BACKGROUND:The pathogenicity of the different genetic variants causing hypertrophic cardiomyopathy (HCM) and the genotype/phenotype correlations are difficult to assess in clinical practice, as most mutations are unique or identified in non-informative families. Pathogenic variants in the sarcomeric gene MYBPC3 inherited with an autosomal dominant pattern, whereas incomplete and age-dependent penetrance are the most common causes of HCM.METHODS:We describe the clinical characteristics of a new truncating MYBPC3 variant, p.Val931Glyfs*120, in 75 subjects from 18 different families from northern Spain with the p.Val931Glyfs*120 variant.RESULTS:Our cohort allows us to estimate the penetrance and prognosis of this variant. The penetrance of the disease increases with age, whereas 50% of males in our sample developed HCM by the age of 36 years old, and 50% of women developed the disease by the time they reached 48 years of age (p = 0.104). Men have more documented arrhythmias with potential risk of sudden death (p = 0.018), requiring implantation of cardioverter defibrillators (p = 0.024). Semi-professional/competitive sport among males is related to earlier onset of HCM (p = 0.004).CONCLUSIONS:The p.Val931Glyfs*120 truncating variant in MYBPC3 is associated with a moderate phenotype of HCM, with a high penetrance, onset in middle age, and a worse outcome in males due to higher risk of sudden death due to arrhythmias.

We sought to predict treatment responses and outcomes in older patients with newly diagnosed acute myeloid leukemia (AML) from our FLUGAZA phase III clinical trial (PETHEMA group) based on mutational status, comparing azacytidine (AZA) with fludarabine plus low-dose cytarabine (FLUGA). Mutational profiling using a custom 43-gene next-generation sequencing panel revealed differences in profiles between older and younger patients, and several prognostic markers that were useful in young patients were ineffective in older patients. We examined the associations between variables and overall responses at the end of the third cycle. Patients with mutated DNMT3A or EZH2 were shown to benefit from azacytidine in the treatment-adjusted subgroup analysis. An analysis of the associations with tumor burden using variant allele frequency (VAF) quantification showed that a higher overall response was associated with an increase in TET2 VAF (odds ratio (OR), 1.014; p = 0.030) and lower TP53 VAF (OR, 0.981; p = 0.003). In the treatment-adjusted multivariate survival analyses, only the NRAS (hazard ratio (HR), 1.9, p = 0.005) and TP53 (HR, 2.6, p = 9.8 × 10−7) variants were associated with shorter overall survival (OS), whereas only mutated BCOR (HR, 3.6, p = 0.0003) was associated with a shorter relapse-free survival (RFS). Subgroup analyses of OS according to biological and genomic characteristics showed that patients with low–intermediate cytogenetic risk (HR, 1.51, p = 0.045) and mutated NRAS (HR, 3.66, p = 0.047) benefited from azacytidine therapy. In the subgroup analyses, patients with mutated TP53 (HR, 4.71, p = 0.009) showed a better RFS in the azacytidine arm. In conclusion, differential mutational profiling might anticipate the outcomes of first-line treatment choices (AZA or FLUGA) in older patients with AML. The study is registered at ClinicalTrials.gov as NCT02319135.

BCR-ABL1-like B-cell precursor acute lymphoblastic leukemia (BCP-ALL) remains poorly characterized in adults. We sought to establish the frequency and outcome of adolescent and adult BCR-ABL1-like ALL using a novel RNA-Seq signature in a series of patients with BCP-ALL. To this end, we developed and tested an RNA-Seq custom panel of 42 genes related to a BCR-ABL1-like signature in a cohort of 100 patients with BCP-ALL and treated with risk-adapted ALL trials. Mutations related to BCR-ABL1-like ALL were studied in a panel of 33 genes by next-generation sequencing (NGS). Also, CRLF2 overexpression and IKZF1/CDKN2A/B deletions were analyzed. Twenty out of 79 patients (12–84 years) were classified as BCR-ABL1-like (25%) based on heatmap clustering, with significant overexpression of ENAM, IGJ, and CRLF2 (P ≤ 0.001). The BCR-ABL1-like subgroup accounted for 29% of 15–60-year-old patients, with the following molecular characteristics: CRLF2 overexpression (75% of cases), IKZF1 deletions (64%), CDKN2A/B deletions (57%), and JAK2 mutations (57%). Among patients with postinduction negative minimal residual disease, those with the BCR-ABL1-like ALL signature had a higher rate of relapse and lower complete response duration than non-BCR-ABL1-like patients (P = 0.007). Thus, we have identified a new molecular signature of BCR-ABL1-like ALL that correlates with adverse prognosis in adult patients with ALL.

