الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
Epigenetics is changing in gene expression with out changing in DNA itself. Epigenetics mechanisms achieved by adding chemical groups covalently attached to DNA and histones by the acion of three players (writers, erasers and readers) making chromatine more or less accissible to transcription machinery. Epigenetic modifications can be affected by environmental exposures, providing a link between genes and environment and offering an explanation for phenotypic differences between monozygotic twins.
Epigenetic control exerted by four types of modifications DNA methylation, Histone modification, chromatin remodeling and RNA interference.As Epigenetics regulates cellular differentiation and most of basic biological processes, epigenetic deregulation leads to a lot of medical disorders including diabetes, cancer, autoimmune and degenerative diseases.
Deregulation in epigenetic regulators like DNA methyltransferase3A (DNMT3A), ten eleven translocation (TET) enzyme and isocitrate dehyrogenase (IDH) enzyme leads to impaired hematopoietic stem cell differentiation and present an important pathway to development of hematological malignency.The reversible nature of epigenetics makes them highly attractive targets for cancer therapies.HDACi and DNMTi are the first era of epigenetic therapy and reactivate the previously suppressed tumor suppressor genes with significant clinical improvement.
Although success rate of histone deacetylating drugs and DNA demethylating drug in some blood disorders, the exact mechanism of action remains unclear .so more development in our knowledge about epigenetic mechanisms and dysregulation to provide anew classes of epigenetic drugs.
Summary
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MiRNAs provide an additional level of control beyond the transcription factors by fine-tuning differentiation, so Deregulation of miRNAs causes the cells to “play out of tune”. MiRNAs involved in the anti-neoplastic drug responses are emerging and the modulation of their expression is becoming a possible central tool to improve the efficacy of current therapeutic protocols and are described as reliable biomarkers for risk-stratification of blood malignancy.