[Show abstract][Hide abstract] ABSTRACT: In recent years, the development of novel molecular techniques has been instrumental in deciphering the genetic heterogeneity of acute myeloid leukemia (AML) as well as in gaining important insights into the pathomechanisms of AML. Genetic diagnostics has become an essential component in the initial work-up for disease classification, prognostication, and genotype-specific therapies. A major prerequisite for such individualized treatment strategies is a rapid pretherapeutic genetic analysis, which includes screening for the recurrent AML-associated gene fusions as well as mutations in the genes NPM1, FLT3, and CEBPA. Some of these molecular markers can be used for monitoring minimal residual disease and therefore provide clinically relevant information. There is an increasing number of promising molecularly targeted therapies in clinical development for distinct genetic AML subgroups. Solid data exist for the combination of all-trans retinoic acid and arsentrioxid in the treatment of acute promyelocytic leukemia; the addition of the immunoconjugate gemtuzumab ozogamicin (GO) to induction therapy has been shown to improve outcome in cytogenetic low- and intermediate-risk AML. Furthermore, there are encouraging data on the combination of intensive chemotherapy with tyrosine kinase inhibitors in patients with AML harboring FLT3 mutations or with core-binding factor AML. Other novel therapeutic approaches address mutations or alterations in epigenetic regulators, such as IDH or DOT1L inhibitors. The comprehensive characterization of the underlying genetic mechanisms is essential for the development of novel target-specific compounds with the aim of improving outcome in AML patients.
[Show abstract][Hide abstract] ABSTRACT: The objective was to evaluate the prognostic and predictive impact of allelic ratio and insertion site (IS) of internal tandem duplications (ITD), as well as concurrent gene mutations with regard to postremission therapy in 323 patients with FLT3-ITD positive acute myeloid leukemia (AML). Increasing FLT3-ITD allelic ratio (p=0.004) and IS in the tyrosine kinase domain 1 (TKD1, p=0.06) were associated with low complete remission (CR) rates. After postremission therapy including intensive chemotherapy (CTX, n=121) or autologous hematopoietic stem cell transplantation (HSCT, n=17), an allelic ratio ≥0.51 was associated with an unfavorable relapse-free (RFS, p=0.0008) and overall survival (OS, p=0.004); after allogeneic HSCT (n=93), outcome was significantly improved in patients with a high allelic ratio (RFS, p=0.02; OS, p=0.03), whereas no benefit was seen in patients with low allelic ratio (RFS, p=0.38; OS, p=0.64). Multivariable analyses revealed a high allelic ratio as a predictive factor for the beneficial effect of allogeneic HSCT; ITD IS in TKD1 remained an unfavorable factor, whereas no prognostic impact of concurrent gene mutations was observed. The clinical trials described herein were previously published or are registered as follows: AML HD93, reference 29; AML HD98A, reference 30; AMLSG 07-04, ClinicalTrials.gov identifier: NCT00151242.
[Show abstract][Hide abstract] ABSTRACT: Outcome of AML patients older than 60 years has remained poor due to unfavorable disease characteristics and patient-related factors. The randomized AMLSG 06-04 protocol was designed based on in vitro synergistic effects of valproic acid (VPA) and all-trans retinoic acid (ATRA) with chemotherapy. Between 2004 and 2006, 186 patients were randomized to receive 2 induction cycles with idarubicin, cytarabine and ATRA with VPA (VPA) or without (STANDARD). In all patients consolidation therapy was intended. Complete remission rates after induction tended to be lower in VPA compared to STANDARD (40% vs. 52%; p=0.14) due to a higher early death rate (26% vs. 14%; p=0.06). The main toxicities attributed to VPA were delayed hematologic recovery and grade 3/4 infections observed predominantly during the second induction cycle. After restricting VPA to the first induction cycle and reducing the dose of idarubicin, these toxicities dropped to rates observed in STANDARD. After a median follow-up time of 84 months, event-free and overall survival were not different between the two arms (p=0.95 and p=0.57, respectively). However, relapse-free-survival was significantly superior in VPA compared to STANDARD (24.4% vs. 6.4% at 5 years, p=0.02). Explorative subset analyses revealed that AML with mutated NPM1 may particularly benefit from VPA. This study was registered at clinicaltrials.gov, identifier: NCT00151255.
