C A Schmidt

Publications (71)294.78 Total impact

• Article: Heterogeneity of V52 TCR 8 Gene Rearrangements in Acute Myeloid Leukemia

  C. A. Schmidt, G. Przybylski, H. Oettle, K. H. Seeger, W. D. Ludwig, W. Siegert
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  ABSTRACT: In a previous study, we described the occurrence of T-cell receptor (TCR)δ gene rearrangements in 9/100 acute myeloid leukemia (AML) cases. In this study, we further characterized these rearrangements by Southern Blot hybridization using a Vδ2 specific probe and polymerase chain reaction (PCR). Southern Blot analysis revealed that rearrangements involved the Vδ2 gene segment in four patients. Interestingly the restriction fragments detected by the Vδ2 probe differed markedly in size. PCR analysis revealed a complete Vδ2(Dn)Jδ1 gene rearrangement, an incomplete Vδ2Dδ3 rearrangement and a large amplification product, which cannot be explained with normal VDJ recombinatorial processes, in one case each. Furthermore although Vδ2 and Jδ1 were rearranged, no comigration of rearranged fragments was observed and no PCR product was obtained in one case. Obtained results in AML differ from findings in acute lymphoblastic leukemia (ALL) of B-cell lineage, where a more homogeneous pattern of rearrangements has been described. This heterogeneity might be related to the illegitimate occurrence of TCRδ gene rearrangements in AML.
  06/2009; 16(1-2):73-77.
• Article: TCRδ Gene Rearrangements in Acute Myeloid Leukemia with T-lymphoid Antigen Expression

  C. A. Schmidt, G. Przybylski, K. Seeger, W. Siegert
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  ABSTRACT: In this review we present our data concerning T-cell receptor (TCR) δ gene rearrangements in acute myeloid leukemia with cuexpression of T-lymphoid features (CD2/CD4/CD7; Ly+ AML). We found a correlation between TCRδ gene rearrangements and coexpression of these T-lymphoid features. Ten of 66 Ly+ AML and only one of 44 AML cases without this coexpression exhibited TCRδ gene rearrangements (p =. 028). In contrast, no correlation was observed between terminal deoxynucleotidyl transferase (TdT) expression and the occurence of TCRδ gene rearrangements in AML. Rearrangements were found in two of 25 AML with and seven of 71 AML cases without TdT expression. Interestingly, nucleotide sequencing of junctional sites revealed up to 36 N-nucleotides in cases without or with only weak TdT expression indicating downregulation of TdT expression after the TCR rearrangement took place. Complete Vδ1Jδ1 and incomplete Dδ2Jδ1 gene rearrangements were observed most frequently in Ly+ AML. These recombination patterns were similar to patterns observed in acute T-lymphoblastic leukemia with coexpression of myeloid features (My+ T-ALL) suggesting transformation of a common myeloid/T-lymphoid progenitor cell in these cases.
  06/2009; 20(1-2):45-49.
• Article: Inhibition of BCL11B expression leads to apoptosis of malignant but not normal mature T cells.

  P Grabarczyk, G K Przybylski, M Depke, U Völker, J Bahr, K Assmus, B M Bröker, R Walther, C A Schmidt
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  ABSTRACT: The B-cell chronic lymphocytic leukemia (CLL)/lymphoma 11B gene (BCL11B) encodes a Krüppel-like zinc-finger protein, which plays a crucial role in thymopoiesis and has been associated with hematopoietic malignancies. It was hypothesized that BCL11B may act as a tumor-suppressor gene, but its precise function has not yet been elucidated. Here, we demonstrate that the survival of human T-cell leukemia and lymphoma cell lines is critically dependent on Bcl11b. Suppression of Bcl11b by RNA interference selectively induced apoptosis in transformed T cells whereas normal mature T cells remained unaffected. The apoptosis was effected by simultaneous activation of death receptor-mediated and intrinsic apoptotic pathways, most likely as a result of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) upregulation and suppression of the Bcl-xL antiapoptotic protein. Our data indicate an antiapoptotic function of Bcl11b. The resistance of normal mature T lymphocytes to Bcl11b suppression-induced apoptosis and restricted expression pattern make it an attractive therapeutic target in T-cell malignancies.
  Oncogene 06/2007; 26(26):3797-810. · 6.37 Impact Factor
• Source

  Available from: Anton W Langerak

  Article: Disruption of the BCL11B gene through inv(14)(q11.2q32.31) results in the expression of BCL11B-TRDC fusion transcripts and is associated with the absence of wild-type BCL11B transcripts in T-ALL.

