Parasii Tymur Sergiyovych

Acute lymphoblastic leukemia (ALL), is a form of leukemia, or cancer of the white blood cells characterized by excess lymphoblasts.

Malignant, immature white blood cells continuously multiply and are overproduced in the bone marrow. ALL causes damage and death by crowding out normal cells in the bone marrow, and by spreading (metastasizing) to other organs. ALL is most common in childhood with a peak incidence at 2-5 years of age, and another peak in old age. The overall cure rate in children is less than 30%, and about 35%-60% of adults have long-term disease-free survival.

Acute refers to the relatively short time course of the disease (being fatal in as little as a few weeks if left untreated) to differentiate it from the very different disease of Chronic Lymphocytic Leukemia which has a potential time course of many years. It is interchangeably referred to as Lymphocytic or Lymphoblastic. This refers to the cells that are involved, which if they were normal would be referred to as lymphocytes but are seen in this disease in a relatively immature (also termed 'blast') state.

Diagnosing ALL begins with a medical history and physical examination, complete blood count, and blood smears. Because the symptoms are so general, many other diseases with similar symptoms must be excluded. Typically, the higher the white blood cell count, the worse the prognosis. Blast cells are seen on blood smear in 90% of cases. A bone marrow biopsy is conclusive proof of ALL. A lumbar puncture (also known as a spinal tap) will tell if the spinal column and brain has been invaded.

Pathological examination, cytogenetics (particularly the presence of Philadelphia chromosome) and immunophenotyping, establish whether the "blast" cells began from the B lymphocytes or T lymphocytes. DNA testing can establish how aggressive the disease is; different mutations have been associated with shorter or longer survival. Immunohistochemical testing may reveal TdT or CALLA antigens on the surface of leukemic cells. TdT is a protein expressed early in the development of pre-T and pre-B cells while CALLA is an antigen found in 80% of ALL cases and also in the "blast crisis" of CML.

Medical imaging (such as ultrasound or CT scanning) can find invasion of other organs commonly the lung, liver, spleen, lymph nodes, brain, kidneys and reproductive organs.