Nearly 50% of patients with de novo acute myeloid leukemia (AML) harbor an apparently normal karyotype (NK) by conventional cytogenetic techniques showing a very heterogeneous prognosis. This could be related to the presence of cryptic cytogenetic abnormalities (CCA) not detectable by conventional methods. The study of copy number alterations (CNA) and loss of heterozygozity (LOH) in hematological malignancies is possible using a high resolution SNP-array. Recently, in clinical practice the karyotype study has been complemented with the identification of point mutations in an increasing number of genes. We analyzed 252 de novo NK-AML patients from Hospital La Fe (n = 44) and from previously reported cohorts (n = 208) to identify CCA by SNP-array, and to integrate the analysis of CCA with molecular alterations detected by Next-Generation-sequencing. CCA were detected in 58% of patients. In addition, 49% of them harbored CNA or LOH and point mutations, simultaneously. Patients were grouped in 3 sets by their abnormalities: patients carrying several CCA simultaneously, patients with mutations in FLT3, NPM1 and/or DNMT3A and patients with an amalgam of mutations. We found a negative correlation between the number of CCA and the outcome of the patients. This study outlines that CCA are present in up to 50% of NK-AML patients and have a negative impact on the outcome. CCA may contribute to the heterogeneous prognosis.

Follicular lymphoma (FL) is considered an indolent disorder with a relatively favourable course. With modern day treatments, long remissions are often achieved both in front-line and relapsed settings. However, a subset of patients has a more aggressive course and a poorer outcome. Both, PET-CT and minimal residual disease (MRD) evaluation by PCR defines groups of patients with different prognoses. MRD measurement by NGS is being studied to predict relapse prior to diagnostic imaging in large B cell lymphoma; however, it has never been used in FL. The aim of the present study is to validate a sensitive and standardizable approach to measure liquid Biopsy MRD (LiqBio-MRD) by NGS with >90% applicability and 2E-4 resolution, and to analyse its prognostic impact in FL patients. Firstly, the best source to identify genetic MRD markers was determined. Genomic DNA from paraffin embedded (FFPE) lymph node biopsies and/or cell free DNA (cfDNA) from peripheral blood (PB) was obtained from 29 FL cases at diagnosis and sequenced with a short length Ampliseq Custom Panel (Thermo-Fisher). This panel was designed to cover all coding regions of 56 lymphoma specific genes in FFPE and cfDNA samples. By applying this panel with an average depth of 700X, a total of 122 somatic mutations were detected in 37 baseline samples. 15 of these lymph node samples presented 65 mutations (average of 4 mutations per patient, rank 1-9), with a mean Variant Read Frequency (VRF) of 0.33 (0.06-0.77). On the other hand, the 21 cfDNA samples presented 71 mutations (average of 3 mutations per patient, rank 0-8), with a mean VRF of 0.21 (0.02-1.0). Notably, in 3 cases the mutations were only detected in the lymph node. Paired samples were available for 13 cases. Of the 72 somatic mutations identified in these cases, only 14 were present in both samples (Figure 1A, left). Besides the higher number of mutations in the lymph nodes, a mean decrease of 0.14 VRF was observed in cfDNA (0.21; 0.03-0.53) compared to lymph nodes (0.35; 0.09-0.76) (Figure 1A, Right). From the initial 29 FL cases, 16 had PB sequential samples available. Three patients were put under observation and the rest received an anthracycline based regimen plus R-maintenance. In treated patients, PET-CT was carried out at diagnosis and after 4 and 6 cycles of treatment. During follow-up, cfDNA was available after 4 (n=10) and 6 cycles of treatment (n=10). Median follow up was 18 months. To quantify LiqBio-MRD in the 31 follow-up samples, we defined an approach involving the sequencing of 12 NGS data points per mutation identified at diagnosis. Three of these data points were tumour sample replicates. The other 