Rare Cytogenetic Abnormalities and Alteration of microRNAs in Acute Myeloid Leukemia and Response to Therapy.

Acute myeloid leukemia (AML) is the most common acute leukemia in adults, which is heterogeneous in terms of morphological, cytogenetic and clinical features. Cytogenetic abnormalities, including karyotype aberrations, gene mutations and gene expression abnormalities are the most important diagnostic tools in diagnosis, classification and prognosis in acute myeloid leukemias. Based on World Health Organization (WHO) classification, acute myeloid leukemias can be divided to four groups. Due to the heterogeneous nature of AML and since most therapeutic protocols in AML are based on genetic alterations, gathering further information in the field of rare disorders as well as common cytogenetic abnormalities would be helpful in determining the prognosis and treatment in this group of diseases. Recently, the role of microRNAs (miRNAs) in both normal hematopoiesis and myeloid leukemic cell differentiation in myeloid lineage has been specified. miRNAs can be used instead of genes for AML diagnosis and classification in the future, and can also play a decisive role in the evaluation of relapse as well as response to treatment in the patients. Therefore, their use in clinical trials can affect treatment protocols and play a role in therapeutic strategies for these patients. In this review, we have examined rare cytogenetic abnormalities in different groups of acute myeloid leukemias according to WHO classification, and the role of miRNA expression in classification, diagnosis and response to treatment of these disorders has also been dealt with.