Acute lymphoblastic leukemia (ALL) is a blood cancer in which the bone marrow starts to produce too many immature lymphocytes (a type of white blood cell), called lymphoblasts. This kind of cancer is called "acute" because it is usually a fast-growing kind of leukemia.
Some people with ALL have chromosome abnormalities in the cancer cells (extra chromosomes or structural changes in chromosomes), but it is not clear what causes the mutations that can lead to ALL. Researchers have found that most cases of acute lymphoblastic leukemia are not inherited.
ALL can develop at any age, but most commonly affects young children. About 1,000 new cases are diagnosed in adults each year in the United States.
Risk factors include:
- Past treatment with chemotherapy or radiation therapy
- Being white
- Having certain genetic disorders, such as Down syndrome
- Having an identical twin with ALL
- Having certain viral infections, such as human T-cell lymphoma/leukemia virus-1 (HTLV-1) – uncommon outside of Japan or the Caribbean
Symptoms and Signs
The most common symptoms include:
- Unexplained weight or appetite loss
- Weakness or fatigue
- Pain or fullness below the ribs
- Shortness of breath
- Easy bruising
- Night sweats
- Enlarged lymph nodes
Growth and Spread
ALL is often an aggressive cancer. It can involve lymph nodes, spleen, bone marrow and blood, skin, or the central nervous system.
Factors Affecting Prognosis
As with any cancer, prognosis (chance of recovery) and long-term survival can vary greatly. The prognosis depends partly on:
- Certain molecular mutations
- Age — children (over the age of 1) with ALL have better prognoses than adults with the disease
- Response to therapy