Short Telomeres Combined with Low Telomerase Activity Are Associated with a Longer Survival in Patients with Acute Myeloid Leukemia.

Abstract Telomeres - the terminal regions of human chromosomes, and enzyme telomerase - a ribonucloprotein that synthesizes telomeric DNA onto chromosomal ends, have been thoroughly investigated as potential markers for the prognosis of various cancers including leukemia. However, it is important to consider both parameters and only few studies have investigated the prognostic value of these two combined biomarkers in patients with acute myeloid leukemia (AML). Our work was designed to determine the impact of telomere length together with telomerase activity (TA) on survival in patients with AML. In this current retrospective study, TA (reflected by the quantitative expression of the catalytic subunit of telomerase i.e the hTERT mRNA/18s RNA ratio measured by Q-RT-PCR) and telomere length (determined by southern blot analysis of terminal restriction fragments) were assayed in the bone marrow of 40 patients diagnosed with AML between 1999 and 2003 at Institute Gustave Roussy’s division of Hematology. The patients’ characteristics are shown on table 1. All patients were treated according to standard AML-type chemotherapy protocols. The median of TA (hTERT mRNA/18s RNA ratio) was 0.0458. TA was not detectable in 4 patients. The median of telomere length was 7.6 Kb (range: 3.5–11.2 Kb). No correlation was found between TA and telomere length. A negative correlation existed between telomere length and age (r= −0.42; p=0.0097). The Kaplan-Meier statistical method and logrank test were used for univariate survival analysis and the Cox proportional hazard regression models for multivariate survival analysis. In multivariate analysis, when adjusted for age (>= 50 years versus younger), cytogenetics findings (poor prognosis versus others) and the nature of leukemia (secondary versus de novo), improved survival was found in patients with a combination of short telomere length (<7.6 Kb) and weak TA (<0.09, cut off point separating the upper tertile) and the worse survival was found in patients with long telomere length (>=7.6 Kb) and high TA (>=0.09) (hazard ratio=9.91; 95% CI: 1.75–56.03; p=0.01). Our results suggest that the combination of telomere length and telomerase activity can be considered as an independent prognostic factor for survival in patients with AML. Table 1: Patients characteristics Sex (no. of patients) * AML post solid tumor (n=7), post myelodysplastic syndrome (n=1), post chronic myeloid leukemia (n=1) M 18 F 22 Age (years) Median 50 Range 22–74 Leukocyte count (Giga/L) Median 24.2 Range 1.3–360 Bone marrow blast percentage Median 76.5 Range 20–99 FAB Classification (no. of patients) M0 6 M1 9 M2 5 M4–M5 12 M4Eo 3 M6 1 Biphenotypic AL 3 NK AML 1 Type of leukemia (no. of patients) De novo 31 Secondary 9* Prognosis (based on karyotype) Good 5 Intermediate 21 Poor 10 Missing 4

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Shorter Remission Telomere Length Predicts Delayed Neutrophil Recovery After Acute Myeloid Leukemia Therapy: A Report From the Children’s Oncology Group

Journal of Clinical Oncology ◽

10.1200/jco.2016.66.9622 ◽

2016 ◽

Vol 34 (31) ◽

pp. 3766-3772 ◽

Cited By ~ 12

Author(s):

Robert B. Gerbing ◽

Todd A. Alonzo ◽

Lillian Sung ◽

Alan S. Gamis ◽

Soheil Meshinchi ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Telomere Length ◽

