Karyotype abnormalities and their clinical significance in blast crisis of chronic myeloid leukemia.

We examined karyotypes and their prognostic significance in a series of 122 patients with chronic myeloid leukemia in blast crisis. Of 73 patients cytogenetically examined at the onset of blast crisis 63% had developed secondary cytogenetic abnormalities in addition to the Philadelphia chromosome. These newly emerging abnormalities included a double Philadelphia chromosome in 20 patients, a trisomy 8 in 17, and an isochromosome 17q in 11 patients. Development of such additional karyotypic abnormalities was significantly associated with a shorter median survival and less response to cytoreductive treatment and was significantly more common in nonlymphoid blast crisis than in the lymphoid-type blast crisis. Thus, assessment of karyotypes at the onset of chronic myeloid leukemia blast crisis appears to be of prognostic significance for both remission duration and survival.