  G K Przybylski, W A Dik, J Wanzeck, P Grabarczyk, S Majunke, J I Martin-Subero, R Siebert, G Dölken, W-D Ludwig, B Verhaaf, J J M van Dongen, C A Schmidt, A W Langerak
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  ABSTRACT: T-cell acute lymphoblastic leukemia (T-ALL) is associated with chromosomal aberrations characterized by juxtaposition of proto-oncogenes to T-cell receptor gene loci (TCR), resulting in the deregulated transcription of these proto-oncogenes. Here, we describe the molecular characterization of a novel chromosomal aberration, inv(14)(q11.2q32.31), in a T-ALL sample, involving the recently described BCL11B gene and the TCRD locus. The inversion joined the 5' part of BCL11B, including exons 1-3, to the TRDD3 gene segment of the TCRD locus, whereas the reciprocal breakpoint fused the TRDV1 gene segment to the fourth exon of BCL11B. The TRDV1-BCL11B joining region was 1344 bp long and contained fragments derived from 20q11.22, 3p21.33 and from 11p12, indicating the complex character of this aberration. A strong expression of in-frame transcripts with truncated BCL11B and TCRD constant region (TRDC) were observed, but in contrast to normal T cells and other T-ALL samples, no wild-type BCL11B transcripts were detected in the T-ALL sample. Screening of 37 other T-ALLs revealed one additional case with expression of the BCL11B-TRDC fusion transcript. As BCL11B appears to play a key role in T-cell differentiation, BCL11B disruption and disturbed expression may contribute to the development of T-cell malignancies in man.
  Leukemia 03/2005; 19(2):201-8. · 9.56 Impact Factor
• Article: Extramedullary manifestation of a donor-derived acute myeloid leukemia in a liver transplant patient.

  M Subklewe, M Nagy, C Schoch, S Jenisch, R Siebert, S Gesk, P Neuhaus, B Dörken, C A Schmidt
  Leukemia 01/2005; 18(12):2050-3. · 9.56 Impact Factor
• Article: Minimal impact of CMV infection on long-term survival after liver transplantation.

  D Seehofer, N Rayes, T Steinmüller, C A Schmidt, U Settmacher, A R Müller, P Neuhaus
  Transplantation Proceedings 10/2002; 34(6):2272-3. · 1.00 Impact Factor
• Source

  Available from: gene-quantification.de

  Article: Quantitative analysis of beta-actin, beta-2-microglobulin and porphobilinogen deaminase mRNA and their comparison as control transcripts for RT-PCR.

  J Lupberger, K A Kreuzer, G Baskaynak, U R Peters, P le Coutre, C A Schmidt
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  ABSTRACT: Quantitation of target mRNAs using the reverse-transcription polymerase chain reaction found a widespread field of application in diverse biomedical diagnostic assays. However, the problem of varying sample quality has to be solved by correcting target molecule amounts through detection of an endogenous control template. The choice of an appropriate reference gene is still object of debate as pseudogene co-amplification and expression level variations may limit the usefulness of some currently used reference reactions. We compared quantitative expression levels of the commonly used endogenous reference genes beta-actin (beta-actin), beta-2-microglobulin (beta2-MG) and porphobilinogen deaminase (PBDG) using the TaqMan chemistry. With these assays we investigated the respective expression patterns in K562 cells and leucocytes of normal individuals as well as of malignoma patients. In K562 cells 1544+246 beta-actin, 65+30 beta2-MG and 22+/-8 PBDG copies/cell were detected. In normal leucocytes 491+/-97 beta-actin, 40+/-17 beta2-MG and <1 PBDG copies/cell were quantified. Leucocytes of various malignancies exhibited 84+/-51 beta-actin, 106+/-8 beta2-MG and <1 PBDG copies/cell. We conclude that beta2-MG is the most suitable reference gene tested as its variation between different sample origins and within distinct cell types was acceptable low.
  Molecular and Cellular Probes 03/2002; 16(1):25-30. · 2.08 Impact Factor
• Article: Novel T-cell receptor delta gene rearrangement involving a recombining element located 2.6 kb 3' from the Vdelta2 gene segment.

