TP53 mutations and MDM2(SNP309) identify subgroups of AML patients with impaired outcome.

BackgroundTP53 is commonly mutated in several cancers and confers treatment resistance and poor prognosis. Altered expression of mouse double minute 2 (MDM2), 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. Experimental designWe investigated the frequency and impact of TP53 mutations (TP53mut) and MDM2(SNP309) on treatment outcome and overall survival (OS) in 189 Swedish acute myeloid leukemia patients. The genetic analyses were performed using SSCA and direct sequencing (for mutations in exon 5-8 of TP53) and Pyrosequencing (for the MDM2(SNP309)). ResultsWe found a high frequency (22%) of TP53mut in patients with cytogenetic aberrations, with association to high-risk cytogenetics (P<0.001). TP53mut patients had lower response rates (22% compared with 76% CR in TP53 wild-type (wt) patients, P<0.001) and reduced OS (2 and 16months, respectively, P<0.001). In TP53wt patients with high or intermediate risk cytogenetic aberrations, the MDM2(SNP309) conferred an impaired outcome, with patients carrying the alternative G-allele having shorter OS compared with T/T patients (median 9 vs. 50months, P=0.020). ConclusionsOur results show that TP53mut analysis and MDM2(SNP309) 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.