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:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The EWS gene is fused in Ewing sarcoma-like tumors by a chromosomal translocation to one of the four ETS-family genes: FLI1, ERG, ETV1, and E1AF. The orientation of EWS and FLI1 on chromosomes 22 and 11, respectively, is 5' centromeric and 3' telomeric, whereas that of ERG on chromosome 21 is the reverse. Although 10% of Ewing-family tumors express the EWS-ERG fusion transcript, there have been no reports on tumors with t(21;22)(q22;q12) identified by banding cytogenetics. We found the karyotype 50, XY, +8, +8, +12, +mar in all metaphase cells from a tumor. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis performed on the tumor and direct sequencing of the products identified the EWS-ERG fusion transcript. Subsequent two-color fluorescence in situ hybridization (FISH) analysis with EWS and ERG clones showed the fused signals on the der(21) chromosome, but no ERG signals on the chromosome 22 homologs. Thus, our RT-PCR and FISH analyses indicated that the chromosome 22 fragment containing the 5' portion of EWS had been inverted and inserted into chromosome 21 and had fused to the 3' portion of ERG. This subtle chromosome aberration could not be identified by routine cytogenetics. A chromosomal inversion/insertion has also been described in acute leukemia with the MLL-AF10 fusion gene, and this may be a common pathway for producing fusion of reverse-oriented genes in leukemias and solid tumors.
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PMID:EWS-ERG fusion transcript produced by chromosomal insertion in a Ewing sarcoma. 907 76

In more than 95% of patients, the Ewing family of tumors (ET) has chimeric transcripts caused by fusion of the EWS gene to either FLI1 or ERG. The presence of specific EWS-FLI1 or EWS-ERG transcripts in peripheral blood (PB) samples of patients being treated for ET was prospectively evaluated, and these data were correlated to their clinical status. The authors studied 113 PB samples from 28 patients with ET. Treatment included chemotherapy, radiotherapy, and surgical excision of tumor after induction therapy. PB samples were taken prospectively at least 2 weeks after resection of tumor. Nested reverse-transcriptase polymerase chain reaction (RT-PCR) followed by Southern blot was performed in all samples. Resected tumors were reviewed for the degree of response to chemotherapy and volume. Seventy-seven PB samples from 28 patients had EWS-FLI1/ERG transcripts. In 11 patients, PB samples became negative with treatment, and, in 5 of them, the samples remained negative throughout the study. Samples taken during progression were always positive and, in 4 patients, became positive before progression was clinically evident. All patients with transcripts other than EWS-FLI1 type 1 (n = 3) died from tumor progression. This is a sensitive assay to monitor circulating tumor cells in Ewing tumors. The preliminary data suggest that progression is preceded by positive samples and may be related to specific transcript types.
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PMID:Ewing family tumors: potential prognostic value of reverse-transcriptase polymerase chain reaction detection of minimal residual disease in peripheral blood samples. 983 70

Polymerase chain reaction (PCR)-based nucleotide sequence analysis was performed in 12 cases of Ewing sarcoma on the cDNA and/or genomic DNA breakpoint regions of a t(11;22)(q24;q12), which joins the EWS gene located on chromosome 22 with the FLI1 gene located on chromosome 11, in order to understand the molecular mechanism of this translocation. Reverse transcriptase-PCR on total tumor cell RNA from the examined cases showed five types of EWS-FLI1 chimeric product, resulting from various junctions between EWS exon 7 or 10 with FLI1 exon 5, 6, or 8. Sequencing of the genomic fusion junctions of EWS-FLI1 in seven cases showing three types of the chimeric cDNA products revealed that most of the breakpoint junctions shared common nucleotide(s) from both genes, and that the breakpoints in EWS introns 7 and 10 clustered within 100 bp and 300 bp, respectively. All the junctions were found to be flanked by various oligomers, among which a consensus sequence, 5'-AGAAAARDRR-3', was found near the breakpoints of both genes in four cases, suggesting that these oligomers may have a functional significance in the genesis of t(11;22). In addition to these oligomers, sequences highly homologous to Alu repeats and/or eukaryotic topoisomerase II cleavage sites were located near, or flanked, or even encompassed, the breakpoints in most of the cases examined. Thus, these sequences may also mediate DNA double-strand breakage and rejoining to generate the t(11;22). Genomic sequence analysis of both EWS-FLI1 and FLI1-EWS chimeric genes in three of the seven cases demonstrated a deletion and duplication of both EWS and FLI1 sequences in two cases and no gain or loss in one case. The present findings suggest that multiple mechanisms may be operative for the break and rejoining of the fragments of chromosomes 11 and 22 in the genesis of t(11;22), and that some of these translocations are asymmetric at the molecular level.
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PMID:Molecular characterization of the genomic breakpoint junction in a t(11;22) translocation in Ewing sarcoma. 1022 34

