TP53 mutations identify a subgroup of AML patients with dramatically impaired outcome

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.