Risk Stratification In Acute Myeloid Leukemia Research Articles

TWIST-1 promotes cell growth, drug resistance and progenitor clonogenic capacities in myeloid leukemia and is a novel poor prognostic factor in acute myeloid leukemia.

Alterations of TWIST-1 expression are often seen in solid tumors and contribute to tumorigenesis and cancer progression. However, studies concerning its pathogenic role in leukemia are scarce. Our study shows that TWIST-1 is overexpressed in bone marrow mononuclear cells of patients with acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). Gain-of-function and loss-of-function analyses demonstrate that TWIST-1 promotes cell growth, colony formation and drug resistance of AML and CML cell lines. Furthermore, TWIST-1 is aberrantly highly expressed in CD34+CD38- leukemia stem cell candidates and its expression declines with differentiation. Down-modulation of TWIST-1 in myeloid leukemia CD34+ cells impairs their colony-forming capacity. Mechanistically, c-MPL, which is highly expressed in myeloid leukemia cells and associated with poor prognosis, is identified as a TWIST-1 coexpressed gene in myeloid leukemia patients and partially contributes to TWIST-1-mediated leukemogenic effects. Moreover, patients with higher TWIST-1 expression have shorter overall and event-free survival (OS and EFS) in AML. Multivariate analysis further demonstrates that TWIST-1 overexpression is a novel independent unfavourable predictor for both OS and EFS in AML. These data highlight TWIST-1 as a new candidate gene contributing to leukemogenesis of myeloid leukemia, and propose possible new avenues for improving risk and treatment stratification in AML.

Molecular Genetic Markers in Acute Myeloid Leukemia.

Genetics play an increasingly important role in the risk stratification and management of acute myeloid leukemia (AML) patients. Traditionally, AML classification and risk stratification relied on cytogenetic studies; however, molecular detection of gene mutations is playing an increasingly important role in classification, risk stratification, and management of AML. Molecular testing does not take the place of cytogenetic testing results, but plays a complementary role to help refine prognosis, especially within specific AML subgroups. With the exception of acute promyelocytic leukemia, AML therapy is not targeted but the intensity of therapy is driven by the prognostic subgroup. Many prognostic scoring systems classify patients into favorable, poor, or intermediate prognostic subgroups based on clinical and genetic features. Current standard of care combines cytogenetic results with targeted testing for mutations in FLT3, NPM1, CEBPA, and KIT to determine the prognostic subgroup. Other gene mutations have also been demonstrated to predict prognosis and may play a role in future risk stratification, although some of these have not been confirmed in multiple studies or established as standard of care. This paper will review the contribution of cytogenetic results to prognosis in AML and then will focus on molecular mutations that have a prognostic or possible therapeutic impact.

Emerging diagnostic and therapeutic approaches in core binding factor acute myeloid leukaemia.

In acute myeloid leukaemia (AML), the presence of t(8;21)(q22;q22) and inv(16)(p13q22)/t(16;16)(p13;q22) and/or the corresponding molecular rearrangements RUNX1/RUNX1T1 and CBFB/MYH11 [collectively referred to as core binding factor (CBF) AML] predict for a more favourable outcome in patients receiving cytarabine-anthracycline based induction and upon achievement of complete remission, high-dose cytarabine consolidation chemotherapy. However, 40-45% of these patients eventually relapse and die of their disease. Here, we review emerging molecular and therapeutic results that may be used to guide the clinical management of this subset of patients. Integration of cytogenetic results with molecular genetic and epigenetic data refines the diagnosis, classification and risk-stratification of CBF AML. Clinical studies with targeting compounds (e.g. gemtuzumab ozogamicin, dasatinib) added to intensive chemotherapy appear beneficial both in younger and older patients, albeit the latter continue to have a significantly worse outcome than the former. Regularly molecular monitoring of disease during remission may provide a strategy for early therapeutic intervention before overt relapse. Emerging evidence supports that novel diagnostic, treatment and molecular disease monitoring approaches may improve the prognosis of CBF AML.

Is it time to change conventional consolidation chemotherapy for acute myeloid leukemia in CR1?

Choosing the most appropriate postremission therapy (PRT) for a patient with acute myeloid leukemia (AML) in first complete remission remains a challenging task. Factors such as risk for disease relapse, nonrelapse mortality associated with different PRT approaches, donor availability, prospects for salvage should disease relapse, and patient preference all affect PRT choice. New genetic markers refine AML risk stratification and identify patients within the 'classical' risk groups who may benefit from transplant-based or chemotherapy-based PRT. The use of minimal residual disease in first remission to guide PRT choice and the application of novel, targeted therapies have the potential to alter PRT approaches across AML risk groups. The advent of alternative donor sources, use of reduced intensity regimens, and improved supportive care all affect the availability and safety of transplant-based PRT and challenge the relevance of the older legacy 'donor/no-donor' genetically randomized trials. Genetic risk assessment, monitoring of minimal residual disease in first remission, use of targeted agents, and the newer transplant strategies all have the potential to 'personalize' PRT choice in the AML patient. The clinical value of these novel interventions awaits validation in prospective, risk-adapted clinical trials.

