Incidence of chromosome abnormalities and clinical significance of karyotype in de novo acute myeloid leukemia

Cytogenetic studies with high-resolution banding were performed on specimens from 132 consecutive patients with de novo acute myeloid leukemia (AML). All patients were treated according to therapeutic protocols in the same institution. Clonal abnormalities were detected in 97 of the 124 patients in whom an adequate number of mitoses was obtained (78.2%). Neither sex, FAB classification, WBC, or the extent of bone marrow infiltrate affected the rate of chromosomal aberrations, whereas patients younger than 40 years had a greater proportion of normal karyotypes (p = 0.047). Two different chromosomal classifications were evaluated: the presence of normal and abnormal metaphases (NN-AN-AA classification), and a classification in cytogenetic categories, the latter being based on the frequency of cytogenetic abnormalities. Both classifications were found to correlate significantly with the clinical outcome. They also showed independent prognostic significance when age, sex, and FAB morphology were considered in a multivariate analysis. Two abnormalities were closely associated with specific clinical-pathologic subsets of AML. All the 15 patients with t(15;17) had acute promyelocytic leukemia; this translocation was not found in any other subset of AML. Eight of the nine patients presenting rearrangements at 11q23 belonged to a FAB subset with monocytic differentiation (M4 and M5). Our data suggest that cytogenetic findings should influence the therapeutic approach to AML. In particular, young patients with karyotypes associated with poor responses may be considered for more eradicating treatments, including allogenic bone marrow transplantation.