FISH analysis of patient no. 35 after 11 months on imatinib.

(A) Metaphase and (B) interphase preparations were hybridized with anAML1-ETO translocation probe. The 3 green signals (white arrows) correspond to chromosome 21q22 and indicate a break in this region in one chromosome 21; the 2 red signals correspond to the normal chromosome 8p22. (C) Metaphases were hybridized with a chromosome 3 paint (large green signals) and a locus-specific probe corresponding to chromosome 21q22.13-q22.2 (small red signals). There is colocalization of both probes (yellow arrows). Note the additional green signal corresponding to the translocated part of chromosome 3 (white arrow).