Insertion (22;9)(q11;q34q21) in a patient with chronic myeloid leukemia characterized by fluorescence in situ hybridization

An unusual cytogenetic rearrangement described as ins(22;9)(q11;q34q21), wa s detected in a 49-year-old male patient diagnosed with chronic myeloid leu kemia (CML). Reverse transcriptase polymerase chain reaction (RT-PCR) revea led a b3a2 fusion transcript. In order to confirm the cytogenetic findings and fully characterize the inverted insertion, we performed fluorescence in situ hybridization (FISH) assays using locus-specific and whole chromosome painting probes. Our FISH analysis showed the presence of the BCR/ABL fusi on gene, verified the insertion and determined that the breakpoint on chrom osome 22 where the insertion took place was located proximal to the BCR gen e and distal to the TUPLE1 gene on 22q11. (C) 2001 Elsevier Science Inc. Al l rights reserved.