Spectral karyotyping study of chromosome abnormalities in human leukemia

Chromosomal analysis plays an important role in the diagnosis, treatment ac id prognosis of human leukemia. Currently, the GTG-banding technique (G-ban ding) is the most commonly used diagnostic method in clinical cytogenetics. G-banding analysis of subtle chromosomal rearrangements or complex karyoty pes with multiple markers can be inadequate because of poor chromosome morp hology and/or an insufficient yield of analyzable metaphases. Fluorescence in situ hybridization (FISH) is a highly sensitive and specific method to d etect chromosomal alterations. Conventional FISH is used optimally in insta nces where only one or a few abnormalities are investigated. Spectral karyo typing (SKY), a novel cytogenetic technique, has been developed to unambigu ously display and identify all chromosomes at one time using a spectrum of 24 different colors. This report presents the use of SKY for examination of the entire karyotype in specimens with complex chromosomal abnormalities f rom three leukemia patients. Conventional cytogenetic analysis (G-banding) showed complex hyperdiploid clones with multiple markers in each case. SKY was able to clarify and identify additional cryptic chromosomal translocati ons [e.g.. t(2;10), t(3;10), t(5:7): t(7,18), t(9:17), t(10:12), t(13;16)] insertions [e.g., ins(17,9), ins(20,Y)], duplications [e.g., i(8)(q10). dup (4)(q31q35)] and marker chromosomes in each case, This study demonstrates t hat the combination of SKY and G-band techniques results in a more complete characterization of the complex chromosomal aberrations seen in leukemia. (C) 2001 Elsevier Science Inc. All rights reserved.