Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leukemia is a disease characterized by the malignant transformation of hematopoietic stem cells. Previous studies have shown that the Wilms' tumor antigen-1 (WT1) transcription factor is expressed at elevated levels in hematopoietic stem cells of leukemia patients compared with normal stem cells. In the past, we have generated cytotoxic T lymphocytes (CTL) specific for WT1, and we have shown that they killed WT1-expressing leukemia cell lines and inhibited the in vitro colony-forming activity of leukemia cells of patients. We used a xenotransplantation model to address whether WT1-specific CTL can selectively inhibit engraftment of malignant but not normal stem cells. CD34+ hematopoietic cells isolated from individuals with chronic myeloid leukemia or normal hematopoiesis were treated with WT1-specific CTL and injected into immunodeficient non-obese diabetic-severe combined immunodeficient mice. After 5 to 8 weeks, engraftment of leukemic or normal human cells was analyzed using immunohistology, flow cytometry, and polymerase chain reaction amplification of human sequences. The data showed that exposure of chronic myeloid leukemia CD34+ cells to WT1-specifc CTL completely prevented the development of leukemia in the recipient mice, whereas CTL treatment did not inhibit engraftment of normal CD34+ stem cells. The experiments indicate that WT1-specific CTL can discriminate between stem cells that give raise to leukemia and normal hematopoiesis in the xenogenic transplantation model. This supports the use of CTL with this specificity for treatment of leukemia patients undergoing stem-cell transplantation.
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PMID:Human cytotoxic T lymphocytes specific for Wilms' tumor antigen-1 inhibit engraftment of leukemia-initiating stem cells in non-obese diabetic-severe combined immunodeficient recipients. 1279 92

Anthracycline cardiotoxicity can induce dilated cardiomyopathy (DCM). Nine patients (four men) experienced postchemotherapy DCM: age at time of tumour diagnosis ranged from 1-45 years (mean 13.5 +/- 19 years); interval time between tumour and HT was 3-23 years (mean 10.8 +/- 6.6) and age at HT ranged from 10-65 years (30.8 +/- 20.1). Interval between end of chemotherapy and beginning of cardiac symptoms was 5.71 +/- 4.6 years. Mean age at DCM diagnosis was 19.2 +/- 19.7 (range 1-50 years). Interval between start of chemotherapy and DCM ranged from 1 month to 10 years (mean 3.15 +/- 3.6 years). Tumours were Ewing sarcoma (7-year-old boy), paratesticular rabdomyosarcoma (1-year-old boy), Wilms tumor with pulmonary metastasis (3-year-old girl), bilateral breast carcinoma (45-year-old woman), uterine leiomyosarcoma (44-year-old woman), acute myelocytic leukemia (1.5-year-old boy and 17-year-old girl), and chronic myelocytic leukemia (5-year-old boy). All patients had high pulmonary resistance values. One patient with chronic myelocytic leukemia (14 year-old at HT) died due to graft failure on the first postoperative day. At follow-up (mean, 80.4 +/- 69.3 months) two patients died: a 32-year-old woman (acute myelocytic leukemia) 1 year after HT for sepsis and a 68-year-old woman who had breast adenocarcinoma recurrence 81 months after HT. The remaining patients are alive, in good condition with no difference in survival from other transplanted patients (P =.757). Patients with end-stage postchemotherapy DCM without evidence of tumour recurrence can safely undergo HT.
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PMID:Heart transplantation in chemotherapeutic dilated cardiomyopathy. 1282 9

Antigens implicated in the graft-versus-leukemia (GVL) effect in chronic myeloid leukemia (CML) include WT1, PR1, and BCR-ABL. To detect very low frequencies of these antigen-specific CD8+ T cells, we used quantitative polymerase chain reaction (qPCR) to measure interferon-gamma (IFN-gamma) mRNA production by peptide-pulsed CD8+ T cells from HLA-A*0201+ healthy volunteers and from patients with CML before and after allogeneic stem cell transplantation (SCT). Parallel assays using cytomegalovirus (CMV) pp65 tetramers demonstrated the IFN-gamma copy number to be linearly related to the frequency of tetramer-binding T cells, sensitive to frequencies of 1 responding CD8+ T cell/100 000 CD8+ T cells. Responses to WT1 and PR1 but not BCR-ABL were detected in 10 of 18 healthy donors. Responses to WT1, PR1, or BCR-ABL were observed in 9 of 14 patients with CML before SCT and 5 of 6 after SCT, often to multiple epitopes. Responses were higher in patients with CML compared with healthy donors and highest after SCT. These antigen-specific CD8+ T cells comprised central memory (CD45RO+CD27+CD57-) and effector memory (CD45RO-CD27-CD57+) T cells. In conclusion, leukemia-reactive CD8+ T cells derive from memory T cells and occur at low frequencies in healthy individuals and at higher frequencies in patients with CML. The increased response in patients after SCT suggests a quantitative explanation for the greater effect of allogeneic SCT.
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PMID:Functional leukemia-associated antigen-specific memory CD8+ T cells exist in healthy individuals and in patients with chronic myelogenous leukemia before and after stem cell transplantation. 1507 Jul 13

