May also be called: Acute Lymphocytic Leukemia; ALL

Acute lymphoblastic leukemia is a type of cancer that causes the body to make too many abnormal immature white blood cells (called lymphoblasts).

More to Know

Normally, white blood cells (WBCs) help fight infection and protect the body against disease. With leukemia, WBCs turn cancerous and multiply when they shouldn't, resulting in too many abnormal WBCs, which then interfere with organ function.

In acute lymphoblastic leukemia (ALL), too many lymphoblasts are made. These cells are abnormal and can't mature into normal white blood cells. Abnormal cells build up, and fewer healthy cells are made, leading to serious complications.

Doctors don't know what causes acute lymphoblastic leukemia, but it affects about 75% of kids with leukemia. ALL is called "acute" because it tends to get worse quickly if left untreated.

Symptoms include fatigue, fever, bone pain, night sweats, recurrent infections, and easy bleeding and bruising. Treatment for ALL involves chemotherapy to kill as many cancer cells as possible, and then maintenance chemotherapy for several years to keep the cancer from coming back.

Keep in Mind

The outlook for kids with ALL is promising. Overall cure rates differ depending on the specific features of a child's disease. With treatment, some forms of childhood ALL have cure rates up to 90%.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.