CLONAL ORIGIN OF PHILADELPHIA-CHROMOSOME NEGATIVE CELLS WITH TRISOMY-8 APPEARING DURING THE COURSE OF ALPHA-INTERFERON THERAPY FOR PH POSITIVE CHRONIC MYELOCYTIC-LEUKEMIA

The transient appearance of a Philadelphia chromosome (Ph) negative cl one with trisomy 8 was found in the bone marrow cells from a patient w ith Ph positive CML during the course of alpha-interferon (IFN) therap y. To determine whether this clone was derived from a Ph positive clon e or from some other cell lineage, we performed molecular cytogenetic studies on bone marrow cells from the patient by fluorescence in situ hybridization (FISH). No fusion of BCR-ABL could be detected in cells with trisomy 8, clearly indicating that the Ph negative trisomy 8 clon e was not derived from the Ph positive CML population.