High frequency of dicentric chromosomes detected by multi-centromeric FISH in patients with acute myeloid leukemia and complex karyotype

Abstract The transcription factor CCAAT/enhancer binding protein alpha (C/EBPalpha) plays an important role in the development of mature neutrophils. Two common types of mutations in the CEBPA gene encoding C/EBPalpha have been identified in approximately 10% of adults with acute myeloid leukemia (AML): N-terminal, dominant-negative frameshift mutations that result in loss of C/EBPalpha function and C-terminal in-frame mutations that result in C/EBPalpha proteins with decreased DNA-binding potential. Previous studies concluded that mutant CEBPA predicts favorable outcome in younger AML patients with intermediate-risk karyotypes or normal cytogenetics. To assess the prevalence of CEBPA mutations in specific cytogenetic subgroups, mutational analysis of the CEBPA gene was performed in 125 AML patients. No CEBPA mutations were detected in 77 patients with t(8;21), inv(16)/t(16;16), t(15;17), or balanced translocations with breakpoints in band 11q23. In 58 patients with various non-complex karyotypic abnormalities, CEBPA mutations were present in 8 (14%). Surprisingly, 5 of the 8 patients with del(9q) as the sole aberration or in combination with a single additional abnormality other than t(8;21) had CEBPA mutations associated with loss of C/EBPalpha function. Consequently, 41 additional del(9q) cases were analyzed; 9 had CEBPA loss-of-function mutations. The overall prevalence of CEBPA loss-of-function mutations in cases with del(9q) within a non-complex karyotype was 41% (14 of 34 patients), whereas none of the patients who had a del(9q) within a complex karyotype (n = 7), in combination with a t(8;21) (n = 10), or together with a t(15;17) (n = 1) demonstrated mutant CEBPA. Analysis of associated mutations indicated that alterations of the FLT3, MLL, and NRAS genes are not common cooperating events in the pathogenesis of del(9q) AML with inactivating CEBPA mutations. This is the first study to show that AML with del(9q) is strongly associated with CEBPA loss-of-function mutations. The coincidence of del(9q) with inactivating CEBPA mutations and the fact that del(9q) is a common secondary cytogenetic abnormality in t(8;21)-positive AML, that is characterized by specific down-regulation of CEBPA, raise the possibility that loss of a critical segment of 9q, most likely in 9q22, and disruption of C/EBPalpha function cooperate in the pathogenesis of these leukemias. Further refinement of the commonly deleted segment of 9q using high-resolution techniques is underway to identify the critical gene(s) involved and their role in normal hematopoiesis and leukemogenesis. A collaborative intergroup study has been initiated to define whether the relatively good prognosis associated with del(9q) is related to the presence of a CEBPA mutation.

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Aberrant Expression of Hepatocyte Growth Factor Induces Autocrine MET Activation Providing a Novel Therapeutic Target In Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v116.21.1042.1042 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1042-1042

Author(s):

Alex Kentsis ◽

Takaomi Sanda ◽

Vu Ngo ◽

Scott J. Rodig ◽

Jeffery Kutok ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Growth Factor ◽

