Karyotype and age in acute myeloid leukemia. Are they linked?

A novel hierarchical cytogenetic classification for acute myeloid leukemia (AML) has been developed. Patients with successful cytogenetics and a diagn osis of AML were categorized into four mutually exclusive karyotype groups: normal, translocation, deletion and trisomy. Patients with more than one c hromosomal abnormality were classified using the hierarchy: established tra nslocation > established deletion > established trisomy > non-established t ranslocation > non-established deletion > non-established trisomy. A total of 593 AML patients from a large population-based case-control study of acu te leukemia were classified according to their diagnostic karyotype. Thc fo ur karyotype groups showed different age distributions. Overall the frequen cy of patients increased with age as did the frequency of patients with a d eletion, trisomy or normal karyotype. Although the increase of patients wit h age was much sharper for patients with a deletion. In contrast, the distr ibution of patients with a translocation was roughly constant with age. We concluded that there was a link between karyotype and the age of the patien t at diagnosis. Furthermore, two karyotype groups, translocations and delet ions, may define disease entities with different etiologies. This novel cyt ogenetic classification will allow other studies to examine whether AML cas es with very different types of chromosomal abnormality have the same etiol ogy. (C) 2001 Elsevier Science Inc. All rights reserved.