9 points were obtained from healthy control donor DNA. All LiqBio-MRD samples were sequenced with at least 100.000x and analysed applying the NGS-MRD algorithm described elsewhere (Onecha, E et al. Hematologica 2019). The mean mutation rate (noise) in controls for the studied mutations was 1.4E-5 (0 - 8E-5) below the targeted sensibility of 2E-4. The LOD was defined for every follow-up sample based on the initial amount of cfDNA used in the test. On average 39.6ng (13-66 ng) were used for cfDNA MRD monitoring. All somatic mutations were considered potential MRD markers (Figure 1B), however the degree of MRD in each follow-up sample was defined by the somatic mutation with higher VRF. MRD values were significantly lower in complete response (CR) cases compared to those with active disease (p=0.001, Figure 1C, left). Notably, MRD positivity in the interim or at the end of treatment resulted in significantly inferior PFS (median 12 months vs not reached, P = 0.09, Figure 1C, right). An extension of the cohort and clinical impact of LiqBio-MRD test will be presented at the meeting. Our results demonstrate for the first time that NGS based MRD quantification is feasible in Liquid Biopsies from FL. Despite the marked spatial genetic heterogeneity of FL, which is better identified in cfDNA, the dilution of the signal in these samples suggests the use of both; lymph node biopsies and cfDNA at diagnosis to identify all potential MRD markers. The lower degree of MRD in CR evaluations (according to the 2014 Lugano response assessment) and the existence of patients in CR with positive and negative MRD suggest the potential of our LiqBio-MRD test to prospectively identify patients with different outcome. Nevertheless, more patients and a longer follow-up are necessary to draw meaningful conclusions. Figure 1 Disclosures Heredia: Altum sequencing: Current Employment. Rufian:Altum sequencing: Current Employment. Carrillo:Altum sequencing: Current Employment. Wang:Hosea Precision Medical Technology Co., Ltd: Current Employment. Canales:Janssen: Honoraria; Karyopharm: Honoraria; Celgene: Honoraria; Takeda: Speakers Bureau; Sandoz: Honoraria; Janssen: Speakers Bureau; Novartis: Honoraria; Sandoz: Speakers Bureau; Janssen: Speakers Bureau; Takeda: Speakers Bureau; Roche: Honoraria; iQone: Honoraria; Janssen: Honoraria; Sandoz: Honoraria; Novartis: Honoraria; Roche: Honoraria; Roche: Speakers Bureau; Karyopharm: Honoraria; Gilead: Honoraria; Sandoz: Speakers Bureau; Roche: Speakers Bureau. Martinez-López:Janssen, BMS, Sanofi, Novartis, Incyte, F. Hoffmann-La Roche and Amgen: Honoraria, Other: Advisory boards; Janssen, Novartis, BMS, Incyte: Consultancy; Hosea and Altum: Membership on an entity's Board of Directors or advisory committees.

Refractoriness to induction therapy and relapse after complete remission are the leading causes of death in patients with acute myeloid leukaemia (AML). This study focussed on the prediction of response to standard induction therapy and outcome of patients with AML using a combined strategy of mutational profiling by next-generation sequencing (NGS, n = 190) and ex vivo PharmaFlow testing (n = 74) for the 10 most widely used drugs for AML induction therapy, in a cohort of adult patients uniformly treated according to Spanish PETHEMA guidelines. We identified an adverse mutational profile (EZH2, KMT2A, U2AF1 and/or TP53 mutations) that carries a greater risk of death [hazard ratio (HR): 3·29, P < 0·0001]. A high correlation was found between the ex vivo PharmaFlow results and clinical induction response (69%). Clinical correlation analysis showed that the pattern of multiresistance revealed by ex vivo PharmaFlow identified patients with a high risk of death (HR: 2·58). Patients with mutation status also ran a high risk (HR 4·19), and the risk was increased further in patients with both adverse profiles (HR 4·82). We have developed a new score based on NGS and ex vivo drug testing for AML patients that improves upon current prognostic risk stratification and allows clinicians to tailor treatments to minimise drug resistance.

