MicroRNAs in acute leukemia: from biological players to clinical contributors.

MicroRNAs (miRNAs) are involved in the management of hematopoiesis. As a consequence, miRNA dysregulation causes disruption of the hematopoietic system and leukemia may arise. We here comprehensively discuss miRNAs found discriminative for cytogenetic and molecular subtypes of acute leukemia. These miRNAs are either known miRNAs involved in leukemogenesis with proven tumor suppressor or oncogenic activities or are newly identified by high-throughput sequencing with yet unknown function. Furthermore, forces are outlined that drive aberrant miRNA function, which include genetic abnormalities (for example, deletions, translocations and mutations) and epigenetic aberrations (for example, aberrant DNA methylation or histone modifications). Interestingly, leukemia-silenced miRNAs can be re-expressed upon treatment with de-methylating agents. Targeting miRNA expression may serve a therapeutical role, albeit at present this way of targeted therapy is in its infancy. However, emerging knowledge about the biology of miRNAs in leukemia may result into a role for these miRNAs in the diagnosis and treatment of acute leukemia.