Different Genomic Patterns in Patients with Primary Acute Myeloid Leukemia (AML) Compared to Secondary AML in Patients with Normal Karyotype

BackgroundFor decades, cytogenetic analysis has played an essential role in AML risk stratification. Among the 50% of AML patients (pts) with normal karyotype (NK), outcome can vary widely. More recently, whole genome sequencing (WGS) and whole exome sequencing (WES) have identified several recurrent mutations that play an important role in AML pathogenesis and impact outcome. Pts with secondary AML (sAML) have a particularly poor prognosis, are not as responsive to standard induction chemotherapy, and often are referred in first complete remission to hematopoietic stem cell transplantation. We hypothesized that different genomic patterns exist between primary AML (pAML) and sAML that can distinguish the two, and can alter treatment recommendations. To negate the impact of chromosomal abnormalities, we focused our analyses on pts with NK.MethodsWe performed WES and multi-amplicon targeted deep sequencing on samples from bone marrow and peripheral blood of pts diagnosed with sAML at our institution between 1/2003- 1/2013 and who had NK cytogenetics. We compared them to pts with NK primary AML (pAML) whose data were extracted from The Cancer Genome Atlas (TCGA). A panel of 62 gene mutations that has been described as recurrent mutations in myeloid malignancies was included. Mutations were considered individually and grouped based on their functional pathways: RNA splicing (SF3B1, U2AF1/2, SRSF2, ZRSR2), DNA methylation (TET2, DNMT3A, IDH1/2), chromatin modification (ASXL1, EZH2, MLL, SUZ12, KDM6A), transcription (RUNX1, CEBPA, NPM1, BCOR/BCORL1, SETBP1, ETV6), activating signaling (FLT3, JAK2), cohesion (STAG2, SMC3, RAD21), RAS superfamily (K/NRAS, NF1, PTPN11, CBL) and tumor suppressor genes (TP53, APC, WT1, PHF6). Using deep sequencing methodology for resequencing or targeted sequencing, variant allelic frequency (VAF) was measured for each mutation detected. VAF was adjusted by zygosity evaluated by SNP-array karyotyping. For confirmation of clonal architecture, serial sample sequencing and single colony PCR were applied. Differences were compared using Fisher-exact test and Mann-Whitney U test for categorical and continues variables respectively.Results:Of 143 pts included, 101 (71%) had pAML and 42 (29%) had sAML. Compared to pAML, sAML pts were older (59 vs 69 years, p <.001), and had lower white blood cell count (28 vs 3.5 X 109/L, p <.001). Median hemoglobin (10 vs 10) g/dl and platelet counts (57 vs 60) k/uL were similar between the two groups. With a median follow up of 26.4 months (mo, range, .93-95.4), median OS was shorter for sAML than for pAML (12.9 vs 16.2 mo, p= .03). Overall, the most common mutations were: NPM1 (35%), DNMT3A (27%), FLT3 (25%), RUNX1 (14%), IDH1 (12%), IDH2 (12%), STAG2 (12%), TET2 (11%), NRAS (8%), ASXL1 (8%), U2AF1 (8%), PTPN11 (7%), WT1 (6%), BCOR (5%), and PHF6 (5%). Mutations in SF3B1, U2AF1/2, BCOR/BCORL1, ETV6, ASXL1, JAK2, STAG2, and APC were more common in sAML compared to pAML, whereas mutations in DNMT3A, NPM1, CEBPA, and FLT3 were more common in pAML. Mutations in activated pathways in splicing machinery, transcription, chromatin modification, cohesion and RAS pathway were more prominent in sAML, while mutations in DNA methylation and signaling pathways occurred more frequently in pAML. Serial sample analyses at multiple time points demonstrated intra-tumor heterogeneity in most cases of sAML, which was supported by additional cross sectional analyses of VAF in multiple gene mutations in each case. These findings prompted us to evaluate secondary events in the cohort of pts whose sAML originated from an initial MDS stage, defined by ancestral mutations. Among genes frequently affected by mutations, TET2 and ASXL1 were identified as founder events, whereas STAG2, NRAS and PTPN11 were observed in subclonal sAML derived from founder MDS clones. In pAML, however, TET2 and ASXL1 mutations were found to be secondary lesions, while IDH1 and DNMT3A were identified as ancestral events.ConclusionClear genomic variations exist between sAML and pAML that suggest differences in the pathophysiology of both diseases. Specific therapies should be directed to the activated pathways according to the unique clonal hierarchy in each AML subtype. DisclosuresNo relevant conflicts of interest to declare.

Comprehensive Geriatric Assessment Does Not Predict Overall Survival in Older Patients with Acute Myeloid Leukemia (AML)