Among clinicians, initial awareness of the Wilms' tumor gene was limited mostly to pediatric oncologists. Almost a decade ago, overexpression of Wilms' tumor 1 (WT1) was observed in adult acute leukemia. Subsequent studies indicated that WT1 overexpression occurs in most cases of acute myelogenous leukemia, acute lymphoblastic leukemia, chronic myelogenous leukemia (CML), and myelodysplastic syndrome (MDS). Limited tissue expression of WT1 in adults suggests that WT1 can be a target for leukemia/MDS therapy. WT1 expression in stem/progenitor cells remains unsettled. However, lack of progenitor cell suppression by WT1 antisense or WT1-specific cytotoxic T cells provide some assurance that WT1 expression in progenitor cells is minimal or absent. Immunotherapy-based WT1 approaches are furthest along in preclinical development. WT1-specific cytotoxic lymphocytes can be generated from normals and leukemic patients. In mice, WT1 vaccines elicit specific immune responses without evidence of tissue damage. In this paper, we review studies validating the immunogenicity of WT1 and propose that leukemia and MDS may be a good clinical model to test the efficacy of a WT1 vaccine.
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PMID:WT1 in acute leukemia, chronic myelogenous leukemia and myelodysplastic syndrome: therapeutic potential of WT1 targeted therapies. 1283 18

Quantification of mRNAs deriving from malignant cells is useful for estimating leukemic states. In this study, we have developed RT-PCR methods using real-time PCR detection system, a LightCycler, for quantification of bcr/abl chimerical genes in peripheral blood and bone marrow of chronic myeloid leukemia patients. Total amounts of RNA extracted were corrected using beta-actin gene as an internal standard. The coefficients of variation of intra-assay variation and inter-assay variation for each gene were within a range of 1.7-26.0% which showed more precise quantification than the competitive PCR method. The coefficients of variation of assay are within a range of 7.7-27.6% in the case of using three samples of normal subjects from blood collecting to quantification of bcr gene. Bcr/abl and WT1 genes could be measured from 10(2) to 10(8) copies and 10 to 10(5) copies with linearity, respectively. Using real-time PCR detection with LightCycler system, 2 x 10(3) K562 cells among 2 x 10(6) total cells demonstrated the bcr/abl gene, while 2 x 10(1) K562 cells among 2 x 10(6) total cells could be detected using the nested PCR method. In tests of seven clinical samples, five samples demonstrated bcr/abl and WT1 genes, while those in two other patients after bone marrow transplantation and a normal subject could not detected. This result suggests that our quantitative method reflect the clinical stages of CML patients.
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PMID:[Real-time PCR quantification of bcr/abl chimera and WT1 genes in chronic myeloid leukemia]. 1456 Jun 50

After allogeneic stem cell transplantation (SCT), we evaluated the use of the Wilms' tumor gene (WT1) as a minimal residual disease (MRD) marker in 32 patients (28 chronic myeloid leukemia, three acute lymphoblastic leukemia and one acute myeloid leukemia). All patients expressed BCR-ABL and the kinetics of WT1 were compared with those of BCR-ABL using real-time quantitative PCR. WT1 expression was seen in the peripheral blood (PB) of healthy controls with a median expression level of 7 x 10(-5) (WT1/ABL ratio). The corresponding values for BCR-ABL-negative and BCR-ABL-positive patient samples were 1 x 10(-4) and 1.6 x 10(-4), respectively. Kinetic studies in individual patients showed that WT1 and BCR-ABL levels usually did not copy each other. In four out of six patients who relapsed, an increase in WT1 from the background level (10(-4)) was observed only at the time of or after relapse, and in two patients increasing WT1 levels were observed before the relapse. In addition, the WT1 values found at the time of relapse were only two logs higher than the background level, indicating a sensitivity of 10(-2). In conclusion, there is a constitutive low expression of WT1 in normal hematopoietic cells. The sensitivity and ability of WT1 to predict a relapse were poor in this study.
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PMID:Poor correlation of kinetics between BCR-ABL and WT1 transcript levels after allogeneic stem cell transplantation. 1525 61