Myeloid Leukemia ◽

Protein Structures ◽

Telomere Maintenance ◽

Oncology Group ◽

Neutrophil Recovery ◽

The Impact ◽

Acute Myeloid

Purpose Suboptimal outcomes for children with acute myeloid leukemia (AML) necessitate maximally intensive therapy. Consequently, serious adverse events, such as prolonged periods of profound myelosuppression, contribute to AML treatment–related mortality. Telomeres, the repetitive DNA–protein structures at chromosome ends, influence cellular replicative capacity in that critically short telomeres can induce cell senescence or apoptosis. Our objective was to evaluate the impact of telomere length on duration of post-therapy neutropenia in a pediatric AML cohort. Patients and Methods Patients were diagnosed with de novo AML, enrolled in Children’s Oncology Group study AAML0531, and included those with (n = 53) and without (n = 62) significantly delayed neutrophil recovery after chemotherapy. We used quantitative polymerase chain reaction to measure telomere content (TC), a validated proxy for telomere length, from remission bone marrow samples obtained after the second induction chemotherapy course. Results Less TC was significantly associated with prolonged neutropenia after the fourth ( P < .001) and fifth chemotherapy courses ( P = .002). Cox regression adjusting for age at diagnosis confirmed that TC remained independently predictive of time to recovery of absolute neutrophil count for both the fourth and fifth courses ( P = .002 and .009, respectively). DNA from patients was analyzed for germline mutations in four telomere maintenance genes associated with telomere biology disorders. Sequence analysis revealed no enrichment of rare or novel variants in the delayed recovery group. Conclusion Our results suggest that TC at end of AML induction is associated with hematopoietic reconstitution capacity independently of age and may identify those at highest risk for markedly delayed bone marrow recovery after AML therapy.

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AML1/RUNX1 mutations in 470 adult patients with de novo acute myeloid leukemia: prognostic implication and interaction with other gene alterations

Blood ◽

10.1182/blood-2009-05-223784 ◽

2009 ◽

Vol 114 (26) ◽

pp. 5352-5361 ◽

Cited By ~ 211

Author(s):

Jih-Luh Tang ◽

Hsin-An Hou ◽

Chien-Yuan Chen ◽

Chieh-Yu Liu ◽

Wen-Chien Chou ◽

...

Keyword(s):

Overall Survival ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

De Novo ◽

Remission Rate ◽

Adult Patients ◽

Poor Prognostic Factor ◽

The Impact ◽

Runx1 Mutation ◽

Acute Myeloid

AbstractSomatic mutation of the AML1/RUNX1(RUNX1) gene is seen in acute myeloid leukemia (AML) M0 subtype and in AML transformed from myelodysplastic syndrome, but the impact of this gene mutation on survival in AML patients remains unclear. In this study, we sought to determine the clinical implications of RUNX1 mutations in 470 adult patients with de novo non-M3 AML. Sixty-three distinct RUNX1 mutations were identified in 62 persons (13.2%); 32 were in N-terminal and 31, C-terminal. The RUNX1 mutation was closely associated with male sex, older age, lower lactic dehydrogenase value, French-American-British M0/M1 subtypes, and expression of HLA-DR and CD34, but inversely correlated with CD33, CD15, CD19, and CD56 expression. Furthermore, the mutation was positively associated with MLL/PTD but negatively associated with CEBPA and NPM1 mutations. AML patients with RUNX1 mutations had a significantly lower complete remission rate and shorter disease-free and overall survival than those without the mutation. Multivariate analysis demonstrated that RUNX1 mutation was an independent poor prognostic factor for overall survival. Sequential analysis in 133 patients revealed that none acquired novel RUNX1 mutations during clinical courses. Our findings provide evidence that RUNX1 mutations are associated with distinct biologic and clinical characteristics and poor prognosis in patients with de novo AML.

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Low expression of MN1 associates with better treatment response in older patients with de novo cytogenetically normal acute myeloid leukemia

Blood ◽

10.1182/blood-2011-06-357764 ◽

2011 ◽

Vol 118 (15) ◽

pp. 4188-4198 ◽

Cited By ~ 40

Author(s):

Sebastian Schwind ◽

Guido Marcucci ◽

Jessica Kohlschmidt ◽

Michael D. Radmacher ◽

Krzysztof Mrózek ◽

...

