Childhood Leukemia and Lymphoma Facts

April 26, 2024 
This page was reviewed under our medical and editorial policy by Lindsey Murphy, M.D., Pediatric Hematologist-Oncologist and Assistant Professor in the Department of Pediatrics, City of Hope Duarte

Childhood leukemia and lymphoma, or cancer of the bone marrow and the lymphatic system, are two of the most common childhood cancers. For every 1,000,000 people ages 20 and younger in the United States, there are 48.3 cases of leukemia and 29.2 cases of lymphoma. 

Childhood leukemia and lymphoma diagnosis rates differ by race and ethnicity. From 2016 to 2020, the incidence of leukemia in Hispanic and American Indian/Alaska Native children and adolescents was twice as high, compared to Black children and adolescents in the United States, and significantly greater than the incidence among whites and Asians..

What Are Childhood Leukemia and Lymphoma?

Leukemia is a cancer of the blood cells. It develops in bone marrow, the soft, spongy tissue where blood cells are made. Types of leukemia vary according to what part of the blood is cancerous, and whether the cancer grows quickly or slowly.

Lymphoma is a term used to describe cancers of the lymphatic system, a part of the body’s defenses against infection. Types of lymphoma vary based on the type of lymphocyte, or immune cell, that is affected. The lymph system includes lymph, a clear fluid that carries white blood cells through the body, lymph vessels, lymph nodes, the spleen, the thymus, tonsils and bone marrow.

Types of Childhood Leukemia

The most common types of childhood leukemia are acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML). ALL is a cancer of the blood and bone marrow, in which the body makes too many abnormal white blood cells, called lymphocytes (types B or T). ALL is the most common type of childhood leukemia.

AML is a type of cancer that occurs when the bone marrow makes too many abnormal blood cells, called myeloblasts (a type of immature white blood cell).

Acute leukemias progress more rapidly than chronic leukemias and require treatment right away.

Chronic myeloid leukemia (CML), the rarest leukemia found in children, is a disease in which the bone marrow makes too many white blood cells, called granulocytes, crowding out healthy cells. It is most often linked to an acquired genetic mutation known as the Philadelphia chromosome.

Types of Childhood Lymphoma

The two main types of lymphomas are Hodgkin lymphoma and non-Hodgkin lymphoma.

Childhood Hodgkin lymphoma is a cancer that develops in the lymph system. It is marked by the presence of large, abnormal lymphocytes called Reed-Sternberg cells, and it mostly affects teens. Common subtypes of Hodgkin lymphoma found in children include nodular sclerosis, mixed cellularity and nodular lymphocyte-predominant.

Childhood non-Hodgkin lymphoma is also a cancer that develops in the lymph system, but it is seen in a different type of lymphocyte, such as B lymphocytes, T lymphocytes or natural killer (NK) cells. Common subtypes of non-Hodgkin lymphoma found in children include Burkitt lymphoma, diffuse large B cell lymphoma, anaplastic large-cell lymphoma and lymphoblastic lymphoma.

What Causes Childhood Leukemia and Lymphoma?

The exact causes of childhood leukemia and lymphoma are unknown.

Leukemia occurs when changes inside the DNA of normal bone marrow occur, causing them to grow abnormally and become leukemia cells. Many changes in chromosomes and genes have been tied to leukemia, but most are acquired, or happen after birth, and not passed down from parents. One of the more common mutations found in CML is referred to as the Philadelphia chromosome, a change that makes leukemia cells grow and stay alive longer than typical cells.

Lymphoma is a cancer with origins in the lymphocytes, a type of white blood cell. Acquired changes in the DNA (genetic instructions inside normal lymphocytes) from some type of outside exposure, or risk factor, may give rise to why lymphocytes become abnormal and grow out of control. Researchers continue to study how and why leukemia and lymphoma cells form, and how to treat these changes in the cells’ blueprints.

Childhood Leukemia and Lymphoma Risk Factors

Though these conditions are incredibly rare overall, certain factors may increase their risk. If a child has these risk factors, it does not mean that they will get leukemia or lymphoma, or that these factors are a direct cause. They only mean that someone may be more likely to develop the disease.

Certain genetic disorders may increase a child’s risk for developing leukemia or lymphoma. While still rare, children with Down syndrome are more likely than others to develop ALL or AML with between a 2% and 3% chance, respectively.

Another rare condition, called Li-Fraumeni syndrome, may also increase a child’s risk for developing leukemia. Children with other genetic disorders, such as neurofibromatosis and Fanconi anemia, as well as those born with immune system problems, may also have a greater risk for developing leukemia. Exposure to radiation, chemotherapy and treatments to suppress the immune system may also elevate leukemia risk. Some chemicals, such as benzene, polyfluoroalkyl substances (PFAS) and pesticides, have also been implicated, but more research is necessary to help inform patients and doctors.

Children with weakened immune systems are also more likely to develop lymphoma.

Syndromes inherited from parents, such as Wiskott-Aldrich syndrome, Nijmegen breakage syndrome, ataxia-telangiectasia, common variable immunodeficiency and X-linked lymphoproliferative syndrome, may also put children at increased risk for developing lymphoma and leukemia.

Organ transplants, HIV infections, Epstein-Barr virus infections and radiation exposure are other factors that may increase the risk for developing childhood lymphoma.

Researchers continue to examine other risk factors.