Hepatocyte Growth Factor ◽

Therapeutic Target ◽

Myeloid Leukemia ◽

Complex Karyotype ◽

Aberrant Expression ◽

Hepatocyte Growth ◽

Acute Myeloid ◽

Novel Therapeutic

Abstract Abstract 1042 Despite improvements in the treatment of acute myeloid leukemia (AML), high risk disease such as complex aberrant karyotype AML remains largely refractory to current therapy, and is mostly fatal. Identification of effective therapeutic targets by using candidate gene approaches has been limited by the number and variety of genetic defects associated with AML. Thus, we carried out a genome-wide functional screen in complex karyotype AML using a retroviral library of short hairpin RNAs (shRNAs), and discovered that shRNA-mediated depletion of hepatocyte growth factor (HGF) specifically inhibits growth of AML cells but not a panel of lymphoid cancer cells. HGF was to found to be aberrantly expressed in about 15% of patients with AML, including most patients with complex karyotype disease. In contrast to normal CD34+ cells that express MET (but not HGF), 5 of 7 cell lines derived from patients with complex karyotype AML exhibited aberrant expression of HGF that was associated with autocrine activation of its receptor MET. Depletion of HGF or MET using multiple independent shRNAs profoundly reduced proliferation and induced cell death in AML cells lines that express HGF but not those that lack HGF expression. Inhibition of MET using the tyrosine kinase inhibitor (SU11274) or HGF using neutralizing anti-HGF antibody (R&D Systems) also inhibited growth and induced apoptosis in AML cell lines dependent on HGF/MET activation but not those that lack HGF expression. Thus, aberrant HGF expression causes autocrine MET activation and oncogene dependence in a subset of patients with AML, confers sensitivity to HGF/MET inhibition, and provides a novel therapeutic target for this otherwise lethal disease. Disclosures: No relevant conflicts of interest to declare.

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Validation of Monosomal Karyotype Based Model In the Risk Stratification of Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v116.21.2745.2745 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2745-2745

Author(s):

Murtadha K. Al-Khabori ◽

Karen Yee ◽

Vikas Gupta ◽

Aaron Schimmer ◽

Andre Schuh ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Risk Stratification ◽

Induction Chemotherapy ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Structural Abnormality ◽

Complex Karyotype ◽

Poor Risk ◽

Monosomal Karyotype ◽

Acute Myeloid

Abstract Abstract 2745 Background: The influence of cytogenetic abnormalities on the prognosis of acute myeloid leukemia (AML) has been well-documented; however, the relative impact of certain miscellaneous abnormalities remains controversial. Recently, monosomal karyotype-based risk stratification has been shown to further discriminate the prognosis within the poor-risk karyotype group (Breems et al. JCO 2008), but this finding requires further validation. Methods: We retrospectively reviewed 779 consecutive adult AML patients treated with standard induction chemotherapy, consisting of daunorubicin plus cytarabine (3+7), at our institution from 1998–2008. After excluding patients with favourable risk, normal, missing or failed karyotype, 290 patients remained and were included in the analysis. Results: The baseline characteristics of these 290 patients were as follows: median age 59 y (range 18–81), male 181, prior malignancy 110, median white cell count (WBC) 7.6 × 10^9/L (range 0–246). The karyotypic features included single monosomy in 42, 2 or more monosomies in 51, and non-monosomy structural and numerical abnormalities in 197 patients. Of the 290, 116 (40 %) had three or more abnormalities (complex karyotype, CK). A total of 141 patients (49 %) achieved complete remission (CR) with 3+7 induction chemotherapy. Sixty-four patients received allogeneic stem cell transplantation in CR. The median overall survival (OS) for all patients was 12 months (95% CI: 10–14 months). The median OS was 10 (95% CI: 6–18), 7 (95% CI: 6–10) and 14 months (95% CI: 12–16) in the single monosomy, 2+ monosomy and non-monosomy groups, respectively (p < 0.0001 by log-rank test comparing the three groups). Among the patients containing at least one monosomy, the OS was not significantly different between the CK and non-CK groups (p = 0.08 by log rank). Similarly, in the non-monosomy structural abnormality group, the OS was not significantly different between the CK and non-CK groups (p = 0.2). Conclusions: Our results provide validation for the monosomal karyotype-based risk stratification for AML, indicating that patients with at least one monosomy have an inferior OS compared to other poor-risk non-monosomy groups. Within each of the monosomy and non-monosomy groups, the presence of a complex karyotype does not significantly influence the OS. Disclosures: No relevant conflicts of interest to declare.

