Acute lymphoblastic leukemia (ALL) is a cancer of the blood and bone marrow. Lymphocytes are a type of white blood cell. With ALL, the bone marrow makes too many of these cells.

Leukemia cells do not function normally. In this case, they cannot fight infections. This means that the person is more likely to become infected with viruses or bacteria. The cancerous cells also overgrow the bone marrow. This forces other normal components, like platelets out. Platelets are needed to help the blood clot. As a result, people with leukemia may bleed more easily.

White Blood Cells
White Blood Cells
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The cause of ALL is unknown. Research shows that certain risk factors are associated with the disease.