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Wolfgang Kern

Publications and source records attributed to Wolfgang Kern.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of mRNA abundance quantified by gene expression profiling and percentage of positive cells using immunophenotyping for diagnostic antigens in acute and chronic leukemias.

BACKGROUND: Microarray analysis is considered a future diagnostic tool in leukemias. Whereas data accumulate on specific gene expression patterns in biologically defined leukemia entities, data on the correlation between flow cytometrically determined protein expression, which are essential in the diagnostic setting today, and microarray results are limited. METHODS: The results obtained by microarray analysis were compared using the Affymetrix GeneChip HG-U133 system in parallel with flow cytometric findings of 36 relevant targets in 814 patients with newly diagnosed acute and chronic leukemias as well as in normal bone marrow samples. RESULTS: In a total of 21,581 individual comparisons between signal intensities obtained by microarray analysis and percentages of positive cell as determined by flow cytometry, coefficients of correlation in the range of 0.171 to 0.807 were obtained. In particular, the degree of correlation was high in the following genes critical in the diagnostic setting: CD4, CD8, CD13 (ANPEP), CD33, CD23 (FCER2), CD64 (FCGR1A), CD117 (KIT), CD34, MPO, CD20 (MS4A1), CD7 (range of r, 0.589-0.807). CONCLUSIONS: The present data prove the high degree of correlation between findings obtained by microarray analysis and flow cytometry. They are in favor of a future application of the microarray technology as a robust diagnostic tool in leukemias.

Antigens, CD↗
PubMed2006

Acute myeloid leukemia (AML) with t(8;21)(q22;q22) relapsing as AML with t(3;21)(q26;q22).

We here report on an 48-year-old male patient with a primary diagnosis of acute myeloid leukemia (AML)-M2 with t(8;21)(q22;q22), who developed complete hematologic and molecular remission after induction chemotherapy. Thirteen months later, he relapsed and showed an AML-M2 with t(3;21)(q26;q22). Retrospectively, polymerase chain reaction (PCR) for AML1-EVI1 and EVI1 overexpression was performed on bone marrow and peripheral blood samples taken at diagnosis and during the first year after the first manifestation of AML to quantify the AML1-EVI1-positive clone. In a bone marrow sample taken 25 days from diagnosis, PCR for AML1-EVI1 was negative, and EVI1 expression, as assessed by quantitative real-time PCR, was within the same range as that of healthy controls. These data suggest that this patient developed a secondary therapy-related AML rather than a relapse.

Chromosomes, Human, Pair 21↗
PubMed2006

Immunostimulatory oligonucleotide-induced metaphase cytogenetics detect chromosomal aberrations in 80% of CLL patients: A study of 132 CLL cases with correlation to FISH, IgVH status, and CD38 expression.

Compared with fluorescence in situ hybridization (FISH), conventional metaphase cytogenetics play only a minor prognostic role in chronic lymphocytic leukemia (CLL) so far, due to technical problems resulting from limited proliferation of CLL cells in vitro. Here, we present a simple method for in vitro stimulation of CLL cells that overcomes this limitation. In our unselected patient population, 125 of 132 cases could be successfully stimulated for metaphase generation by culture with the immunostimulatory CpG-oligonucleotide DSP30 plus interleukin 2. Of 125 cases, 101 showed chromosomal aberrations. The aberration rate is comparable to the rate detected by parallel interphase FISH. In 47 patients, conventional cytogenetics detected additional aberrations not detected by FISH analysis. A complex aberrant karyotype, defined as one having at least 3 aberrations, was detected in 30 of 125 patients, compared with only one such case as defined by FISH. Conventional cytogenetics frequently detected balanced and unbalanced translocations. A significant correlation of the poor-prognosis unmutated IgV(H) status with unbalanced translocations and of the likewise poor-prognosis CD38 expression to balanced translocations and complex aberrant karyotype was found. We demonstrate that FISH analysis underestimates the complexity of chromosomal aberrations in CLL. Therefore, conventional cytogenetics may define subgroups of patients with high risk of progression.

ADP-ribosyl Cyclase 1↗
PubMed2006

High-dose cytosine arabinoside in the treatment of acute myeloid leukemia: Review of three randomized trials.