BackgroundAge and cytogenetics are the strongest predictors of overall survival (OS) in older patients with acute myeloid leukemia (AML), but practitioners recognize that outcomes are also affected by medical comorbidities, physical function and a variety of psychosocial factors. Recent data suggest that geriatric assessment, including measures of physical, cognitive and psychological function, may be predictive of OS and helpful for risk stratification in AML (Klepin 2013). We evaluated the ability of a comprehensive geriatric assessment (CGA) to predict overall survival in newly diagnosed older patients with AML.Patients and MethodsAll newly diagnosed AML patients age ≥60 years treated at Weill Cornell Medical Center and The New York Presbyterian Hospital completed a CGA including the OARS Physical Health Section, Mental Health Inventory (MHI-17), MOS Social Activity Survey, Activities of Daily Living (ADL) subscale of the MOS Physical Health, OARS Instrumental ADL subscale, Timed Up & Go, Blessed-Orientation-Memory-Concentration Test, and Karnofsky Performance Status (KPS). Laboratory data, medications, transfusions and days of hospitalization were also collected. Comorbidities were assessed using the Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI). OS was estimated by the Kaplan-Meier method and the log-rank test was used to compare survival profiles. The independent effects of the CGA and clinical risk factor variables on OS were estimated using hazard ratios in an adjusted Cox regression model.ResultsIn total, 126 patients were evaluated (median age 74, range 60-90). Fifty-one percent of patients had a HCT-CI score >1, with the most common comorbidities being a history of cancer (28.57%), cardiac disease (20.6%), and psychiatric disturbances (17.5%). Half of the patients had prior hematologic disorders and 29% had poor-risk cytogenetics. Most patients (84.9%) received decitabine-based induction strategies; 44 of these patients (34.9%) subsequently received intensive salvage regimens (median age 69). The other 19 patients (15.1%) were treated with standard induction chemotherapy, and 29 patients (21%) underwent allogeneic stem cell transplantation (median age 68). One hundred twenty-three patients (96.6%) completed the CGA with a mean time to completion of 26 minutes (± 8.9 minutes). Thirty-five percent of patients did not complete the entire assessment and only 61.1% completed the follow up CGA. Median OS was 11.1 months (range 0.36-52.64), with 1-year survival of 47.6%, complete remission (CR) rate of 39.8%, and 30-day mortality of 2.4%. In univariate analysis, age (P=0.0289), physician-assigned KPS (P=0.0031), sex (P=0.0074), ELN cytogenetic risk (P=0.0194), creatinine (P=0.027), albumin (P=0.0052), white blood cell (WBC) count (P=0.0135), LDH (P=0.0004), and treatment response (P=0.0001) were significant clinical predictors of OS. Significant CGA variables included Blessed Orientation-Memory-Concentration score (P=0.0035), Bend-Kneel-Stoop (P=0.0239), “someone to prepare your meals” (P=0.0253) and self-reporting of heart disease (P<0.001). In a multivariate analysis controlling for age and cytogenetic risk, physician-assigned KPS (HR, 1.804; 95% CI 1.175 to 2.768), self-reported cardiac history (HR, 2.290; 95% CI 1.383 to 3.794), and WBC count <11.2/ul (HR, 2.360; 95% CI 1.415 to 3.936) were the only independent prognostic factors for overall survival.ConclusionIn this study, age and cytogenetics remain the strongest predictors of OS in older patients with AML. While completion of the CGA was feasible, only performance status (KPS) was predictive of OS. Many measures previously reported as significant predictors of outcome, including impaired physical function (Klepin 2013), medication intake (Hurria 2011), pain (Sherman 2013), and HCT-CI score (Sorror 2005, 2009) were not predictive in our study population. The role of the CGA as a predictor of OS in AML requires further evaluation. The utility of the CGA in predicting functional performance and/or quality of life for older AML patients throughout treatment should also be investigated. DisclosuresRitchie:Celgene, Incyte: Speakers Bureau. Feldman:Ariad: Honoraria, Speakers Bureau; Novartis: Honoraria, Research Funding, Speakers Bureau.

H3K27me3 Level of the HIST1 Cluster Defines an Epigenetic Marker of Acute Myeloid Leukemia with Prognostic Value

Acute myeloid leukemia (AML) is the most common acute leukemia diagnosed in adults, characterized by significant heterogeneity in terms of biology and clinical outcome. Improvements in sequencing technologies have led to the discovery of frequent somatic mutations in epigenetic modifiers, placing epigenetic deregulation in the center of AML. Yet, the global view and the impact of this deregulation on disease characteristics are under investigation.To gain a more comprehensive understanding of epigenetic deregulation in AML, particularly the heterogeneous subset with normal karyotype (CN-AML), associated with intermediate clinical prognosis, we performed H3K27me3 profiling on CN-AML patient samples. Primary bone marrow or peripheral blood samples containing more than 80% of blasts were selected from the Institut Paoli-Calmettes Biological Resources Center inventory for the purpose of genetic and epigenetic studies. We initially analyzed 35 CN-AML samples by ChIP coupled with hybridization on oligonucleotide promoter arrays (Chip-chip) for genomic H3K27me3 distribution. Clustering analysis revealed 586 highly H3K27me3-variable genomic regions across patients corresponding to 461 genes mostly involved in chromatin organization. The heterogeneity in the H3K27me3 profile was characterized by a remarkable H3K27me3 enrichment at the chromosome 6 p22.2-22 region that encompasses 70 kbp within the major HIST1 cluster. This striking H3K27me3 enrichment was covering 11 histone genes and was partially overlapping with the focal deletion at 6p22 found in acute lymphoblastic leukemia.The HIST1 H3K27me3 enrichment profile clearly distinguished 2 groups of CN-AML patients based on their HIST1 H3K27me3 level. In order to independently extend this observation, we analyzed the H3K27me3 status by using ChIP followed by qPCR (ChIP-qPCR) at the same HIST1 genomic locations, in an independent cohort of 51 CN-AML patients. This revealed the presence of this abnormal epigenetic profile in about 50% of the patients.CN-AML samples were split in two groups, according to the median H3K27me3 enrichment levels at the HIST1 cluster genes. These two groups were analyzed for clinical and molecular characteristics. Patients with high HIST1 H3K27me3 level had a markedly higher incidence of NPM1 mutation (89% vs. 40%; p= 1.75x10-5) and a lower incidence of WT1 mutation (0% vs. 20%; p=0.028). No significant association was observed with FLT3 (ITD and TKD), IDH1/2, DNMT3A nor ASXL1 mutations. Patients with high HIST1 H3K27me3 level had a significant longer leukemia free survival at 5 years (allo-grafted patients censored, LFS-allo; 13.33 vs. 8.92 months p=0.0053). Moreover, multivariate analysis showed that HIST1 H3K27me3 status provided a more powerful prognostic indicator than the NPM1mut/FLT3-ITDneg and NPM1/FLT3-ITD genotypes.In conclusion,using epigenetic profiling, our analysis has enabled the discovery of a new epigenetic alteration that affects CN-AML and impacts prognosis. We demonstrate that the HIST1 cluster is targeted by epigenetic events that lead to high H3K27me3 level and predicts a good prognosis. This may help refine risk stratification in AML, identifying a further group of patients unlikely to benefit from allogeneic transplantation in first remission. Overall, our data provide a proof of concept that epigenetic profiling could be used to discover new biomarkers with prognostic value. DisclosuresNo relevant conflicts of interest to declare.

