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)

In pediatric solid tumors, such as neuroblastoma (NB), it has been reported that the frequency of TP53 gene alterations is lower than that in adult tumors, suggesting that other tumor suppressor genes may play more important roles in the development of pediatric solid tumors. The CHK2 gene, whose product is a checkpoint kinase that plays a central role in DNA damage response and acts upstream of TP53, has been found to be mutated in a subset of Li-Fraumeni syndrome without mutations of TP53 and in some other sporadic human tumors, earmarking this serine/threonine kinase as a candidate tumor suppressor gene. Thus, we analyzed the CHK2 gene to address whether it is a candidate tumor suppressor gene for pediatric solid tumors. We screened for mutations of the CHK2 gene in 25 NB, 8 rhbdomyosarcoma, 12 Ewing sarcoma, and 26 other pediatric solid tumor cell lines as well as 77 fresh tumors including two cases of multiple cancers. Using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis and reverse transcriptase (RT)-PCR-SSCP followed by direct sequence analysis, we detected only one missense mutation (S505T) in one NB cell line and two silent mutations in one NB cell line and one NB fresh tumor, respectively. Through RT-PCR and subcloning analysis, we detected a similar expression of the CHK2 gene in all of the NB cell lines and fresh tumors; however, we identified at least three isoforms of the CHK2 gene, two of which have not been reported previously. These results suggest that aberrations of the CHK2 gene are rare in pediatric solid tumors.
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PMID:Aberrations of the CHK2 gene are rare in pediatric solid tumors. 1594 82

Extraskeletal Ewing's sarcoma (EES) is a rare soft tissue tumor morphologically indistinguishable from the more common Ewing's sarcoma of bone. We report a case of EES arising in the hard palate of 34-yr-old male patient. Microscopically, the monotonous small round cells without neuronal differentiation showed membranous positive immunoreactivity for MIC2/CD99 and vimentin. Ultrastructurally, the tumor cells showed a few intracytoplasmic organelles without evidence of neurosecretory granules or neurofilaments. The EWS-FLI1 chimeric gene was identified using the nested reverse transcriptase-polymerase chain reaction.
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PMID:Extraskeletal Ewing's sarcoma of the hard palate. 1610 Apr 68

Ewing sarcoma/primitive neuroectodermal tumor (EWS/PNET) is a diagnostically challenging malignant round cell tumor with signature translocations involving the EWS gene. These translocations are detectable with both reverse transcriptase-polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH) in formalin-fixed paraffin-embedded tissue. However, RT-PCR is less sensitive in formalin-fixed paraffin-embedded than frozen tissue. Similarly, commercial FISH probes have recently become available, but have yet to be rigorously tested in the clinical setting. Therefore, we have compared RT-PCR with FISH using 'home brew' fusion probes for Ewing sarcoma (EWS)-FLI1 and a commercial EWS break apart probe set in 67 archival round cell tumors, including 27 EWS/PNETs. Sensitivities and specificities for both FISH assays were 91 and 100%, respectively, whereas RT-PCR had a sensitivity of 54% and a specificity of 85%. The break apart strategy was easier to interpret than probe fusion approach. We conclude that FISH is a more sensitive and reliable ancillary technique than RT-PCR for the diagnosis of EWS/PNET in formalin-fixed paraffin-embedded tissue, although the latter provides additional information regarding fusion transcript subtype and prognosis. The commercial break apart probe set is both readily available and easy to interpret, making it particularly attractive. Nonetheless, complex round cell tumors often benefit from molecular testing with multiple methods.
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PMID:Molecular diagnosis of Ewing sarcoma/primitive neuroectodermal tumor in routinely processed tissue: a comparison of two FISH strategies and RT-PCR in malignant round cell tumors. 1625 12

