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)

To assess the clinical significance of AML1/ETO gene detected by nested reverse transcriptase polymerase chain reaction, the outcome of 7 patients with acute myeloblastic leukemia between 3 and 14 years of age were presented. All patients had complete remission (CR) at the end of induction (AML-MRC 10 protocol) and 4 underwent unpurged autologous, 2 allogeneic (from matched siblings) non-T-cell-depleted bone marrow transplantations (BMT) in first CR. One patient died due to allogeneic BMT-related complications, and 4 patients relapsed at 13, 17, 18, and 26 months. Only one patient achieved second CR. All relapsed patients died between 18 and 36 months with resistant disease (n = 3) or infection during salvage chemotherapy (n = 1). Two patients who had autologous BMT are alive and disease free at 44 and 50 months. Although statistical significance could not be shown, event-free survival and overall survival rates of AML1/ETO-positive patients (28.57 and 28.57%, respectively) at 3.5 years were even lower than those of AML1/ETO-negative patients. The results confirm some previous reports that AML1/ETO gene in children and adolescents is not a favorable prognostic factor.
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PMID:Is AML1/ETO gene expression a good prognostic factor in pediatric acute myeloblastic leukemia? 1103 33

A 4-year-old boy admitted with exophthalmos was diagnosed as having acute myeloblastic leukemia with maturation (AML-M2). Chromosomal analysis (G-banding) showed t(8;15;21). Fluorescence in situ hybridization (FISH), reverse transcriptase-polymerase chain reaction (RT-PCR), spectral karyotyping (SKY), and nucleolar organizer region (NOR) staining suggested that this complex translocation might have resulted from stepwise translocation, namely an initial translocation between chromosomes 8 and 21, followed by a second translocation between der(21) and chromosome 15, rather than the other possibility of clockwise translocation. During chemotherapy, RT-PCR demonstrated the short form of AML1-MTG8 mRNA, in addition to chimeric mRNA of the usual length. Sequence analysis revealed that this shorter chimeric mRNA had resulted from deletion of a 250-bp sequence at the 5' end of MTG8. A literature search failed to reveal any similar cases of t(8;21) AML-M2 associated with this deletion of chimeric mRNA.
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PMID:[Complex translocation (8;15;21) (q22;p12;q22) in a child with AML-M2 showing de novo appearance of the short form of AML1-MTG8 chimeric mRNA during the course]. 1128 Sep 16

Acute promyelocytic leukemia (AML M3) is a well-defined subtype of leukemia with specific and peculiar characteristics. Immediate identification of t(15;17) or the PML/RARA gene rearrangement is fundamental for treatment. The objective of the present study was to compare fluorescent in situ hybridization (FISH), reverse transcriptase-polymerase chain reaction (RT-PCR) and karyotyping in 18 samples (12 at diagnosis and 6 after treatment) from 13 AML M3 patients. Bone marrow samples were submitted to karyotype G-banding, FISH and RT-PCR. At diagnosis, cytogenetics was successful in 10 of 12 samples, 8 with t(15;17) and 2 without. FISH was positive in 11/12 cases (one had no cells for analysis) and positivity varied from 25 to 93% (mean: 56%). RT-PCR was done in 6/12 cases and all were positive. Four of 8 patients with t(15;17) presented positive RT-PCR as well as 2 without metaphases. The lack of RT-PCR results in the other samples was due to poor quality RNA. When the three tests were compared at diagnosis, karyotyping presented the translocation in 80% of the tested samples while FISH and RT-PCR showed the PML/RARA rearrangement in 100% of them. Of 6 samples evaluated after treatment, 3 showed a normal karyotype, 1 persistence of an abnormal clone and 2 no metaphases. FISH was negative in 4 samples studied and 2 had no material for analysis. RT-PCR was positive in 4 (2 of which showed negative FISH, indicating residual disease) and negative in 2. When the three tests were compared after treatment, they showed concordance in 2 of 6 samples or, when there were not enough cells for all tests, concordance between karyotype and RT-PCR in one. At remission, RT-PCR was the most sensitive test in detecting residual disease, as expected (positive in 4/6 samples). An incidence of about 40% of 5' breaks and 60% of 3' breaks, i.e., bcr3 and bcr1/bcr2, respectively, was observed.
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PMID:Acute promyelocytic leukemia: the study of t(15;17) translocation by fluorescent in situ hybridization, reverse transcriptase-polymerase chain reaction and cytogenetic techniques. 1137 61

