الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Acute myeloid leukemia (AML) is a genetically heterogeneous disease characterized by a malignant clonal proliferation of immature myeloid cells in the bone marrow, peripheral blood, and occasionally other body tissues. AML is the most common acute leukemia in adults with an overall 5-year survival rate of approximately 25%. Genetic and epigenetic profile of the leukaemic cells affects the rate of achieving remission and risk of relapse. Many of these genetic and molecular mutations in AML have prognostic implications yet; the role of epigenetics genes mutations is less clearly understood.
Enhancer of Zeste Homolog 2 (EZH2) is the catalytic subunit of the chromatin modifying enzyme polycomb group (PRC)2. As a complex these proteins selectively silence target genes through trimethylation of histone H3 at lysine 27. EZH2 is strongly oncogenic. It has been observed in various malignancies which makes it an interesting therapeutic target. Whether it function as a tumor suppressor or oncogene is not settled in AML.
The study was done to determine the relative expression level of EZH2 gene in a cohort of Egyptian patients with adult newly diagnosed AML.
The present study included 45 de novo AML and 40 healthy persons of matched age and sex as a control group. The following was done to all patients: complete blood count, bone marrow examination, cytochemical and immunophenotyping study and conventionl cytogentics, hepatic and renal function tests. Detection of EZH2 gene expression level by real time quantitative polymerase chain reaction (RQ-PCR) was done to all patients and controls.
The median age of our patients was 33 year. Males constitute 66.7% (30 patients) of our patients and females constitute 33.3% (15 patients). The majority of our patients (71.1%, 32 patients) were M5. Cytogenetic study revealed presence of normal cytogenetic in 28 (62.1%) patients. EZH2 was lower in AML patients as compared with controls (p-value<0.001). There was no significant difference in EZH2 level when considering age, sex, bone marrow blasts, cytogenetic study, type or site of infection. Low EZH2 was associated with higher mortality in 31 patients (68.9%) and resistance to chemotherapy in 39 patients (86.6%).
from this study we concluded that low EZH2 is common in Egyptian acute myeloid leukemia patients. It functions as tumor suppressor gene rather than an oncogene. Its presence is associated with resistance to chemotherapy and high mortality rate