Acute lymphocytic leukemia (ALL) is a cancer of the blood and blood-forming tissues of the body that quickly gets worse when left untreated. It is most prevalent in children and the rarest of the four common leukemias.
About acute lymphocytic leukemia (ALL)
ALL forms from lymphoid stem cells. These disease cells multiply rapidly and are poor at fighting infection. They also crowd out healthy cells, leaving people with ALL weak and prone to infection.
The two main subtypes of ALL are B cell, which makes up about 85% of ALL cases, and T cell, which makes up 15%.
Both these subtypes are also divided into smaller groups based on chromosome and other genetic markers. An important subtype of B cell ALL is Philadelphia chromosome-positive B-ALL.
Chromosomes are sections of DNA found in every cell; each person’s DNA contains his or her unique genetic instructions. The Philadelphia chromosome forms when pieces of chromosome 9 and chromosome 22 swap places in a blood cell.
As a result, the now-cancerous cell produces a protein (in the tyrosine kinase family of proteins) that encourages it to multiply rapidly. Leukemias with the Philadelphia chromosome can be treated with targeted therapies called tyrosine kinase inhibitors. These drugs interfere with the tyrosine kinase protein and therefore the multiplication of cancerous white blood cells.
About 6,000 ALL cases are diagnosed in the United States each year. More than half of these are in pediatric patients. Among adults, the risk of developing ALL begins increasing around age 50.
The five-year survival rate for ALL is about 70%. This is largely due to a 90% survival rate among pediatric patients. For adults, the survival rate lowers with age.
This is partly due to chromosome changes that are connected with worse outcomes. Many of these changes are more common in adult ALL patients than pediatric patients. In addition, the chance of developing ALL increases as people enter their 50s and beyond. Older patients often have other health problems that can impact their care and prognosis.
Blood cell creation
The body produces millions of blood cells each day. Most develop in the bone marrow, the spongy interior of bones that contains immature stem cells.
In a healthy person, these immature stem cells first become either lymphoid stem cells or myeloid stem cells.
Lymphoid stem cells develop into white blood cells, which are immune system cells. They start by becoming immature white blood cells known as lymphoblasts, then mature into lymphocytes. The two types of lymphocytes that are usually involved in leukemia are B cells and T cells. B cells produce the antibodies responsible for attacking bacteria and viruses that invade the body. T cells help alert other immune cells to the presence of infection or fight infection directly.
Myeloid stem cells also develop into white blood cells. The myeloid stem cells first become immature white blood cells known as myeloblasts. They then mature into monocytes and granulocytes, including neutrophils, all of which fight disease. Other myeloid stem cells develop into red blood cells, which carry oxygen throughout the body; and platelets, which help the blood clot.
Leukemia occurs when the DNA (the genetic instructions that control cell activity) of a bone marrow stem cell mutates at some point in its development. The cell becomes cancerous, begins multiplying rapidly and crowds out healthy cells in the blood and bone marrow. These diseased cells can also gather in specific parts of the body, including the liver, lymph nodes, spleen and skin.
How is leukemia classified?
While there are many types of leukemia, they are typically classified by the type of stem cell that has turned cancerous, either lymphoid or myeloid.
Many types are also classified as either chronic or acute. Acute leukemia impacts immature cells, preventing them from developing and carrying out their function. These cells tend to multiply rapidly, making acute leukemia more aggressive.
Chronic leukemia involves mature or partially mature cells. These cells multiply more slowly and are less aggressive, making chronic leukemia less aggressive than acute leukemia.
Risk factors
A risk factor is anything that increases the risk of developing a disease. Knowing a disease’s risk factors can be an important step towards catching it early. It's important to note that not everyone with risk factors will develop the disease.
Risk factors for acute lymphocytic leukemia (ALL) include:
- Sex: Men are slightly more likely to develop ALL than women.
- Age: While more than half of ALL cases are in pediatric patients, among adults, the risk of ALL begins increasing around age 50.
- Past treatment with chemotherapy or radiation therapy for a previous cancer. While these therapies are risk factors for ALL, their benefits as cancer treatments far outweigh their risks.
- Genetic disorders: Individuals with certain genetic disorders are at a higher risk of developing ALL. These include:
- Ataxia telangiectasia
- Bloom syndrome
- Down syndrome
- Fanconi anemia
- Klinefelter syndrome
- Li-Fraumeni syndrome, a hereditary cancer syndrome
- Wiskott-Aldrich syndrome
- Ataxia telangiectasia
- Chemical exposure: Long-term exposure to benzene, a chemical used in the petroleum industry, can cause ALL, though it is more commonly connected to acute myeloid leukemia.
Some cases of leukemia can be passed down from one generation to the next. Genetic counseling may be right for you. Learn more about the risk to you and your family on our genetic testing page.
Blood cell creation (click to enlarge).
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Why choose MD Anderson for your leukemia treatment?
Choosing the right cancer center may be the most important decision you can make as a leukemia patient. At MD Anderson’s Leukemia Center and Stem Cell Transplantation and Cellular Therapy Center, you’ll get treatment from one of nation’s the largest, most experienced leukemia teams at a top-ranked cancer center.
Using a comprehensive team approach, we work together to give you customized care that includes the most advanced diagnostic methods and treatments. These include clinical trials of new drugs and drug combinations. We offer clinical trials for all situations – from patients receiving their first treatment, to patients who have exhausted all standard treatment options.
As a leading center for leukemia care, we offer access to innovative new therapies and clinical trials that may help increase your chances for successful treatment. Many of these were developed by our own researchers.
Treatment designed specifically for you
Successful leukemia treatment begins with accurate and precise diagnosis. Many of our leukemia patients have been misdiagnosed before they come to MD Anderson. We have the expertise and experience gained from being one of the most active programs in the world, and our specialized pathologists are highly skilled in diagnosing leukemia.
Our approach to leukemia is customized especially for you. We carefully evaluate your risk factors and the specific characteristics of your leukemia to determine if immediate treatment is necessary. If it is, we recommend the most effective therapies while aiming to limit treatment side effects.
Whether you are treated as an inpatient or outpatient, our comprehensive program offers all the services needed to care for leukemia and respond to its impact on your body. We aim to accomplish as much care as possible on an outpatient basis. If hospitalization is needed, our expert staff is specially trained to care for patients at every phase of the treatment journey.
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