210 BAALC-associated miR-3151 is an Independent Prognostic Factor in Young Patients With Intermediate- Risk Cytogenetic Acute Myeloid Leukemia M. Díaz-Beyá, 1,2 A. Navarro, 3 M. Pratcorona, 1 S. Brunet, 4,2 J. Nomdedéu, 4,2 J.M. Ribera, 5,2 M. Tormo, 6 R. Duarte, 7 O. Salamero, 8 D. Gallardo, 9 L. Escoda, 10 M. Nomdedeu, 1 R.M. Risueño, 2 F. Cervantes, 1 J. Sierra, 4,2 M. Monzó, 3 J. Esteve 1 1 Hematology Department, Hospital Clínic; 2 Josep Carreras Leukaemia Research Institute; 3 Molecular Oncology and Embryology Laboratory, Human Anatomy Unit, School of Medicine, University of Barcelona; 4 Hematology Department Hospital de Sant Pau, Barce- lona; 5 Hematology Department Institut Català d’Oncologia (ICO)- Hospital Germans Trias i Pujol, Badalona; 6 Hematology Department, Hospital Clínico, Valencia; 7 Instituto catalán de oncología (ICO), He- matology Department, Hospital Duran i Reynals, l’Hospitalet de Llo- bregat; 8 Hematology Department, Hospital Vall d’Hebron, Barcelona; 9 Hematology Department, ICO-Josep Trueta, Girona; 10 Hematology Department, Hospital Joan XXIII, Tarragona Introduction: Recently, a new microRNA localized in intron 1 of the BAALC gene, namely miR-3151, has been described. It has been found that miR-3151 expression either alone or in combina- tion with BAALC independently correlates with poor prognosis in patients  60 years with cytogenetic normal AML (CN-AML). Patients with intermediate-risk cytogenetic AML (IR-AML) have a heterogeneous prognosis and are stratified based on molecular markers. However, the optimal therapy, especially in younger pa- tients, is uncertain. Since the prognostic value of miR-3151 in younger patients (60 years) with IR-AML has not been evaluated, we hypothesized that miR-3151 expression could be helpful to prognosticate patients with IR-AML. Aim: To analyze whether miR-3151 expression either alone or in combination with BAALC improved prognostic assessment in younger patients with IR-AML and to characterize the microRNA signature associated with high miR-3151expression. Methods: In the training set, we analyzed samples from 76 patients with IR-AML from a single center who received intensive therapy. The validation series was composed by 108 patients treated intensively within the CETLAM AML-2003 protocol. In both series information on NMP1, FLT3-ITD and CEBPA was available. Expression analysis of miR-3151 and BAALC were performed using TaqMan Ò MicroRNA Assay and TaqMan Ò Gene Expression Assay (Applied Biosystems), respectively. Statisti- cal analysis was performed with SPSS v.15.0.1, R software v.2.9.0 and TIGR MultiExperiment Viewer v4.0. Results: In the training set higher expression of miR-3151 correlated with a shorter 5 year- overall survival (OS) (32%17% vs. 6117%, p¼0.029) and 5 year-leukemia-free survival (LFS) (29%17% vs. 5817%, p¼0.036) in patients  60 yrs. When the analysis was restricted to patients with CN, miR-3151expression retained its prognostic sig- nificance (p¼ 0.016). Moreover, increased BAALC expression conveyed shorter OS (28%20% vs. 5814%, p¼0.054) and LFS (17%18% vs. 5514%, p¼0.039). We also investigated patients’ outcome according to the expression of both miR-3151 and BAALC. Patients with low expression of both miR-3151 and BAALC were identified as a favorable subgroup with better prog- nosis (OS: 66%18% vs. 3416%, p¼0.027; LFS: 67%20% vs. 2716%, p¼0.009). Interestingly, the combination of both miR- 3151 and BAALC retained its prognostic value in the favorable molecular subgroup defined as NPMmut without FLT3-ITD or biallelic CEBPAmut (LFS: 44%30% vs. 100%, p¼0.017) while a trend was observed in the unfavorable molecular subgroup (OS: p¼0.064 and LFS: p¼0.072). In the multivariate analysis for OS including NPMmut, FLT3-ITD, age, WBC, BAALC and miR-3151 expression levels as covariates, besides age, WBC, and FLT3-ITD, miR-3151 showed prognostic significance (p ¼ 0.016; HR ¼ 2.52, 95% IC: 1.2-5.4). Finally, a supervised analysis revealed a distinc- tive miRNA signature including miR-509, miR-135a, miR-100*, miR-186*, let-7a* and miR-501. Importantly, in the validation series miR-3151 overexpression confirmed its prognostic impact in the univariate analysis for OS (45%12% vs. 2619%, p ¼ 0.039) and LFS (51%14% vs. 3024%, p¼0.034) and in the multivariate analysis for OS (OS: p ¼ 0.038; HR 1.88, IC 95%: Abstracts S122 - Clinical Lymphoma, Myeloma & Leukemia September 2014