  G K Przybylski, H Oettle, W Siegert, C A Schmidt
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  ABSTRACT: In this study, we describe a novel T-cell receptor delta (TCRdelta) gene rearrangement observed in acute myeloid leukemia with coexpression of T-lymphoid antigens (Ly+AML) and in peripheral blood leukocytes (PBL) from one out of ten healthy donors. The rearrangement was identified by Southern blot analysis using a joining region (Jdelta1) specific probe and amplified by polymerase chain reaction (PCR) with a variable region (Vdelta2) and Jdelta1 specific primers. The nucleotide sequence analysis of an atypical 3000 bp PCR product allowed localization of the breakpoint within the TCRdelta gene locus, 2.6 kb 3' from the Vdelta2 gene segment. A regular Ddelta2-Ddelta3-Jdelta1 joining was found at the 3' end of the breakpoint, indicating that the rearrangement was mediated by the VDJ recombinase, but no TCRdelta gene segment was detected at the 5' end. Analysis of the germline sequence 3' from the breakpoint revealed an isolated recombination signal sequence (RSS) capable of initiating a rearrangement. The RSS motif described by us is the second TCRdelta recombining element (deltaRec2). The deltaRec2(Ddelta)Jdelta1 recombination is a rather rare event and can be found in acute leukemia and in PBL from healthy individuals. Most likely, the nonfunctional deltaRec2(Ddelta)Jdelta1 rearrangement is a transient step during the VDJ recombination. It may potentially lead to deletion of the deltaRec2(Ddelta)Jdelta1 complex and either to direct joining of a Vdelta region to one of the downstream Jdelta regions or to a rearrangement of the TCRalpha gene.
  Leukemia Research 01/2002; 25(12):1059-65. · 2.92 Impact Factor
• Article: Selection of B-cell chronic lymphocytic leukemia cell variants by therapy with anti-CD20 monoclonal antibody rituximab.

  T Pickartz, F Ringel, M Wedde, H Renz, A Klein, N von Neuhoff, P Dreger, K A Kreuzer, C A Schmidt, S Srock, D Schoeler, F Schriever
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  ABSTRACT: Anti-CD20 chimeric monoclonal antibody rituximab (Mabthera; IDEC-C2B8) is currently tested in several clinical trials for the treatment of B-cell chronic lymphocytic leukemia (B-CLL). In the present study, we investigated whether rituximab therapy may select for CD20(-) subclones. Leukemic B-CLL cells were isolated from patients with B-CLL and sensitivity to rituximab-induced cell death was examined. Levels of CD20 protein and mRNA were determined using flow cytometry and real-time PCR, respectively. Clonality analyses of leukemic cells throughout rituximab therapy were performed by GeneScan analysis of patient clone specific rearrangements of the complementarity determining region III of the heavy chain immunoglobulin. Cytotoxicity of rituximab in vitro did not depend on the protein levels of CD20. During therapy with rituximab CD20(+) B-CLL cells were depleted and CD20(-) leukemic cells emerged. After treatment, the initial CD20(+) B-CLL cell clone reexpanded. CD20(-) B-CLL cells retained their capacity to synthesize the CD20 molecule. These data support the concept that in B-CLL rituximab treatment may not lead to the emergence of CD20(-) leukemic variants. Our findings support clinical studies investigating the benefit of prolonged period of rituximab therapy in B-CLL disease.
  Experimental Hematology 01/2002; 29(12):1410-6. · 2.90 Impact Factor
• Article: [Epidemiology and interventional treatment strategies of infectious complications after allogenic stem-cell transplantation].

