FISH analysis of t(9;22) with deletion.

R = red signal; G = green signal; F = fusion color signal (red/green or yellow). (A) Expected D-FISH signal pattern in Ph⁺ interphase, 1R1G2F. (B) Atypical D-FISH signal in Ph⁺ interphase with deletions, 1R1G1F. (C) Expected D-FISH signal pattern in Ph⁺ metaphase, 1R1G2F. (D) Atypical D-FISH signal in Ph⁺ metaphase with deletions, 1R1G1F. Colocalization of red and green signals (ABL and BCR) identified the Ph chromosome. A single red signal was seen on the normal chromosome 22 homologue and a single green signal on normal chromosome 9. (E,F) Sequential G-banding and D-FISH analysis of a Ph⁺ metaphase with deletions of 5′ ABL and 3′ BCR sequences and corresponding loss of the second fusion second signal on the derivative chromosome 9.