Keyword(s):

Overall Survival ◽

Acute Myeloid Leukemia ◽

Older Patients ◽

Myeloid Leukemia ◽

Hox Genes ◽

De Novo ◽

Prognostic Significance ◽

The Impact ◽

Favorable Group ◽

Acute Myeloid

AbstractLow MN1 expression bestows favorable prognosis in younger adults with cytogenetically normal acute myeloid leukemia (CN-AML), but its prognostic significance in older patients is unknown. We analyzed pretherapy MN1 expression in 140 older (≥ 60 years) de novo CN-AML patients treated on cytarabine/daunorubicin-based protocols. Low MN1 expressers had higher complete remission (CR) rates (P = .001), and longer overall survival (P = .03) and event-free survival (EFS; P = .004). In multivariable models, low MN1 expression was associated with better CR rates and EFS. The impact of MN1 expression on overall survival and EFS was predominantly in patients 70 years of age or older, with low MN1 expressers with mutated NPM1 having the best outcome. The impact of MN1 expression was also observed in the Intermediate-I, but not the Favorable group of the European LeukemiaNet classification, where low MN1 expressers had CR rates and EFS similar to those of Favorable group patients. MN1 expresser-status-associated gene- and microRNA-expression signatures revealed underexpression of drug resistance and adverse outcome predictors, and overexpression of HOX genes and HOX-gene–embedded microRNAs in low MN1 expressers. We conclude that low MN1 expression confers better prognosis in older CN-AML patients and may refine the European LeukemiaNet classification. Biologic features associated with MN1 expression may help identify new treatment targets.

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The impact of therapy-related acute myeloid leukemia (AML) on outcome in 2853 adult patients with newly diagnosed AML

Blood ◽

10.1182/blood-2010-08-301713 ◽

2011 ◽

Vol 117 (7) ◽

pp. 2137-2145 ◽

Cited By ~ 216

Author(s):

Sabine Kayser ◽

Konstanze Döhner ◽

Jürgen Krauter ◽

Claus-Henning Köhne ◽

Heinz A. Horst ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Complete Remission ◽

Myeloid Leukemia ◽

Topoisomerase Ii ◽

De Novo ◽

Negative Impact ◽

Primary Malignancy ◽

De Novo Aml ◽

The Impact ◽

Acute Myeloid

Abstract To study the characteristics and clinical impact of therapy-related acute myeloid leukemia (t-AML). 200 patients (7.0%) had t-AML and 2653 de novo AML (93%). Patients with t-AML were older (P < .0001) and they had lower white blood counts (P = .003) compared with de novo AML patients; t-AML patients had abnormal cytogenetics more frequently, with overrepresentation of 11q23 translocations as well as adverse cytogenetics, including complex and monosomal karyotypes, and with underrepresentation of intermediate-risk karyotypes (P < .0001); t-AML patients had NPM1 mutations (P < .0001) and FLT3 internal tandem duplications (P = .0005) less frequently. Younger age at diagnosis of primary malignancy and treatment with intercalating agents as well as topoisomerase II inhibitors were associated with shorter latency periods to the occurrence of t-AML. In multivariable analyses, t-AML was an adverse prognostic factor for death in complete remission but not relapse in younger intensively treated patients (P < .0001 and P = .39, respectively), relapse but not death in complete remission in older, less intensively treated patients (P = .02 and P = .22, respectively) and overall survival in younger intensively treated patients (P = .01). In more intensively treated younger adults, treatment-related toxicity had a major negative impact on outcome, possibly reflecting cumulative toxicity of cancer treatment.

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Expression of Angiopoietins and Their Receptor Tie2 in the Bone Marrow of Patients with Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v108.11.1894.1894 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1894-1894

Author(s):

Christoph Schliemann ◽

Ralf Bieker ◽

Teresa Padro ◽

Torsten Kessler ◽

Heike Hintelmann ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Critical Role ◽

