Abstract 4906: TP53 mutations are mutually exclusive with FLT3 and NPM mutations in AML patients and are strongly associated with complex karyotype and poor outcome

Abstract

Abstract AML is a heterogeneous disease with a variety of structural and numerical chromosomal and genetic alterations that provided important prognostic information capable to guide therapy and predict outcome. The reported TP53 mutation rate in AML is low (2.1%). By contrast, the incidence of FLT3 disruption is frequent (20-30%) and is an independent predictor of unfavourable outcome of acquired clinical resistance to FLT3 inhibitors. TP53 mutations in AML with a complex karyotype (CK) is higher (69-78%), but few data are available for association between the most common AML associated lesions such as FLT3, NPM1, DNMT3A, IDH2 and TP53 mutation or CK. Aims: To investigate the frequency, the types of mutations, the associated cytogenetic, the molecular abnormalities, the correlation with known molecular alterations (FLT3, NPM, etc.) and the prognostic role TP53 mutations in adult AML pts. Patients and Methods: 886 AML patients were analysed for cytogenetic and for a panel of genetic alterations (FLT3, NPM, WT1, DNMT3A, IDH1-2 etc). Of these, 200 adult AML pts were also examined for TP53 mutations using several methods, including Sanger sequencing, NGS and HiSeq 2000 platform (38/200) and were correlated with cytogenetic analysis. Results: 55 pts (27.5%) showed 3 or more chromosome abnormalities (CK-AML), 83 (41.5%) presented one or two cytogenetic abnormalities (other-AML) and 43 pts (21.5%) have normal karyotype (nK). In 19 cases the karyotype was not available. Sanger sequencing analysis detected TP53 mutations on 29 patients with 36 different types of mutations (32 deleterious point mutations; 4 deletions); seven pts (4%) have 2 mutations. Mostly (23/29) of the TP53 mutated pts (79.3%) had CK while only 6/29 (21%) mutated pts have “no CK”. Overall, between pts with CK, TP53 frequency is 41.8% (P>0,0001). 120 pts were analysed for concomitant presence of TP53 mutations and FLT3/NPM1 disruption/mutation: revealing a significant relation between pts with FLT3-ITD or NPM1 and TP53 wild-type (p = 0.043 and 0.022 respectively). As for clinical outcome alterations of TP53 were significantly associated with poor outcome (OS and EFS p<0.0001). The very worsened outcome of TP53 mutations overcome the negative prognostic role of FLT3 mutations (P0.0001). WES analysis done in 38 pts (33 TP53 wt and 5 pts TP53 mutated) revealed no genes exclusively mutated in the 5 TP53 mutated pts. Conclusions: Our data demonstrated that TP53 mutations occur in 14.5% of AML with a higher frequency in the subgroup of CK-AML (p<0.0001) and are mutually exclusive with FLT3 and/or NPM1; they predicted to be deleterious and significantly correlated with worse prognosis and may confer resistance to conventional and innovative therapy. For these reasons, TP53 mutation screening should be recommended at least in CK-AML pts. ELN, AIL, AIRC, PRIN, 2010-12 L. Bolondi, FP7 NGS-PTL project. Citation Format: Anna Ferrari, Cristina Papayannidis, Elisa Zuffa, Carmen Baldazzi, Antonella Padella, Eugenia Franchini, Ilaria Iacobucci, Stefania Paolini, Viviana Guadagnuolo, Margherita Perricone, Valentina Robustelli, Claudia Venturi, Maria Chiara Abbenante, Sarah Parisi, Chiara Sartor, Francesca Volpato, Federica Cattina, Giorgia Simonetti, Maria Chiara Fontana, Maria Teresa Bochicchio, Federica Frabetti, Elisa Lani, Katia Mancuso, Beatrice Zannetti, Simona Luatti, Emanuela Ottaviani, Nicoletta Testoni, Giovanni Martinelli. TP53 mutations are mutually exclusive with FLT3 and NPM mutations in AML patients and are strongly associated with complex karyotype and poor outcome. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4906. doi:10.1158/1538-7445.AM2015-4906