del(15)(q11q15) associated with transformation of chronic myelomonocytic leukemia.

Nonrandom cytogenetic abnormalities have been described in a variety of human malignancies including myelodysplastic syndromes (MDS). Acquisition of new chromosomal abnormalities may herald onset of a more aggressive disease. We report a patient with chronic myelomonocytic leukemia (CMMoL) who initially had a normal karyotype, but in whom the clonal interstitial deletion of chromosome 15 (q11-q15) was coincident with development of acute myeloid leukemia (AML) one year later. To date, this chromosomal change has not been reported in CMMoL, AML, or any other human malignancy.