BACKGROUND: The use of high-dose cytosine arabinoside (HDAraC) during induction may improve outcomes in patients with acute myeloid leukemia (AML) compared with standard-dose AraC (SDAraC). The objective of this review was to assess the impact of HDAraC during induction therapy for patients with AML based on results from randomized trials. METHODS: All randomized trials in the field were identified by using a predefined search strategy. Trials that assessed the impact of HDAraC compared with SDAraC as induction therapy for adult patients with AML in a randomized fashion and that reported the relevant endpoints were included. Data were extracted from each trial by both reviewers according to prespecified criteria. RESULTS: No differences between HDAraC and SDAraC were found with regard to complete remission rates (relative risk, 1.00; 95% confidence interval [95% CI], 0.92-1.10). The weighted mean difference (WMD) for median recurrence-free survival (RFS) was 4.19 in favor of HDAraC (95% CI, 0.59-7.78; P = .02). The WMD for 4-year RFS was 10.98 in favor of HDAraC (95% CI, 1.02-20.94; P = .03). The WMD for median overall survival (OS) was - 0.22 for HDAraC compared with SDAraC (95% CI, - 2.76-2.32; P = .9). Data regarding the median OS was heterogeneous between studies (chi-square P = .00), with 2 studies in favor of HDAraC and 2 studies in favor of SDAraC. The WMD for 4-year OS was 6.21 in favor of HDAraC (95% CI, 2.70-9.72; P = .0005). CONCLUSIONS: Induction therapy with HDAraC improved long-term disease control and overall survival in adults age < 60 years with de novo AML. It remains unknown whether patients should receive HDAraC during induction or if it is to be given during postremission therapy. Further analyses should focus on this issue and on the effects of HDAraC in prognostically different subgroups of patients with AML.

Adolescent↗
PubMed2006

Double induction containing either two courses or one course of high-dose cytarabine plus mitoxantrone and postremission therapy by either autologous stem-cell transplantation or by prolonged maintenance for acute myeloid leukemia.

PURPOSE: Intensification by high-dose cytarabine in postremission or induction therapy and prolonged maintenance are established strategies to improve the outcome in patients with acute myeloid leukemia (AML). Whether additional intensification can add to this effect has not yet been determined. PATIENTS AND METHODS: A total of 1,770 patients (age 16 to 85 years) with de novo or secondary AML or high-risk myelodysplastic syndrome (MDS) were randomly assigned upfront for induction therapy containing one course with standard dose and one course with high-dose cytarabine, or two courses with high-dose cytarabine, and in the same step received postremission prolonged maintenance or busulfan/cyclophosphamide chemotherapy with autologous stem-cell transplantation. RESULTS: The complete remission rate in patients younger than 60 and > or = 60 years of age was 70% and 53%, respectively. The overall survival at 3 years in the two age groups was 42% and 19%, the relapse-free survival was 40% and 19%, and the ongoing remission duration was 48% and 22%, respectively. There were no significant differences in these results between the two randomized induction arms or between the two postremission therapy arms. There was no significant difference in any prognostic subgroup according to secondary AML/MDS, cytogenetics, WBC, lactate dehydrogenase, and early blast clearance. CONCLUSION: The regimen of one course with standard-dose cytarabine and one course with high-dose cytarabine for induction, and prolonged maintenance for postremission chemotherapy in patients with AML is not improved by additional escalation in cytotoxic treatment.

Acute Disease↗
PubMed2006

Evaluation of complete disease remission in acute myeloid leukemia: a prospective study based on cytomorphology, interphase fluorescence in situ hybridization, and immunophenotyping during follow-up in patients with acute myeloid leukemia.

BACKGROUND: Different diagnostic methods add information to define complete remission (CR) in patients with acute myeloid leukemia (AML). The detection of minimal residual disease (MRD) for predicting prognosis and for therapeutic planning still are under discussion. METHODS: The authors studied 216 patients with AML at the time of initial diagnosis and during follow-up and correlated cytomorphology, interphase fluorescence in situ hybridization (FISH), and flow cytometry results to evaluate response status. They further tested the prognostic impact of those results, especially in patients who achieved a morphologic CR. RESULTS: Interphase FISH was found to be correlated significantly with the clinical course at the time of complete cytomorphologic remission and was more reliable than morphology for defining CR. Furthermore, interphase FISH was correlated with immunophenotyping results at all times during follow-up. CONCLUSIONS: The current results indicated that interphase FISH may be used as a valid MRD parameter in patients with AML. Multiparameter immunophenotyping for MRD also was correlated strongly with the clinical course, and the authors suggest integrating such immunophenotyping into the routine diagnostic panel at the time of diagnosis and during the clinical course in patients with AML.

Acute Disease↗
PubMed2006

Implications of NRAS mutations in AML: a study of 2502 patients.