  H Einsele, H Bertz, J Beyer, M G Kiehl, V Runde, H J Kolb, E Holler, R Beck, R Schwerdfeger, U Schumacher, H Hebart, H Martin, J Kienast, A J Ullmann, G Maschmeyer, W Krüger, H Link, C A Schmidt, H Oettle, T Klingebiel
  DMW - Deutsche Medizinische Wochenschrift 12/2001; 126(45):1278-84. · 0.53 Impact Factor
• Article: Prospective randomized trial to assess the value of preemptive oral therapy for CMV infection following liver transplantation.

  N Rayes, D Seehofer, C A Schmidt, H Oettle, A R Müller, T Steinmüller, U Settmacher, W O Bechstein, P Neuhaus
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  ABSTRACT: With the development of sensitive tests to detect cytomegalovirus (CMV) viremia, preemptive approaches become a reasonable alternative to general CMV prophylaxis. We performed a randomized trial comparing pp65-antigenemia guided preemptive therapy using oral ganciclovir with symptom-triggered intravenous ganciclovir treatment. Eighty-eight of 372 liver transplant recipients developed antigenemia early after orthotopic liver transplantation. Twenty-eight symptomatic patients with antigenemia were excluded from randomization and treated with intravenous ganciclovir. Sixty pp65-antigen-positive asymptomatic patients were randomized to receive either oral ganciclovir 3x1 g/day for 14 days (group 1) or no preemptive treatment (group 2). Patients that developed CMV disease were treated with intravenous ganciclovir 2x5 mg/kg body weight for 14 days. The high-risk (Donor+/Recipient-) patients were equally distributed in the two study groups. Three of 30 (10%) patients on oral ganciclovir developed mild to moderate CMV disease compared with 6/30 (20%) patients in the control group. In the Donor+/Recipient- patients, the incidence of CMV disease was 1/6 and 3/7. All disease episodes resolved after intravenous treatment. The 1- and 3-year patient and organ survival was the same in the study groups and in the patients with or without CMV infection. No deaths related to CMV occurred. The positive predictive value of pp65-antigenemia for the development of CMV disease was very low, and, in 28/88 patients (32%), antigenemia did not precede symptoms. Therefore, pp65-antigenemia is of limited value in deciding on the timing and need for ganciclovir therapy after liver transplantation.
  Transplantation 10/2001; 72(5):881-5. · 4.00 Impact Factor
• Article: Fluorescent 5'-exonuclease assay for the absolute quantification of Wilms' tumour gene (WT1) mRNA: implications for monitoring human leukaemias.

  K A Kreuzer, A Saborowski, J Lupberger, C Appelt, I K Na, P le Coutre, C A Schmidt
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  ABSTRACT: The Wilms' tumour gene (WT1) has been suggested as a powerful parameter for molecular monitoring of minimal residual disease (MRD) in leukaemias. However, molecular monitoring via WT1 RNA levels is far from being routinely performed, which is possibly owing to the complex and inaccurate quantitative reverse transcription polymerase chain reaction (RT-PCR) procedures. Using a newly-developed quantitative real time RT-PCR, we measured WT1 transcripts in peripheral blood leucocytes of patients with acute myeloid (AML), acute lymphoid (ALL) and chronic myeloid leukaemia (CML). While healthy blood donors did not show measurable amounts of WT1 transcripts, WT1 RNA levels were detectable in all types of leukaemia. Furthermore, intraindividual WT1 transcript kinetics were exclusively dependent on disease progression, treatment and subsequent disease outcome. Using this approach, we could distinguish between treatment response and failure within the first days of therapeutic intervention. Moreover, gradually rising WT1 levels over a period of weeks and months paralleled long-term disease progression and appeared to be a prognostic indicator for subsequent clinical relapse. A linear correlation between quantities of WT1 and bcr/abl fusion transcripts could be seen in CML. We conclude that quantitative assessment of WT1 transcripts using real-time PCR is an appropriate method for molecular monitoring of AML, ALL and CML, and can be used independently for both short- and long-term monitoring of leukaemia patients.
  British Journal of Haematology 09/2001; 114(2):313-8. · 4.94 Impact Factor
• Article: Epstein-Barr virus DNA quantitation assessed by a real-time polymerase chain reaction in a case of Burkitt's lymphoma.

