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In this study, we provide a molecular signature of highly enriched CD34+ cells from bone marrow of untreated patients with chronic myelogenous leukemia (CML) in chronic phase in comparison with normal CD34+ cells using microarrays covering 8746 genes. Expression data reflected several BCR-ABL-induced effects in primary CML progenitors, such as transcriptional activation of the classical mitogen-activated protein kinase pathway and the phosphoinositide-3 kinase/AKT pathway as well as downregulation of the proapoptotic gene IRF8. Moreover, novel transcriptional changes in comparison with normal CD34+ cells were identified. These include upregulation of genes involved in the transforming growth factorβ pathway, fetal hemoglobin genes, leptin receptor, sorcin, tissue inhibitor of metalloproteinase 1, the neuroepithelial cell transforming gene 1 and downregulation of selenoprotein P. Additionally, genes associated with early hematopoietic stem cells (HSC) and leukemogenesis such as HoxA9 and MEIS1 were transcriptionally activated. Differential expression of differentiation-associated genes suggested an altered composition of the CD34+ cell population in CML. This was confirmed by subset analyses of chronic phase CML CD34+ cells showing an increase of the proportion of megakaryocyte-erythroid progenitors, whereas the proportion of HSC and granulocyte–macrophage progenitors was decreased in CML. In conclusion, our results give novel insights into the biology of CML and could provide the basis for identification of new therapeutic targets.Leukemia (2007) 21, 494–504. doi:10.1038/sj.leu.2404549; published online 25 January 2007 [ABSTRACT FROM AUTHOR]

Objective: As peripheral blood (PB) Wilm's Tumor 1 (WT1)-mRNA expression is established as MRD-marker during conventional AML chemotherapy, impact of pretransplant WT1 expression remains unclear. Therefore, we aimed to assess prognostic impact of pretransplant WT1 expression on post-transplant outcome in patients with AML/MDS., Methods: In 64 AML/MDS patients, pretransplant WT1 expression was retrospectively analyzed using a standardized assay offering high sensitivity, specificity, and a validated cut-off. Patients were divided into three groups determined by pretransplant remission and WT1 expression. Post-transplant outcome of these groups was compared regarding cumulative incidence of relapse (CIR), relapse-free (RFS), and overall survival (OS)., Results: Pretransplant forty-six patients (72%) showed hematologic remission, including 21 (46%) MRD-negative and 25 (54%) MRD-positive patients indicated by WT1 expression, while 18 refractory patients (28%) showed active disease. Two-year estimates of post-transplant CIR, RFS, and OS were similar in MRD-positive (61%, 37%, 54%) and refractory patients (70%, 26%, 56%), but significantly inferior compared with MRD-negative patients (10%, 89%, 90%). After multivariable adjustment, pretransplant MRD negativity measured by WT1 expression retained its prognostic impact on CIR (P = .008), RFS (P = .005), and OS (P = .049)., Conclusions: PB WT1 expression represents a useful method to estimate pretransplant MRD, which is highly predictable for post-transplant outcome and may help improving peri-transplant management in AML/MDS patients., (© 2021 The Authors. European Journal of Haematology published by John Wiley & Sons Ltd.)

Hypomethylating agents (HMA) for relapsed acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) after allogeneic transplantation (allo-SCT) are most effective when used at the stage of molecular relapse. As Wilm's Tumor 1 (WT1)- expression has proven to serve as broadly applicable, sensitive and specific minimal residual disease (MRD) marker, we measured WT1-expression in 35 AML and MDS patients using a standardized assay for the guidance of therapy with HMA and donor lymphocyte infusions (DLI). Molecular relapse was detected in median 168 days post-transplant prompting therapy with a median of six HMA cycles and at least one DLI (n = 22, 63%). Hereby, 13 patients (37%) achieved major response (=MRD - complete remission [CR]), and 7 patients (20%) achieved minor response (=MRD + CR), whereas 15 patients (43%) progressed into hematologic relapse. Two-year overall survival (OS) rate was 35% including 11 patients (31%) with ongoing MRD - remission for a median of 21 months. Patients with the major response after six cycles had significantly better OS suggesting that those not achieving MRD negativity after six cycles are candidates for alternative therapies. Combining MRD-monitoring of WT1-expression and preemptive therapy with HMA and DLI appears as a practicable and efficient approach for imminent relapse after allo-SCT.