Angiogenic Factor ◽

Term Survival ◽

Bone Marrow Biopsies ◽

Cox Regression Analysis ◽

The Impact ◽

Acute Myeloid

Abstract Angiopoietin-1 (Ang-1) and its natural antagonist Angiopoietin-2 (Ang-2), both ligands for the receptor tyrosine kinase Tie2, are known to play an essential role in normal and pathological angiogenesis. However, the importance of angiopoietin signaling in the pathophysiology of hematologic neoplasias such as acute myeloid leukemia (AML) remains to be elucidated. We investigated the expression of Ang-1, Ang-2 and Tie2 by immunohistochemical analyses in bone marrow biopsies of 64 adult patients with newly diagnosed AML and correlated angiogenic factor expression with clinicopathological variables and long-term survival. Expression of Ang-2 was significantly increased in the bone marrow of AML patients (median [interquartile ranges]: 4.7 [3.3 – 5.7] AU [arbitrary units]) as compared with 16 control patients (1.5 [1.5 – 1.8] AU; P < 0.0001). In contrast, Ang-1 expression levels in AML patients did not differ from those found in controls. Thus, we observed a reversal of the Ang-1 and Ang-2 expression balance in the neoplastic bone marrow (Ang-2:Ang-1 ratio: 1.73) as compared with normal bone marrow (0.51; P < 0.0001). Furthermore, the angiopoietin receptor Tie2 was significantly overexpressed in leukemic blasts (3.8 [2.8 – 4.9] AU vs. 1.8 [1.6 – 2.3] AU; P < 0.0001). Patients expressing high levels of Ang-2 showed significantly longer overall survival (OS) than those with low Ang-2 levels (52.7 vs. 14.7 months; P = 0.039). The impact of Ang-2 expression on OS was especially evident in AML patients simultaneously expressing low levels of Ang-1 (P = 0.0298). Multivariate Cox regression analysis revealed karyotype and Ang-2 expression as independent prognostic factors for OS (hazard ratio [CI]: 3.06 [1.39 – 6.70] and 0.31 [0.14 – 0.69], respectively; P < 0.01). In conclusion, these data provide evidence that the alteration of angiopoietin balance in favor of Ang-2 may play a critical role in the pathophysiology of AML. Furthermore, high pre-therapeutic bone marrow Ang-2 levels indicate a favorable prognosis in polychemotherapy treated AML by a yet unknown mechanism.

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Clinical Activity, Pharmacokinetics, and Pharmacodynamics of Sorafenib In Pediatric Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v116.21.1073.1073 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1073-1073

Author(s):

