Translocation of c-abl to "masked" Ph in chronic myeloid leukemia.

In two patients with chronic myeloid leukemia (CML), the nature of the chromosomal rearrangement giving rise to "masked" Ph has been studied by in situ hybridization of human c-abl sequences. The c-abl probes hybridized to the 22q11 region of the "masked" Ph, demonstrating that translocation of sequences from 9q34 to the Ph did occur exactly as in standard Ph or in other types of variants previously studied. These results provide additional evidence for the occurrence of a constant molecular rearrangement in Ph-positive CML.