A Philadelphia chromosome positive CML patient with a unique translocation studied via GTG-banding and fluorescence in situ hybridization.

The Philadelphia (Ph) chromosome was the first consistently occurring chromosome abnormality associated with a single cancer type, chronic myelogenous leukemia (CML). This translocation has since been reported with other chromosome abnormalities. The present report describes a case of Ph chromosome positive CML with a unique complex translocation identified using molecular cytogenetics in addition to routine techniques. GTG-banding revealed abnormalities in at least chromosomes 9, 13, 17, and 22. Fluorescence in situ hybridization (FISH) studies were performed as an adjunct to conventional cytogenetic analyses. Using FISH with the Oncor bcr/abl probe, the Ph translocation previously hypothesized was confirmed. Applying FISH with paired painting probes in various combinations, a complex translocation involving chromosomes 9, 13, 15, 17, and 22 was observed. The results of the GTG-banding and FISH studies were compared with each other and correlated with those of the hematological findings. In an extensive search of the medical literature database (Medline, Health, Cancerlit, Ovid, and CINAHL) spanning nearly three decades (1965-1994), we found no previous report of this specific translocation. Therefore, to the best of our knowledge, this is a unique translocation associated with Ph chromosome positive CML.