General Information About Childhood Acute Lymphoblastic Leukemia
KEY POINTS
Childhood acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many immature lymphocytes (a type of white blood cell).
Leukemia may affect red blood cells, white blood cells, and platelets.
Past treatment for cancer and certain genetic conditions affect the risk of having childhood ALL.
Signs of childhood ALL include fever and bruising.
Tests that examine the blood and bone marrow are used to detect (find) and diagnose childhood ALL.
Certain factors affect prognosis (chance of recovery) and treatment options.
Childhood acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many immature lymphocytes (a type of white blood cell).
ENLARGEAnatomy of the bone. The bone is made up of compact bone, spongy bone, and bone marrow. Compact bone makes up the outer layer of the bone. Spongy bone is found mostly at the ends of bones and contains red marrow. Bone marrow is found in the center of most bones and has many blood vessels. There are two types of bone marrow: red and yellow. Red marrow contains blood stem cells that can become red blood cells, white blood cells, or platelets. Yellow marrow is made mostly of fat.
ALL is the most common type of cancer in children.
Leukemia may affect red blood cells, white blood cells, and platelets.
In a healthy child, the bone marrow makes blood stem cells (immature cells) that become mature blood cells over time. A blood stem cell may become a myeloidstem cell or a lymphoid stem cell.
A myeloid stem cell becomes one of three types of mature blood cells:
ENLARGEBlood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell.
In a child with ALL, too many stem cells become lymphoblasts, B lymphocytes, or T lymphocytes. The cells do not work like normal lymphocytes and are not able to fight infection very well. These cells are cancer (leukemia) cells. Also, as the number of leukemia cells increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets. This may lead to infection, anemia, and easy bleeding.
This summary is about acute lymphoblastic leukemia in children, adolescents, and young adults. See the following PDQ summaries for information about other types of leukemia:
Past treatment for cancer and certain genetic conditions affect the risk of having childhood ALL.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your child's doctor if you think your child may be at risk.
Possible risk factors for ALL include the following:
Constitutional mismatch repair deficiency (mutations in certain genes that stop DNA from repairing itself, which leads to the growth of cancers at an early age).
Having certain changes in the chromosomes or genes.
Signs of childhood ALL include fever and bruising.
These and other signs and symptoms may be caused by childhood ALL or by other conditions. Check with your child's doctor if your child has any of the following:
Tests that examine the blood and bone marrow are used to detect (find) and diagnose childhood ALL.
The following tests and procedures may be used to diagnose childhood ALL and find out if leukemia cells have spread to other parts of the body such as the brain or testicles:
Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.
The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
The portion of the sample made up of red blood cells.
ENLARGEComplete blood count (CBC). Blood is collected by inserting a needle into a vein and allowing the blood to flow into a tube. The blood sample is sent to the laboratory and the red blood cells, white blood cells, and platelets are counted. The CBC is used to test for, diagnose, and monitor many different conditions.
Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease.
Bone marrow aspiration and biopsy: The removal of bone marrow and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. A pathologistviews the bone marrow and bone under a microscope to look for signs of cancer.ENLARGEBone marrow aspiration and biopsy. After a small area of skin is numbed, a bone marrow needle is inserted into the child’s hip bone. Samples of blood, bone, and bone marrow are removed for examination under a microscope.
The following tests are done on blood or the bone marrow tissue that is removed:
Cytogenetic analysis: A laboratory test in which the cells in a sample of blood or bone marrow are viewed under a microscope to look for certain changes in the chromosomes of lymphocytes. For example, in Philadelphia chromosome –positive ALL, part of one chromosome switches places with part of another chromosome. This is called the “Philadelphia chromosome.”ENLARGEPhiladelphia chromosome. A piece of chromosome 9 and a piece of chromosome 22 break off and trade places. The BCR-ABL gene is formed on chromosome 22 where the piece of chromosome 9 attaches. The changed chromosome 22 is called the Philadelphia chromosome.
Immunophenotyping: A laboratory test in which the antigens or markers on the surface of a blood or bone marrow cell are checked to see if they are lymphocytes or myeloid cells. If the cells are malignant lymphocytes (cancer) they are checked to see if they are B lymphocytes or T lymphocytes.
Lumbar puncture: A procedure used to collect a sample of cerebrospinal fluid (CSF) from the spinal column. This is done by placing a needle between two bones in the spine and into the CSF around the spinal cord and removing a sample of the fluid. The sample of CSF is checked under a microscope for signs that leukemia cells have spread to the brain and spinal cord. This procedure is also called an LP or spinal tap.ENLARGELumbar puncture. A patient lies in a curled position on a table. After a small area on the lower back is numbed, a spinal needle (a long, thin needle) is inserted into the lower part of the spinal column to remove cerebrospinal fluid (CSF, shown in blue). The fluid may be sent to a laboratory for testing.
This procedure is done after leukemia is diagnosed to find out if leukemia cells have spread to the brain and spinal cord. Intrathecal chemotherapy is given after the sample of fluid is removed to treat any leukemia cells that may have spread to the brain and spinal cord.
Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body. The chest x-ray is done to see if leukemia cells have formed a mass in the middle of the chest.
Certain factors affect prognosis (chance of recovery) and treatment options.
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