الفهرس 
Introduction
Acute leukemiaOnly 14 pages are availabe for public view
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Abstract
The World Health Organization (WHO) classifies hematological malignancies according to their lineage (myeloid, lymphoid, histolytic/dendritic) and distinguishes neoplasms of precursor cells from those comprised of functionally mature cells. Within each category, distinct diseases are defined according to a combination of morphology, immunophenotyping, genetic features and clinical syndromes.Acute leukemia represents one-third of all cancer cases among patients under the age of 15 years and constitutes the most common type of pediatric cancer. Among patients younger than 15 years of age with childhood leukemia, acute lymphoblastic leukemia (ALL) comprises 80% of cases, acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) account for 18% and 2% of cases, respectively. chronic lymphocytic leukemia (CLL) rarely occurs in children.ALL is the major pediatric cancer in developed countries.This pathology is characterized by many chromosomal abnormalities that produce aberrant gene fusions or inappropriate expression of oncogenes. Among them, rearrangements of the mixed-lineage leukemia (MLL) gene localized in 11q23 are common chromosomal abnormalities associated with acute leukemia, especially infant leukemia and secondary leukemia following treatment with DNA topoisomerase II inhibitors.Translocation(9;22) associated with the Bcr-Abl transcript is the most frequent genetic aberration in adult ALL and is found in 20–30 % of patients overall.