[Show abstract][Hide abstract] ABSTRACT: Leukemia is one of the leading journals in hematology and oncology. It is published monthly and covers all aspects of the research and treatment of leukemia and allied diseases. Studies of normal hemopoiesis are covered because of their comparative relevance.
No preview · Article · Mar 2014 · Leukemia: official journal of the Leukemia Society of America, Leukemia Research Fund, U.K
[Show abstract][Hide abstract] ABSTRACT: Mutations in TP53, NOTCH1, and SF3B1 were analyzed in the CLL8 study evaluating first-line therapy with fludarabine and cyclophosphamide (FC) or FC with rituximab (FCR). TP53, NOTCH1, and SF3B1 were mutated in 11.5%, 10.0%, and 18.4% of patients, respectively. While NOTCH1(mut) and SF3B1(mut) virtually showed mutual exclusivity (0.6% concurrence), TP53(mut) was frequently found in NOTCH1(mut) (16.1%) and in SF3B1(mut) (14.0%) patients. There were few significant associations with clinical and laboratory characteristics but genetic markers had strong influence on response and survival. In multivariable analyses, an independent prognostic impact was found for FCR, thymidine kinase (TK) ≥10, unmutated IGHV, 11q deletion, 17p deletion, TP53(mut), and SF3B1(mut) on progression-free survival; and of FCR, age ≥65 years, ECOG performance status ≥0, β2-microglobulin ≥3.5, TK ≥10, unmutated IGHV, 17p deletion, and TP53(mut) on overall survival. Notably, predictive marker analysis identified an interaction of NOTCH1 mutational status and treatment, in that rituximab failed to improve response and survival in patients with NOTCH1(mut). In conclusion, TP53 and SF3B1 mutations appear among the strongest prognostic markers in CLL patients receiving current standard first-line therapy. NOTCH1(mut) was identified as a predictive marker for decreased benefit from the addition of rituximab to FC (FCR). This study is registered at ClinicalTrials.gov, identifier: NCT00281918.
[Show abstract][Hide abstract] ABSTRACT: Aberrant expression of the secreted protein, acidic, cysteine-rich (osteonectin) (SPARC) gene, which encodes a matricellular protein that participates in normal tissue remodeling, is associated with a variety of diseases including cancer, but the contribution of SPARC to malignant growth remains controversial. We previously reported that SPARC was among the most upregulated genes in cytogenetically normal acute myeloid leukemia (CN-AML) patients with gene-expression profiles predictive of unfavorable outcome, such as mutations in isocitrate dehydrogenase 2 (IDH2-R172) and overexpression of the oncogenes brain and acute leukemia, cytoplasmic (BAALC) and v-ets erythroblastosis virus E26 oncogene homolog (ERG). In contrast, SPARC was downregulated in CN-AML patients harboring mutations in nucleophosmin (NPM1) that are associated with favorable prognosis. Based on these observations, we hypothesized that SPARC expression is clinically relevant in AML. Here, we found that SPARC overexpression is associated with adverse outcome in CN-AML patients and promotes aggressive leukemia growth in murine models of AML. In leukemia cells, SPARC expression was mediated by the SP1/NF-κB transactivation complex. Furthermore, secreted SPARC activated the integrin-linked kinase/AKT (ILK/AKT) pathway, likely via integrin interaction, and subsequent β-catenin signaling, which is involved in leukemia cell self-renewal. Pharmacologic inhibition of the SP1/NF-κB complex resulted in SPARC downregulation and leukemia growth inhibition. Together, our data indicate that evaluation of SPARC expression has prognosticative value and SPARC is a potential therapeutic target for AML.
Full-text · Article · Mar 2014 · The Journal of clinical investigation
[Show abstract][Hide abstract] ABSTRACT: Acute myeloid leukemia (AML) with t(8;21) or inv(16) is commonly referred to as core-binding factor AML (CBF-AML). The incorporation of high-dose cytarabine for postremission therapy has substantially improved the outcome of CBF-AML patients, especially when administered in the setting of repetitive cycles. For many years, high-dose cytarabine was the standard treatment in CBF-AML resulting in favorable long-term outcome in approximately half of the patients. Therefore, CBF-AML patients are generally considered to be a favorable AML group. However, a substantial proportion of patients cannot be cured by the current treatment. Additional genetic alterations discovered in CBF-AML help in our understanding of the process of leukemogenesis and some of them may refine the risk assessment in CBF-AML and, importantly, also serve as targets for novel therapeutic approaches. We discuss the clinical and genetic heterogeneity of CBF-AML, with a particular focus on the role of KIT mutations as a prognosticator, and also discuss recent efforts to target the KIT kinase in the context of existing therapeutic regimens.
