Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary granulocytic sarcoma (GS) is a rare disease defined by the absence of antecedent or concomitant leukemic cells in the bone marrow and the peripheral blood. Immunohistochemical staining for myeloperoxidase is necessary for a definite diagnosis. Otherwise, primary GS is often misdiagnosed as a malignant lymphoma or other malignancies. Primary GS is well known to frequently develop into acute myeloid leukemia (AML). Here we describe a 28-year-old woman with primary GS manifesting as an epidural tumor in the sacral region accompanied by meningeal dissemination. Fluorescence in situ hybridization analysis detected the AML1/MTG8 fusion gene in neoplastic cells obtained from her cerebrospinal fluid specimen and the epidural mass. The AML1/MTG8 fusion gene transcript was also detected by a nested reverse transcriptase-polymerase chain reaction analysis of mononuclear cells from the bone marrow, although leukemic cells were not recognized in a microscopical examination of the patient's bone marrow. Systemic chemotherapy with high-dose cytarabine followed by local radiotherapy was performed, and the patient clinically achieved a complete response. These molecular analyses provide a precise method of diagnosis, especially with respect to the French-American-British AML classification, according to the characteristic karyotypic alterations, and a patient consequently can quickly be given appropriate systemic chemotherapy as induction therapy.
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PMID:The application of molecular analyses for primary granulocytic sarcoma with a specific chromosomal translocation. 1620 93

A series of 92 Chinese children newly diagnosed with acute lymphoblastic leukemia (ALL) were examined for the ETV6-RUNX1 (previously TEL-AML1) fusion gene by using a nested reverse transcriptase-polymerase chain reaction. ETV6-RUNX1 fusion transcripts were detected in 21 of 92 patients (22.8%): 16 with common ALL, 4 with precursor B-cell ALL, and 1 with T-ALL. The prevalence of ETV6-RUNX1 positivity was 24.7% (20/81) in childhood B-lineage ALL. The prevalence of ETV6-RUNX1 in Chinese pediatric ALL patients proved to be similar to that found in other countries.
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PMID:Prevalence of ETV6-RUNX1 fusion gene in children with acute lymphoblastic leukemia in China. 1788 9

We report a case that revealed the characteristics of acute myeloblastic leukemia with maturation (AML-M2) on the morphology of the bone marrow biopsy and 45,X,-Y in conventional cytogenetic study, but was confirmed to have a typical AML1/ETO translocation by molecular studies using reverse transcriptase polymerase chain reaction and fluorescence in situ hybridization. Insertion of ETO gene on chromosome 8 into chromosome 21 in this patient resulted in the development of the chimeric gene, AML1/ETO, on the long arm of chromosome 21. Our final report on the patient's karyotype: 45,X,-Y.ish ins(21;8)(q22;q22q22)(AML1 +,ETO +;ETO +,AML1-). In case typical morphologic features compatible with recurrent cytogenetic abnormalities are shown, molecular studies in addition to conventional cytogenetic study might be required to confirm the diagnosis.
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PMID:[A Case of Acute Myeloid Leukemia with Masked t(8;21).]. 1815 48

We encountered a case of acute myeloblastic leukemia (AML), with extramedullary leukemia (EML) and a masked type of the variant translocation t(8;21)(q22;q22). Morphologically, the AML M2 subtype according to the French-American-British (FAB) classification was present. Phenotypically, leukemic cells were negative for CD19 and positive for CD56. Clinically, the case showed chemo-refractoriness and a poor outcome. The initial karyotypic interpretation was t(8;9)(q22;q34) on G-banding. Multiplex-fluorescence in situ hybridization (multiplex-FISH) analysis revealed a three-way translocation involving chromosomes 8, 9, and 21, and identified a masked type of variant t(8;21)q22;q22) translocation. The karyotype was finally determined as 45,X,-Y,der(8)t(8;21)(q22;q22), der(9)(8;9)(q22;q34), and der(21)t(9;21)(q34;q22). Results of FISH using the AML1/ETO probe and detection of the AML1/ETO fusion transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) support the karyotype as well as the sequence of the PCR product. Additionally, C-KIT mutation was detected.
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PMID:A case of acute myeloblastic leukemia with a novel variant of t(8;21)(q22;q22). 1822 18

