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

---

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

The Wilms' tumor gene (wt1) is strongly expressed in malignant blasts of acute myeloid leukemia (AML) in approximately 80% of all cases. However, the role of wt1 expression in non malignant hematopoietic cells remains unclear. To characterize the expression of wt1 in differentiating hematopoietic progenitors, we isolated and cultured CD34+ progenitor cells from four healthy bone marrow donors with stem cell factor (SCF) and granulocyte colony stimulating-factor (G-CSF) to induce differentiation into granulocytes. Four different cultures were carried out for 12 days. During culture, wt1 mRNA expression was analyzed by defining its ratio relative to beta-actin using reverse transcriptase polymerase chain reaction (RT-PCR). To monitor the stage of differentiation, expression of cell surface markers and peroxidase was analyzed daily. The initial purity of CD34+ cells ranged between 80% and 90%; after 12 days, the frequency of neutrophil bands and segmented neutrophils was approximately 60%. Using RT-PCR to determine the ratio of wt1 to beta-actin expression, we reproducibly detected maximum expression of wt1 mRNA at day 0 in two cultures and at day 1 in two other CD34+ cell cultures; at both these time points nearly all cells fulfilled the morphological and immunephenotypical criteria of early hematopoietic blast cells. Wt1 expression dropped rapidly at day 1 and 2, respectively, in these two pairs of cultures, and was accompanied by an increase of cells expressing CD33 surface antigen. Our data suggest that wt1 expression is restricted to a subset of CD34+ progenitors and downregulated in later stages of differentiation in vitro.
...
PMID:The Wilms' tumor gene is expressed in a subset of CD34+ progenitors and downregulated early in the course of differentiation in vitro. 925 7

Desmoplastic small round cell tumor is an aggressive neoplasm first described in 1991. Recently, a reciprocal translocation t(11;22)(p13;q12) has been characterized by conventional cytogenetic studies and molecular analysis. This translocation involves the Ewing's sarcoma gene on chromosome 22 and the Wilms' tumor gene WT1 on chromosome 11. The chimeric transcript corresponding to the fusion gene could be detected by the reverse transcriptase-polymerase chain reaction (RT-PCR). Using an anti-WT1 antibody, the WT1 part of the putative chimeric protein could be recognized by immunohistochemistry. We describe two well-characterized cases of intraabdominal desmoplastic small round cell tumor in two male patients aged 14 and 28 with both RT-PCR analysis and immunostaining for WT1. In this report, we insist on the necessity to increase the RT-PCR analysis in DSRCT in order to obtain a precise differential diagnosis. In addition, WT1 immunostaining may serve as a useful diagnostic marker for DSRCT.
...
PMID:Desmoplastic small round cell tumor: RT-PCR analysis and immunohistochemical detection of the Wilm's tumor gene WT1. 982 Aug 65

To determine the role of the Wilms' tumor gene WT1 in tumorigenesis of solid tumors, expression of the WT1 gene was examined in 34 solid tumor cell lines (four gastric cancer cell lines, five colon cancer cell lines, 15 lung cancer cell lines, four breast cancer cell lines, one germ cell tumor cell line, two ovarian cancer cell lines, one uterine cancer cell line, one thyroid cancer cell line, and one hepatocellular carcinoma cell line) by means of quantitative reverse transcriptase-polymerase chain reaction. WT1 gene expression was detected in three of the four gastric cancer cell lines, all of the five colon cancer cell lines, 12 of the 15 lung cancer cell lines, two of the four breast cancer cell lines, the germ cell tumor cell line, the two ovarian cancer cell lines, the uterine cancer cell line, the thyroid cancer cell line, and the hepatocellular carcinoma cell line. Therefore, of the 34 solid tumor cell lines examined, 28 (82%) expressed WT1. Three cell lines expressing WT1 (gastric cancer cell line AZ-521, lung cancer cell line OS3, and ovarian cancer cell line TYK-nu) were further analyzed for mutations and/or deletions in the WT1 gene by means of single-strand conformation polymorphism analysis. However, no mutations or deletions were detected in the region of the WT1 gene ranging from the 3' end of exon 1 to exon 10 (the WT1 gene consists of 10 exons) in these three cell lines. Furthermore, when AZ-521, OS3, and TYK-nu cells were treated with WT1 antisense oligomers, the growth of these cells was significantly inhibited in association with a reduction in WT1 protein levels. Furthermore, constitute expression of the transfected WT1 gene in cancer cells inhibited the antisense effect of WT1 antisense oligomer on cell growth. These results indicated that the WT1 gene plays an essential role in the growth of solid tumors and performs an oncogenic rather than a tumor-suppressor gene function.
...
PMID:Expression of the Wilms' tumor gene WT1 in solid tumors and its involvement in tumor cell growth. 1018 90