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The Influence of Monosomal Karyotype On Survival in Patients with Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Survey On Behalf of the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT)

Blood ◽

10.1182/blood.v118.21.158.158 ◽

2011 ◽

Vol 118 (21) ◽

pp. 158-158 ◽

Cited By ~ 1

Author(s):

Angelique V.M. Brands-Nijenhuis ◽

Myriam Labopin ◽

Harry C. Schouten ◽

Liisa Volin ◽

Gérard Socié ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Stem Cell ◽

Hematopoietic Stem Cell Transplantation ◽

Stem Cell Transplantation ◽

Myeloid Leukemia ◽

Poor Prognosis ◽

Complex Karyotype ◽

Hematopoietic Stem ◽

Monosomal Karyotype ◽

Acute Myeloid

Abstract Abstract 158 Introduction: Monosomal karyotype (MK) has been shown to be associated with a very poor prognosis in AML patients (Breems, 2008). Whether allogeneic hematopoietic stem cell transplantation (alloHSCT) performed in an early phase can overcome the adverse prognosis in this cytogenetic patient category is currently unknown. To address this issue we performed a retrospective analysis on data from the registry of the EBMT among patients with primary AML who underwent alloHSCT in CR1. Patients and methods: A total of 4119 patients with primary AML and known cytogenetic abnormalities at diagnosis that underwent alloHSCT in CR1 were included in the analysis. Survival curves were calculated with Kaplan-Meier method. Log rank test and Cox regression analysis were used to determine statistical significance. Results: Median follow-up was 24 months (range 2–374). Overall, 171 patients (4.2%) fulfilled criteria for MK and 297 patients (7.2%) for complex karyotype (CK), with 115 patients fulfilling both conditions (MK and CK). Both the presence of a MK (2-yr OS: 35.5% versus 63.2%, p<0.0001) and CK (2-yr OS: 48.8% versus 61.9%, p<0.0001) were associated with a poorer outcome when compared with the remaining cytogenetics subtypes. Given the significant overlap between both categories, we further analyzed their prognostic impact after defining four subgroups of patients: MK but not CK (56 patients; MK+CK-), no MK but CK (180 patients; MK-CK+), MK and CK (115 patients; MK+CK+), and patients without either MK or CK (MK-CK-). Outcome of the MK-CK- subgroup did not differ according to cytogenetics. Patients harboring a MK, regardless concomitant presence of a CK, presented with a poorer OS after alloHSCT (2-yr OS: 31.7–43.0% versus 61.1%, p<0.0001). On the contrary patients with a CK but not MK showed a similar outcome than MK-CK- (2-yr OS: 61.1% versus 63.3%, p=0.170). Moreover, multivariate analysis confirmed the independent negative impact of MK (HR:1.90, range 1.5–2.4; p<0.0001) together with age, interval diagnosis-transplant, AML subtype, WBC at diagnosis, T-cell depletion, number of induction cycles and use of TBI during conditioning, whereas the presence of a CK did not retain its negative prognostic value. Conclusion: These results indicate that MK is a better indicator for poor outcome than CK after alloHSCT in patients with primary AML in CR1. Nonetheless, the potential curative role of alloHSCT for a subset of patients with MK should be further investigated. Reference: DA Breems, WLJ van Putten, GE de Greef, SL van Zelderen-Bhola, KBJ Gerssen-Schoorl, CHM Mellink, A Nieuwint et al. Monosomal karyotype in acute myeloid leukemia: a better indicator of poor prognosis than a complex karyotype. J Clin Oncol 2008;26(29):4791–7. Disclosures: No relevant conflicts of interest to declare.

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TP53 Alterations in Acute Myeloid Leukemia with Complex Karyotype Correlate with Specific Copy Number Alterations, Monosomal Karyotype, and Dismal Outcome,

Blood ◽

10.1182/blood.v118.21.3558.3558 ◽

2011 ◽

Vol 118 (21) ◽

pp. 3558-3558 ◽

Cited By ~ 3

Author(s):

Frank G. Rücker ◽

Richard F. Schlenk ◽

Lars Bullinger ◽

Sabine Kayser ◽

Veronica Teleanu ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Copy Number ◽