ABL1 Kinase Domain (ABL1-KD) mutations are a common resistance mechanism to tyrosine-kinase inhibitors (TKIs) in Chronic Myeloid Leukemia (CML) and Philadelphia Positive Acute Lymphoblastic Leukemia (ALL). Different ABL1-KD mutations induce different degrees of resistance to different TKIs. The early detection of these resistant mutations helps to adjust patient's treatment. Here we present an Ultra-Deep Sequencing approach to detect and quantify acquired ABL1-KD mutations in genomic DNA (gDNA), aiming to define a robust test to detect such alterations in TKIs exposed Philadelphia-Positive Leukemia Patients with a resolution below 1E-4. Firstly, we defined an ABL1 specific next-generation sequencing (NGS) panel designed to cover all coding regions of ABL1 exons 4-10. The 9 amplicons were designed to cover full exons where possible to detect co-occurring mutations (Figure 1A). A panel was then applied to 3 biological replicates of 3 Healthy control donors (9 NGS data points each with 220ng of gDNA). The average coverage per amplicon in all samples was at least 500,000x. The NGS data was then analyzed applying the NGS-MRD algorithm described elsewhere (Onecha, E et al. Haematologica 2019) to 25 known ABL1-KD hotspots. After applying our error correcting algorithm, we obtained an average of 135,000 (22,000-503,000) refined reads for the 25 hotspots. The limit of detection (LOD) was calculated for every position in the DNA as the mean noise (Variant Read Frequency; VRF) per position in the controls ± 3SD (standard deviation); the limit of quantification (LOQ) being defined as mean ± 10SD. For all the hotspots analyzed, the LOD was below 1E-4 and the LOQ below 3E-4 (Figure 1B), except for p.F311L (c.931T>C; LOD=2.7E-3). The high level of noise in this position, constant in the different control samples sequenced in different sequencing runs, is most likely related to the high number of homopolymers in the region. Ten Philadelphia-Positive Leukemia patients were then screened after TKI treatment (8 CML and 2 ALL). The median BCR-ABL1 defined by quantitative PCR (ratio BCR-ABL1 vs ABL1) in these follow-up samples was 0.6% (0.034% - 95%). All patients were screened in triplicates (220ng gDNA each) and the data-points ± 1SD from the mean were considered outliers (NGS false positives) and excluded from further analysis. Five patients presented a signal above the LOD for p.T315I (c.944C>T). This position is covered by 2 different amplicons in our panel. By bioinformatically demultiplexing the signal, the detection of those five mutations in both amplicons was confirmed (Amp_4; LOD=3E-5, Amp_5; LOD=4E-5). Moreover, aiming to validate this new approach, we applied to paired RNA samples an in-house BCR-ABL1/ABL1 nested PCR + NGS approach designed to quantify those alterations in cDNA. This approach confirmed the presence of 4 out of 5 gDNA detected mutations, with a Pearson correlation of 0.92 (Pval<0.001) (Figure 1C). The only mutation not confirmed by nested PCR presented the lowest BCR-ABL1 quantification (0.034%). Here we show an Ultra-Deep NGS based test which allows the early detection of TKI resistant emerging clones in genomic DNA samples with a resolution of 1E-4. Despite the facts that in Phi-positive leukemia patients' other techniques such as the nested PCR are available, for most of heme- dyscrasias it is not easy to detect acquired mutations below 1% VRF. Our test can reduce this limit by at least 2 logarithms. The clinical impact of this approach is illustrated by the two LLA patients included, both under dasatinib therapy when the p.T315I mutations were detected. Those 2 patients were changed to ponatinib, reducing BCR-ABL1 levels. An extension of the cohort and the validation of our test at clinical level will be presented at the meeting. Figure Disclosures Heredia: Altum sequencing: Current Employment. Carrillo:Altum sequencing: Current Employment. Rufian:Altum sequencing: Current Employment. Wang:Hosea Precision Medical Technology Co., Ltd: Current Employment. Ribera:Pfizer, Amgen: Research Funding; Pfizer, Amgen, Ariad, Novartis: Consultancy, Speakers Bureau. Martinez-López:Janssen, BMS, Sanofi, Novartis, Incyte, F. Hoffmann-La Roche and Amgen: Honoraria, Other: Advisory boards; Hosea and Altum: Membership on an entity's Board of Directors or advisory committees; Janssen, Novartis, BMS, Incyte: Consultancy.