A 16-Gene Signature Associated with High Levels of Wilms Tumor-1 (WT1) Expression Is an Adverse Prognostic Factor in Acute Myeloid Leukemia

Wilms Tumor-1 (WT1) expression level has long been found to be implicated in acute myeloid leukemia (AML) prognosis, though this is not reflected in current AML risk stratification. We hypothesized that a gene expression profile (GEP) associated with WT1expression could be of prognostic value.We analyzed two publically available AML GEP series in order to identify a gene signature associated with high-WT1 expression (hi-WT1). The first, herein called Netherlands series, comprised of 524 younger adult patients who have been treated according to sequential Dutch-Belgian Hemato-Oncology Cooperative Group and the Swiss Group for Clinical Cancer Research (HOVON/SAKK) AML-04, 04A, 29, 32, 42, and 43 protocols (GSE14468). The second series, herein called Germany series, consisted of 562 younger and older AML patients who were treated in the German AMLCG 1999 trial (GSE37642). We identified the hi-WT1 gene sets by comparing GEP among the highest and lowest quartiles of WT1 expression in both AML studies. About 62% of the probe sets in the Netherlands hi-WT1 set were found to be common with the Germany hi-WT1 set; 97% differed in the same direction. Moreover, a high degree of correlation of the fold differences was found among the two hi-WT1 sets (r2 = 0.81, p < 10-18), collectively suggesting a biological relevance for hi-WT1gene sets.In order to assess the prognostic implication of the hi-WT1 set, we used K-Nearest Neighborhood algorithm to generate various lists of hi-WT1 probe sets predicting event-free survival (EFS) as the favorable, and all others (dead, no remission, progressive disease/relapse) as the unfavorable events in the Netherlands series. Stepwise screening of the lists of 10 to 100 probe sets by Cox Regression identified a 16-gene subset of hi-WT1 set with distinct GEP and as the optimal predictor of overall survival (OS) and EFS in the Netherlands series. It comprised of GPR56, FAM30A, NGFRAP1, WBP5, LTK, PTP4A3, CD109, ZC3H12C, PYGB, CHIC1, HAVCR2, TMEM110, HAL, HDAC4, BLVRA, and P2RY2. In this series, the hi-WT1 cluster of patients showed lower 5y-probability of OS (10% vs 44%) and EFS (6% vs 38%) as compared to the remaining clusters. Accordingly, the hi-WT1 cluster showed shorter median OS (8.3 [CI 6.7-9.9] vs 31.3 [CI 17.1-45.5] months, P = 6 x 10-18) and EFS (4.9 [CI 3.2-6.5] vs 14.5 [CI 9.4-19.5] months, P = 3 x 10-16). Although the hi-WT1 cluster was associated with some of the cytogenetic and molecular aberrations including FLT3-ITD, it remained significant for both OS (P = 3 x 10-5) and EFS (P = 3 x 10-6) after adjustment for known AML risk factors.In order to validate our findings, we performed a supervised clustering of the Germany AML series using the 16-gene signature. The hi-WT1 cluster predicted both adverse OS and relapse-free survival (RFS) (Fig. 1), which remained statistically significant after adjustment for known AML risk factors (Table 1). The median OS was 7.1 (CI 5.7-8.5) months for the hi-WT1 cluster as compared to 20.1 (CI 15.2- 25.0) months for other cases (P = 2 x 10-13), and the median RFS was 5.8 (CI 4.8-6.8) vs 20.3 (CI 10.6-30.0) months, respectively (P = 2 x 10-11). Moreover, the rate of complete remission was significantly lower in hi-WT1 cluster as compared to other clusters (42% vs 61%, P = 2 x 10-5). The positive (PPV) and negative predictive value (NPV) of the marker for prediction of adverse OS were 90% and 34%, respectively. These values were found to be 88% and 38%, respectively, for prediction of adverse RFS. MetaCore analysis identified the Antigen Presentation by MHC-II as the most implicated biological pathway in hi-WT1sets, with many genes downregulated in the pathway.In brief, we identified a 16-gene signature associated with WT1 expression and demonstrated its adverse and independent prognostic impact in adult AML patients. These promising results should be validated in further trials and provide new clues to the molecular mechanisms underlying WT1regulation. [Display omitted] Table 1Multivariate analysis of OS and RFS in the Germany AML series. VariableOSRFSP valHR95% CI for HRP valHR95% CI for HRLowerUpperLowerUpperWT1 signature.0011.4851.1861.860.0001.8341.3262.536Age.0001.2911.1971.391.0011.1981.0811.327ELN2.0002.3951.7433.291.0003.1472.1244.663ELN3.0002.3951.7323.312.0002.1531.4053.299ELN4.0003.3062.3764.599.0006.4014.02710.175 DisclosuresNo relevant conflicts of interest to declare.

