SNP array analysis of acute promyelocytic leukemia may be of prognostic relevance and identifies a potential high risk group with recurrent deletions on chromosomal subband 1q31.3.

To search for new copy number alterations (CNAs) in acute promyelocytic leukemia (APL), we analyzed DNA from leukemic blasts of 93 acute promyelocytic leukemia (APL) patients with Genome-Wide SNP 6.0 arrays (SNP-A). We identified 259 CNAs consisting of 170 heterozygous deletions, 82 amplifications, and 7 regions of copy number neutral loss of heterozygosity. One of the most common CNAs was a deletion on chromosomal subband 1q31.3 in 13 of 93 (14%) patients encompassing the coding regions for the microRNAs mir181a1/b1. In multivariable analysis with the covariates age, white blood cell count, platelet count, and FLT3-ITD/FLT3 D835 mutations we found that after adjustment for patients' age (P<0.0001), patients with 2 or more CNAs detected by SNP-A had a higher risk of death (hazard ratio=5.942, P=0.0015) than patients with 0 or 1 CNA. Deletions of 1q31.3 were associated with a higher number of CNAs (median 2 vs. 8, P<0.0001) and were a strong independent prognostic factor for an increased risk of relapse (hazard ratio=28.9, P=0.0031). This study presents a comprehensive assessment of new CNAs as pathomechanistically relevant targets and possible prognostic factors which could refine risk stratification of APL.

Age-dependent frequencies of NPM1 mutations and FLT3-ITD in patients with normal karyotype AML (NK-AML).

Prognosis of AML in elderly patients is poor due to adverse patient characteristics and comorbidities. In addition, disease-associated parameters reveal differences between older and younger patients with AML. Survival in normal karyotype AML (NK-AML) is influenced by different clinical and molecular markers. The aim of this work was to investigate the frequencies of molecular markers in patients with NK-AML with a focus on NPM1 mutations and FLT3-ITD in different age groups. In the present study, we analyzed the frequencies of mutations of NPM1 and FLT3-ITD in a cohort of 1,321 adult patients and 148 children with AML treated within the AMLCG99, the AML98, and AML04 trials and their distribution in different age groups. Additionally, the frequencies of mutations in CEBPA genes, FLT3-TKD, and MLL-PTD were analyzed in the cohort with NK-AML (n = 729). Our data show that the presence of mutations of NPM1 (from 60% to 40%) and FLT3-ITD (from 50% to 20%) significantly decreased with age in adult AML. Consequently, the proportion of NPM1-/FLT3-ITD- patients increased with age. The decreasing frequency of NPM1 mutations in elderly patients was paralleled by a reduced complete remission (CR) rate in the elderly of 55% compared to 80% in the younger patients. By contrast, the frequencies of other gene mutations, like FLT3-TKD and MLL-PTD, and mutations in CEBPA were not age-dependent. The decreasing frequency of the favorable NPM1 mutations with increasing age may partially explain the worse outcome in the elderly patients. Furthermore, the increasing amount of elderly patients without NPM1 mutations or FLT3-ITD suggests that other molecular and clinical risk factors may influence prognosis in this age group.

NPM1 but not FLT3-ITD mutations predict early blast cell clearance and CR rate in patients with normal karyotype AML (NK-AML) or high-risk myelodysplastic syndrome (MDS).

Mutations in the NPM1 gene represent the most frequent genetic alterations in patients with acute myeloid leukemia (AML) and are associated with a favorable outcome. In 690 normal karyotype (NK) AML patients the complete remission rates (CRs) and the percentage of patients with adequate in vivo blast cell reduction 1 week after the end of the first induction cycle were significantly higher in NPM1(+) (75% and 80%, respectively) than in NPM1(-) (57% and 57%, respectively) patients, but were unaffected by the FLT3-ITD status. Multivariate analyses revealed the presence of a NPM1 mutation as an independent positive prognostic factor for the achievement of an adequate day-16 blast clearance and a CR. In conclusion, NPM1(+) blast cells show a high in vivo sensitivity toward induction chemotherapy irrespective of the FLT3-ITD mutation status. These findings provide insight into the pathophysiology and help to understand the favorable clinical outcome of patients with NPM1(+) AML.