This study was supported by the Centro de Investigacion Biomedica en Red—Area de Oncologia—del Instituto de Salud Carlos III (CIBERONC; CB16/12/00369; and CB16/12/00489), Instituto de Salud Carlos III/Subdireccion General de Investigacion Sanitaria (FIS No. PI13/02196), Asociacion Espanola Contra el Cancer (GCB120981SAN and the Accelerator Award), CRIS against Cancer foundation grant 2014/0120, and the Black Swan Research Initiative of the International Myeloma Foundation.

Introduction: Myeloid malignancies are clonal disorders of hematopoietic stem cells and include acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and myeloproliferative neoplasm (MPN). Common biological markers have been described in the molecular pathogenesis, including gene mutations in splicing factors, epigenetic modifiers, transcription factors, signal pathways and tumor suppressors. These mechanisms have been associated with MDS and MPN progression to AML. Objectives: The main objective of this study is to identify differences in the mutational landscape of myeloid malignancies and describe mutation frequencies of genes and functional pathways in each neoplasm, as well as determine their clinical impact. Methods: This study involved a retrospective analysis of 430 patients with AML (209), MDS (106) and Philadelphia negative MPN (86) diagnosed in the Hospital Universitario 12 de Octubre (Spain). They were analyzed by a next generation sequencing (NGS)- panel for myeloid malignancies. The panel include 32 genes: CALR, ASXL1, EZH2, PHF6, DNMT3A 2, TET2, IDH1, IDH2, KDM6A, KMT2A, SF1, SF3A1, SF3B1, SRSF2, U2AF1, ZRSR2, PRPF40B, EPOR, FLT3, JAK2, KIT, SH2B3, MPL, CBL, HRAS, NRAS, KRAS, ETV6, RUNX1, VHL, TP53, PTEN. In addition, there were included 29 patients diagnosed with benign pathology that were referred to rule out MPN or congenital polyglobulia. Results: In the analyzed cohort we obtained a larger number of mutations in the more aggressive malignancies, AML and MDS. Mutations in epigenetic modifiers and signal pathways were the most frequent detected (31% and 24% respectively). The epigenetic modifiers were notably affected in AML (78%) and MDS (60.4%), whereas signal pathways were mutated more frequently in MPN (70.9%). Transcription factors, tumor suppressors and splicing factors mutations were more detected in AML and MDS (40%, 32%, 44% and 22%, 13%, 32% respectively). The mutation landscape obtained by genes was: Signal pathways: FLT3, NRAS, KIT, KRAS y SH2B3 were specially detected in AML (25%, 11%, 6%, 5% and 4% respectively). JAK2, CALR and MPL in MPN (38%, 15% and 6% respectively). Transcription factors: RUNX1, ETV6, PHF6, CEBPA and WT1 mutations were regularly observed in AML (21%, 6%, 6%, 6% and 5% respectively), and GATA1 in SMD (3.8%). Tumor suppressors: TP53 was particularly affected in AML (21%) and MDS (11%). Epigenetic modifiers: TET2 was notably mutated in MDS (32%), whereas ASXL1, DNMT3A, IDH2, IDH1 and EZH2 were in AML (21%, 21%, 17% 16% and 8% respectively). Splicing factors: SF3B1 was more frequently detected in MDS (18%) than AML (7%), whereas ZRSR2 presented a similar frequency in both pathologies (around 8%). U2AF1 was most commonly mutated in MPN (9%). SRSF2 was specially mutated in AML (23%). SF3A1 was altered in around 1%, similar in all three malignancies. With regard to survival studies, the presence of mutations in splicing factors (primarily in U2AF1) and its absence in signal pathways conferred an adverse outcome for overall survival (OS) in MPN. In MDS, gene mutations in tumor suppressors (especially TP53), U2AF1 splicing factor and EZH2 epigenetic modifier were associated with poor outcome. In our series of AML, gene mutations in tumor suppressors and TP53 were related to unfavorable prognosis in OS. Conclusion: The largest number of mutations and affected genes observed in AML suggest that leukemic transformation of MDS and MPN is conditioned by acquisition of new mutations. We observed different frequencies of mutations between AML, MDS and MPN that could guide the diagnostic and identify new targets of treatment. Further, some mutations have demonstrated differential prognostic impact. An extension of this study and the design of an algorithm with mutation data to elucidate a more accurate molecular prognosis will be presented at the meeting. This work has been financed thanks to the grant PI16/01225, PI 19/01518 and PI19/00730 from the Instituto de Salud Carlos III (Ministerio de Economia, Industria y Competititvidad) and cofinanced by the European Development Fund. Figure 1. Mutations detected (%) in AML, MDS and MPN classified by function. Table 1. Median overall survival of patients with MPN, MDS and AML according to gene state (mutated or not). Figure Disclosures No relevant conflicts of interest to declare.