Single cell analysis exposes intratumor heterogeneity and suggests that FLT3-ITD is a late event in leukemogenesis

FMS-like tyrosine kinase 3 receptor-internal tandem duplication (FLT3-ITD) commonly occurs in acute myeloid leukemia and is considered rare in acute lymphocytic leukemia. Acute leukemia has poor prognosis, mainly due to relapse. Standard FLT3-ITD diagnostic techniques are based on genomic polymerase chain reaction and have recently incorporated GeneScan (Applied Biosystems, Foster City, CA) to identify variations of the FLT3 gene. As this is an average-based assay utilized in a heterogeneous leukemic cell population, we hypothesized that cells of acute leukemia, considered FLT3-ITD-negative by standard methods, could possess a fraction of FLT3-ITD-positive cells. The present study employed single cell mutation analysis to evaluate the FLT3-ITD status in newly diagnosed acute myeloid leukemia (n = 5) and acute lymphocytic leukemia (n = 3) patients. A total of 541 single leukemic cells and 36 mononuclear cells from healthy volunteers were analyzed. Seven patients, considered FLT3-ITD-negative according to bulk DNA analysis, appeared to possess a small fraction of FLT3-ITD-positive cells based on single cell analysis. Moreover, this approach revealed the heterogeneity of the tumor as evident by different FLT3-ITD mutations present in the same patient. The presence of a minor clone carrying FLT3-ITD in almost all patients tested provides evidence that this lesion is a common late event in leukemogenesis. Additionally, 3 relapsed patients demonstrated loss of heterozygosity of the normal allele, affecting 25%-100% of the cells found to be FLT3-ITD-positive. Though further clinical testing is warranted, these findings may have implications on the prognostic significance of FLT3-ITD and the use of targeted therapy.

Molecular and Cytogenetic Risk Stratification For Core-Binding Factor-Positive Adult AML With Analysis Of Post-Remission Treatment Outcomes Including Transplantation

Core-binding factor (CBF)-positive acute myeloid leukemia (AML) is regarded as a favorable group with good complete remission (CR) rate after induction chemotherapy and is generally treated by repeated high-dose cytarabine consolidation or autologous hematopoietic stem cell transplantation (auto-HSCT). However, emerging molecular studies have recently identified the unfavorable CBF-AML subgroup which should be treated by further intensified treatments.This single center retrospective study enrolled 264 adult CBF-AML patients from 2002 to 2011. Except 15 patients, 217 patients were treated by intensive induction chemotherapy and 32 were treated by reduced intensity treatment. After CR achievement, patients with available donor were treated by allogeneic (allo)-HSCT and the rest were treated by auto-HSCT or chemotherapy alone. We evaluated 206 patients who achieved CR after intensive chemotherapy regarding survival outcomes according to post-remission therapies and prognostic factors which affected the outcomes. The factors included cytogenetic study and subgroup analysis with additional chromosomes and normal karyotype (NK) mosaicism, c-kit mutation, minimal residual disease (MRD) qPCR level, BAALC and WT1 expression.We achieved CR in 94.9% with intensive chemotherapy and 115 patients went on allo-HSCT and 72 were treated by auto-HSCT. There were no significant OS differences between CBF¥â/MYH11 and RUNX1/RUNX1T1 (p=0.173), and auto-HSCT showed favorable EFS (p=0.038) compared to allo-HSCT and chemotherapy alone. For cytogenetic analysis, inv(16) or t(16;16) with NK mosaicism showed the most favorable OS compared to t(8;21) with additional chromosome (¡Ã2) which showed the worst OS. c-kit mutation was a poor prognostic factor with lower reduction rate of post-induction MRD qPCR, however the effect was not definite after HSCT. For HSCT patients, we analyzed post-HSCT MRD qPCR and WT1 expression level. We found that undetected level of post-HSCT MRD qPCR and lower level of WT1 expression (<0.015) showed the most favorable OS with no relapse cases.For CBF-AML, the role of auto-HSCT and allo-HSCT for selected patients should be re-evaluated by large prospective studies and the values like post-treatment MRD qPCR and WT1 expression level can be used for prediction of patients who might relapse with higher probability.▪▪ Disclosures:No relevant conflicts of interest to declare.

Total genomic alteration as measured by SNP-array-based molecular karyotyping is predictive of overall survival in a cohort of MDS or AML patients treated with azacitidine

Metaphase cytogenetics (MC) has a major role in the risk stratification of patients with myelodysplastic syndromes (MDSs) and can affect the choice of therapies. Azacitidine (AZA) has changed the outcome of patients with MDS or acute myeloid leukemia (AML) unfit for intensive chemotherapy. Identification of patients without the benefit of AZA would allow AZA combination or other drugs in first-line treatments. New whole-genome scanning technologies such as single nucleotide polymorphism microarray (SNP-A)-based molecular karyotyping (MK) improve the risk stratification in MDS and AML. Maintenance of genomic integrity is less than three megabases (Mbs) total disruption of the genome correlated with better overall survival (OS) in patients with lower-risk MDS. In this SNP-A study, we aimed at defining a cutoff value for total genomic copy number (CN) alterations (TGA) influencing the median OS in a cohort of 51 higher-risk MDS/AML patients treated with AZA. We observed that the relative risk of worse OS increased >100 Mb of TGA, as detected by SNP-A-based MK (8 and 15 months respectively, P=0.02). Our data suggest that precise measurement of TGA could provide predictive information in poor and very poor revised International Prognostic Scoring system (IPSS-R) patients treated with AZA.