Hiroto Inaba ◽

Jeffrey E Rubnitz ◽

Elaine Coustan-Smith ◽

Lie Li ◽

Brian D Furmanski ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

De Novo ◽

Leukemic Cells ◽

Clinical Activity ◽

Newly Diagnosed ◽

Pediatric Acute Myeloid Leukemia ◽

Rtk Signaling ◽

Acute Myeloid

Abstract Abstract 1073 Background: Aberrant receptor tyrosine kinase (RTK) signaling arising from genetic abnormalities, such as FLT3-internal tandem duplications (FLT3-ITD), is an important mechanism in the development and growth of acute myeloid leukemia (AML) and is often associated with a poor outcome. Hence, inhibition of RTK signaling is an attractive novel treatment option, particularly for disease that is resistant to conventional chemotherapy. We evaluated the clinical activity of the multikinase inhibitor sorafenib in children with de novo FLT3-ITD–positive AML or relapsed/refractory AML. Methods: Fourteen patients were treated. Six patients with newly diagnosed FLT3- ITD–positive AML (aged 9–16 years; median, 12 years) received 2 cycles of remission induction therapy and then started sorafenib (200 mg/m2 twice daily for 20 days) the day after completing induction II (low-dose cytarabine, daunorubicin, and etoposide). Nine patients (aged 6–17 years; median, 9 years) with relapsed AML (including one treated on the above regimen) received sorafenib alone (2 dose levels; 200 and 150 mg/m2) twice daily for the first week of therapy, concurrently with clofarabine and cytarabine on days 8–12, and then alone from days 13 to 28. Sorafenib pharmacokinetics were analyzed at steady-state on day 8 of sorafenib in patients with newly diagnosed AML and on day 7 in patients with relapsed AML. In patients with relapsed AML, the effect of sorafenib on signaling pathways in AML cells was assessed by flow cytometry. Results: All 6 newly diagnosed patients, including 2 whose AML was refractory to induction I, achieved a complete remission (CR) after induction II; 5 had negative minimal residual disease (MRD; <0.1% AML cells in bone marrow) after induction II. Both patients in this group who relapsed achieved second remissions, one with sorafenib alone and one on the relapse regimen described above. Of the 9 patients with relapsed AML, 6 (4 with FLT3-ITD) were treated with sorafenib 200 mg/m2. All 6 had a >50% decrease in blast percentage and/or bone marrow cellularity after 1 week of sorafenib. After concurrent sorafenib and chemotherapy, 5 of the 9 patients with relapsed AML achieved CR (2 had negative MRD) and 2 achieved a partial remission (PR; 5%-25% AML cells in bone marrow); all 4 patients with FLT3-ITD had a CR or PR. After sorafenib treatment, 6 patients underwent HSCT while 2 with FLT3-ITD who could not receive HSCT were treated with single-agent sorafenib and have maintained CR for up to 8 months. Hand-foot skin reaction (HFSR) or rash occurred in all patients and improved with cessation of sorafenib. Dose-limiting toxicity (DLT, grade 3 HFSR and/or rash) was observed in 3 of the 6 patients with relapsed AML treated with 200 mg/m2 of sorafenib; no DLT was observed at 150 mg/m2. The effect of sorafenib on downstream RTK signaling was tested in the leukemic cells of 4 patients: in most samples, phosphorylation of S6 ribosomal protein and 4E-BP1 was inhibited. The mean (± SD) steady-state concentration (Css) of sorafenib was 3.3 ± 1.2 mg/L in the newly diagnosed group and 6.5 ± 3.6 mg/L (200 mg/m2) and 7.3 ± 3.6 mg/L (150 mg/m2) in those with relapsed AML. In both groups, the mean conversion of sorafenib to sorafenib N-oxide was 27%-35% (approximately 3 times greater than previously reported), and mean sorafenib N-oxide Css was 1.0–3.2 mg/L (2.1-6.7 μM). In a 442-kinase screen, the inhibitory profiles of sorafenib N-oxide and sorafenib were similar, and FLT3-ITD phosphorylation was potently inhibited by both forms (sorafenib N-oxide Kd = 0.070 μM; sorafenib Kd = 0.094 μM). Sorafenib N-oxide inhibited the growth of an AML cell line with FLT3-ITD (IC50 = 0.026 μM) and 4 AML cell lines with wild-type FLT3 (IC50 = 3.9–13.3 μM) at approximately half the potency of sorafenib. Conclusion: In children with de novo FLT3-ITD and relapsed/refractory AML, sorafenib given alone or with chemotherapy induced dramatic responses and inhibited aberrant RTK signaling in leukemic cells. Sorafenib and its active metabolite (sorafenib N-oxide) likely contribute to both efficacy and toxicity. These results warrant the incorporation of sorafenib into future pediatric AML trials. Disclosures: Inaba: Bayer/Onyx: Research Funding. Off Label Use: Sorafenib and clofarabine: both used for treatment of pediatric acute myeloid leukemia.

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The Prognostic Impact and Stability of IDH2 Mutation and the Insufficiency of the Mutation Alone for Leukemogenesis In Adult Patients with Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v116.21.2697.2697 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2697-2697

Author(s):

