Thesis (Ph.D.) - Cairo University - National Cancer Institute - Department of Clinical Pathology

Introduction: Acute lymphoblastic leukemia (ALL) is a malignant disorder that originates in a single B- or T-lymphocyte progenitor. The disease is most common in children but can be seen in individuals of any age. ALL accounting for 75 {u2013} 80% of all leukemia cases in children.. MicroRNAs are single-stranded RNAs (19-25 nucleotides) that negatively regulate mRNA stability. They play an essential role in many biological functions, such as cell growth, proliferation, differentiation, and apoptosis. miR-100 has very low expression levels in ALL patients suggesting that this miRNA has different roles in myeloid cell and lymphocyte pathogenesis. miR-210 has been investigated intensively, which has identified a variety of functionally important targets involved in cell cycle regulation, cell survival, differentiation, angiogenesis as well as metabolism.Aim of the work: To evaluate the expression of both miRNAs; miR-100 and miR-210, in newly diagnosed children with Acute Lymphoblastic Leukemia (ALL) and to relate their expression levels with clinical and laboratory data, And to evaluate their role as biomarkers for predicting outcome in pediatric acute lymphoblastic leukemia patients (ALL) in the form of overall survival (OS) and disease free survival (DFS). Patients and methods: Detection of miR-100 and miR-210 was done using RT-PCR in newly diagnosed Pediatric ALL patients and age matched controls.Results: The study included 85 newly diagnosed ALL pediatric patients (47 males and 38 females, the mean age was 7.6 years), and 12 age and sex matched control. ALL patients showed significantly lower miR-100 expression, when compared to control group (p=0.035), pediatric ALL patients showed significantly higher miR-210 expression when, compared to the control group(P=0.025). cases with low expression of miR-100 showed longer OS (P=0.046) when compared with high expression group, this discrepancy may be due to the presence of other favorable prognostic factors in the low expression group, While no significant correlation between high or low expression groups of miR-210 with overall survival during follow up period (P=0.939)

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