Doctors categorize leukemia based on which type of white blood cell is involved — lymphocytes or myeloid cells — and whether the illness is developing very quickly (acute disease) or slowly over time (chronic disease).

Lymphocytic leukemias develop from cells that give rise to T lymphocytes (T cells), B lymphocytes (B cells), or natural killer (NK) cells. Each of these cell types has a specialized role in the immune system; some produce antibodies, whereas others directly fight or direct other immune cells to fight infections.

Myeloid leukemias develop from cells that give rise to white blood cells called granulocytes and monocytes. Granulocytes get their name from the enzyme-packed granules they carry inside them. They release these enzymes when encountering invading bacteria or fungi. Monocytes eventually become macrophages, which engulf and destroy bacteria and fungi.

In acute leukemias, which develop rapidly, the malignant cells (called blasts) are immature and incapable of performing their immune system functions. Chronic leukemias develop in more-mature cells, which can perform some of their duties — but not very well. These abnormal cells usually multiply at a slower rate than acute leukemias.

Of the four common types of leukemia in adults, acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL) occur most frequently. 

Acute Lymphocytic Leukemia

Acute lymphocytic leukemia is uncommon among adults, affecting approximately 2,940 adults each year, but it is the most common of childhood cancers. In adults, the incidence of ALL increases with age. ALL is also less common among women and African Americans. (Learn more about pediatric leukemias.)

Doctors perform a variety of different tests to diagnose ALL. These diagnostic tests allow them to analyze the specific features of the leukemia cells and look for any genetic abnormalities, particularly rearrangements in chromosomes (the tightly coiled strands of DNA that contain all the information cells need to function normally and reproduce) — which are common in ALL — or for specific proteins called antigens that appear on the surface of the diseased cells. Learn more about diagnosis.

Chemotherapy and hematopoietic stem cell (or bone marrow) transplantation are the standard approaches for ALL, but the type of treatment that is recommended will vary based on the features of each case. For example, patients with Philadelphia-positive ALL may receive certain targeted therapies that have proven particularly effective against this subtype of the disease.  Learn more about treatment for ALL.

Acute Myeloid Leukemia

Acute myeloid leukemia, one of the most common leukemias in adults, is diagnosed in nearly 15,000 people in the United States each year. The average age at diagnosis is 67. The disease affects more men than women.

Doctors perform a variety of different tests to diagnose AML. These diagnostic tests allow them to analyze the specific features of the leukemia cells and look for any genetic abnormalities, such as chromosomal rearrangements and/or gene mutations, both of which are common in AML — or for specific proteins called antigens that appear on the surface of the diseased cells. Learn more about diagnosis.

Jennifer’s Story about Acute Myelogenous Leukemia (AML)
Unable to find a matching bone marrow donor to treat her acute myelogenous leukemia, Jennifer turned to Memorial Sloan Kettering, where physicians did a stem cell transplant using umbilical cord blood.
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The treatment recommended for an individual patient with AML varies, but standard approaches include chemotherapy and hematopoietic stem cell (or bone marrow) transplantation. Patients with the form of AML called acute promyelocytic leukemia receive initial treatment with all-trans-retinoic acid (ATRA), a medicine developed at Memorial Sloan Kettering, in combination with arsenic trioxide.

Learn more about treatment for AML.

Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia is the most common chronic leukemia in adults. About 15,340 people in the United States will develop CLL this year. The average age at diagnosis is 72, and the disease is twice as common in men as women.

Doctors perform a variety of different tests to diagnose CLL. These diagnostic tests allow them to analyze the specific features of the leukemia cells and look for any genetic abnormalities, such as chromosomal rearrangements — which are common in CLL. Learn more about diagnosis.

The treatment recommended for an individual patient with CLL will vary, and many patients with asymptomatic CLL require only observation. Most patients will derive the most benefit from current standard treatment approaches, which are designed to alleviate symptoms by inducing disease remission or slowing disease progression. These standard treatments generally include a combination of chemotherapy and immunotherapy, as well as novel targeted therapies for relapsed or refractory disease.

To date, no treatment approach other than bone marrow transplantation is considered a cure for CLL. However, this intensive approach is not necessary in most cases and only recommended for those patients with the highest risk types of CLL.

Learn more about treatment for CLL.

Chronic Myeloid Leukemia

Approximately 5,980 new cases of CML were diagnosed in the United States in 2014. The average age at diagnosis is 65, and the disease is slightly more common in men than women. In recent years, an increasing proportion of younger people have been diagnosed with CML, but the reason for this is not currently understood.

CML develops when genetic material is exchanged between chromosomes 9 and 22 to generate what is called the Philadelphia chromosome. Doctors perform a variety of tests to diagnose this disease. Learn more about diagnosis.

The standard treatment for patients with CLL includes a choice between several targeted therapies that are very effective in the vast majority of cases. Patients with disease that relapses or is unresponsive to one of these therapies may receive another targeted therapy or other treatments.

Learn more about treatment for CML.