We analyzed 2502 patients with acute myeloid leukemia at diagnosis for NRAS mutations around the hot spots at codons 12, 13, and 61 and correlated the results to cytomorphology, cytogenetics, other molecular markers, and prognostic relevance of these mutations. Two hundred fifty-seven (10.3%) of 2502 patients had NRAS mutations (NRAS(mut)). Most mutations (112 of 257; 43.6%) were found at codon 12, mostly resulting in changes from glycine to asparagine. The history of AML did not differ significantly in association with NRAS mutations. The subgroups with inv(16)/t(16;16) and inv(3)/t(3;3) showed a significantly higher frequency of NRAS(mut) (50 of 133, 37.6% [P < .001], and 11 of 41, 26.8% [P = .004], respectively) than the total cohort. In addition, in these 2 subgroups, mutations of codon 61 were significantly overrepresented (both P < .001). In contrast, NRAS mutations were significantly underrepresented in t(15;17) (2 of 102; 2%; P = .005) in the subgroup with MLL/11q23 rearrangements (3 of 77; 3.9%; P = .061) and in the complex aberrant karyotype (4 of 258; 1.6%; P < .001). Overall, we did not find a significant prognostic impact of NRAS(mut) for overall survival, event-free survival, and disease-free survival. However, there was a trend to better survival in most subgroups, especially when other molecular markers (FLT3-LM, MLL-PTD, and NPM) were taken into account.

Amino Acid Substitution↗
PubMed2006

D324N single-nucleotide polymorphism in the FLT3 gene is associated with higher risk of myeloid leukemias.

Mutations within the FLT3 gene are of growing importance for classification, risk assessment, and therapeutic targeting of acute myeloid leukemia (AML). We analyzed 656 AML patients for a recently described single-nucleotide polymorphism (SNP) in the third immunoglobulin-like domain of the extracellular region of FLT3. The FLT3 D324N variant was present in 42 cases (6.4%), but it was not associated with a specific AML subtype and did not show an elevated leukocyte count, as do other FLT3 mutations. In remission samples, a 50% ratio of the normal to the D324N variant was detectable. Stably expressed in IL-3 dependent Ba/F3 cells, the D324N variant did not confer receptor autophosphorylation, factor independent growth, or increased resistance to apoptotic cell death in response to varying doses of FLT3 ligand. In 400 healthy donors, the FLT3 D324N variant was detected in 6 cases (1.5%) and segregated in a family. Thus, it was shown to be a polymorphism with a lower frequency in healthy controls than in patients with AML (P < 0.001). In addition, 21 of 234 CML (9.0%) and 7 of 155 ALL (4.5%) cases carried the FLT3 D324N. Our data suggest that the FLT3 D324N variant might be associated with a predisposition to different subtypes of leukemia.

Acute Disease↗
PubMed2006

Impact of trisomy 8 on expression of genes located on chromosome 8 in different AML subgroups.

Trisomy 8 is the most frequently observed trisomy in acute myeloid leukemia (AML) occurring as a sole karyotype abnormality or in addition to other chromosome aberrations. It was the aim of this study to analyze the impact of trisomy 8 on the expression of genes located on chromosome 8 in distinct AML subgroups characterized by different chromosome abnormalities in addition to trisomy 8. Gene expression analyses were performed on a total of 567 AML cases comprising the following subgroups: +8 sole, +8 within a complex aberrant karyotype, +8 in addition to t(15;17), inv(16), t(8;21), 11q23/MLL, or other abnormalities, AML with normal karyotype and the before mentioned subgroups without trisomy 8. A significant higher mean expression of genes located on chromosome 8 was observed in subgroups with +8 in comparison to their respective control groups. A varying number of significantly higher expressed genes was identified in all comparisons. No gene was significantly overexpressed in all comparisons, and no distinct gene expression pattern was identified allowing the identification of cases with trisomy 8. In conclusion, the gain of chromosome 8 leads to a higher expression of genes located on chromosome 8. However, no consistent pattern of genes was identified, which shows a higher expression in all AML subtypes with trisomy 8. These data suggest that trisomy 8 rather provides a platform for a higher expression of chromosome 8 genes which are individually up-regulated by the respective primary genetic abnormalities. Therefore, trisomy 8 in AML determines no specific disease characteristic but is a disease modulating secondary event.

Acute Disease↗
PubMed2006

Classification of AML by DNA-oligonucleotide microarrays.

Accurate diagnosis and classification of leukemias are the bases for the appropriate management of patients. The diagnostic accuracy and efficiency of present methods may be improved by the use of microarrays. The following chapter gives an overview of the method of gene expression profiling of leukemia samples, its laboratory procedure, and how to approach the analysis of the data.

