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The isocitrate dehydrogenase (IDH1/IDH2) genes are frequently mutated and reported to associate with poor prognosis in acute myeloid leukemia (AML). We have investigated the frequency and outcome of the acquired IDH1/IDH2 mutations and the IDH1 SNP 105C>T (rs11554137) in 207 unselected de novo AML patients. IDH1 codon 132 mutations were present in 7.7%, whereas IDH2 mutations were more frequent and mutations were identified in codon 140 and 172 in a frequency of 10.1% and 2.9%, respectively. The SNP 105C>T was present in 10.1% of the patients, similar to the normal population. A significantly reduced overall survival (OS) for patients carrying IDH2 codon 140 mutation compared with patients carrying wild-type IDH2 gene (p=0.009) was observed in the intermediate risk patient group with cytogenetically normal karyotype (CN-AML). Neither in the entire patient group nor subdivided in different risk groups, IDH1 mutations had any significance on OS compared to the wild-type IDH1 patients. A significant difference in OS between the heterozygous SNP variant and the homozygous wild-type was observed in the intermediate risk FLT3 negative CN-AML, (p=0.007). Our results indicate that IDH2 mutations and the IDH1 SNP 105C>T variant may represent a new subgroup for risk stratification and may indicate new treatment options.

TP53 is commonly mutated in several cancers and confers treatment resistance and poor prognosis. Altered expression of MDM2 (mouse double minute 2), a negative regulator of p53, may also attenuate normal p53 signaling, thereby enhancing tumor transformation and resistance to apoptosis. The single nucleotide polymorphism (SNP) 309 has been reported to increase MDM2 expression and impair normal p53 response. We investigated the frequency and impact of TP53 mutations (TP53mut) and MDM2SNP309 on treatment outcome and overall survival (OS) in 207 Swedish AML patients. We found a high frequency (22%) of TP53mut in patients with cytogenetic aberrations, with strong association to high risk cytogenetics (p<0.001). TP53mut patients had lower response rates compared to TP53 wild-type (wt) patients (22% and 76% CR, respectively, p<0.001) and reduced OS (5 and 21 months, respectively, p<0.001). In TP53wt patients with abnormal karyotype, the MDM2SNP309 conferred an impaired outcome, with patients carrying the alternative G allele having shorter OS compared to T/T patients (13 and 29 months, p=0.031). In conclusion, our results show that TP53mut analysis as well as MDM2SNP309 genotyping may be useful tools for prognostication, risk stratification and selection of patients most likely to benefit from new drugs targeting the p53 signaling pathway.