Rearrangements of the EWS gene with ETS transcription factor genes as a result of chromosomal translocation and high expression levels of CD99MIC2 characterize the Ewing family of tumors (EFT). This group of rather undifferentiated neoplasms affects bone and soft tissue in children and young adults mostly between 5 and 30 years of age (median, 15 years). This study reports a case of a CD99MIC2 positive small round cell tumor in the breast of a 60-year-old woman in whom a t(11;22)(q24;q12) chromosomal aberration was identified by cytogenetic analysis. Reverse transcriptase (RT)-polymerase chain reaction (PCR) followed by sequence analysis revealed expression of a chimera transcript in which EWS exon 10 was fused to FLI1 exon 6. Previously, this gene fusion has been reported to occur in approximately 3% of EFT. The specific gene rearrangement of EWS intron 10 was confirmed on Southern blot of genomic DNA. This study further contributes to the growing list of unusual neoplasms in adults that carry genotypic and phenotypic traits of the EFT.
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PMID:CD99 positivity and EWS-FLI1 gene rearrangement identify a breast tumor in a 60-year-old patient with attributes of the Ewing family of neoplasms. 1056 82

A reciprocal t(11;22)(q24;q12) is found in 85% of Ewing sarcomas (ES) cases. We report a case of a child with ES, in whom trisomy 8 was observed as the sole chromosomal abnormality. Fluorescence in situ hybridization---using a set of probes that localize to 22q12 (EWS) and 11q24 (FLI-1) and usually show the translocation as fusion (red-green) signal on der(22)---showed a fusion signal on der(11) suggesting an insertion as the mechanism that led to the EWS-FLI-1 gene rearrangement. Reverse transcriptase-polymerase chain reaction studies revealed the presence of two EWS/FLI1 fusion gene products.
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PMID:EWS/FLI-1 fusion signal inserted into chromosome 11 in one patient with morphologic features of Ewing sarcoma, but lacking t(11;22). 1189 Sep 93

Pre-mRNA splicing and polyadenylation are tightly connected to transcription, and transcriptional stimuli and elongation dynamics can affect mRNA maturation. However, whether this regulatory mechanism has a physio/pathological impact is not known. In cancer, where splice variant expression is often deregulated, many mutated oncogenes are transcriptional regulators. In particular, the Ewing sarcoma (EwSa) oncogene, resulting from a fusion of the EWS and FLI1 genes, encodes a well characterized transcription factor. EWS-FLI1 directly stimulates transcription of the CCND1 protooncogene encoding cyclin D1a and a less abundant but more oncogenic splice isoform, D1b. We show that, although both EWS and EWS-FLI1 enhance cyclin D1 gene expression, they regulate the D1b/D1a transcript ratio in an opposite manner. Detailed analyses of RNA polymerase dynamics along the gene and of the effects of an inhibitor of elongation show that EWS-FLI1 favors D1b isoform expression by decreasing the elongation rate, whereas EWS has opposite effects. As a result, the D1b/D1a ratio is elevated in EwSa cell lines and tumors. The endogenous D1b protein is enriched in nuclei, where the oncogenic activity of cyclin D1 is known to occur, and depleting D1b in addition to D1a results in a stronger reduction of EwSa cell growth than depleting D1a only. These data show that elevated expression of a splice isoform in cancer can be due to an alteration of the transcription process by a mutated transcriptional regulator and provide evidence for a physio/pathological impact of the coupling between transcription and mRNA maturation.
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PMID:Alteration of cyclin D1 transcript elongation by a mutated transcription factor up-regulates the oncogenic D1b splice isoform in cancer. 1841 12