In cases of treatment failure in acute myeloid leukemia (AML), the utility of mutational profiling in primary refractoriness and relapse is not established. We undertook a perspective study using next-generation sequencing (NGS) of clinical follow-up samples (n=91) from 23 patients with AML with therapeutic failure to cytarabine plus idarubicin or fludarabine. Cases of primary refractoriness to treatment were associated with a lower number of DNA variants at diagnosis than cases of relapse (median 1.67 and 3.21, respectively, p=0.029). The most frequently affected pathways in patients with primary refractoriness were signaling, transcription and tumor suppression, whereas methylation and splicing pathways were mainly implicated in relapsed patients. New therapeutic targets, either by an approved drug or within clinical trials, were not identified in any of the cases of refractoriness (0/10); however, 8 potential new targets were found in 5 relapsed patients (5/13) (p=0.027): 1 IDH2, 3 SF3B1, 2 KRAS, 1 KIT and 1 JAK2. Sixty-five percent of all variants detected at diagnosis were not detected at complete response (CR). Specifically, 100% of variants in EZH2, RUNX1, VHL, FLT3, ETV6, U2AF1, PHF6 and SF3B1 disappeared at CR, indicating their potential use as markers to evaluate minimal residual disease (MRD) for follow-up of AML. Molecular follow-up using a custom NGS myeloid panel of 32 genes in the post-treatment evaluation of AML can help in the stratification of prognostic risk, the selection of MRD markers to monitor the response to treatment and guide post-remission strategies targeting AML, and the selection of new drugs for leukemia relapse.

Next-generation sequencing (NGS) has redefined the genetic landscape of acute myeloid leukemia (AML), providing new molecular markers for diagnostic and prognostic classifications. However, its application in the clinical setting is still challenging. We hypothesized that a 19-gene AML-targeted NGS panel could be a valid approach to obtain clinically relevant information. Thus, we assessed the ability of this panel to classify AML patients according to diagnostic and prognostic indexes in a cohort of 162 patients. The assay yielded a median read depth >2000x, with 88% of on-target reads and a mean uniformity >93% without significant global strand bias. The method was sensitive and specific, with a valid performance at the clinical variant allele frequency cutoff of 3% for point mutations and 5% for insertions or deletions (INDELs). Three-hundred thirty-nine variants were found (36% INDELs and 64% single nucleotide variants). Concordance between NGS and other conventional techniques was 100%, but the NGS approach was able to identify more clinically relevant mutations. Finally, all patients could be classified into one of the 2016 World Health Organization diagnostic categories and virtually all into the recently proposed prognostic indexes (2017 European LeukemiaNet and Genomic classification). To sum up, we validate a reliable and reproducible method for AML diagnosis and demonstrate that small, well-designed NGS panels are sufficient to guide clinical decisions according to the current standards.