Expression of VEGF-C and its receptor VEGFR-3 in the bone marrow of patients with acute myeloid leukaemia.

Vascular endothelial growth factor-C (VEGF-C) has been shown to promote survival and resistance to chemotherapy of AML-cells in vitro. We investigated the expression of VEGF-C/VEGFR-3 in the bone marrow and pretherapeutic plasma levels of VEGF-C in patients with newly diagnosed AML. Expression of VEGF-C/VEGFR-3 was significantly higher in AML patients than in controls, while circulating levels did not differ. However, VEGF-C/VEGFR-3 expression was not able to predict clinical outcome. In conclusion, AML is associated with an increased expression of VEGF-C/VEGFR-3. Although expression levels display no prognostic significance in our study, strategies targeting the VEGF-C/VEGFR-3-pathway might be a promising treatment approach.

Long-term follow-up of cytogenetically normal CEBPA-mutated AML.

BACKGROUND: The aim of this study was to analyze the long-term survival of AML patients with CEBPA mutations. PATIENTS AND METHODS: We investigated 88 AML patients with a median age of 61 years and (1) cytogenetically normal AML (CN-AML), (2) monoallelic (moCEBPA) or biallelic (biCEBPA) CEBPA mutation, and (3) intensive induction treatment. 60/88 patients have been described previously with a shorter follow-up. RESULTS: Median follow-up time was 9.8 years (95% CI: 9.4-10.1 years) compared to 3.2 and 5.2 years in our former analyses. Patients with biCEBPA mutations survived significantly longer compared to those with moCEBPA (median overall survival (OS) 9.6 years vs. 1.7 years, p = 0.008). Patients ≤ 60 years and biCEBPA mutations showed a favorable prognosis with a 10-year OS rate of 81%. CONCLUSIONS: In this long-term observation we confirmed the favorable prognostic outcome of patients with biCEBPA mutations compared to moCEBPA-mutated CN-AML. The high probability of OS (81%) in younger patients is helpful to guide intensity of postremission therapy.

The NPM1 mutation type has no impact on survival in cytogenetically normal AML.

NPM1 mutations represent frequent genetic alterations in patients with acute myeloid leukemia (AML) associated with a favorable prognosis. Different types of NPM1 mutations have been described. The purpose of our study was to evaluate the relevance of different NPM1 mutation types with regard to clinical outcome. Our analyses were based on 349 NPM1-mutated AML patients treated in the AMLCG99 trial. Complete remission rates, overall survival and relapse-free survival were not significantly different between patients with NPM1 type A or rare type mutations. The NPM1 mutation type does not seem to play a role in risk stratification of cytogenetically normal AML.

Combined molecular and clinical prognostic index for relapse and survival in cytogenetically normal acute myeloid leukemia.