[Show abstract][Hide abstract] ABSTRACT: The clinical value of allogeneic and autologous hematopoietic stem cell transplantation (alloHSCT, autoHSCT) in the subtype of acute myeloid leukemia (AML) with double mutant CEBPA (CEBPAdm) has remained unsettled. Among 2983 patients analyzed for CEBPA mutational status (age 18-60 years) treated on four HOVON/SAKK and three AMLSG protocols; 124 had AML with CEBPAdm and achieved first complete remission (CR1). Evaluation of the clinical impact of alloHSCT and autoHSCT versus chemotherapy was performed by addressing time dependency in the statistical analyses. Thirty-two patients proceeded to alloHSCT from a matched related (MRD, n=29) or matched unrelated donor (MUD, n=3) and 20 to autoHSCT in CR1; 72 received chemotherapy. Relapse-free survival (RFS) was significantly superior in patients receiving an alloHSCT or autoHSCT in CR1 as compared to chemotherapy (p<0.001), whereas overall survival (OS) was not different (p=0.12). Forty-five patients relapsed. Of 42 patients treated with reinduction therapy, 35 achieved a second CR (83%) and most (n=33) patients received an alloHSCT (MRD, n=11; MUD, n=19; haplo-identical donor, n=3). Survival of relapsed patients measured from date of relapse was 46% after 3 years. Adult AML patients with CEBPAdm benefit from alloHSCT and autoHSCT; relapsed patients still have a favorable outcome after reinduction followed by alloHSCT. All patients had been included in 6 multicenter treatment trials, of which 5 had been published previously and one is registered at clinicaltrials.gov (NCT00151255).
[Show abstract][Hide abstract] ABSTRACT: We studied the incidences, associations and prognostic roles of NOTCH1 and SF3B1 mutations (NOTCH1(mut), SF3B1(mut)) as compared to TP53(mut) in fludarabine-refractory chronic lymphocytic leukemia (CLL) patients treated with alemtuzumab on the CLL2H trial. We found NOTCH1(mut), SF3B1(mut) and TP53(mut) in 13.4%, 17.5% and 37.4% of patients, respectively. NOTCH1(mut) and SF3B1(mut) were mutually exclusive, whereas TP53(mut) were evenly distributed within both subgroups. Apart from correlation of SF3B1(mut) with 11q deletion (p=.029), there were no other significant associations of the mutations with any baseline characteristics or response rates. However, NOTCH1(mut) cases had a significantly longer progression-free survival (PFS) compared to wild type (WT) cases (15.47 vs. 6.74 months; p=.025) while there was no significant difference regarding OS. SF3B1(mut) had no significant impact on PFS and overall survival (OS). In multivariable analyses, NOTCH1(mut) was identified as an independent favorable marker for PFS. This clinical trial is registered at www.clinicaltrials.gov as #NCT00274976.
[Show abstract][Hide abstract] ABSTRACT: Mutations in the nucleophosmin 1 (NPM1) gene are considered as a founder event in the pathogenesis of acute myeloid leukemia (AML). To address the role of clonal evolution in relapsed NPM1 mutated (NPM1(mut)) AML, we applied high-resolution genome-wide single-nucleotide polymorphism (SNP) array profiling to detect copy number alterations (CNA) and uniparental disomies (UPD) and performed comprehensive gene mutation screening in 53 paired bone marrow/peripheral blood samples obtained at diagnosis and relapse. At diagnosis, 15 aberrations (CNAs, n=10; UPDs, n=5) were identified in 13 patients (25%), whereas at relapse 56 genomic alterations (CNAs, n=46; UPDs, n=10) were detected in 29 patients (55%) indicating an increase in genomic complexity. Recurrent aberrations acquired at relapse included deletions affecting tumor suppressor genes [ETV6 (n=3), TP53 (n=2), NF1 (n=2), WT1 (n=3), FHIT (n=2)] and homozygous FLT3 mutations acquired via UPD13q (n=7). DNMT3A mutations (DNMT3A(mut)) showed the highest stability (97%). Persistence of DNMT3A(mut) in 5 patients who lost NPM1(mut) at relapse suggests that DNMT3A(mut) may precede NPM1(mut) in AML pathogenesis. Of note, all relapse samples shared at least one genetic aberration with the matched primary AML sample implying common ancestral clones. In conclusion, our study reveals novel insights into clonal evolution in NPM1(mut) AML.
