Cytogenetic abnormalities in acute leukemia complicating melphalan-treated multiple myeloma

The cytogenetic findings in 11 patients with multiple myeloma in whom a myelodysplastic syndrome or an acute nonlymphocytic leukemia developed are reported. All patients were treated with oral melphalan for 2-9 years in a total dose of 0.5-4.1 g. When examined during the myelodysplastic or leukemic phase, all patients had an abnormal bone marrow karyotype, hypodiploid in nine of the 11 cases. The chromosome abnormalities were clearly nonrandom and comprised a 5q deletion in three cases, monosomy 5 in four cases, deletion 7q--in two cases, and monosomy 7 in three cases. Loss of material from the long arm of chromosomes 5, 7, or both was found in eight patients. The different chromosome abnormalities were not associated with any specific morphological or clinical features.