BACKGROUND: Older patients with acute myeloid leukaemia (AML) who are unsuitable for standard induction therapy have limited treatment options. While DNMT3A, TET2, IDH1/2 and TP53 mutations have been previously associated to better response to hypomethylating agents, there are no molecular biomarkers for low-dose cytarabine (LDAC)-based regimens. AIMS: To predict outcome in AML older patients at diagnosis based on mutation status in the context of FLUGAZA trial. FLUGAZA trial was focus on >65 years AML de novo patients comparing azacytidine vs. fludarabine and LDAC (FLUGA Scheme). METHODS: We analyzed bone marrow (BM) samples at diagnosis from 209 out of 285 AML patients treated according Flugaza trial (NCT02319135), azacytidine-arm (n=97) and FLUGA-arm (n=112). In this trial, patients were randomized to receive 3 induction cycles with fludarabine and cytarabine (FLUGA) followed by 6 consolidation cycles with reduced intensity FLUGA, vs 3 induction cycles with 5-azacytidine (AZA) followed by 6 consolidation cycles with AZA. Median age at diagnosis was 75 years (65-90). Both treatment groups were balanced for age, leucocytes count, baseline BM blasts, karyotype risk (ELN), and FLT3-internal tandem duplication and NPM1 gene mutations. Mutational profile analysis was carried out by NGS targeted gene sequencing (Ion Torrent S5XL System-Thermo Fisher Scientific) using a 43 genes custom panel implicated in leukemia prognosis. RESULTS: We detected 893 variants, 247 Indels and 646 SNVs. 206 (23.1%) of them were included as pathogenic or like-pathogenic by clinvar database. Ninety-five percent of patients (n=203) had at least one detectable mutation, and the median number of mutations was 4 (range = 0-8 mutations). The most common gene mutations were TET2 (N=55), FLT3 (n=52), SRSF2 (n=49), TP53 (n=45), DNMT3A (n=45), ASXL1 (n=45), RUNX1 (n=43), IDH2 (n=36), IDH1 (n=34), NPM1, (n=33) and NRAS (n=23). This mutational landscape is different to previous published in younger patients (Grimwade, Blood 2016), with higher number of patients with mutations in TP53 (21.5 vs 8%), SRSF2 (23.9 vs 2%), IDH1 (16.3 vs 7%) and IDH2 (17.2 vs 9%) and lower number of patients with mutation in NMP1 (15.8 vs 33%). The median OS of global series was 6 months (range 0-40). Multivariate Cox regression in the global series showed that NRAS and TP53 mutations predict reduced OS (Table 1). Distribution of mutations between both arms was not homogeneous (Figure 1) and NRAS (p=0.012) was more frequent among patients randomized to the FLUGA-arm. However, TP53 mutation frequency distribution was homogeneous: 23.7% in AZA-arm and 19.6% in FLUGA-arm (p=NS). In the AZA-arm, patient´s age was the only variable associated with not achieving composite complete remission (CR plus CR with incomplete recovery) and TET2 and EZH2 mutations were predictors to achieve composite CR. In the FLUGA-arm, TP53 and NRAS mutations were associated with not reaching composite CR (table 2). In the AZA-arm, cytogenetic was the only variable associated with risk of early death. In the FLUGA-arm, leucocyte count, TP53 and NRAS mutations were associated with risk of early death (table 3). In the AZA-arm, BCORL1 mutations (4.1%) were the only variable associated with high risk of relapse. In the FLUGA-arm, BCOR (7.1%) and TP53 (19.6%) mutations were associated with high risk of relapse (table 4). CONCLUSION The mutational profile of AML in elderly patients is different from the previously published in young patients. We have confirmed that a molecular pattern can identify patients with poor prognosis in elderly AML patients. NRAS and TP53 mutations confer a poor prognosis in LDAC (FLUGA-arm) patients, but this effect disappeared in the AZA-arm. BCOR and BCORL1 mutations were associated to a reduced DFS. These results confirm that azacytidine could be more efficacious than LDAC treatment for older patients with AML and mutations in TP53, NRAS, TET2 and EZH2. The percentage of patients who presented mutations in these genes amounted to 77% in this AML series. The study is registered at www.ClinicalTrials.gov as NCT02319135. This study was supported by the Subdirección General de Investigación Sanitaria (ISCIII, Spain) grants PI13/02387 and PI16/01530. Disclosures Salamero: Celgene: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; Daichii Sankyo: Honoraria. Paiva:Amgen, Bristol-Myers Squibb, Celgene, Janssen, Merck, Novartis, Roche, and Sanofi; unrestricted grants from Celgene, EngMab, Sanofi, and Takeda; and consultancy for Celgene, Janssen, and Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau. Fernandez:Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Cheng et al . (1) in their study explored the use of the next-generation sequencing (NGS) technology to evaluate post-remission minimal residual disease (MRD) in B acute lymphoblastic leukaemia/lymphoma (B-ALL) patients and its potential to be implemented in clinical settings. The authors propose an NGS-based method with an applicability of around 90% of B-ALL patients and a sensitivity of up to 10−6 and losing only 6.25% of the cases where leukaemia-specific clonotypes were not identified.