Primary poorly differentiated (small round and non-small) sinonasal neoplasms comprise histogenetically and biologically diverse entities with overlapping morphologic features. Because of the limited initial biopsy tissue materials, differential diagnostic difficulties may arise and complicate timely management of some cases. We used immunohistochemical and molecular marker analyses in a large cohort of these tumors to optimize their early diagnosis and classification. Fifty-two tumors of the skull base and sinonasal regions and, for comparison, 19 poorly differentiated neoplasms of other head and neck sites were analyzed by a panel of immunohistochemical markers including those of epithelial, mesenchymal, melanocytic, and neuroectodermal origin using tissue microarray. Reverse transcriptase-polymerase chain reaction analysis of messenger RNA for EWS-FLI1 and PAX-FKHR fusion transcripts and the human achaete-scute homolog-1 gene was performed on 24 of the 52 sinonasal tumors and the 19 tumors of other sites for comparison. The immunohistochemical results substantiated the phenotypic assessment and the initial diagnosis in 49 of the 52 tumors. In 4 instances the integrated markers and phenotypic analyses led to reclassification of 3 tumors and confirmed the histogenesis of a mesenchymal tumor with aberrant cytokeratin expression. Molecular analysis of the EWS-FLI1 fusion gene transcript revealed 4 (9.3%) of the 43 tumors to be positive; all were Ewing sarcomas. The human achaete-scute homolog-1 gene transcript was identified in 10 (23.8%) of 42 tumors: 3 of 6 neuroblastomas, all 4 neuroendocrine carcinomas, and 1 each in sinonasal undifferentiated carcinoma, rhabdomyosarcoma, and melanoma. The PAX-FKHR fusion transcript was not detected in any tumors. We conclude that (1) an integrated morphologic and biomarker algorithm may better optimize the early diagnosis of poorly differentiated sinonasal and skull-base tumors; (2) molecular analysis may assist in future biological stratification of certain classes of these tumors; and (3) the human achaete-scute homolog-1 gene transcript is a nonspecific marker for the diagnosis of neuroblastoma.
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PMID:Molecular and phenotypic analysis of poorly differentiated sinonasal neoplasms: an integrated approach for early diagnosis and classification. 1915 Jan 7

Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) family of tumor is a very aggressive malignant round cell tumor characterized by translocations involving EWS-FLI1 genes. They are increasingly recognized in extraosseous sites as a result of improvements in diagnostic tools. In this paper, we report 2 additional cases arising in vulva of young adults who have been treated aggressively and have survived fore more than 7 and 4 years successively. Histologic examination showed small round (blue) cell morphology in both cases. The tumor cells contained glycogen and were positive for CD99 and vimentin and negative for keratins, lymphoid markers, S-100, synaptophysin, chromogranin, and desmin. Reverse transcriptase polymerase chain reaction analysis from paraffin-embedded tissue revealed EWS-FLI1 fusion product in 1 case. Collectively, 13 cases of vulvar ES/PNET have been reported in the literature. Only 8 cases have detailed follow-up information with an average follow-up data of 28 months. Ewing sarcoma/PNET should be considered in the differential diagnosis of any undifferentiated tumors involving the lower gynecologic tract and all axillary tests including molecular tests should be performed for correct diagnosis because prolonged survival is possible for this dreadful disease after complete surgical resection, followed by adjuvant therapy.
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PMID:Primary vulvar Ewing sarcoma/primitive neuroectodermal tumor: a report of 2 cases and review of the literature. 1982 Mar 81

There may be a number of tumors made up by small round blue cells in the kidneys of children. One of them is primitive neuroectodermal tumor (PNET). The differences in therapeutic approaches determine the need to establish an accurate diagnosis. The differential diagnosis of PNET and the blastemal component of Wilms tumor can be difficult due to the similar histological pattern. There is a need for a close analysis of morphological manifestations, by keeping in mind the age of patients, and supplementary studies. A strong CD99 membrane expression and nuclear FLI1 expression in tumor cells are the signs of PNET. Reverse transcriptase-polymerase chain reaction and fluorescence in situ hybridization can determine PNET-specific translocations [t(11;22)(q24;q12), by involving the EWS gene.
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PMID:[Primitive neuroectodermal tumor of the kidney in children; its differential diagnosis with Wilms tumor]. 2013 7

Detection of EWSR1 translocations - particularly t(11;22)(q24;q12) - is of great value in the differential diagnosis of the Ewing family of tumors. We report two cases that highlight the problems and pitfalls of identifying Ewing tumors using conventional chromosome analysis and a commercial EWSR1 fluorescence in situ hybridization (FISH) probe. In both cases, the tumor karyotype was abnormal, but a visible t(11;22)(q24;q12) was not present. The commercial EWSR1 "break-apart" probe was not split in either case. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis, however, identified EWSR1-FLI1 fusion transcripts in both tumors, and the gene fusions were corroborated by FISH analysis with "in house" probes and confirmed by sequencing RT-PCR products. The occurrence of cryptic EWSR1-FLI1 fusions mandates that RT-PCR should be performed, particularly in those cases in which the genetic findings are not in agreement with the histologic picture.
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PMID:Cryptic EWSR1-FLI1 fusions in Ewing sarcoma: potential pitfalls in the diagnostic use of fluorescence in situ hybridization probes. 2051 36


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