DNA, Complementary↗
PubMed2006

A combination of cytomorphology, cytogenetic analysis, fluorescence in situ hybridization and reverse transcriptase polymerase chain reaction for establishing clonality in cases of persisting hypereosinophilia.

To evaluate the frequency of clonal abnormalities in patients with unexplained persisting eosinophilia we analyzed 40 patients (27 males, 13 females) using cytomorphology, cytogenetic analysis, interphase fluorescence in situ hybridization (FISH), and reverse transcriptase polymerase chain reaction (RT-PCR). Cytogenetic analysis revealed clonal abnormalities in five patients (four of whom were males) including t(8;9)(p21;p24), ins(9;4)(q34;q12q31), del(6)(q24), and trisomy 8 (n=2). RT-PCR confirmed a PCM1-JAK2 fusion underlying the t(8;9). FISH analysis suggested a rearrangement involving PDGFRA in the ins(9;4). A FIP1L1-PDGFRA fusion gene was identified in four male patients by interphase FISH and RT-PCR. These methods in combination demonstrated clonality in 8/40 patients (20%) with a male predominance (6/8; 75%).

Chromosome Mapping↗
PubMed2005

Further correlations of morphology according to FAB and WHO classification to cytogenetics in de novo acute myeloid leukemia: a study on 2,235 patients.

In routine diagnostic procedures of acute myeloid leukemia (AML), the French-American-British (FAB) and World Health Organization (WHO) classifications both play a central role. Some morphologic subtypes are specifically associated to distinct cytogenetic and molecular aberrations; however, such close correlations do not exist for the majority of entities. We evaluated cytogenetics in 2,235 patients at diagnosis of AML with the FAB subtypes M0-2, M4, and M5-7. The cytogenetic patterns of these subtypes showed differences with respect to the clonal aberration rate and the incidence of complex aberrant karyotypes. The frequency of numerical gains and losses and of structural losses and the incidence of 11q23/MLL rearrangements differed. Thus, cytomorphology of AML may be helpful to support or even initiate other diagnostic procedures, e.g., interphase fluorescence in situ hybridization and polymerase chain reaction. In conclusion, the central role of morphology as defined by the FAB and WHO classification in AML at diagnosis is still justified in combination with other techniques.

Adolescent↗
PubMed2005

KIT-D816 mutations in AML1-ETO-positive AML are associated with impaired event-free and overall survival.

Mutations in codon D816 of the KIT gene represent a recurrent genetic alteration in acute myeloid leukemia (AML). To clarify the biologic implication of activation loop mutations of the KIT gene, 1940 randomly selected AML patients were analyzed. In total, 33 (1.7%) of 1940 patients were positive for D816 mutations. Of these 33 patients, 8 (24.2%) had a t(8;21), which was significantly higher compared with the subgroup without D816 mutations. Analyses of genetic subgroups showed that KIT-D816 mutations were associated with t(8;21)/AML1-ETO and other rare AML1 translocations. In contrast, other activating mutations like FLT3 and NRAS mutations were very rarely detected in AML1-rearranged leukemia. KIT mutations had an independent negative impact on overall (median 304 vs 1836 days; P = .006) and event-free survival (median 244 vs 744 days; P = .003) in patients with t(8;21) but not in patients with a normal karyotype. The KIT-D816V receptor expressed in Ba/F3 cells was resistant to growth inhibition by the selective PTK inhibitors imatinib and SU5614 but fully sensitive to PKC412. Our findings clearly indicate that activating mutations of receptor tyrosine kinases are associated with distinct genetic subtypes in AML. The KIT-D816 mutations confer a poor prognosis to AML1-ETO-positive AML and should therefore be included in the diagnostic workup. Patients with KIT-D816-positive/AML1-ETO-positive AML might benefit from early intensification of treatment or combination of conventional chemotherapy with KIT PTK inhibitors.

Adult↗
PubMed2005

Treatment of older patients with AML.

Undertreatment of the older patients with AML can explain, in part, their inferior outcome when compared with that in younger patients. In analogy to the benefit of patients under the age of 60 years from high-dose AraC there are dosage related therapeutic effects in the patients over 60 years in particular for daunorubicin in the induction treatment, and for maintenance versus no maintenance in the post-remission treatment. Utilizing these effects can partly overcome the mostly unfavorable disease biology in older age AML, whereas the role of risk factors involved is not completely understood and the concept of dose-response needs to be requestioned. We recommend an adequate dosage of 60 mg/(m2day) daunorubicin for 3 days in a combination with standard dose AraC and 6-thioguanine given for induction and consolidation and followed by a prolonged monthly maintenance chemotherapy. Further improvements in supportive care may help delivering additional anti-leukemic cytotoxicity. As a novel approach, reduced toxicity preparative regimens may open up allogeneic transplantation for older patients with AML. Other new options like MDR modulators, antibody targeted therapies and tyrosine kinase inhibitors are under clinical investigation. A questionnaire study in patients with AML showed that according to patients' self-assessment intensive and prolonged treatment did not result in decreasing quality of life. This finding did not vary by age under or above 60 years. Given the actual median age in this disease being more than 60 years the adequate management of older age AML remains as the major challenge.

