The clinical outcome of acute myelold leukemia (AML) is extremely variable, ranging from survival of a few days to cure [1-3]. In the recent years, different biological features at presentation have been reported as useful for the prediction of clinical outcome; in particular, nonrandom clonal chromosome aberrations, which are detectable in the leukemic cells of approximately 50% of adult AML patients, are not only diagnostic markers for specific AML subtypes but also provide prognostic Information for achievement of complete remission (CR), relapse risk, and survival [4-7]. Accordingly, pretreatment cytogenetics represent part of the routine diagnostics in patients with AML and the new World Health Organization classification of hematologic malignancies takes Into account specific chromosome aberrations and their molecular counterparts together with morphology, Immunophenotype, and clinical features [8]. Despite continuous Improvements In cytogenetic methodology, microscopically detectable chromosome abnormalities are not found in approximately 50% of AML patients and patients with normal karyotype are usually classified in the Intermediate-risk prognostic category [9,10]; In this AML patient subset, the clinical outcome Is very heterogeneous and 5-year survival rates vary between 25% and 45% in different studies. As a consequence, It is of utmost Importance to discriminate within this AML subgroup subjects with different prognostic characteristics at diagnosis [11-14].