alpha- and beta-tryptase genes encode serine proteases that are abundantly expressed by mast cells. Under physiologic conditions other myeloid cells are virtually tryptase negative. However, tryptases are also expressed in several myeloid leukemia cell lines. In this study, serum total tryptase levels were determined in 150 patients with acute leukemias (de novo acute myeloid leukemia [AML], n = 108; secondary AML, n = 25; acute lymphoid leukemia [ALL], n = 17) by fluoroenzyme immunoassay. In healthy subjects (n = 30), tryptase levels ranged between 2.0 and 12.6 ng/mL. Elevated tryptase levels (> 15) were detected in 42 (39%) of 108 patients with de novo AML and in 11 (44%) of 25 patients with secondary AML. No elevated tryptase levels were found in patients with ALL. In de novo AML, elevated tryptase levels were frequently detected in patients with French-American-British classification M0 (6 of 9), M2 (9 of 14), M3 (4 of 6), and M4eo (7 of 7), and less frequently in M1 (7 of 20), M4 (6 of 26), M5 (2 of 18), M6 (0 of 5), or M7 (1 of 3). The highest tryptase levels were found in M4eo. Immunohistochemical staining of bone marrow sections with anti-tryptase antibody as well as immunoelectron microscopy revealed tryptase expression in the cytoplasm of myeloblasts. As assessed by Northern blotting and reverse transcriptase-polymerase chain reaction, AML cells expressed alpha-tryptase messenger RNA (mRNA) but little or no beta-tryptase mRNA. In AML patients with elevated serum tryptase before chemotherapy, who entered complete remission, tryptase levels returned to normal or near normal values. Blast cell persistence or regrowth was associated with a persistently elevated level or recurrent increase of tryptase. Together, tryptase is expressed in myeloblasts in a group of AML and may serve as a useful disease-related marker.
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PMID:Expression of mast cell tryptase by myeloblasts in a group of patients with acute myeloid leukemia. 1156 8

A 63-year-old male was diagnosed as chronic myelomonocytic leukemia with normal karyotype in September 1998. He developed acute myelogenous leukemia (AML-M4Eo) in September 2001. The cytogenetic analysis disclosed double t(3;21) at a ratio of 1/20, and the reverse transcriptase-polymerase chain reaction showed AML1/EVI-1 mRNA. He could not achieve complete remission after two courses of induction chemotherapy, and his leukemia cells carrying double t(3;21) were relatively increased. He died of interstitial pneumonia in December 2001. This is the first leukemia case with double t(3;21) and this chromosomal abnormality might play a role in leukemia cell proliferation by generating two AML1/EVI-1 genes.
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PMID:[Double t (3; 21) in acute myelomonocytic leukemia transformed from chronic myelomonocytic leukemia]. 1241 94

OBJECTIVE: To observe the expression of stem cell factor (SCF) mRNA in primary human leukemia cells and investigate its significance in deciding the prognosis of leukemia patients. METHODS: Primary leukemia cells were isolated form the bone marrow of 49 patients with leukemia, and the expression of SCF mRNA determined by nested reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Among the 19 patients with acute lymphatic leukemia (ALL), 5 were positive and 14 negative for SCF mRNA. In cases of acute myeloid leukemia (AML, n=30), 24 of M1 to M4 subtypes were found positive for SCF mRNA but 4 of M5 subtype and 2 of M6 subtype were negative. There was a significant difference between ALL and AML groups (P<0.05). Eight (27.6%) cases were refractory leukemia in the total of 29 patients who were positive for SCF, while 12 (60.0%) were refractory among the 20 patients negative for SCF (P<0.05). CONCLUSIONS: The expression rate of SCF was significantly higher in AML than in ALL cases, and the negative expression of SCF mRNA might be indicative of unfavorable prognosis, but the exact mechanism needs futher investigation.
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PMID:Expression of stem cell factor mRNA in primary leukemia cells. 1242 78