Analysis of hematogones in bone marrow from acute myeloid leukaemia cases posttherapy

Increased bone marrow (BM) hematogones (HGs) are often observed in patients with marrow regenerating status. Many studies have focused on the role of HGs in acute lymphoblastic leukaemia (ALL), but very little has been done to understand their effects on acute myeloid leukaemia (AML). Through immunophenotyping, HGs were quantified in 471 BM samples from 292 postchemotherapy AML cases. These samples were analysed to determine whether there is any relationship between HGs percentages and French-American-British (FAB) subtypes or risk stratification of AML. HGs were identified in 57.75% of 471 patient samples (271) with a mean percentage of 3.87 ± 0.25%. No significant differences were found amongst different FAB subtypes of AML (P > 0.05). However, significant differences (P < 0.05) in HG numbers were noted between AML patients experiencing haematological complete remission (HCR) and those who have relapsed. HGs were identified in 59.9% of samples under HCR with a mean per cent of 3.98 ± 0.31%, and 36.7% of individuals who have relapsed have detectable HGs with a mean per cent of 1.75 ± 0.47. In addition, HGs in patients groups with low risk or intermediate risk were elevated when compared with high-risk groups (P < 0.05), whilst no significant difference was found between low-risk patients and intermediate-risk patients (P > 0.05). Patients with >0.1% of HGs had a significantly better median leukaemia-free survival (LFS) and overall survival (OS) than those with <0.1% of HGs (P < 0.01). Therefore, our data indicate that HGs in bone marrow may be used as a favourable prognostic factor that predict for a better outcome of AML patients.

Role of mutations in epigenetic regulators in pathogenesis of myeloid malignancies

Clinical, cytogenetic, and gene-based studies have been used to inform biology and improve prognostication for patients with acute myeloid leukemia (AML), myelodysplasia (MDS), and myeloroliferative neoplasms (MPN). Most recently, a series of candidate gene and whole genome studies have identified recurrent somatic mutations in AML, MDS, and MPN patients including TET2, ASXL1, DNMT3A, and EZH2, mutations. We and others have shown these mutations are of prognostic relevance, and can be used to improve risk stratification in AML, MDS, and MPN.

A stem cell-like gene expression signature associates with inferior outcomes and a distinct microRNA expression profile in adults with primary cytogenetically normal acute myeloid leukemia

Acute myeloid leukemia (AML) is hypothesized to be sustained by self-renewing leukemia stem cells (LSCs). Recently, gene expression signatures (GES) from functionally defined AML LSC populations were reported, and expression of a 'core enriched' (CE) GES, representing 44 genes activated in LCSs, conferred shorter survival in cytogenetically normal (CN) AML. The prognostic impact of the CE GES in the context of other molecular markers, including gene mutations and microRNA (miR) expression alterations, is unknown and its clinical utility is unclear. We studied associations of the CE GES with known molecular prognosticators, miR expression profiles, and outcomes in 364 well-characterized CN-AML patients. A high CE score (CE(high)) associated with FLT3-internal tandem duplication, WT1 and RUNX1 mutations, wild-type CEBPA and TET2, and high ERG, BAALC and miR-155 expression. CE(high) patients had a lower complete remission (CR) rate (P=0.003) and shorter disease-free (DFS, P<0.001) and overall survival (OS, P<0.001) than CE(low) patients. These associations persisted in multivariable analyses adjusting for other prognosticators (CR, P=0.02; DFS, P<0.001; and OS, P<0.001). CE(high) status was accompanied by a characteristic miR expression signature. Fifteen miRs were upregulated in both younger and older CE(high) patients, including miRs relevant for stem cell function. Our results support the clinical relevance of LSCs and improve risk stratification in AML.

Genomic and Epigenomic Landscapes of Adult De Novo Acute Myeloid Leukemia

BackgroundMany mutations that contribute to the pathogenesis of acute myeloid leukemia (AML) are undefined. The relationships between patterns of mutations and epigenetic phenotypes are not yet clear.MethodsWe analyzed the genomes of 200 clinically annotated adult cases of de novo AML, using either whole-genome sequencing (50 cases) or whole-exome sequencing (150 cases), along with RNA and microRNA sequencing and DNA-methylation analysis.ResultsAML genomes have fewer mutations than most other adult cancers, with an average of only 13 mutations found in genes. Of these, an average of 5 are in genes that are recurrently mutated in AML. A total of 23 genes were significantly mutated, and another 237 were mutated in two or more samples. Nearly all samples had at least 1 nonsynonymous mutation in one of nine categories of genes that are almost certainly relevant for pathogenesis, including transcription-factor fusions (18% of cases), the gene encoding nucleophosmin (NPM1) (27%), tumor-suppressor genes (16%), DNA-methylation–related genes (44%), signaling genes (59%), chromatin-modifying genes (30%), myeloid transcription-factor genes (22%), cohesin-complex genes (13%), and spliceosome-complex genes (14%). Patterns of cooperation and mutual exclusivity suggested strong biologic relationships among several of the genes and categories.ConclusionsWe identified at least one potential driver mutation in nearly all AML samples and found that a complex interplay of genetic events contributes to AML pathogenesis in individual patients. The databases from this study are widely available to serve as a foundation for further investigations of AML pathogenesis, classification, and risk stratification. (Funded by the National Institutes of Health.)