Weng-Chi Lei ◽

Wen-Chien Chou ◽

Bor-Shen Ko ◽

Hsin-An Hou ◽

Hwei-Fang Tien

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

De Novo ◽

Normal Karyotype ◽

Idh1 Mutation ◽

Group 12 ◽

Worse Prognosis ◽

Idh2 Mutation ◽

Acute Myeloid

Abstract Abstract 2697 Purpose: Although the clinical and biological features of Isocitrate dehydrogenase (IDH) mutations in acute myeloid leukemia (AML) have been characterized, its stability and in vivo sufficiency of the mutation alone for leukemogenesis remain uninvestigated. Patients and Methods: Mutations of IDH and other clinically relevant genes were analyzed in the bone marrow from 446 adult patients with de novo non-M3 AML. IDH2 mutations were examined serially in 140 patients at diagnosis and after chemotherapy. Results: Among the 446 adults with de novo non-M3 AML, IDH2 R172, R140, and IDH1 R132 mutations occurred at a frequency of 2.9%, 9.2%, and 6.1%, respectively. IDH2 mutation was associated with higher platelet counts (p=0.046), intermediate-risk (p=0.002) or normal karyotype (p=0.023), and isolated +8 (p=0.014), but was inversely correlated with expression of HLA-DR (p=0.002), CD34 (p=0.039), CD15 (p=0.003), CD7 (p=0.010), and CD56 (p=0.048), and was mutually exclusive with WT1 mutation (p=0.037) and core-binding factor translocations (p=0.001). All these correlations became stronger when IDH1 and IDH2 mutations were considered together, suggesting similarity of biological roles between these 2 mutations. However, IDH2 but not IDH1 mutation conferred a better prognosis (Fig 1), especially in those with normal karyotype or intermediate cytogenetics (median overall survival: not reached vs. 58 months, p=0.044 and not reached vs. 19 months, p=0.027 for normal and intermediate karyotype group, respectively). Importantly, IDH2 but not IDH1 mutation was an independent favorable prognostic factor (HR: 0.332, 95% CI: 0.159–0.694; p=0.003). Patients with IDH2−/FLT3-ITD+ genotype had especially worse prognosis (median OS of IDH2−/FLT3-ITD+ vs. IDH2+/FLT3-ITD− group: 12 months vs. not reached; p=0.003; median OS of IDH2−/FLT3-ITD+ vs. IDH2+/FLT3-ITD+ or IDH2−/FLT3-ITD− group : 12 months vs. 35 months; p<.0001) (Fig 2A). The worse prognosis was also seen in patients with IDH−/FLT3-ITD+ genotype (Fig 2B). Serial analyses of IDH2 mutations during the clinical course of 140 patients confirmed the stability of this mutation; all the patients with IDH2 mutations at diagnosis harbored the same mutation at relapse with the exception of one patient who had extramedullary but not bone marrow relapse, while none of the IDH2-wild patients acquired this mutation at relapse. Importantly, sequential samples from two patients in long-term remission retained the original R140Q mutation while other accompanied mutations, FLT3-ITD in the first patient and NPM1 in the second, respectively, disappeared. In the first patient, the skin tissue was absent of the mutation and in the second, the mutation was restricted in myeloid cells but spared in lymphocytes indicating the mutation was acquired in these two patients. Conclusion: IDH2 mutation is a stable marker during disease evolution and confers favorable prognosis. FLT3-ITD combined with wild type IDH2 exerted synergistic negative impact on survival. IDH2 mutation alone is insufficient for leukemogenesis. Disclosures: No relevant conflicts of interest to declare.

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Characterization of Extramedullary Acute Myeloid Leukemia – Results of the AML96 Trial

Blood ◽

10.1182/blood.v116.21.2154.2154 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2154-2154

Author(s):

Friedrich Stölzel ◽

Christoph Röllig ◽

Michael Kramer ◽

Brigitte Mohr ◽

Uta Oelschlägel ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Induction Chemotherapy ◽

