Undetected Chromosome Abnormalities in Leukemia: A Cautionary Note

Abstract
To the Editor: We and others have demonstrated that in patients in whom acute nonlymphocytic leukemia develops after cytotoxic therapy for a primary neoplasm (often malignant lymphoma), an aneuploid clone is frequently present in their leukemic cells.1 2 3 Most commonly, the abnormality is a loss of part or all of Chromosomes 5 or 7 or both.1 , 2 Of 33 patients with secondary leukemia whose chromosomes we analyzed, only three appeared to have a normal karyotype in the first sample that we received; two of these patients were in the leukemic phase and the third was in the preleukemic phase. Our findings in . . .