  J Solassol, K A Kreuzer, U Lass, C A Schmidt
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  ABSTRACT: A real-time PCR technique was used to quantify EBV DNA load in plasma, leukocytes, peritoneal cells, ascites and cerebrospinal fluid (CSF) at diagnosis and during the follow-up of a 21-year-old patient suffering from an abdominal form of EBV-associated Burkitt's lymphoma. The EBV DNA load correlated well with the clinical and biological remission status of the patient after chemotherapy confirming that EBV DNA quantitation in plasma and leukocytes from peripheral blood can be considered as a marker of the tumor load and can be analyzed in parallel for monitoring of EBV-related malignancies.
  Leukemia and Lymphoma 06/2001; 41(5-6):669-73. · 2.58 Impact Factor
• Article: Simultaneous absolute quantification of target and control templates by real-time fluorescence reverse transcription-PCR using 4-(4'-dimethylaminophenylazo)benzoic acid as a dark quencher dye.

  K A Kreuzer, A Bohn, J Lupberger, J Solassol, P le Coutre, C A Schmidt
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  ABSTRACT: Despite the many advantages of real-time fluorescence reverse transcription-PCR (RT-PCR) as a quantitative analytical tool, simultaneous quantification of target and reference templates within one reaction has not been reported. We developed such an assay with an internal reference template. For quantification of target and reference sequences, we used two fluorescent probes in one reaction vessel on an ABI PRISM 7700 SDS instrument. Fluorescent probes were labeled with either 6-carboxy-fluorescein or hexachloro-6-carboxy-fluorescein as reporter dye and 4-(4'-dimethylaminophenylazo)benzoic acid (DABCYL) as a dark quencher fluorophore. To test the sensitivity and specificity of this assay, serial dilutions of reference and target templates were analyzed in one PCR reaction. In the presence of 10 beta-actin molecules as control templates, 10(5) bcr/abl molecules were amplified, and 10(5) beta-actin molecules were amplified in the presence of 10 bcr/abl copies. We also performed single and duplex measurements on samples from five patients with documented Philadelphia chromosome-positive chronic myelogenous leukemia disease courses (72 samples) and three with minor bcr/abl+ acute myelogenous leukemias (26 samples). For M-bcr/abl duplex RT-PCR, the correlation coefficient (r) for starting template amounts and threshold cycle values was 0.99; for m-bcr/abl, r = 0.96, indicating a precise log-linear relation for 10-10(5) copies/100 ng of cDNA. In the same PCR reactions, r = 0.99 for beta-actin (coamplified with M-bcr/abl or m-bcr/abl) for 10(3)-10(7) copies/100 ng cDNA. The linear correlation coefficient for single and duplex measurements was 0.98 for M- and m-bcr/abl in patient samples. DABCYL can be used as dark quencher fluorophore in real-time fluorescence PCR. The duplex fluorescence RT-PCR assay for bcr/abl and beta-actin transcripts allows monitoring of bcr/abl+ leukemias.
  Clinical Chemistry 04/2001; 47(3):486-90. · 7.91 Impact Factor
• Article: Molecular quantification of response to therapy and remission status in TEL-AML1-positive childhood ALL by real-time reverse transcription polymerase chain reaction.

