http://repub.eur.nl/res/aut/36257/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/33931/ 2011-11-01T00:00:00Z Mutations in the NADP-dependent isocitrate dehydrogenase genes 1 and 2 (IDH1 and IDH2) have recently been found in adult acute myeloid leukemia (AML) patients with a prevalence rising up to 33%. To investigate the frequency of IDH1/2 mutations in pediatric AML, we characterized the mutational hotspot (exon 4) of these genes in diagnostic samples from 460 pediatric AML patients. Our analysis identified somatic IDH1/2 mutations in 4% of cases (IDH1 R132 n8; IDH2 R140 n10) and the minor allele of single-nucleotide polymorphism (SNP) rs11554137 in 47 children (10.2%). IDH mutations were associated with an intermediate age (P0.008), FAB M1/M2 (P0.013) and nucleophosmin1 mutations (P0.001). In univariate analysis, IDHmutatedcompared with IDHwildtypepatients showed a significantly improved overall survival (OS; P=0.032) but not event-free survival (EFS; P=0.14). However, multivariate analysis did not show independent prognostic significance. Children with at least one minor allele of IDH1 SNP rs11554137 had similar EFS (P=0.27) and OS (P0.62) compared with major allele patients. Gene expression profiles of 12 IDHmutatedwere compared with 201 IDHwildtypepatients to identify differentially expressed genes and pathways. Although only a small number of discriminating genes were identified, analysis revealed a deregulated tryptophan metabolism, and a significant downregulation of KYNU expression in IDH mutated cases. http://repub.eur.nl/res/pub/26391/ 2011-06-01T00:00:00Z To integrate available clinical and molecular information for cytogenetically normal acute myeloid leukemia (CN-AML) patients into one risk score, 275 CN-AML patients from multicenter treatment trials AML SHG Hannover 0199 and 0295 and 131 patients from HOVON/SAKK protocols as external controls were evaluated for mutations/polymorphisms in NPM1, FLT3, CEBPA, MLL, NRAS, IDH1/2, and WT1. Transcript levels were quantified for BAALC, ERG, EVI1, ID1, MN1, PRAME, and WT1. Integrative prognostic risk score (IPRS) was modeled in 181 patients based on age, white blood cell count, mutation status of NPM1, FLT3-ITD, CEBPA, single nucleotide polymorphism rs16754, and expression levels of BAALC, ERG, MN1, and WT1 to represent low, intermediate, and high risk of death. Complete remission (P = .005), relapse-free survival (RFS, P < .001), and overall survival (OS, P < .001) were significantly different for the 3 risk groups. In 2 independent validation cohorts of 94 and 131 patients, the IPRS predicted different OS (P < .001) and RFS (P < .001). High-risk patients with related donors had longer OS (P = .016) and RFS (P = .026) compared with patients without related donors. In contrast, intermediate-risk group patients with related donors had shorter OS (P=.003) and RFS(P=.05). Donor availability had no impact on outcome of patients in the low-risk group. Thus, the IPRS may improve consolidation treatment stratification in CN-AML patients. Study registered at www.clinicaltrials.gov as #NCT00209833.