MicroRNA‐125b‐1 and BLID upregulation resulting from a novel IGH translocation in childhood B‐Cell precursor acute lymphoblastic leukemia

Chromosomal translocations involving the immunoglobulin heavy chain ( IGH ) locus are common abnormalities in mature B‐cell neoplasms. Recent findings have also revealed their significant role in B‐cell precursor acute lymphoblastic leukemia. As a rule, IGH translocations generate transcriptional activation of the oncogene localized in the proximity of the breakpoint. In this study, we describe a pediatric case of B‐cell precursor acute lymphoblastic leukemia showing microRNA‐125b‐1 ( MIR125B1 ) and BLID gene overexpression, resulting from a novel t(11;14)(q24.1;q32) translocation involving IGH . This is the first report describing the upregulation of a microRNA due to its juxtaposition to protein‐coding gene regulatory elements and the overexpression of two neighboring genes as a consequence of transcriptional enhancers localized in the vicinity of the IGH gene. © 2010 Wiley‐Liss, Inc.