[Show abstract][Hide abstract] ABSTRACT: In this study, we evaluated the frequency and prognostic impact of DNMT3A mutations (DNMT3A(mut)) in 1,770 younger adult patients with acute myeloid leukemia (AML) in the context of other genetic alterations and the European LeukemiaNet (ELN) classification. DNMT3A(mut) were found in 20.9% of AMLs and were associated with higher age (p<0.0001), higher white blood cell counts (p<0.0001), cytogenetically-normal AML (CN-AML; p<0.0001), as well as with NPM1 mutations (p<0.0001), FLT3 internal tandem duplications (p<0.0001) and IDH1/2 mutations (p<0.0001). In univariable and multivariable analyses, DNMT3A(mut) did not impact event-free, relapse-free (RFS) and overall survival (OS), neither in the whole cohort nor in CN-AML; a negative prognostic effect was only found in the ELN unfavorable CN-AML subset (OS, p=0.011). In addition, R882 mutations versus non-R882 mutations showed opposed clinical effects, unfavorable for R882 on RFS (all: HR 1.29, p=0.026; CN-AML: HR 1.38, p=0.018), and favorable for non-R882 on OS (all: HR 0.77; p=0.057; CN-AML: HR 0.73; p=0.083). In our statistically highly powered study with minimized selection bias, DNMT3A(mut) represents a frequent genetic lesion in younger adults with AML, but has no significant impact on survival endpoints; only moderate effects on outcome were found dependent on molecular subgroup and DNMT3A(mut) type.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this analysis was to provide six-year follow-up of the GCLLSG CLL3X trial which studied reduced-intensity allogeneic hematopoietic stem cell transplantation (HSCT) in patients with poor-risk chronic lymphocytic leukemia (CLL), and to investigate the impact of TP53, SF3B1, and NOTCH1 mutations on HSCT outcome. Six-year overall survival (OS) and event-free survival (EFS) of 90 allografted patients was 58% and 38%, respectively. TP53, SF3B1, and NOTCH1 mutations were found in 30%, 26%, and 14% of the trial population. By univariate and multivariate analyses, the mutational status of the TP53, SF3B1, and NOTCH1 genes had no significant impact on OS and EFS. Studies of minimal residual disease confirmed durability of CLL eradication in mutated patients. We conclude that HSCT can provide long-term disease control in patients with poor-risk CLL independent of the presence of TP53, SF3B1, and NOTCH1 mutations. The trial has been registered at the US National Cancer Institute (Protocol Identity # EU-20554, NCT00281983).
[Show abstract][Hide abstract] ABSTRACT: The inv(16)(p13q22)/t(16;16)(p13;q22) in acute myeloid leukemia results in multiple CBFB-MYH11 fusion transcripts, with type A being most frequent. The biologic and prognostic implications of different fusions are unclear. We analyzed CBFB-MYH11 fusion types in 208 inv(16)/t(16;16) patients with de novo disease, and compared clinical and cytogenetic features and the KIT mutation status between type A (n=182; 87%) and non-type A (n=26; 13%) patients. At diagnosis, non-type A patients had lower white blood counts (P=.007), and more often trisomies of chromosomes 8 (P=.01) and 21 (P<.001) and less often trisomy 22 (P=.02). No patient with non-type A fusion carried a KIT mutation, whereas 27% of type A patients did (P=.002). Among the latter, KIT mutations conferred adverse prognosis; clinical outcomes of non-type A and type A patients with wild-type KIT were similar. We also derived a fusion-type-associated global gene-expression profile. Gene Ontology analysis of the differentially expressed genes revealed - among others - an enrichment of up-regulated genes involved in activation of caspase activity, cell differentiation and cell cycle control in non-type A patients. We conclude that non-type A fusions associate with distinct clinical and genetic features, including lack of KIT mutations, and a unique gene-expression profile.
