IDENTIFICATION OF CHROMOSOMAL REARRANGEMENTS IN THE HUMAN MYELOID-LEUKEMIA CELL-LINE GF-D8 BY DUAL-COLOR FLUORESCENCE IN-SITU HYBRIDIZATION

Fluorescence In Situ Hybridization (FISH) studies with chromosome-spec ific libraries and repetitive probes were performed on the human acute myeloid leukemia cell line GF-D8 in order to define the complex chrom osomal rearrangements observed by conventional cytogenetic analysis. T wo-colour FISH with whole chromosome painting probes 8 and 11 showed t hat the add(8) chromosome had an 8-derived region inserted at q24, whe reas the add(11) chromosome had an 8-derived region translocated onto q23. It also demonstrated that no normal chromosome 11 is present in G F-D8 cells, since a translocation involving chromosomes 11 and 17q was detected in addition to the add(11). The der(7) chromosome with extra material in its long arm, identified by QFQ and GTG banding, turned o ut to have a chromosome 15-derived segment translocated to q22. The de letion of 7q was proved to be interstitial, as the 7q-specific telomer e as well as a tiny 7-specific band were observed on an unknown chromo some. Fine mapping of the breakpoints involved in the multiple chromos omal rearrangements of the GF-D8 cell line might provide insights into the mechanisms of myeloid leukaemogenesis.