Leukemia is the collective name for a group of diseases that involve an uncontrolled increase in white blood cells, known as leukocytes. Leukocytes are produced in the bone marrow and help defend the body against infectious disease.

Types of Leukemia

Acute Myelogenous Leukemia (AML)

AML is a type of cancer that begins in the body’s myeloid cells (stem cells that typically develop into blood cells). AML spreads quickly and results in the suppression of normal stem cells. The disease typically affects older people but has been known to affect children as well. AML patients may need treatment immediately after diagnosis due to the rapid onset of the disease. Depending on the case, this can include chemotherapy and stem cell transplantation.

Acute Lymphocytic Leukemia (ALL)

ALL involves the overproduction and uncontrolled accumulation of malignant and immature white blood cells, known as lymphocytes, in the bone marrow. ALL spreads quickly to the body’s other organs and is fatal if left untreated. It is common among children and is sometimes referred to as Acute Lymphoblastic Leukemia. Treatment may include chemotherapy and stem cell transplantation.

Chronic Myelogenous Leukemia (CML)

CML affects myeloid stem cells, much like AML. Unlike AML, however, CML permits the development of mature white cells and platelets that can function normally. Due to the chronic nature of the disease, CML can lay dormant for years before it reaches an accelerated phase. Treatments can include chemotherapy and stem cell transplantation.

Chronic Lymphocytic Leukemia (CLL)

CLL is similar to ALL, but the lymphocytes that accumulate in the marrow do not impede normal blood cell production as severely as in the case of ALL. In its early stages, CLL may present few symptoms. Treatment can include chemotherapy, radiation therapy, and in some cases, stem cell transplantation. Unlike AML, ALL and CML, CLL is not typically associated with exposure to high doses of radiation or benzene.

Hairy Cell Leukemia (HCL)

HCL is a rare type of leukemia that gets worse slowly or sometimes not at all. Like CLL, HCL is a slowly progressing cancer of lymphocytes. The disease is called hairy cell leukemia because the leukemia cells look "hairy" when viewed under a microscope. HCL differs from CLL primarily in how it is managed. Treatment is typically only given when symptoms interfere with a patient’s daily life and most often includes some form of chemotherapy.