  K Seeger, K A Kreuzer, U Lass, T Taube, D Buchwald, C Eckert, G Körner, C A Schmidt, G Henze
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  ABSTRACT: Although TEL-AML1 positivity [translocation t(12;21)(p13;q22)], detected in 20-25% of initial childhood acute lymphoblastic leukemia (ALL), has been associated with an excellent prognosis, its positive predictive value is insufficient for appropriate treatment stratification considering reported prevalence in relapsed ALL (3-28%). Molecular quantification of response to therapy by PCR-based methods has been shown to improve risk assessment. Here, we report on the sensitive quantification of leukemia-specific TEL-AML1 fusion transcript levels normalized to beta-actin expression (sensitivity threshholds, 10(-5)) by a novel real-time reverse transcription-PCR (RQ-RT-PCR) based on fluorescent TaqMan technique providing early and rapid evidence on the treatment efficacy of children with initial or relapsed TEL-AML1+ ALL enrolled in frontline or relapse trials of the Berlin-Frankfurt-Münster (BFM)-Study Group. In initial ALL, TEL-AML1/beta-actin decrease was > or =10(5)-fold in 50% of patients after induction therapy (day 33) and stayed TEL-AML1-negative throughout therapy, which suggested high sensitivity of leukemic cells to antineoplastic therapy. The remaining patients were still TEL-AML1+ before reintensification (ratios, 0.7 x 10(-2):10(-4)). In relapsed ALL, TEL-AML1/beta-actin decrease was generally less pronounced at corresponding time points, and conversion to TEL-AML1 negativity was observed in 40% of patients. Most notably, subsequent relapses occurred only among molecular poor responders, whereas all early responders remain in their second complete remission. In conclusion, real-time quantification of TEL-AML1/beta-actin kinetics distinguishes distinct molecular response groups, and provides indications capable of directing therapeutic interventions for patients with TEL-AML1+ ALL. Before considering modification of therapy, results should be interpreted cautiously taking into account the long duration of remission associated with TEL-AML1+ ALL.
  Cancer Research 03/2001; 61(6):2517-22. · 7.86 Impact Factor
• Article: What can we learn from leukemia as for the process of lineage commitment in hematopoiesis?

  C A Schmidt, G K Przybylski
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  ABSTRACT: Most contemporary models of hematopoiesis assume lineage fidelity of early progenitor cells. Along with this concept normal hematopoietic cells and the majority of leukemias express exclusively myeloid or lymphoid specific antigens. On the other hand, growing evidence exists challenging the lineage fidelity model. Chronic myeloid leukemia (CML) in the blast crisis may switch to acute lymphoblastic leukemia (ALL) and as a result of the chemotherapy ALL may converse to acute myeloid leukemia (AML). Furthermore, a substantial portion of leukemia cases, named acute mixed-lineage leukemia (AMLL), show simultaneous expression of both myeloid and lymphoid antigens. Immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements, correlating with myeloid-lymphoid immunophenotype in AMLL, support the hypothesis of lineage infidelity of early progenitor cells, rather than the aberrant antigen expression. Based on a detailed characterization of AMLL we present a modified model of a "common myeloid/lymphoid progenitor cell". This hypothetical very early hematopoietic progenitor cell shows a transient expression of myeloid and B- or T-lymphoid antigen and may also have rearranged its Ig and/or TCR genes. Subsequently, myeloid or lymphoid markers are downregulated and the hematopoietic cell enters either myeloid, T-lymphoid or B-lymphoid differentiation pathway.
  International Reviews Of Immunology 03/2001; 20(1):107-15. · 3.43 Impact Factor
• Article: [Prophylaxis of infection in neutropenic patients. Guidelines of the Working Party on Infections in Hematology and Oncology].

  W V Kern, J Beyer, A Böhme, D Buchheidt, O Cornely, H Einsele, J Kisro, W Krüger, G Maschmeyer, M Ruhnke, C A Schmidt, S Schwartz, H Szelenyi
  DMW - Deutsche Medizinische Wochenschrift 01/2001; 125(51-52):1582-8. · 0.53 Impact Factor
• Article: Presence of human beta- and gamma-herpes virus DNA in Hodgkin's disease.