[Show abstract][Hide abstract] ABSTRACT: In this study we evaluated the impact of secondary genetic lesions in acute myeloid leukemia (AML) with inv(16)(p13.1q22) or t(16;16)(p13.1;q22); CBFB-MYH11. One hundred and seventy-six patients, all enrolled on prospective treatment trials, were studied for secondary chromosomal aberrations and mutations in N-/KRAS, KIT, FLT3, and JAK2 (V617F) genes. Most frequent chromosomal aberrations were trisomy 22 (18%) and trisomy 8 (16%). Overall, 84% of patients harbored at least one gene mutation with RAS being affected in 53% [45% NRAS; 13% KRAS] of the cases, followed by KIT (37%), and FLT3 [17%; FLT3-TKD (14%), FLT3-ITD (5%)]. None of the secondary genetic lesions influenced achievement of complete remission. In multivariable analyses, KIT mutation [hazard ratio (HR)=1.67; P=.04], log(10)(WBC) (HR=1.33; P=.02), and trisomy 22 (HR=0.54; P=.08) were relevant factors for relapse-free survival; for overall survival FLT3 mutation (HR=2.56; P=.006), trisomy 22 (HR=0.45; P=.07), trisomy 8 (HR=2.26; P=.02), age (difference of 10 years, HR=1.46; P=.01), and therapy-related AML (HR 2.13; P=.14) revealed as prognostic factors. The adverse effects of KIT and FLT3 mutations were mainly attributed to exon 8 and TKD mutations, respectively. Our large study emphasizes the impact of both secondary chromosomal aberrations as well as gene mutations for outcome in AML with inv(16)/t(16;16).
[Show abstract][Hide abstract] ABSTRACT: Acute myeloid leukemia (AML) is characterized by molecular heterogeneity. As commonly altered genomic regions point to candidate genes involved in leukemogenesis, we used microarray-based comparative genomic hybridization and single nucleotide polymorphism profiling data of 391 AML cases to further narrow down genomic regions of interest. Targeted resequencing of 1000 genes located in the critical regions was performed in a representative cohort of 50 AML samples comprising all major cytogenetic subgroups. We identified 120 missense/nonsense mutations as well as 60 insertions/deletions affecting 73 different genes (~3.6 tumor-specific aberrations/AML). While most of the newly identified alterations were non-recurrent, we observed an enrichment of mutations affecting genes involved in epigenetic regulation including known candidates like TET2, TET1, DNMT3A and DNMT1, as well as mutations in the histone methyltransferases NSD1, EZH2 and MLL3. Furthermore, we found mutations in the splicing factor SFPQ and in the non-classical regulators of mRNA processing CTCF and RAD21. These splicing-related mutations affected 10% of AML patients in a mutually exclusive manner. In conclusion, we could identify a large number of alterations in genes involved in aberrant splicing and epigenetic regulation in genomic regions commonly altered in AML, highlighting their important role in the molecular pathogenesis of AML.
[Show abstract][Hide abstract] ABSTRACT: The tet oncogene family member 2 (TET2) gene was recently identified to be mutated in myeloid disorders including acute myeloid leukemia (AML). To date, there is increasing evidence for a functional role of TET2 mutations (TET2(mut)) in AML. Thus, we explored the frequency, gene-expression pattern, and clinical impact of TET2(mut) in a large cohort of patients with AML in the context of other AML-associated aberrations.
Samples from 783 younger adult patients with AML were analyzed for the presence of TET2(mut) (coding exons 3 to 11), and results were correlated with data from molecular genetic analyses, gene-expression profiling, and clinical outcome.
In total, 66 TET2(mut) were found in 60 patients (60 of 783 patients; 7.6%), including missense (n = 37), frameshift (n = 16), and nonsense (n = 13) mutations, which, with one exception, were all heterozygous. TET2(mut) were not correlated with distinct clinical features or genetic alterations, except for isocitrate dehydrogenase mutations (IDH(mut)) that were almost mutually exclusive with TET2(mut) (P < .001). TET2(mut) were characterized by only a weak gene-expression pattern, which, nevertheless, reflected TET2(mut)-associated biology. TET2(mut) did not impact the response to induction therapy and clinical outcome; the combination of patients who exhibited TET2(mut) and/or IDH(mut) revealed shorter overall survival (P = .03), although this association was not independent from known risk factors.
TET2(mut) were identified in 7.6% of younger adult patients with AML and did not impact the response to therapy and survival. Mutations were mutually exclusive with IDH(mut), which supported recent data on a common mechanism of action that might obscure the impact of TET2(mut) if compared against all other patients with AML.
No preview · Article · Mar 2012 · Journal of Clinical Oncology