FISH analysis of an AML-M5a with segmental rearrangements involving 11q23-MLL region

A 66-year-old man was diagnosed 10 years ago with thrombocytosis and treate d with hydroxyurea. Recently: his condition deteriorated and he rr as found to have 68% blasts in the blood and AML-M5a, Conventional cytogenetic anal ysis and fluorescence in situ hybridization studies using 11-painting and A LL probes showed that chromosome 11 had duplications or triplications; the markers were also derived from the chromosome 11-MLL region. Therefore, we have demonstrated segmental rearrangement of chromosome II involving the ML L region resulting in multiple copies of the MLL gene. (C) Elsevier Science Inc., 2000. All rights reserved.