Figure 2

Gains of the BCR/ABL1 fusion taking the form of an ider(22)t(9;22)(q34;q11). (A) A representative metaphase cell with co-hybridization of FISH probes RP11-83J21 (3' ABL1; signal in red) and 9qter (in green) as seen in patients no 14-15, showing a duplicated fusion signal on the isoderivative 22 (block arrow) and a third fusion signal at 9q34 of the unrearranged homologue of chromosome 9. Top right, close-up of the ider(22) DAPI banding. (B) A representative metaphase cell from patient no 13 with co-hybridization of FISH probes RP11-83J21 (in green) and RP11-323H21 (5'RAPGEF1; in red) showing a duplicated fusion signal on the isoderivative 22 (block arrow). A deletion of the homologue of chromosome 9 not involved in the t(9;22) is detected by the hybridization of only the red signal from RP11-323H21. (C) A representative metaphase cell from patient no 16 with co-hybridization of FISH probes RP11-83J21 (in green) and RP11-323H21 (in red) showing the presence of four fusion signals on two isoderivative 22 chromosomes (block arrows) and a fifth fusion signal on the normal homologue of chromosome 9. (D) A representative metaphase cell in patient no 17 with co-hybridization of FISH probes RP11-544A12 (NUP214; in green) and 9qter (in red), showing a normal 9 homologue and unmasking a cryptic translocation between the ider(22) (block arrow) and a marker chromosome (dashed arrow).