Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 9 1 2015 03 15 33 49 Najmaldin Saki Department of Hematology and Blood Banking, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Saeid Abroun Department of Hematology and Blood Banking, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Masoud Soleimani Department of Hematology and Blood Banking, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Saeideh Hajizamani Health research institute, Research Center of Thalassemia & Hemoglobinopathy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Mohammad Shahjahani Department of Hematology and Blood Banking, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Richard E Kast IIAIGC Headquarters, Dean of Studies, Burlington, VT, USA. Yousef Mortazavi Department of Pathology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran. 2015 10 14 MicroRNAs are 19-22 nucleotide RNAs involved in such important processes as development, proliferation, differentiation and apoptosis. Different miRNAs are uniquely expressed in lymphoid T cells, and play a role indevelopment and differentiation of various subtypes by targeting their target genes. Recent studies have shown that aberrant miRNA expression may be involved in T cell leukemogenesis and lymphogenesis, and may function as tumor suppressor (such as miR-451, miR-31, miR-150, and miR-29a) or oncogene (e.g. miR-222, miR-223, miR-17-92, miR-155). MiRNAs can be used as new biomarkers for prognosis and diagnosis or as an index of disease severity in T-cell leukemia and lymphoma. This article presents a review of studies in recent years on the role of miRNAs in T-cell development and their aberrant expression in pathogenesis of T-cell leukemia and lymphoma. Characterizing miRNAs can help recognize their role as new important molecules with prognostic and therapeutic applications. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/396 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/396/401