الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Acute lymphoblastic leukemia is a malignant neoplasm of the lymphocyte precursor cells - lymphoblasts. ALL is the most common malignancy in children and accounts for approximately 80 percent of childhood leukemia. In 2001 according to Middle East Cancer Consortium (MECC), the incidence rate of childhood leukemia in Egypt in children less than 15 years is 3.19 per 100,000 populations.
Diagnosis of ALL includes peripheral blood and bone marrow examination and cytochemistry together with immunophenotyping by flowcytometry, cytogenetics& molecular techniques.
Improvements in outcome are mostly attributable to risk-adapted intensive chemotherapy. It is well recognized that overall prognosis and risk of relapse in patients with ALL correlate with genetic alterations. There has been great progress in the understanding of ALL pathogenesis, resulting in improved pathologic classification, risk stratification, and novel therapeutic approaches. As molecular knowledge continues to expand, we also need to include abnormalities of new molecular markers or pathways likely to be important for risk stratification or choice of therapy. For these reasons, several efforts have been made to find new biomarkers in ALL enabling early diagnosis of asymptomatic disease and individualization of the therapy. Among the potential markers of interest are miRNAs.
MicroRNAs (miRNAs) are a family of small non protein-coding RNAs approximately 22 nucleotides in length, that are involved in post-transcriptional gene regulation. Numerous studies investigated the potential clinical utility of miRNAs as a diagnostic, prognostic and therapeutic target in cancer.