Chromosomal abnormalities are found in 80-90% of childhood cases of acute lymphoblastic leukemia (ALL). Leukemia-specific chromosome aberrations not only have prognostic value, but also provide important clues for further investigation into leukogenesis, leukemic cell transformation, and proliferation. This study used reverse transcriptase-polymerase chain reaction techniques to detect transcripts of the leukemia-specific chromosome fusion gene, TEL/AML1, and to monitor the expression levels of the TEL-AML1 fusion transcript in ALL patients at sequential intervals during their treatment course. Twenty-five ALL patients were enrolled, including 20 who were newly diagnosed and five in relapse. The incidence of the TEL/AML1 fusion gene in this study was 32%. The clinical features of our eight TEL/AML1-positive ALL cases were similar to those in other studies. Blotting analysis of the levels of the TEL-AML1 fusion transcript was used to detect minimal residual disease. Reduced levels of TEL/AML1 expression were found in four of the six patients whose bone marrow or peripheral blood samples were obtained after treatment. Further investigation with a larger sample size is warranted.
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PMID:TEL/AML1 fusion gene in childhood acute lymphoblastic leukemia in southern Taiwan. 1863 14

The characterization of leukemia-associated chromosome translocations has contributed relevant insights into our understanding of leukemia pathogenesis and has provided new specific tumor markers essential in prognostic assessment and minimal residual disease studies. The aim of this work is to study the frequency of AML1/ETO fusion gene in a series of Egyptian childhood AML cases. The clinical significance and prognostic implications of this aberration, including CR rate, duration of first CR, extramedullary leukemia (EML), and survival are investigated as well. Peripheral blood and/or bone marrow mononuclear cells were available for analysis from 78 children, all newly diagnosed with AML. AML1/ ETO fusion transcript was detected by the reverse transcriptase- polymerase chain reaction (RT-PCR) technique. Patients with de novo AML were treated by 2 courses of induction chemotherapy, followed by 4 courses of consolidation treatment if the patient achieved complete remission (CR). The marrow status was evaluated after each course in order to check bone marrow cellularity and presence of blasts. Patients with less than 5% blasts by the end of the second course of ADE passed to consolidation chemotherapy. Patients with more than 5% blasts by the end of the second course of ADE were excluded from the study. The AML1/ETO fusion transcript was detected by a singleround RT-PCR reaction and was found to be expressed in 15 out of 78 cases (19.2%). AML1/ETO positive patients were 7 girls and 8 boys, with ages ranging from 5 to 15 years. Seven cases (46.67%) belonged to FAB subtype M1, 7 (46.67%) M2, while only one case (6.67%) belonged to M5a subtype. Their total leukocytic counts ranged from 7.1 to 183.0 x 109/l with a median of 21.0 x 109/l. Their hemoglobin concentrations ranged from 4.8 to 10.3g/dl with a median of 7.4g/dl, while their platelet counts ranged from 6.0 to 96.0 x 109/l with a median of 25.5 x 109/l. Lymph nodes were enlarged in 8/15 cases (53.34%), hepatomegly was observed in 4/15 cases (26.67%), splenomegaly in 8/15 cases (53.34%), purpura in 6/15 cases (40%), while pallor was observed in all fifteen cases.Extramedullary leukemia occurred in 4/15 cases (26.67%). As regards the fate of the positive cases, thirteen cases (86.67%) attained complete remission (CR) following induction chemotherapy. Two patients (13.33%) died during induction in active disease. Eight patients were in complete continuous remission (CCR), four patients (26.67%) relapsed and died during relapse, and one patient (6.67%) died in complete remission due to severe neutropenia and infection. On comparing the AML1/ETO fusion gene status with overall survival, no significant difference was found between AML1/ETO positive and negative cases. Likewise, no difference could be found between positive and negative cases as regards disease-free survival (p=0.354). In conclusion, we report a frequency of 19.2% of AML1/ETO fusion gene in our newly diagnosed pediatric AML cases. Positive cases showed good response to induction therapy, as well as high complete remission rates, which are features of good prognosis. Key Words: Pediatric acute myeloid leukemia , AML1/ETO fusion gene , RT-PCR , Clinical outcome , Prognostic significance.
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PMID:AML1/ETO Fusion Gene in de novo Pediatric Acute Myeloid Leukemia: Clinical Significance and Prognostic Implications. 1883 34