Myeloid Leukemia ◽

Multivariable Analysis ◽

Complex Karyotype ◽

Copy Number Alterations ◽

Free Survival ◽

Genomic Complexity ◽

Monosomal Karyotype ◽

Acute Myeloid

Abstract Abstract 3558 Acute myeloid leukemia with complex karyotype (CK-AML, CK+) is defined as ≥3 acquired chromosome abnormalities in the absence of recurrent genetic abnormalities (WHO 2008). CK-AML account for 10–15% of all AML and are characterized by a dismal outcome. To delineate prognostic markers in this unfavorable subgroup, we performed integrative analysis using genomic profiling (array-comparative genomic hybridization [CGH] and/or single-nucleotide polymorphism [SNP] analysis), as well as TP53 mutation screening in 234 CK-AML. TP53 mutations were found in 141/234 (60%) CK-AML comprising 130 missense, 21 insertion/deletion, nine nonsense, and eight splice site mutations; genomic losses of TP53 were identified in 94/234 (40%). Combining these data, TP53 alterations were detected in 70% of patients, and at least 66% of these exhibited biallelic alterations. TP53 alterations (loss and/or mutation in TP53) were characterized by a higher degree of genomic complexity, as measured by total number of copy number alterations per case (mean±SD 14.30±9.41 versus 6.16±5.53, P <.0001), and by the association with specific genomic alterations, that is, monosomy 3 or losses of 3q (-3/3q-) (P=.002), -5/5q- (P<.0001), -7/7q- (P=.001), -16/16q- (P<.0001), -18/18q- (P=.001), and -20/20q- (P=.004); gains of chromosome 1 or 1p (+1/+1p) (P=.001), +11/+11q (P=.0002), +13/+13q (P =.02), and +19/+19p (P =.04); and amplifications in 11q13∼25 [amp(11)(q13∼25)]. The recently described cytogenetic category “monosomal karyotype” (MK), defined as two or more autosomal monosomies or one single autosomal monosomy in the presence of structural abnormalities, for which a prognostic impact could be demonstrated even in CK-AML, was correlated with TP53 alterations (P <.0001). Clinically, TP53altered CK-AML patients were older (median age, 61 versus 54 years, P =.002), had lower bone marrow (BM) blast counts (median 65% versus 78%, P=. 04), and had lower complete remission (CR) rates (28% versus 50%, P =.01). For multivariable analysis, a conditional model was used with an age cut point at 60 years to address the different treatment intensities applied in the different age cohorts. In this model the only significant factors for CR achievement were TP53altered (OR, 0.55; 95%-CI, 0.30 to 1.00; P =.05) and age (OR for a 10 years difference, 0.67; 95%-CI, 0.52 to 0.87; P =.003). TP53 altered predicted for inferior survival; the 3-year estimated survival rates for CK+/TP53altered and CK+/TP53unaltered patients were as follows: event-free survival (EFS), 1% versus 13% (log-rank, P =.0007); relapse-free survival (RFS), 7% versus 30% (P =.01); and overall survival (OS), 3% versus 28% (P <.0001), respectively. Other variables predicting for inferior OS in univariable analyses were age and MK. Among the cohort of CK+/MK+ AML, TP53altered patients had a significantly worse OS (P =.0004). Multivariable analysis (stratified for age at cut point of 60 years) revealed TP53altered (HR, 2.43; 95%-CI, 1.56 to 3.77; P =.0001), logarithm of WBC (HR, 1.62; 95%-CI 1.17 to 2.26; P =.004), and age (HR for 10 years difference, 1.26; 95%-CI, 1.01 to 1.56, P =.04), but not MK as significant variables for OS. In addition, explorative subset analysis suggested that allogeneic hematopoietic stem-cell transplantation in first CR which was performed in 30 CK-AML did not impact outcome in TP53altered CK-AML. In summary, TP53 is the most frequently known altered gene in CK-AML. TP53 alterations are associated with older age, genomic complexity, specific DNA copy number alterations, MK, and dismal outcome. In multivariable analysis, TP53 alteration is the most important prognostic factor in CK-AML, outweighing all other variables, including the MK category. TP53 mutational status should be assessed in clinical trials investigating novel agents in order to identify compounds that may be effective in this subset of patients. Disclosures: No relevant conflicts of interest to declare.

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