Acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell).

Acute lymphoblastic leukemia (ALL; also called acute lymphocytic leukemia) is a cancer of the blood and bone marrow. This type of cancer usually gets worse quickly if it is not treated.

Leukemia may affect red blood cells, white blood cells, and platelets.

The bone marrow and thymus make blood stem cells (immature cells) that become mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell.

A lymphoid stem cell becomes a lymphoblast cell and then one of three types of lymphocytes (white blood cells):

• B lymphocytes that make antibodies to help fight infection
• T lymphocytes that help B lymphocytes make the antibodies that help fight infection
• natural killer cells that attack cancer cells and viruses

In ALL, too many stem cells become lymphoblasts, B lymphocytes, or T lymphocytes. These cells are also called leukemia cells. Leukemia cells are not able to fight infection very well. 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 cause infection, anemia, and easy bleeding. The cancer can also spread to the central nervous system (brain and spinal cord), lymph nodes, spleen, liver, testicles, and other organs.

Previous chemotherapy and exposure to radiation may increase the risk of developing ALL.

ALL is caused by certain changes to the way blood stem cells function, especially how they grow and divide into new cells. A risk factor is anything that increases the chance of getting a disease. Some risk factors for cancer, like smoking, can be changed. However, risk factors also include things people cannot change, like their genetics, getting older, and their health history.

There are many risk factors for ALL, but many do not directly cause cancer. Instead, they increase the chance of DNA damage in cells that may lead to ALL. Learn more about how cancer develops at What Is Cancer?

Having one or more of these risk factors does not mean that you will get ALL. Many people with risk factors never develop ALL, while others with no known risk factors do.

Possible risk factors for ALL include:

• being male
• being White
• being older than 70
• past treatment with chemotherapy or radiation therapy
• being exposed to high levels of radiation in the environment (such as nuclear radiation)
• having certain genetic disorders, such as Down syndrome

Talk with your doctor if you think you may be at risk.

Signs and symptoms of ALL include fatigue, fever, and easy bruising or bleeding.

The early signs and symptoms of ALL may be like the flu or other common diseases. Check with your doctor if you have:

• weakness or fatigue
• fever or drenching night sweats
• easy bruising or bleeding
• petechiae (flat, pinpoint spots under the skin, caused by bleeding)
• shortness of breath
• weight loss or loss of appetite
• pain in the bones or stomach
• pain or feeling of fullness below the ribs
• painless lumps in the neck, underarm, stomach, or groin
• frequent infections

These and other signs and symptoms may be caused by ALL or by other conditions.

Tests that examine the blood and bone marrow are used to diagnose ALL.

In addition to asking about your personal and family health history and doing a physical exam, your doctor may perform the following tests and procedures:

• Complete blood count (CBC) with differential is a procedure in which a sample of blood is drawn and checked for:
  • the number of red blood cells and platelets
  • the number and type of white blood cells
  • the amount of hemoglobin (the substance that carries oxygen) in the red blood cells
  • the amount of hematocrit (whole blood that is made up of red blood cells)
  
• Blood chemistry study is a laboratory test 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.
• Peripheral blood smear is a laboratory test in which a sample of blood is checked for blast cells, the number and kinds of white blood cells, the number of platelets, and changes in the shape of blood cells.
• Bone marrow aspiration and biopsy is the removal of bone marrow, blood, and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. A pathologist views the bone marrow, blood, and bone under a microscope to look for abnormal cells.

  The following tests may be done on the samples of blood or bone marrow tissue that are removed:

  • Cytogenetic analysis checks the chromosomes of cells in a blood or bone marrow sample for changes, such as broken, missing, rearranged, or extra chromosomes. Changes in certain chromosomes may be a sign of cancer. For example, in Philadelphia chromosome–positive ALL, part of one chromosome switches places with part of another chromosome. This is called the "Philadelphia chromosome." Cytogenetic analysis is used to help diagnose cancer, plan treatment, or find out how well treatment is working.
  • Immunophenotyping uses antibodies to identify cancer cells based on the types of antigens or markers on the surface of the cells. This test is used to help diagnose specific types of leukemia. For example, a cytochemistry study may test the cells in a sample of tissue using chemicals (dyes) to look for certain changes in the sample. A chemical may cause a color change in one type of leukemia cell but not in another type of leukemia cell.

After ALL has been diagnosed, tests are done to find out if the cancer has spread to the central nervous system (brain and spinal cord) or to other parts of the body.

The following tests and procedures may be used to find out if the leukemia has spread outside the blood and bone marrow:

• Chest x-ray is a type of radiation that can go through the body and make pictures of the organs and bones inside the chest.
• Lumbar puncture is 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.
• CT scan (CAT scan) uses a computer linked to an x-ray machine to make a series of detailed pictures of areas inside the body, such as the abdomen. The pictures are taken from different angles and are used to create 3-D views of tissues and organs. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• MRI (magnetic resonance imaging) uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).

Some people decide to get a second opinion.

You may want to get a second opinion to confirm your ALL diagnosis and treatment plan. If you seek a second opinion, you will need to get medical test results and reports from the first doctor to share with the second doctor. The second doctor will review the pathology report, slides, and scans. They may agree with the first doctor, suggest changes or another treatment approach, or provide more information about your cancer.

To learn more about choosing a doctor and getting a second opinion, see Finding Cancer Care. You can contact NCI's Cancer Information Service via chat, email, or phone (both in English and Spanish) for help finding a doctor, hospital, or getting a second opinion. For questions you might want to ask at your appointments, see Questions to Ask Your Doctor About Cancer.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis and treatment options depend on:

• the person's age
• whether the cancer has spread to the brain or spinal cord
• whether there are certain changes in the genes, including the Philadelphia chromosome
• whether the cancer has been treated before or has recurred (come back)