Chronic myeloid leukemia with a rare variant Philadelphia translocation: t(9;22;21)(q34;q11;q22)

A case of chronic myeloid leukemia displaying an uncommon t(21;22)(q22;q11) is reported. For the first time, this translocation has been characterized by fluorescence in situ hybridization (FISH) and the reverse transcriptase polymerase chain reaction (RT-PCR). FISH, with the use of whole-chromosome painting probes and probes specific for the BCR and ABL genes, showed a three-way variant Philadelphia translocation (9;22;21)(q34;q11;q22) with a BCR/ABL fusion residing on the der(22). In addition, RT-PCR demonstrated a b2a3 BCR/ABL fusion transcript. Underlying mechanisms and prognostic implications are discussed.