Recent studies have detected Wilms tumor antigen (WT1)-specific cytotoxic T lymphocytes (CTLs) in patients with acute myelogenous leukemia (AML) and chronic myelogenous leukemia (CML) and demonstrated that most of these CTLs were low avidity. Although HLA-mismatched donors can mount high-avidity CTLs against HLA-A2-presented peptides of WT1, a dominant anti-alloimmune response usually obscures detection of peptide-specific CTLs. Here we explored the feasibility of using recombinant HLA-A2 monomers containing single peptide epitopes as immunogens to generate peptide-specific CTLs from allogeneic donors. We demonstrate that the coating of HLA-A2(-) B lymphocytes with A2/peptide monomers provides a strong stimulus for autologous peptide-specific CTLs. After 3 to 5 rounds of stimulation a population of CD8(+) T cells binding A2/peptide tetramers is easily detectable by fluorescence-activated cell sorting analysis. Furthermore, sorted A2/WT1 tetramer-positive CTLs display strong cytotoxic activity against leukemia cells expressing WT1 endogenously but not against WT1(-) human tumor cells. Thus, HLA/peptide monomers may be useful to isolate peptide-specific donor lymphocytes for treatment of patients with leukemia after HLA-mismatched transplantation.
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PMID:Use of B cell-bound HLA-A2 class I monomers to generate high-avidity, allo-restricted CTLs against the leukemia-associated protein Wilms tumor antigen. 1498 55

The WT1 gene is considered to be highly expressed in patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia and chronic myeloid leukemia and is thought to play a key role in maintaining the viability of leukemia cells. However, little is known about the WT1 gene expression levels in pediatric patients with juvenile myelo-monocytic leukemia (JMML) and myelodysplastic syndromes (MDS). We studied WT1 expression in diagnostic bone marrow (BM) and peripheral blood (PB) samples of 90 patients with JMML, low grade MDS, advanced MDS and myelodysplasia-related AML in BM (n = 20) and PB (n = 18) samples of normal healthy volunteer donors.
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PMID:WT1 gene expression: useful marker for minimal residual disease in childhood myelodysplastic syndromes and juvenile myelo-monocytic leukemia? 1518 34

Wilms' tumor gene WT1 mRNA is a new marker of leukemic blast cells for AML, ALL, and CML. The minimal residual disease(MRD) of leukemia can be detected at frequencies as low as 1 in 10(3) to 10(4) normal bone marrow cells and 1 in 10(5) normal peripheral blood mononuclear cells by means of the quantitation of WT1 mRNA (WT1 assay) using reverse transcriptase-polymerase chain reaction. Thus, the WT1 assay makes it possible to rapidly assess the effectiveness of treatment and to evaluate the degree of eradication of leukemic cells in individual leukemia patients. Furthermore, the WT1 assay can continuously assess the disease progression of myelodysplastic syndrome(MDS) and predict the evolution of MDS to overt AML within 6 months. Moreover, WT1 protein is highly immunogenic, thus, WT1 peptide-based cancer immunotherapy is effective.
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PMID:[Development of a new inspection diagnostic method: genetic screening of cancer]. 1520 29

The Wilms' tumor gene WT1 is highly expressed in leukemias and myelodysplastic syndrome (MDS), and WT1 expression levels increase along with the disease progression in chronic myeloid leukemia and MDS. We previously reported that IgM and IgG WT1 antibodies were detected with significantly higher detection rate and antibody titers in leukemias and MDS compared to those in healthy volunteers. In this study, whether IgG humoral immune responses against WT1 protein were Th1- or Th2-type were determined by measurement of four subclasses of IgG WT1 antibody, IgG1, IgG2, IgG3, and IgG4. In leukemias and MDS, Th1-type WT1 antibodies such as IgG1, IgG2, and IgG3 were significantly increased in both detection rate and antibody titers compared to those in healthy volunteers, whereas Th2-type WT1 antibody such as IgG4 did not increase. These results showed that Th1-biased humoral immune responses against WT1 protein were generated in leukemias and MDS. These results should allow us to consider that Th1-biased cellular immune responses against WT1 protein, which was essentially needed for cancer immunotherapy targeting WT1, should be elicited in patients with hematopoietic malignancies.
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PMID:Th1-biased humoral immune responses against Wilms tumor gene WT1 product in the patients with hematopoietic malignancies. 1553 7


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