A high proportion of patients with acute myeloid leukemia who achieve minimal residual disease negative status ultimately relapse because a fraction of pathological clones remains undetected by standard methods. We designed and validated a high-throughput sequencing method for minimal residual disease assessment of cell clonotypes with mutations of NPM1, IDH1/2 and/or FLT3-single nucleotide variants. For clinical validation, 106 follow-up samples from 63 patients in complete remission were studied by sequencing, evaluating the level of mutations detected at diagnosis. The predictive value of minimal residual disease status by sequencing, multiparameter flow cytometry, or quantitative polymerase chain reaction analysis was determined by survival analysis. The sequencing method achieved a sensitivity of 10-4 for single nucleotide variants and 10-5 for insertions/deletions and could be used in acute myeloid leukemia patients who carry any mutation (86% in our diagnostic data set). Sequencing-determined minimal residual disease positive status was associated with lower disease-free survival (hazard ratio 3.4, P=0.005) and lower overall survival (hazard ratio 4.2, P<0.001). Multivariate analysis showed that minimal residual disease positive status determined by sequencing was an independent factor associated with risk of death (hazard ratio 4.54, P=0.005) and the only independent factor conferring risk of relapse (hazard ratio 3.76, P=0.012). This sequencing-based method simplifies and standardizes minimal residual disease evaluation, with high applicability in acute myeloid leukemia. It is also an improvement upon flow cytometry- and quantitative polymerase chain reaction-based prediction of outcomes of patients with acute myeloid leukemia and could be incorporated in clinical settings and clinical trials.

Next-generation sequencing has substantially improved our understanding of the genomic landscape of multiple myeloma; however, the application of this technology has been confined mostly to research studies. Here, we report on a customized panel to characterize the mutational profile of 79 newly diagnosed patients with multiple myeloma, older than 65 years and who were not transplant candidates, applying the highest read depth to date that has been used for equivalent studies in multiple myeloma. Overall, we identified 53 genes mutated in 85% of patients, including KRAS, NRAS, BRAF, DIS3 and TP53, and found a complex subclonal structure. In addition, the total number of mutations, as well as mutations in TP53 and the Cereblon pathway, were negatively associated with survival. The latter result is particularly noteworthy as patients enrolled in this phase II clinical trial were treated with lenalidomide, which targets this pathway. Our next-generation sequencing strategy not only identified a group of patients with poor outcome, but also provided an extensive genetic profile that should prove useful in the search for new biomarkers and therapeutic targets in multiple myeloma, at an affordable price and with a small amount of sample, which are indispensable features for translating personalized medicine protocols to clinical practice.

Mitochondria are bioenergetic and biosynthetic organelles which control crucial biological pathways such as cell growth, proliferation and apoptosis among others. Over the last two decades, many studies have examined the role of mitochondrial DNA (mtDNA) alterations in carcinogenesis, via inactivating genetic mutations or dysregulation of the mtDNA copy number in the cell. However, the status of the mtDNA copy number and its implication in the pathogenesis of Multiple Myeloma (MM) remains unknown. Here, we have analyzed the mtDNA copy number in asymptomatic and symptomatic stages of MM and evaluated its clinical impact.

[This corrects the article DOI: 10.18632/oncotarget.22157.].