PURPOSE: Cytogenetically normal (CN) acute myeloid leukemia (AML) is the largest and most heterogeneous cytogenetic AML subgroup. For the practicing clinician, it is difficult to summarize the prognostic information of the growing number of clinical and molecular markers. Our purpose was to develop a widely applicable prognostic model by combining well-established pretreatment patient and disease characteristics. PATIENTS AND METHODS: Two prognostic indices for CN-AML (PINA), one regarding overall survival (OS; PINAOS) and the other regarding relapse-free survival (RFS; PINARFS), were derived from data of 572 patients with CN-AML treated within the AML Cooperative Group 99 study (www.aml-score.org). RESULTS: On the basis of age (median, 60 years; range, 17 to 85 years), performance status, WBC count, and mutation status of NPM1, CEBPA, and FLT3-internal tandem duplication, patients were classified into the following three risk groups according to PINAOS and PINARFS: 29% of all patients and 32% of 381 responding patients had low-risk disease (5-year OS, 74%; 5-year RFS, 55%); 56% of all patients and 39% of responding patients had intermediate-risk disease (5-year OS, 28%; 5-year RFS, 27%), and 15% of all patients and 29% of responding patients had high-risk disease (5-year OS, 3%; 5-year RFS, 5%), respectively. PINAOS and PINARFS stratified outcome within European LeukemiaNet genetic groups. Both indices were confirmed on independent data from Cancer and Leukemia Group B/Alliance trials. CONCLUSION: We have developed and validated, to our knowledge, the first prognostic indices specifically designed for adult patients of all ages with CN-AML that combine well-established molecular and clinical variables and that are easily applicable in routine clinical care. The integration of both clinical and molecular markers could provide a basis for individualized patient care through risk-adapted therapy of CN-AML.

Downregulation of neuropilin-1 in patients with acute myeloid leukemia treated with thalidomide.

OBJECTIVE: Neuropilin-1 (NRP-1), a non-tyrosine kinase receptor functioning as a mediator of angiogenesis and neuronal guidance, was recently found to be significantly overexpressed in newly diagnosed acute myeloid leukemia (AML) patients with significant correlation to survival. The role of NRP-1 in refractory or relapsed AML patients and its regulation during anti-angiogenic treatment remain to be elucidated. METHODS: Bone marrow biopsies of 10 patients with refractory or relapsed AML were evaluated for NRP-1 expression by immunohistochemical analysis, and NRP-1 expression level was determined before and after start of thalidomide therapy and correlated to response and growth factor expression. RESULTS: NRP-1 expression was significantly increased in AML patients [median 7 arbitrary units (AU)] when compared with controls (n = 38, median 2.75 AU). Under thalidomide treatment, a marked difference in the course of NRP-1 expression between responders and non-responders was observed, however, without a statistical significance (P = 0.071) being reached. Additionally, a significant correlation of the NRP-1 expression level to microvessel density could be detected under treatment with thalidomide (P = 0.018). CONCLUSION: Our data provide evidence of increased NRP-1 expression in relapsed or refractory AML. Additionally, our results suggest that thalidomide-induced antileukemic properties might at least in part be mediated by NRP-1 downregulation.

Efficacy and safety of thalidomide in patients with acute myeloid leukemia.

Emerging data suggest an involvement of angiogenesis in the pathophysiology of acute myeloid leukemia (AML). Thus, antiangiogenic therapy could constitute a novel strategy for the treatment of AML. To test this hypothesis, a phase I/II dose-escalating trial was performed to study the safety and efficacy of thalidomide, a putative inhibitor of angiogenesis, in 20 patients with AML. Thirteen patients were assessable for both toxicity and response, tolerating a maximum dose of 200 to 400 mg daily for at least 1 month. Seven patients had to be prematurely withdrawn from drug administration owing to progressive disease and death (3 patients), personal decision (2 patients), or inability to tolerate thalidomide (2 patients). Overall, adverse events were fatigue, constipation, rash, and neuropathy (grade 1 to 2 in most patients). In 4 patients, a partial response, defined as reduction of at least 50% in the blast cell infiltration of the bone marrow accompanied by increases in platelet counts and hemoglobin values, was observed. One additional patient showed a hematologic improvement without fulfilling the criteria of a partial response. The responses lasted a median of 3 months (range, 1-8 months). In parallel, microvessel densities significantly decreased in these 5 patients during treatment with thalidomide (P <.05). This decrease was accompanied by declining plasma levels of basic fibroblast growth factor, one of the most potent angiogenic growth factors. In conclusion, single-agent thalidomide has antiangiogenic and antileukemic activity in AML, although a causal relationship between both effects has still to be proven.