Myeloid Leukemia ◽

The Body ◽

Hematopoietic Stem ◽

Npm1 Mutation ◽

Mutation Status ◽

The Impact ◽

Acute Myeloid

Abstract Abstract 2154 Background: Myeloid Sarcoma (MS) is defined as an extramedullary mass composed of myeloid blasts occurring at an anatomical site other than the bone marrow. Furthermore, the term extramedullary manifestation (EM) is applied if it accompanies overt acute myeloid leukemia (AML) and represents non-effacing tissue infiltration. EM is reported to correspond often to the skin but can affect almost every site of the body. The prognosis of MS or EM has been discussed controversially in the past. EM at diagnosis of AML is generally thought to be a rare event. However, data defining the prevalence of EM at diagnosis of AML and its prognostic value are missing. The aim of this analysis was to provide data for estimating the prevalence of EM at diagnosis of AML and to determine its relevance by including clinical and laboratory data from patients being treated in the prospective AML96 trial of the Study Alliance Leukemia (SAL) study group. Patients and Methods: A total of 326 patients with AML (age 17 – 83 years) and EM were treated within the AML96 trial with a median follow up of 8.8 years (95% CI, 8.4 to 9.3 years). All patients received double induction chemotherapy. Consolidation therapy contained high-dose cytosine arabinoside and for patients ≤ 60 years of age the option of autologous or allogeneic hematopoietic stem cell transplantation (HSCT). Logistic regression analyses were used to identify prognostic variables for CR rates. The method of Kaplan-Meier was used to estimate OS and EFS. Confidence interval (CI) estimation for the survival curves was based on the cumulative hazard function using the Greenwood's formula for the SE estimation. Survival distributions were compared using the log rank test. Results: 17% of the AML patients entered into the AML96 trial were diagnosed with EM. In 313 of the 326 patients (96%) EM was evident at diagnosis. The majority of patients with EM were diagnosed with de novo AML (84%, n=273), whereas gingival infiltration (51%, n=166) displayed the main EM of AML with CNS involvement being less common (4%, n=14). The majority of patients had a cytogenetic intermediate risk profile (71%, n=221) with a total of 172 patients (56%) harboring a normal karyotype. Patients with EM had a statistically significant lower median CD34-positivity of bone marrow blasts, higher percentage of FAB subtypes M4 and M5, higher WBC counts and LDH at diagnosis and higher percentage of NPM1 mutations compared to those patients without EM (all p<.001). When comparing achievement of CR between patients with EM to patients without EM, no statistical difference between these two groups was observed. Analysis according to the NPM1/FLT3-ITD mutation status revealed highest 5-year-OS (37%, 95% CI: .24 - .508) and 5-year-EFS (36%, 95% CI: .224 - .448) in the NPM1-mut/FLT3-wt group and lowest 5-year-OS (12%, 95% CI: 0 - .261) and 5-year-EFS (4%, 95% CI: 0 - .124) in the NPM1-wt/FLT3-ITD group, p=.007 and p=.001, respectively. Of the 49 relapsed patients with EM who had a NPM1-mutation at diagnosis 48 deceased despite of intensified relapse therapies. Conclusions: This analysis represents the largest study so far investigating the impact of EM AML. Patients with EM AML have distinct differences from AML patients without EM regarding their clinical and molecular characteristics at diagnosis. However these differences do not translate into differences in response to induction chemotherapy. Compared to patients without EM, survival analysis revealed differences according to the NPM1/FLT3-ITD mutation status which is also described for patients without EM AML. However, the prognosis for patients with EM who harbor a mutated NPM1 the prognosis at relapse seems to be dismal. Disclosures: No relevant conflicts of interest to declare.

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EZH2 Mutations Are Associated with Low Blast Percentage in Bone Marrow and −7/Del(7q) Karyotype in De Novo Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v120.21.2544.2544 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2544-2544

Author(s):

Xiuli Wang ◽

Haiping Dai ◽

Qian WANG ◽

Qinrong Wang ◽

Yang Xu ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

De Novo ◽

Conflicts Of Interest ◽

Univariate Analysis ◽

Myelogenous Leukemia ◽

Prognostic Impact ◽

Coding Region ◽

Acute Myeloid

Abstract Abstract 2544 Somatic mutation of the EZH2 gene is seen in myelodisplastic syndrome, myelofibrosis, and chronic myelomonocytic leukemia patients. The prevalence and prognostic impact of somatic mutations of EZH2 in patients with acute myelogenous leukemia (AML) remains unknown. In this study, we sought to determine the incidence and clinical implications of somatic EZH2 mutations in 714 patients with de novo AML by PCR amplification of the entire coding region followed by direct bidirectional DNA sequencing. EZH2 mutations were identified in 13/714 (1.8%) of AML patients and occurred almost exclusively in males (11/13, P=0.033). In univariate analysis, the presence of EZH2 mutations was significantly associated with lower blast percentage (21–30%) in bone marrow (P=0.0001) and −7/del(7q) (P=0.025). There was no difference in the incidence of mutations in 13 genes, including ASXL1, CBL, c-KIT, DNMT3A, FLT3, IDH1, IDH2, MLL, NPM1, NRAS, RUNX1, TET2, and WT1, between patients with and without EZH2 mutations. Complete remission, event-free survival or overall survival was similar between AML patients with and without EZH2 mutation (p>0.05). These results demonstrated EZH2 mutation as a recurrent genetic abnormality associated with lower blast percentage in BM and −7/del(7q) in de novo acute myeloid leukemia. Disclosures: No relevant conflicts of interest to declare.