The expression of the Wilms' tumor gene (wt1) was detected in various tissues during embryonic development. Mutations in the wt1 gene probably play an important role in certain tumors, e.g. the Wilms' tumor. Furthermore the expression of wt1 gene was found in some human leukemias. In the present study we investigated the expression of wt1 gene in several types of childhood leukemia by reverse transcriptase-polymerase chain reaction. Bone marrow or peripheral blood of 61 pediatric patients (48 at initial diagnosis, 13 at first or second relapse) were analyzed. wt1 gene expression was detected in 35/48 patients (73%) with newly diagnosed leukemias and in 12/13 cases (92%) who had suffered from relapse. The expression levels were higher for AML than for ALL. The frequency of wt1 expression in different subtypes of acute leukemia was compared with results found in adult patients. Our results show that the frequency of wt1 gene expression in acute childhood leukemias is similar to previous data reported for adults.
...
PMID:wt1 gene expression in childhood leukemias. 1052 9

Wilms' tumor gene WT1 mRNA is a new marker of leukemic blast cells for AML, ALL, and CML. 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 cell in individual leukemia patients. Furthermore, WT1 assay can continuously assess the disease progression of myelodysplastic syndromes(MDS) and predict the evolution of MDS to overt AML within 6 months.
...
PMID:[Genetic diagnosis of leukemia: diagnosis of relapse and complete remission, and prediction of leukemia onset]. 1080 19

The measurement of Wilms' tumor gene (WT1) mRNA levels by reverse transcriptase-polymerase chain reaction (RT-PCR) is useful in detecting minimal residual disease (MRD) in leukemia patients. In the present study, we quantified the level of WT1 mRNA in the peripheral blood and bone marrow of patients with acute myelocytic leukemia (AML) at initial onset, remission and recurrence by the use of nucleic acid sequence based amplification (NASBA), and then ascertained the clinical usefulness of this method. At initial onset, the level of WT1 mRNA in the peripheral blood was above 10(3) copies/microgram and that in the bone marrow was above 10(4) copies/microgram. The level of WT1 mRNA was decreased in cases where therapy resulted in complete remission, but it was abnormally high in recurring cases. In AML (M3) patients, the relationship between the level of WT1 mRNA and the expression of the PML-retinoic acid alpha receptor (RAR alpha) gene, assessed by fluorescence in situ hybridization (FISH), was investigated. When leukemia was in remission hematologically, the PML-RAR alpha gene was negative and the level of WT1 mRNA decreased. These findings suggest that the quantification of WT1 gene expression by competitive NASBA is useful in assessing therapeutic effects and detecting MRD.
...
PMID:Quantification of WT1 mRNA by competitive NASBA in AML patients. 1150 93

