7023 Background: Acute myeloid leukemia (AML) is a heterogeneous disease with various chromosomal aberrations. The karyotype at diagnosis provides important prognostic information that influences therapy and outcome of this disease. However, using conventional chromosome banding techniques alone, karyotype abnormalities are detected in only half of all AML cases. We performed a genome-wide, single-nucleotide polymorphism (SNP) analysis in order (i) to identify novel genomic regions of interest in normal karyotype AML; (ii) novel candidate regions and disease-related genes, in patients with complex karyotypes. Methods: 20 AML patients were analyzed until now. Cases included FAB-M0, M1, M2, M4, M5, miscellaneous cytogenetic abnormalities and normal karyotype. 250 ng of genomic DNA were processed on 500K SNP array according to protocols provided by the manufacturer. Copy number state was calculated with respect to a set of 48 Hapmap normal individuals and a set of samples obtained from acute leukaemia cases in remission using Partek Genomics Suite. Results: An enormous spectrum of different genetic lesions (gains/losses) involving complete chromosome arms (del 16q, i(13q10), del 3p, del 7p, monosomy 9) or submicroscopic genomic intervals were identified in a substantial proportion of cases without differences in the frequency of losses or gains. The most frequent genomic gains affected: 9p12 (ZNF658B, FOXD4L2), 10q11.2 (PPYR1), 5q31-q33 (CDX1) and 8p23.2 (CSMD1). The most frequent deletions were identified in regions lacking annotated genes. Other recurring genetic lesions were uncommon. Marked differences in the combination of copy number anomalies were identified across the different genetic subtypes of AML. Some lesions affected regions with a single gene, such as: ETAA1, FIGN, STK32B, PRAGMIN, PCM1, GLIS3, MRGPRX1, SESN3, BCL2L14. Conclusions: Different genetic anomalies were identified by using an SNP-based chip array. Genetic abnormalities are associated with disease subtype. Supported by: European LeukemiaNet, AIL, AIRC, FIRB 2006, Fondazione del Monte di Bologna e Ravenna, PIO project 2007, Strategico di Ateneo. No significant financial relationships to disclose.