To provide long-term outcome data and predictors for response and survival, we retrospectively analyzed all 151 patients with relapse of myeloid neoplasms after allogeneic hematopoietic stem cell transplantation (allo-HSCT) who were uniformly treated with first-line azacitidine (Aza) salvage therapy at our center. Patients were treated for molecular (39%) or hematologic relapse (61%), with a median of 5 cycles of Aza and at least one donor lymphocyte infusion in 70% of patients. Overall response was 46%, with 41% achieving complete (CR) and 5% achieving partial remission. CR was achieved after a median of 4 cycles and lasted for a median of 11 months (range 0.9 to 120 months). With a median follow-up of 22 months (range: 1 to 122 months), the 2-year survival rate was 38% ± 9%, including 17 patients with ongoing remission for >5 years. Based on results from multivariate analyses, molecular relapse and time to relapse were integrated into a score, clearly dividing patients into 3 subgroups with CR rates of 71%, 39%, and 29%; and 2-year survival rates of 64%, 38%, and 27%, respectively. In the subgroup of MDS and secondary AML, receiving upfront transplantation was associated with superior response and survival, and therefore pretransplant strategy was integrated together with relapse type into a MDS-sAML-specific score. Overall, Aza enables meaningful responses and long-term survival, which is a predictable with a simple-to-use scoring system.

Few reports suggested a prognostic impact of Wilms'Tumor-1 (WT1)-mRNA overexpression in MDS, but translation into clinical routine was hampered by limited patients numbers, differing sample sources, non-standardized methods/cut-offs. To evaluate whether WT1-mRNA expression yields additional prognostic information, we measured peripheral blood (PB) WT1-mRNA expression in 94 MDS using a standardized assay offering a validated cut-off to discriminate between normal and WT1-mRNA overexpression. Overall, 54 patients (57%) showed WT1-mRNA overexpression, while 40 patients (43%) had normal WT1-mRNA expression. This enabled discrimination between MDS and both healthy controls and non-MDS cytopenias. Furthermore, WT1-mRNA expression correlated with WHO 2016 subcategories and IPSS-R as indicated by mean WT1-mRNA expression and frequency of WT1-mRNA overexpressing patients within respective subgroups. Regarding the entire group, PB WT1-mRNA expression was associated with prognosis, as those patients showing WT1-mRNA overexpression had higher risk for disease progression and AML transformation and accordingly shorter progression-free, leukemia-free and overall survival in univariate analysis. In multivariate analysis, prognostic impact of PB WT1-mRNA expression status was independent of IPSS-R and enabled more precise prediction of PFS, but not OS, within IPSS-R very low/low and intermediate risk groups. Overall, measuring PB WT1-mRNA appears valuable to support diagnostics and refine prognostication provided by the IPSS-R.

