Unusual clonal evolution in a case of chronic myelogenous leukemia

Several unusual cytogenetic changes have occurred during the evolution of chronic myelogenous leukemia in a 32-year-old white male with this disease for 8 years. The first appearance of a hypodiploid cell line containing a dicentric marker occurred 2 years after diagnosis and this line was eliminated by several courses of therapy with hydroxyurea. A second clone, which had a partial deletion of the long arm of one of the number 8 chromosomes (8q-) was noted a year later, but this line has been refractory to intensive combination chemotherapy.