Figure 4

Gains of BCR/ABL1 fusion and a 1.09 Mb region from 9q34 in the cell line KU812. (A) Two representative metaphase cells hybridized with a BCR/ABL1 dual colour, dual fusion FISH probe (D-FISH probe; Vysis) showing the primary clone (80% of cells) with an extra Ph chromosome and a secondary clone (20% of cells) with one Ph and and a marker chromosome with tandem duplications of the BCR/ABL1 fusion (block arrow). (B) Ideograms showing the hybridization signal pattern of the BCR/ABL1 D-FISH probe on the primary (top) and secondary (bottom) clones. There are no normal copies of neither chromosome 9 nor chromosome 22. (C) Representative metaphase cell from the secondary clone with co-hybridization of RP11-40A7 (signal in red) and RP11-323H21 (5' RAPGEF1; in green) showing one fusion signal on a Ph chromosome and tandem duplications of the fusion signal on a marker chromosome (block arrow). Top right, ideogram showing the FISH signal pattern obtained with these probes. Bottom, a close-up of the DAPI banding of the marker chromosome harbouring the tandem duplications. (D) Close-up of a representative metaphase co-hybridized with RP11-544A12 (in green) and RP11-81P5 (in red) showing just one signal from the latter on the marker chromosome (block arrow). An ideogram with the hybridization signal patterns of the two probes is shown on the right. The distal breakpoint of the 9q34 amplicon falls between RP11-323H21 and RP11-81P5 and is estimated to measure approx. 1.09 Mb. Sequences downstream of the distal breakpoint of the 9q34 amplicon also hybridized on the marker chromosome but were not amplified. (E) Close-up and ideogram of the amplified marker with co-hybridization of 9q and 22q sub-telomeric probes (in red and green, respectively).