Cross-species color banding characterization of chromosomal rearrangementsin leukemias with incomplete G-band karyotypes

Karyotype analysis has depended on chromosome banding techniques since thei r introduction in about 1970, and the information thus obtained is indispen sable for the clinical management of patients with hematologic malignancies . Sometimes, however, chromosomal rearrangements involve segments too small , too similarly banded, or too complex to be described adequately or even t o be detected by G-banding. Cross-species color banding is a new FISH-based screening technique that enables the generation of a specific color bandin g pattern for each human chromosome based on the genomic homologies between man and various species of apes. We report the first application of cross- species color banding (RxFISH) to characterize the chromosomal rearrangemen ts of 10 leukemia samples the G-band karyotypes of which were incomplete. T he combination of G-banding and RxFISH in every case yielded additional inf ormation beyond that obtained by either technique used alone, determining t he identity of even the most complex, inter- as well as intrachromosomal, r earrangements. (C) 1999 Wiley-Liss, Inc.