Characterization of the human myeloid leukemia-derived cell line GF-D8 by multiplex fluorescence in situ hybridization, subtelomeric probes, and comparative genomic hybridization

The human myeloid leukemia cell line GF-D8 was established from the periphe ral blood blasts of a patient with acute myeloid leukemia FAB subtype M1 (A ML-M1). The karyotype, which has not changed significantly over several yea rs of culture, was described initially as 44,XY,-5,del(7q),inv(7q),add(8q), add(11q),del(12p),-15,-17,+ mar. With the advent of multicolor fluorescence in situ hybridilation (FISH) techniques, the prospect of accurately charac terizing this complex karyotype became feasible. In the present study, we a pplied 24-color whole-chromosome painting and analyzed the results using a filter-based detection system and proprietary software for multiplex FISH ( M-FISH). This resulted in the refinement of the karyotype and the identific ation of hitherto unsuspected chromosome rearrangements. M-FISH identified the origin of the add(8q) and add(11q) as well as the small marker chromoso me. Both the del(7q) and del(12p) were redefined as unbalanced translocatio ns and an apparently normal chromosome 11 was shown to be t(11;17). Importa ntly, the del(12p) was shown to be a der(12)t(7; 12). Single-color whole-ch romosome painting studies confirmed these findings, but also identified a c ryptic t(Y; 12) not seen in the original M-FISH analysis. We then carried o ut a FISH screening assay using a complete set of chromosome-specific subte lomeric probes, This allowed the identification of p and q subtelomeric reg ions involved in the translocations and indicated amplification of the 8q s ubtelomeric region. Comparative genomic hybridization (CGH) revealed a high ly unbalanced karyotype, as deletions accompanied the majority of transloca tions, and identified the regions of amplification as 8q22.3-qter and 11q21 -qter. Finally, conventional FISH with centromeric and unique sequence prob es was necessary to elucidate all of the rearrangements. Genes Chromosomes Cancer 24:213-221, 1999. (C) 1999 Wiley-Liss, Inc.