Adult↗
PubMed2005

Modern diagnostics in acute leukemias.

Acute leukemias are a heterogeneous group of diseases. The different subtypes are characterized by certain clinical features and specific laboratory findings. Large clinical trials have confirmed the important impact of the underlying biology of each subtype for clinical outcome. Improvements in patient's treatment resulting in better survival rates are closely linked to the biological understanding of the disease subtypes, which is assessed by specific diagnostic approaches. Thus, several diagnostic techniques are mandatory at diagnosis for classification and for individual therapeutic decisions. Furthermore they are also needed for follow up studies focusing especially on minimal residual disease (MRD) to guide further treatment decisions based on the response of the disease to given treatment protocols. Only by using a comprehensive diagnostic panel including cytomorphology, cytochemistry, multiparameter flow cytometry (MFC), cytogenetics, fluorescence in situ hybridization (FISH) and molecular genetic methods the correct diagnosis in acute leukemias can be established today. The results serve as a mandatory prerequisite for individual treatment strategies and for the evaluation of treatment response using especially newly defined and highly specific MRD markers.

Biomarkers, Tumor↗
PubMed2005

Monitoring of minimal residual disease in acute myeloid leukemia.

Monitoring minimal residual disease (MRD) becomes increasingly important in the risk-adapted management of patients with acute myeloid leukemia (AML). The two most sensitive and quantitative methods for MRD detection are multiparameter flow cytometry (MFC) and real-time polymerase chain reaction (QRT-PCR). Fusion gene-specific PCR in AML is based on the RNA level, and thus in contrast to MFC expression levels rather than cell counts are assessed. For both methods independent prognostic values have been shown. The strong power of MFC has been shown mainly in the assessment of early clearance of the malignant clone. MRD levels in AML with fusion genes have the strongest prognostic power after the end of consolidation therapy. In addition, with QRT-PCR highly predictive initial expression levels can be assessed. With both methods early detection of relapse is possible. So far, validated PCR-based MRD was done with fusion genes that are detectable in only 20-25% of all AML MFC is superior since it is applicable for most AML. However, QRT-PCR is still more sensitive in most cases. Thus, it is desirable to establish new molecular markers for PCR-based studies. Large clinical trials will determine the role and place of immunologic and PCR-based monitoring in the prognostic stratification of patients with AML.

Biomarkers, Tumor↗
PubMed2005

Nucleophosmin gene mutations are predictors of favorable prognosis in acute myelogenous leukemia with a normal karyotype.

Nucleophosmin (NPM1) exon-12 gene mutations are the hallmark of a large acute myelogenous leukemia (AML) subgroup with normal karyotype, but their prognostic value in this AML subset has not yet been determined. We screened 401 AML patients with normal karyotype treated within the German AML Cooperative Group Protocol 99 (AMLCG99) study for NPM1 mutations. Results were related with partial tandem duplications within the MLL gene (MLL-PTD), Fms-like tyrosine kinase 3-length mutations (FLT3-LM), the tyrosine kinase domain of FLT3 (FLT3-TKD), NRAS, KIT, and CEBPA mutations and with clinical characteristics and outcome. NPM1 mutations were detected in 212 (52.9%) of 401 patients. Fourteen mutations, including 8 new variants, were identified. NPM1-mutated cases associated frequently with FLT3 mutations but rarely with other mutations. The NPM1-mutated group had a higher complete remission (CR) rate (70.5% vs 54.7%, P = .003), a trend to a longer overall survival (OS; median 1012 vs 549 days, P = .076), and significantly longer event-free survival (EFS; median 428 vs 336 days; P = .012). The favorable impact of NPM1 mutations on OS and EFS clearly emerged in the large group (264 [66.8%] of 395 cases) of normal-karyotype AML without FLT3-LM. This positive effect was lost in the presence of a concomitant FLT3-LM, since survival of the NPM1+/FLT3-LM+ double positive was similar to NPM1-/FLT3-LM+ cases. In conclusion, this study demonstrates that NPM1+/FLT3-LM- mutations are an independent predictor for a favorable outcome in AML with normal karyotype.

Adolescent↗