Complex rearrangement in chronic myeloid leukemia

Sequential g-band (top) and FISH (bottom) images of metaphase chromosomes from a complex variant Philadelphia rearrangement without the typical Philadelphia chromosome. The FISH probe is a dual-color combination of probes that span the ABL (green) and BCR (red) breakpoint regions. Juxtaposition of the ABL and BCR signals on the derivative chromosome 22 results in a yellow fusion signal. This complex rearrangement involves submicroscopic insertion of most of the ABL gene into chromosome 22.