Erythroblasts: These cells normally become red blood cells.
• Megakaryoblasts: These cells normally become megakaryocytes, the cells that make platelets.

AML has many subtypes, which are based mainly on:

• If the leukemia cells look most like cells that were meant to become white blood cells, red blood cells, or platelets and how mature they were before becoming cancer (immunophenotype)
• If the leukemia cells have certain gene or chromosome changes
• If the leukemia is related to the treatment of an earlier cancer (with chemotherapy or radiation)
• If the child with leukemia has Down syndrome

Children with AML may experience symptoms like low energy, fevers, weight loss, and enlarged lymph nodes, spleen or liver. In some cases, children with AML can experience headaches, confusion, or difficulty breathing. This may happen when there are too many myeloblasts in the bloodstream, which can slow or block blood flow.

For more detailed information see Prognostic Factors and Survival Rates for Childhood Leukemia.

For more detailed information on the treatment of AML, see Childhood Acute Myeloid Leukemia (AML) Treatment.

CLL is a cancer of lymphocytes and is described by stage. A stage is assigned based on blood counts and the size of the lymph nodes, spleen, or liver at diagnosis, which tells doctors how far the cancer has spread.

CLL is extremely rare in childhood. For this reason, when it occurs, it is treated similarly to adults. In people with no symptoms, because CLL is slow growing, doctors may hold off on treatment until there are signs that the cancer is progressing. If treatment is needed, targeted drugs, chemotherapy, and immunotherapy may be used for CLL. In some rare cases, radiation or stem cell transplant may be used.

For more information on adult CLL, see Chronic Lymphocytic Leukemia (CLL).  

CML is typically a slower-growing cancer of early (immature) myeloid bone marrow cells. CML accounts for only 3% of leukemias in children and is much more common among adults.

CML is caused by a specific gene change, called the BCR-ABL fusion or Philadelphia chromosome. It is a slow disease with 3 phases: chronic, accelerated, and blast phase. These phases are based on the number of immature blood cells seen in the blood or bone marrow. Depending on the phase at diagnosis, children may have no symptoms or have symptoms like low energy and weight loss.

CML is extremely rare in childhood. For this reason, when it occurs it is treated similarly to adults. Targeted drugs called tyrosine kinase inhibitors (TKIs) are often used to treat CML. These include drugs like imatinib (Gleevec), dasatinib (Sprycel), nilotinib (Tasigna), and bosutinib (Bosulif). Stem cell transplant may be an option if these drugs are not successful.

For more detailed information, see Prognostic Factors and Survival Rates for Childhood Leukemia.

For more detailed information on the treatment of CML in children, see Childhood Chronic Myeloid Leukemia Treatment.