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Inhibition of HDAC8 Reactivates p53 and Abrogates Leukemia Stem Cell Activity in CBFβ-SMMHC Associated Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v124.21.363.363 ◽

2014 ◽

Vol 124 (21) ◽

pp. 363-363

Author(s):

Jing Qi ◽

Qi Cai ◽

Sandeep Singh ◽

Ling Li ◽

Hongjun Liu ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Bone Marrow Cells ◽

Conflicts Of Interest ◽

Cell Activity ◽

Disease Free Survival ◽

Hematopoietic Stem ◽

The Impact ◽

Acute Myeloid

Abstract The inv(16)-created CBFβ-SMMHC fusion protein inhibits differentiation of hematopoietic stem and progenitor cells (HSPCs) and creates pre-leukemic populations predisposed to acute myeloid leukemia (AML) transformation. However, the molecular mechanism underlying the leukemogenic function of CBFβ-SMMHC has been elusive. Given the low TP53 mutation rate in AML, alternative mechanisms disrupting p53 function are expected. We showed thatCBFβ-SMMHC impairs p53 acetylation and p53 target gene activation through formation of an aberrant protein complex with p53 and HDAC8 (Blood, 120: A772; 122(21): 224). We now show that CBFβ-SMMHC binds to p53 and HDAC8 independently through distinct regions and that HDAC8 mediates the deacetylation of p53 associated with CBFβ-SMMHC. In addition, we generated mice carrying a floxed Hdac8 (Hdac8f) allele and crossed with Cbfb56M/+/Mx1-Cre (Kuo YH et al, Cancer Cell 2006). Deletion of Hdac8 signifiacntly (p<0.0001) reduced the incidence of AML and prolonged disease-free survival. Pharmacologic inhibition of HDAC8 activity with HDAC8-selective inhibitors (HDAC8i) reactivates p53 and selectively induces apoptosis of inv(16)+ AML CD34+ cells while sparing normal HSPCs. To test the effect of HDAC8i on LSC engraftment and leukemia-initiating capacity, we generated Cbfb56M/+/Mx1-Cre mice with a Cre-reporter line expressing tdTomato fluorescence protein following Cre-mediated recombination. AML cells (dTomato+/cKit+) treated with HDAC8i (22d) ex vivo showed reduced engraftment (p=0.025) and enhanced survival (p=0.025) in transplanted mice. To examine whether HDAC8i 22d treatment affects the engraftment capacity on surviving cells, we transplanted equal number (2 x 106) of AML cells treated with either 22d or vehicle in another cohort of mice (n=4). We show that HDAC8i 22d treatment reduced the engraftment of dTomato+/cKit+ AML cells and enhanced survival, suggesting that the engraftment capacity is altered in addition to reducing AML cell survival. We next performed preclinical studies to determine the efficacy of in vivo administration of HDAC8i 22d. AML transplanted mice were randomized into two groups, one group treated with vehicle and the other treated with HDAC8i 22d for 2 weeks. Flow cytometry analysis revealed significantly reduced frequency (p=0.0097) and number (p=0.0101) of dTomato+/cKit+ AML cells in the bone marrow and spleen of 22d treated mice compared to vehicle treated group. To further assess the impact on LSC activity, we transplanted bone marrow cells from these treated mice into secondary recipients and analyzed for AML engraftment. Significant reduction in the frequency (p<0.0001) and the number (p=0.0006) of dTomato+/cKit+ AML cells was observed in the bone marrow and spleen. Furthermore, HDAC8i 22d treated transplants showed no signs of leukemia while vehicle treated transplants are moribund with aggressive AML. These results indicate that HDAC8 inhibition by 22d treatment effectively eliminates engraftment and leukemia-initiating capacity of AML LSCs. In conclusion, our studies identify a novel post-translational p53-inactivating mechanism and demonstrate selective HDAC8 inhibition as a promising approach to target inv(16)+ AML LSCs. Disclosures No relevant conflicts of interest to declare.

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