Overexpression of the Wilms' tumor 1 (WT1) gene is informative in many patients with acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS) and is measurable in peripheral blood (PB). Despite these advantages, WT1 has not broadly been established as a marker for minimal residual disease (MRD) monitoring after allogeneic hematopoietic stem cell transplantation (allo-HSCT) due to limited patient numbers, differing sample sources, and nonstandardized in-house methods. To estimate the value of WT1 as an MRD marker, we serially quantified PB WT1 expression using a standardized European LeukemiaNet-certified assay in 59 patients with AML and MDS after allo-HSCT. We compared its performance with routine methods such as chimerism, XY-fluorescence in situ hybridization (FISH), disease-specific cytogenetic, and molecular analyses, which were accessible in 100%, 34%, 68%, and 37%, respectively. Twenty-four patients (41%) relapsed within a median of 126 days after allo-HSCT, and 20 of them showed at least 1 elevated WT1 value above the validated cutoff. The other 35 patients (59%) remained in complete remission, and only 1 patient had a transient increase in WT1 expression. This reflects a sensitivity of 83% and a specificity of 97% for WT1 and appears to be favorable compared with the sensitivities and specificities observed for chimerism (33% and 91%), XY-FISH (67% and 73%), cytogenetic (33% and 77%), and molecular (78% and 85%) analyses. Further supporting its predictive impact, elevated WT1 expression prompted an earlier BM biopsy and consecutively the diagnosis of relapse in 62% of patients. The results of this real-life experience imply that PB WT1 expression is measurable by a standardized assay and predicts imminent relapse after allo-HSCT with high sensitivity and specificity in most patients with AML and MDS., (Copyright © 2018 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Bcl-2/IgH rearrangements can be quantified in follicular lymphoma (FL) from peripheral blood (PB) by polymerase chain reaction (PCR). The prognostic value of Bcl-2/IgH levels in FL remains controversial. We therefore prospectively studied PB Bcl-2/IgH levels from 173 first-line FL patients who were consecutively enrolled, randomized, and treated within the multicenter phase 3 clinical trial NHL1-2003 comparing bendamustine-rituximab (B-R) with rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone. From April 2005 to August 2008, 783 pre- and posttreatment PB samples were quantified by quantitative PCR. At inclusion, 114 patients (66%) tested positive and 59 (34%) were negative for Bcl-2/IgH. High pretreatment Bcl-2/IgH levels had an adverse effect on progression-free survival (PFS) compared with intermediate or low levels (high vs intermediate: hazard [HR], 4.28; 95% confidence interval [CI], 1.70-10.77; P = .002; high vs low: HR, 3.02; 95% CI, 1.55-5.86; P = .001). No PFS difference between treatment arms was observed in Bcl-2/IgH-positive patients. A positive posttreatment Bcl-2/IgH status was associated with shorter PFS (8.7 months vs not reached; HR, 3.15; 95% CI, 1.51-6.58; P = .002). By multivariate analysis, the pretreatment Bcl-2/IgH level was the strongest predictor for PFS. Our data suggest that pre- and posttreatment Bcl-2/IgH levels from PB have significant prognostic value for PFS in FL patients receiving first-line immunochemotherapy. This trial was registered at www.clinicaltrials.gov as #NCT00991211 and at the German Federal Institute for Drugs and Medical Devices as #BfArM-4021335., (© 2015 by The American Society of Hematology.)

Polycythemia vera (PV) is a chronic myeloproliferative disorder with an expansion of multipotent hematopoietic progenitor cells. Although it is known that hematopoietic progenitors in PV are erythropoietin independent and hypersensitive to several cytokines, the molecular oncogenic mechanisms in PV are largely unknown. In this study, we examined gene expression profiles of CD34(+) cells from bone marrow of patients with de novo PV and from healthy volunteers to identify molecular changes associated with the malignant growth of hematopoietic stem and progenitor cells in this myeloproliferative disorder. Using cDNA arrays, we found significant differences (P < .01) in the expression of 107 genes. Proapoptotic genes (CASP2, CASP3, DAPK1, ALG2) were expressed at lower levels in PV-CD34(+) cells, reflecting a lower apoptotic activity. Fibrosis-stimulating growth factors (transforming growth factor beta1, transforming growth factor beta2, bone morphogenetic protein 2, and endothelial growth factor) were expressed at significantly higher levels in PV-CD34(+) cells. Furthermore, PV-CD34(+) cells overexpressed several receptors, protein kinases, and proteasome subunits, which might be targets for directed therapeutic approaches. It is interesting that three retinoid receptors were overexpressed in PV-CD34(+) cells--retinoic acid receptor beta (RARbeta), retinoid X receptor beta (RXRbeta), and cellular retinoic acid binding protein 2 (CRABP2). Using methylcellulose colony-forming assays, we found that the formation of erythroid colonies derived from PV hematopoietic progenitors was inhibited by all-trans-retinoic acid (ATRA), a natural ligand of those receptors, in a dose-dependent manner, showing a maximum inhibition of 89% at 10 microM; the growth of myelomonocytic colonies was not significantly affected. These data suggest that the use of ATRA could be of therapeutic benefit for patients with PV.