  C A Schmidt, H Oettle, R Peng, T Binder, F Wilborn, D Huhn, W Siegert, H Herbst
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  ABSTRACT: Herpes viruses have been implicated in the etiology of Hodgkin's disease (HD). We studied the prevalence of human cytomegalovirus (CMV), human herpes viruses type-6 (HHV-6), type-7 (HHV-7) and type 8 (HHV-8) DNA in up to 88 Hodgkin's disease biopsies in comparison to Epstein-Barr virus (EBV) DNA by polymerase chain reaction (PCR). Non-Hodgkin lymphomas (NHL) and reactive lesions served as controls. CMV and HHV-6 were found in 8/86 (9%) and 11/88 (13%) HD cases, respectively, by nested primer PCR. Except for three cases harbouring HHV-6 type-B, only HHV-6 type-A was detected in HD. HHV-7 was observed by nested PCR in 33/88 (38%) HD cases and was already detectable in 15/88 (17%) HD cases by a single-round PCR indicating elevated virus copy numbers. Seven of these cases showed co-infection with HHV-6, and 11 cases were found to contain EBV DNA. 7/8 CMV-positive HD cases also harboured EBV DNA. HHV-8 DNA was not detected by single round or nested PCR in any HD case investigated. Thus, CMV, HHV-6, and HHV-7 were present in small proportions of HD cases, with frequent co-infection of HHV-6 and HHV-7, and frequent association with EBV. In contrast to EBV, beta-herpes viruses are therefore unlikely to have a role in the aetiology of HD. Rather, the presence of these viruses seems to reflect impaired immunological surveillance.
  Leukemia Research 11/2000; 24(10):865-70. · 2.92 Impact Factor
• Article: Enhanced p73 expression during differentiation and complex p73 isoforms in myeloid leukemia.

  M P Tschan, T J Grob, U R Peters, V D Laurenzi, B Huegli, K A Kreuzer, C A Schmidt, G Melino, M F Fey, A Tobler, J F Cajot
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  ABSTRACT: The p53 homologue p73 is expressed in at least six different isoforms (alpha, beta, gamma, delta, epsilon, and zeta), but unlike p53 it has rarely been found mutated in human cancers. However, altered expression of this gene has been reported in cancer cells. In order to understand if p73 is involved in normal and malignant development of myeloid cells, we investigated the expression pattern of the different p73 isoforms in progenitor and mature normal myeloid cells as well as in cells derived from acute and chronic myeloid leukemias. The results show that expression of p73 is markedly enhanced during differentiation of myeloid leukemic cells and that leukemic blasts from patients show an increased expression of the shorter p73 isoforms (gamma, delta, epsilon, zeta). In particular the epsilon isoform is only expressed in leukemic cells and completely absent in mature myeloid cells. Altogether our data suggest that p73 is involved in myeloid differentiation and its altered expression is involved in leukemic degeneration.
  Biochemical and Biophysical Research Communications 11/2000; 277(1):62-5. · 2.48 Impact Factor
• Article: Quality assurance in RT-PCR-based BCR/ABL diagnostics--results of an interlaboratory test and a standardization approach.

  T Burmeister, J Maurer, M Aivado, A H Elmaagacli, F Grünebach, K R Held, G Hess, A Hochhaus, W Höppner, K U Lentes, [......], C Weber, S Wilhelm, A Christmann, J H Clement, U Ebener, J Enczmann, R Leo, M Schleuning, R Schoch, E Thiel
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  ABSTRACT: Here we describe the results of an interlaboratory test for RT-PCR-based BCR/ABL analysis. The test was organized in two parts. The number of participating laboratories in the first and second part was 27 and 20, respectively. In the first part samples containing various concentrations of plasmids with the ela2, b2a2 or b3a2 BCR/ABL transcripts were analyzed by PCR. In the second part of the test, cell samples containing various concentrations of BCR/ABL-positive cells were analyzed by RT-PCR. Overall PCR sensitivity was sufficient in approximately 90% of the tests, but a significant number of false positive results were obtained. There were significant differences in sensitivity in the cell-based analysis between the various participants. The results are discussed, and proposals are made regarding the choice of primers, controls, conditions for RNA extraction and reverse transcription.
  Leukemia 11/2000; 14(10):1850-6. · 9.56 Impact Factor