9;22;15 complex translocation in Ph1 chromosome positive CML revealed by Giemsa-11 procedure in apparent lymphoid cells of blastic crisis.

A Ph1 chromosome positive chronic myeloid leukemia patient whose chronic phase lasted 7.5 years experienced a blastic transformation originating in the spleen. The spleen was infiltrated with undifferentiated blast cells that on cytogenetic analysis had a hyperdiploid karyotype and were Ph1 chromosome positive. The blast cells were negative for PAS, peroxidase. Sudan black and esterase stains. They were non-T, non-B with TdT activity. Remission was achieved in response to prednisone, vincristine, and adriamycin. Ph1 positive cells were present with cells responding to PHA stimulation throughout the course of the disease. A Giemsa-11 staining procedure male possible the ascertainment of a No. 9 translocation chromosome in blastic crisis cells that had also been present in Ph1 chromosome positive cells early in the disease. The presence of this translocation initially in myeloid cells and subsequently in apparent lymphoid cell types suggests the origin of this patient's leukemia as a pluripotential stem cell.