The t(2;8;21) is a complex translocation of t(8;21), and is very rare. To investigate the laboratory characteristics of a complex translocation t(2;8;21)(p12;q22;q22) in a patient with acute myelogenous leukemia (AML-M2), bone marrow smears were prepared for morphological analysis. Bone marrow samples were collected for FCM, and prepared by short-term (24 h) unstimulated culture for R-binding and conventional cytogenetic assay (CCA). AML1/ETO chimera transcription was detected by reverse transcriptase polymerase chain reaction (RT-PCR), and laboratory test results were studied with multifactorial analysis method. In this case, the chromosomal analysis (R-banding) demonstrated a complex translocation t(2;8;21)(p12;q22;q22). With combined evidence from morphological and immunophenotypic results, the patient was diagnosed as AML-M2. t(2;8;21)(p12;q22;q22) was considered a rare complex translocation of t(8;21). Experience of the present case further emphasises the importance of the laboratory diagnostic methods.
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PMID:Laboratory study of a complex translocation t(2;8;21) (p12;q22;q22) in a patient with acute myelogenous leukemia. 1894 16

Acute lymphoblastic leukemia (ALL) accounts for approximately 80% of all acute leukemias during childhood. Chromosomal anomalies resulting from gene fusion, which are frequent in leukemias, create hybrid transcripts, the great majority of which encode transcription factors. We analyzed 88 pediatric patients (median age 7.3 years) who had B-lineage acute lymphoblastic leukemia (B-ALL), using reverse transcriptase-polymerase chain reaction, to look for gene fusion transcripts of TEL/AML1, E2A/PBX1, BCR/ABL p190, and MLL/AF4. The frequencies of these transcripts were 21.21, 9.68, 3.03, and 0%, respectively. All positive cases had a common B-ALL immunophenotype. The low frequency of the TEL/AML1 transcript that is found in developing countries, such as Brazil, may be due to the low incidence of leukemia; this would support Greaves' hypothesis.
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PMID:Molecular and chromosomal mutations among children with B-lineage lymphoblastic leukemia in Brazil's Federal District. 1944 Sep 70

AML1-ETO fusion gene is generated from chromosomal translocation t(8;21) mainly in acute myeloid leukemia M2 subtype (AML-M2). Its spliced variant transcript, AML1-ETO9a, rapidly induces leukemia in murine model. To evaluate its clinical significance, AML1-ETO9a expression was assessed in 118 patients with t(8;21) AML-M2, using qualitative and nested quantitative reverse transcriptase (RT)-PCR methods. These cases were accordingly divided into the AML1-ETO9a-H group (n=86, positive for qualitative RT-PCR, with higher level of AML1-ETO9a by quantitative RT-PCR) and the AML1-ETO9a-L group (n=32, negative for qualitative RT-PCR, with lower but still detectable level of AML1-ETO9a by quantitative RT-PCR). C-KIT expression was significantly increased in the AML1-ETO9a-H group, as compared with the AML1-ETO9a-L group. Of the 36 patients harboring C-KIT mutations, 32 patients overexpressed AML1-ETO9a (P=0.0209). Clinically, AML1-ETO9a-H patients exhibited significantly elevated white blood cells count, less bone marrow aberrant myelocytes, increased CD56 but decreased CD19 expression (P=0.0451, P=0.0479, P=0.0149 and P=0.0298, respectively). Moreover, AML1-ETO9a overexpression was related to short event-free and overall survival time (P=0.0072 and P=0.0076, respectively). Taken together, these data suggest that AML1-ETO9a is correlated with C-KIT overexpression/mutations and indicates poor disease outcome in t(8;21) AML-M2.
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PMID:AML1-ETO9a is correlated with C-KIT overexpression/mutations and indicates poor disease outcome in t(8;21) acute myeloid leukemia-M2. 1945 28

Contemporary protocols ensure high-remission rate and long-term free survival in children with acute lymphoblastic leukemia (ALL), but small percentage of patients is still incurable. Molecular genetic methods helped to establish submicroscopic classification as well as minimal residual disease follow-up, considered to be responsible for relapse. Our study enrolled 70 pediatric patients with de novo ALL, analyzed using reverse transcriptase-polymerase chain reaction for the presence of four major risk-stratifying translocations (BCR/ABL, MLL/AF4, TEL/AML1, and E2A/PBX1). Bone marrow samples were collected at diagnosis, at the end of induction phase, and after intensive chemotherapy with the aim to establish the correlation between chromosomal aberration, clinical features, and treatment response. Presenting the results of this study, we offer another evidence of variable incidence and clinical characteristics of ALL subtypes.
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PMID:Clinical features of the most common fusion genes in childhood acute lymphoblastic leukemia. 1948 66


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