It is unclear how a paroxysmal nocturnal hemoglobinuria (PNH) clone expands in bone marrow, although immune mechanisms involving cytotoxic T lymphocytes, autosomal proliferation, and apoptosis resistance have been hypothesized. To clarify aspects of immune mechanisms and proliferation of PNH cells, we investigated HLA-DRB1, -DQA1, and -DQB1 alleles by polymerase chain reaction (PCR)-based genotyping and expression of the Wilms' tumor gene, WT1, by real-time reverse transcriptase-PCR (RT-PCR) in 21 PNH and 21 aplastic anemia (AA) patients. HLA genotyping indicated that the frequency of DRB1*1501, DQA1*0102, and DQB1*0602 alleles in PNH patients and of DQB1*0602 allele in AA patients was significantly higher than in 916 Japanese controls, and that the HLA-DRB1*1501-DQA1*0102-DQB1*0602 haplotype, found in 13 of 21 PNH patients, 5 of 7 AA-PNH syndrome patients, and 7 of 21 AA patients showed significant differences compared with healthy individuals. RT-PCR analysis showed that the mean values of WT1 RNA were 3413, 712, and 334 copies/microg RNA in PNH, AA, and healthy individuals, respectively. The values for PNH patients were significantly higher than for AA patients and healthy volunteers and were correlated with the proportion of CD16b(-) granulocytes. The high frequency of HLA-DRB1*1501-DQA1*0102-DQB1*0602 haplotype in PNH, including AA-PNH syndrome, and AA patients suggests that linkage exists between the disorders and that immune mechanisms in an HLA-restricted manner play an important role in the pathogenesis of these disorders. In addition, high expression of WT1 RNA in PNH patients is related to a PNH clone, but it remains unclear whether this causes expansion of a PNH clone.
...
PMID:HLA class II haplotype and quantitation of WT1 RNA in Japanese patients with paroxysmal nocturnal hemoglobinuria. 1207 3

The expression levels of the Wilms' tumor gene WT1 were examined in 56 cases of head and neck squamous cell carcinoma (HNSCC) using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR). They included 4 cases of floor of mouth, 9 of gingiva, 25 of tongue, 10 of oropharynx, 3 of hypopharynx, and 5 larynx squamous cell carcinoma (SCC). All (100%) of 4 cases of floor of mouth, 5 (56%) of 9 gingiva, 17 (68%) of 25 tongue, 8 (80%) of 10 oropharynx, all (100%) of 3 hypopharynx, and all (100%) of 5 larynx SCC overexpressed the WT1 gene in the range of 3.07 x 10(-4)-8.60 x 10(-1) levels (the WT1 expression level in K562 leukemic cells was defined as 1.0). Thus, 42 (75%) out of 56 cases of HNSCC overexpressed the WT1 gene. The high expression level of the WT1 gene significantly correlated with poor histological tumor differentiation and high tumor stage of HNSCC. Immunohistochemical analysis confirmed the expression of WT1 protein in 6 cases (one floor of mouth, 2 tongue, 2 oropharynx, and one larynx SCC) with overexpression of the WT1 gene. The direct sequencing analysis of the WT1 genomic DNA showed no mutations in any of 10 exons of the WT1 gene in 5 different HNSCC. These findings suggest an important role of the wild-type WT1 gene in the tumorigenesis of HNSCC.
...
PMID:Overexpression of the Wilms' tumor gene WT1 in head and neck squamous cell carcinoma. 1282 78

The expression levels of the Wilms' tumor gene WT1 were examined in 34 primary thyroid cancers (24 papillary, 5 follicular, 1 anaplastic, and 4 medullary carcinomas), 17 thyroid follicular adenomas, and 6 normal-appearing thyroid tissues using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR). In 33 of 34 thyroid cancers, the WT1 mRNA was expressed at levels ranging from 5.0 x 10 (-5) to 8.3 x 10 (-2) levels (WT1 expression level in K562 leukemic cells was defined as 1.0). The WT1 mRNA expression levels were significantly higher than those in either thyroid follicular adenomas (P < 0.001) or normal-appearing thyroid tissues (P < 0.01). Immunohistochemical analysis confirmed the expression of WT1 protein in 20 of 21 thyroid cancers with WT1 mRNA expression. WT1 protein was also detected in 6 of 7 follicular adenomas with WT1 mRNA expression. However, the intensity of staining of WT1 protein in adenoma cells was weaker than that in cancer cells and its expression was restricted to approximately 30-80% of adenoma cells in the tumors examined. The direct sequencing analysis of the WT1 genomic DNA showed no mutations in any of the 10 exons of the WT1 gene in all of the 9 different thyroid cancers. These findings indicate an important role of the wild-type WT1 gene in the tumorigenesis of primary thyroid cancer.
...
PMID:Overexpression of the Wilms' tumor gene WT1 in primary thyroid cancer. 1284 69

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.
...
PMID:[Development of a new inspection diagnostic method: genetic screening of cancer]. 1520 29


1 2 Next >>

---