Identification of NPMc+ Acute Myeloid Leukemia in Bone Marrow Smears

The most frequent genetic change currently known in acute myeloid leukemia (AML) is the mutation of the nucleophosmin (NPM) gene. Aberrant cytoplasmic accumulation of NPM protein (NPMc+) is the result of this mutation, and it can be demonstrated by immunohistochemistry for the identification of a favorable subgroup within "AML with normal karyotype" according to the World Health Organization classification. NPM staining pattern was defined in 71 AML and 15 control cases by the use of bone marrow smears in order to overcome limitations observed due to immunohistochemistry. In 13/71 cases (18.3%), clear cytoplasmic staining of the leukemic blast cells was detectable that was comparable with the positivity of mitotic figures physiologically lacking nuclear membrane. The biological and genetic characteristics of the NPMc+ cases determined this way were identical with the previously published results including low CD34 and HLA-DR expression and lack of recurrent karyotype abnormalities. Bone marrow smears are well applicable and therefore a real alternative for the determination of NPM with the highest accuracy for optimal risk stratification in AML.

Comparing Outcomes of Patients with Secondary AML: Treatment-Related MDS/AML, AML Secondary to Myeloproliferative Neoplasms (t-MPN), and AML with Prior Malignancies

AbstractAbstract ▪3557▪This icon denotes a clinically relevant abstract Background:Secondary Acute Myeloid Leukemia (AML) accounts for approximately 10% of AML's and are often associated with adverse outcomes compared to de novo AML. In addition to cytogenetics, multiple gene mutations have been incorporated in the de novo AML risk stratification as independent prognostic and predictive factors. Little is known about these molecular markers in secondary AML. We analyzed the characteristics and outcomes of AML patients arising from myelodysplastic syndrome (MDS), myeloproliferative neoplasm (MPN), treatment-related AML (t-AML), or with prior history of cancer not treated with chemotherapy or radiation compared to de novo AML, and investigated the frequency and prognostic relevance of molecular markers among those groups. Patients and Methods:We analyzed the outcomes of adult patients with AML receiving induction chemotherapy at MDACC (n= 248) from 2010 to 2012. Median age was 67 years (range 17–82) and 142 (57.2 %) patients were >60 yrs. 108 (44%) were female. 146 (59 %) had de novo AML, 43 (17%) had t-AML, 23 (9%) had post-MDS, 16 (7%) post-MPN, and 20 (8%) AML with antecedent cancer not treated with chemotherapy and/or radiation therapy. Median white blood cell count (WBC) at diagnosis was 4.45 × 109/L (r: 0.4–186.5), and 82 (33%) pts had WBC >10 x109/L. Cytogenetics were diploid in 91 (37%), inv 16 in 16 (7%), t(8;21) in 12 (5%), trisomy 8 in 10 (4%), chromosome −5 and/or −7 in 60 (24%), 11q in 11 (4%), miscellaneous in 30 (12%), and insufficient metaphases on 18 (7%). 43(17%) had FLT3 mutations including 26 (10%) with FLT3-ITD, 14 (6%) FLT3-D835, and 3 (1%) double mutant. 32 (13 %) had NPM 1, 15 (6%) CBFb-MYH1, 10 (4%) ABL1/ETO, 6 (2%) JAK2, 34 (14 %) RAS, 1 (0.4%) cKIT, 18 (7%) CEBPA, 10 (4%) IDH1, and 8 (3.2%) IDH2. The pts were treated with several different induction chemotherapies. Idarubicin and cytarabine (IA)-based were more frequent in de novo and in 2nd cancer groups, while hypomethylating agents were more common in post-MDS and post-MPN groups. CR rates were higher in de novo AML than the rest of the groups, and early deaths were more common in the post-MPN group. The frequency of mutations was similar among groups with the exception of JAK 2 mutation, which was more frequent in post-MPN (Table 1). In pts with secondary AML, FLT3 mutations do not seem to further worsen their outcome (median survival 6.2 months for FLT3 wt and 6.4 for FLT3 ITD in 2nd AML; corresponding values for de novo AML are not reached and 13.3 months, respectively). (Figure 1) EFS and OS was worse in the post-MDS and post-MPN groups compared to de novo AML and second cancer group (p>0.001). Conclusion:In patients with secondary AML, antecedent of MDS or MPN are associated with unique molecular signatures (eg, rare FLT3-ITD in post MDS, frequent JAK2 in post-MPN) and have an inferior outcome. In contrast AML in pts with history of previous cancers not previously exposed to chemotherapy or radiation therapy survival outcomes are similar to de novo AML. Mutational status may not be as predictive of outcome among patients with secondary AML as it is for de novo AML.Table 1:Characteristics and molecular abnormalities in AML arising from MDS, MPN and second cancersDe novo (n=143)t-AML (n-=43)Antecedent MDS (n=23)Antecedent MPN (n=16)second cancer (n=20)pAGE59.5606970.567Cytogenetics (%)Diploid4114442555t(8;21)550010inv 16820410Trisomy 850440-5 and/or -7194422311511q abnormality414000Miscelaneous, other111913135ND6217195Outcomes (%)CR6942261980CR p/i32132510Median DFS (months)11.73.51.61.410.9<0.001Median OS (months)18.911.76.94.916.8<0.001AML1/ETO550050.832CBFb-MYH118206100.547FLT3-ITD137013250.208JAK21003100.001NPM11812019300.086RAS16540250.486KIT100000.952CEBPA9290100.445IDH13590100.279IDH2324650.879 [Display omitted] Disclosures:No relevant conflicts of interest to declare.