Myelodysplastic syndromes (MDS) are characterized by peripheral blood cytopenias despite hypercellularity of the bone marrow regarded as the result of ineffective hematopoiesis mainly caused by apoptosis. In this study, we examined the role of tumor necrosis factor (TNF)-induced apoptosis in the bone marrow cells of MDS patients. The constitutive expression of mRNA for TNF receptors (TNFR), including TNFRI and TNFRII, and the adapter molecules, such as the TNF receptor-associated death domain protein (TRADD), Fas-associated death domain protein (FADD), receptor interacting protein (RIP) and TNF receptor-associated factor 2 (TRAF-2) were analyzed by reverse transcriptase (RT)-PCR in bone marrow samples from control, MDS and AML cases. In bone marrow cells from refractory anemia (RA) patients, there was a significant increase in TNFRI expression as compared with control subjects. The expression of TNFRII was also up-regulated in RA cases. In contrast, RA with excess of blasts (RAEB), RAEB in transformation (RAEB-T) and AML cases revealed increased expression of TNFRII, whereas the expression of TNFRI was comparable to control subjects. Immunohistochemical staining revealed that the TNFRI, as well as TNFRII of MDS bone marrow was expressed mainly in hematopoietic cells, but not in macrophage-lineage stromal cells at the protein level. An increased constitutive expression of mRNA for TRADD, FADD and RIP and decreased expression of mRNA for TRAF-2 were observed in bone marrow cells from MDS patients, especially from RA patients, as compared with controls, although the differences were not significant. In many of the AML bone marrow samples, strong expression of TRAF-2 mRNA was marked, while expression levels of other proteins were similar to those in control subjects. These data suggested enhanced signaling by the TNFRI-TRADD-FADD pathway and suppressed signaling by the TRAF-2 pathway in RA. Thus, TNF-alpha-induced apoptosis may play a role in ineffective hematopoiesis in "early stage MDS" bone marrow, although the regulatory mechanisms for TNF-alpha-induced signaling would be complicated and not be simply explained only by these pathways.
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PMID:Expression of TNF receptors and related signaling molecules in the bone marrow from patients with myelodysplastic syndromes. 1268 57

A 43-year-old man was diagnosed with acute myelocytic leukemia with cellular maturation (AML-M2, according to the French-American-British classification criteria). A cytogenetic study with a G-banding method initially reported the karyotype as 45,X,-Y; however, dual-color, dual-fusion fluorescence in situ hybridization (FISH) with probes for the AML1 and the ETO genes showed an unusual pattern of signals, presenting one fusion signal on chromosome 21. Molecular study by reverse transcriptase polymerase chain reaction revealed the presence of a typical AML1/ETO chimeric gene. FISH with whole-chromosome painting probes targeting chromosomes 8 and 21 revealed insertion of part of 8 chromosome into the long arm of chromosome 21. We concluded that complicated translocations involving chromosomes 8 and 21 in this patient resulted in the development of the chimeric gene, AML1/ETO, on the long arm of chromosome 21. This aberrant location of AML1/ETO gene and the final karyotype of 45,X,-Y,ins(21;8)(q22;q22q22) could not be determined without molecular analysis. This abnormality is considered a masked t(8;21).
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PMID:Insertion (21;8)(q22;q22q22): a masked t(8;21) in a patient with acute myelocytic leukemia. 1462 63

The translocation t(8;16)(p11;p13) is associated with acute myeloid leukemia displaying monocytic differentiation (AML FAB M4/5) and fuses the MOZ (also named MYST3) gene (8p11) with the CBP (also named CREBBP) gene (16p13). Detection of the chimeric RNA fusions has proven difficult; only three studies have described successful amplification of the chimeric MOZ-CBP and CBP-MOZ fusions by reverse transcriptase-polymerase chain reaction (RT-PCR). We analyzed four cases of AML M4/5 with t(8;16)(p11;p13) by RT-PCR and fluorescence in situ hybridization (FISH) and characterized the reciprocal RNA fusions from three cases. We cloned both genomic translocation breakpoints from one case by long-range PCR and successfully applied RT-PCR to monitor minimal residual disease (MRD) between clinical complete remission and relapse. In three cases, the genomic breakpoints occurred in MOZ intron 16 and CBP intron 2. In one case, no fusion transcript was detected. The available data suggest clustering of t(8;16)(p11;p13) breakpoints in these introns leading to reciprocal in-frame MOZ exon 16/CBP exon 3 and in-frame CBP exon 2/MOZ exon 17 chimeric transcripts in the majority of cases. The described RT-PCR strategy may be valuable both for the routine detection of the t(8;16)(p11;p13) as well as for monitoring of MRD in this prognostically unfavorable patient group.
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PMID:RT-PCR and FISH analysis of acute myeloid leukemia with t(8;16)(p11;p13) and chimeric MOZ and CBP transcripts: breakpoint cluster region and clinical implications. 1508 63

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


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