The prognostic relevance of miR-212 expression with survival in cytogenetically and molecularly heterogeneous AML

Acute myeloid leukemia (AML) is a highly heterogeneous disease, characterized by various cytogenetic and molecular abnormalities, many of which may express prognostic value. MicroRNAs (miRNAs) are a class of small regulatory RNAs. The prognostic value of miRNAs in AML is yet to be determined. Here, we set out to identify miRNAs that are consistent significant prognostic determinants, independent from other known prognostic factors. A discovery cohort (n=167) and validation cohort (n=409) of a heterogeneous AML population were used to reliably identify miRNAs with prognostic value. We report miR-212 as an independent prognostic factor, significantly associated with a prolonged overall survival (OS) and also event-free and relapse-free survival in a discovery cohort (hazard ratio (HR)s=0.77, P=0.015 for OS) that was subsequently confirmed in an independent validation cohort of 409 cases (HR=0.83, P=0.016). The prognostic significance and the prevalence of high miR-212 did not correlate with specific (cyto)genetic subtypes of AML. High miR-212 expression levels are associated with a gene expression profile that is significantly enriched for genes involved in the immune response. MiR-212 may improve the current prognostic risk stratification of mixed AML including normal karyotype AML and AML with cytogenetic and molecular abnormalities.

High BRE expression predicts favorable outcome in adult acute myeloid leukemia, in particular among MLL-AF9–positive patients

AbstractAberrations in protein ubiquitination have recently been identified in the pathogenesis of acute myeloid leukemia (AML). We studied whether expression changes of more than 1600 ubiquitination related genes correlated with clinical outcome in 525 adult AML patients. High expression of one of these genes, BRE, was observed in 3% of the cases and predicted favorable prognosis independently of known prognostic factors (5-year overall survival: 57%). Remarkably, unsupervised expression profiling showed that 86% of high BRE-expressing patients were confined to a previously unrecognized cluster. High BRE expression was mutually exclusive with FLT3 ITD, CEBPA, IDH1, and IDH2 mutations, EVI1 overexpression, and favorable karyotypes. In contrast, high BRE expression co-occurred strongly with FAB M5 morphology and MLL-AF9 fusions. Within the group of MLL-AF9–positive patients, high BRE expression predicted superior survival, while normal BRE expression predicted extremely poor survival (5-year overall survival of 80% vs 0%, respectively, P = .0002). Both the co-occurrence of high BRE expression with MLL-AF9 and its prognostic impact were confirmed in an independent cohort of 436 AML patients. Thus, high BRE expression defines a novel subtype of adult AML characterized by a favorable prognosis. This work contributes to improved risk stratification in AML, especially among MLL-AF9–positive patients.

Prognostic Importance of Histone MethyltransferaseMLL5Expression in Acute Myeloid Leukemia

To assess the prognostic importance of mixed lineage leukemia 5 (MLL5) expression in acute myeloid leukemia (AML). MLL5 transcript levels from 509 patients with AML who were treated in multicenter trials AML SHG 0199 and AML SHG 0295 and 48 healthy volunteers were analyzed by real-time reverse-transcription polymerase chain reaction in the context of other molecular markers (NPM1, FLT3, CEBPA, IDH1/IDH2, NRAS, KIT, MN1, BAALC, ERG, and WT1). Patients with high (n = 127) compared with low (n = 382) MLL5 expression had a higher complete response rate in multivariate analysis (odds ratio, 1.87; 95% CI, 1.08 to 3.24; P = .026). In multivariate analysis, high MLL5 expression was a favorable prognostic marker for overall survival (OS; hazard ratio [HR], 0.66; 95% CI, 0.49 to 0.89; P = .007) and relapse-free survival (RFS; HR, 0.72; 95% CI, 0.52 to 1.01; P = .057). Patient characteristics, cytogenetic aberrations, and gene mutations were similarly distributed between patients with high and low MLL5 expression except for a higher platelet count in those with high MLL5 expression. MLL5 expression independently predicted prognosis in cytogenetically normal AML patients (n = 268; OS: HR, 0.53; 95% CI, 0.33 to 086; P = .011; RFS: HR, 0.61; 95% CI, 0.38 to 0.99; P = .05) and in patients with core-binding factor leukemias (n = 81; OS: HR, 0.12; 95% CI, 0.02 to 0.91; P = .04; RFS: HR, 0.18; 95% CI, 0.04 to 0.77; P = .02). The prognostic importance of high MLL5 expression was independently validated in 167 patients treated in the AMLSG 07/04 trial (OS: HR, 0.5; 95% CI, 0.27 to 0.92; P = .023; RFS: HR, 0.49; 95% CI, 0.25 to 0.96; P = .033). High MLL5 expression levels are associated with a favorable outcome and may improve risk and treatment stratification in AML.