Extraskeletal Ewing sarcoma (EES) represents a rare soft tissue malignant neoplasm histologically similar to skeletal Ewing sarcoma. It occurs mainly in adolescents and young adults and commonly affects the paravertebral regions. The differential diagnosis includes other small, blue round cells tumors. The authors report a case of an EES involving the spinal epidural and paravertebral spaces in an adolescent boy. EES diagnosis was confirmed by features of histologic analysis and immunohistochemistry and by the presence of the t(11;22)(q24;q12) chromosomal translocation by reverse transcriptase-polymerase chain reaction.
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PMID:Spinal epidural extraskeletal Ewing sarcoma in an adolescent boy: a case report. 1651 42

Ewing sarcoma/peripheral primitive neuroectodermal tumor (pPNET) is a rare primary tumor of the kidney with morphologic features similar to those of other primitive tumors. Previous studies have shown that these tumors frequently stain positively with immunostains against CD99 and FLI-1 and negatively with stains against WT-1, suggesting that these markers may be used for the distinction between Wilms tumor and pPNET. We present 30 cases of primary malignant neuroepithelial tumor with immunohistochemical profiles and reverse transcriptase polymerase chain reaction (RT-PCR) analysis and show that immunophenotypic overlap exists between Wilms tumor and pPNET. A subset of 30 neuroepithelial tumors from the National Wilms Tumor Study originally categorized as putative pPNETs of the kidney was stained with FLI-1, WT-1, and thyroid transcription factor-1. Bicolor fluorescence in situ hybridization studies were performed on 19 of the cases. Other data on these tumors were available from a previous study (Am J Surg Pathol 2001;25:133). Of 7 primary tumors that had the EWS/FLI-1 fusion transcript by RT-PCR, 6 exhibited strong immunopositivity for FLI-1. Nine that were negative by RT-PCR stained positively with the FLI-1 stain. Five fusion-negative cases stained with both FLI-1 and WT-1. Three fusion-negative cases were negative for FLI-1 but positive for WT-1. Five fusion-negative cases were negative for both FLI-1 and WT-1. Of the 30 cases, 29 were positive for CD99. Seven cases that were negative for the EWS-FLI-1 fusion by RT-PCR were positive by fluorescence in situ hybridization. All cases were negative for thyroid transcription factor-1. Reliance upon immunohistochemistry as the sole means of ancillary diagnosis in renal pPNET can lead to confusing results. We recommend molecular fusion studies for clarification of primitive renal tumors with unexpected immunophenotypic results.
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PMID:Immunohistochemistry of primary malignant neuroepithelial tumors of the kidney: a potential source of confusion? A study of 30 cases from the National Wilms Tumor Study Pathology Center. 1713 38

Ewing sarcoma family tumors originating in the palate or adrenal gland are extremely rare and may cause difficulty in diagnosis. More common tumors primary to these sites need to be excluded before one arrives at the correct diagnosis. We have recently diagnosed 2 such cases. The 1st case was that of a 24-year-old woman who presented with a swelling in the right side of the hard palate. The 2nd case was diagnosed in a 28-year-old woman who presented with a mass in the right adrenal gland. In both cases, the diagnosis of Ewing sarcoma family of tumors was confirmed by immunohistochemical studies and reverse transcriptase-polymerase chain reaction (RT-PCR). The hard palate case is the 1st and the adrenal gland the 3rd case of Ewing sarcoma family of tumors arising in these sites, in which the diagnosis was confirmed by RT-PCR and/or cytogenetics. Accurate diagnosis of Ewing sarcoma family of tumors is crucial for the management of patients, and when found in such rare locations, diagnosis should be supported by immunohistochemical and/or molecular genetic studies.
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PMID:Ewing sarcoma family of tumors in unusual sites: confirmation by rt-PCR. 1716 88

We report the first case of a tumor of the Ewing sarcoma family of tumors arising from the urinary bladder 3 years after chemotherapy for acute lymphoblastic leukemia. A 16-year-old boy complained of macrohematuria and dysuria during the posttreatment follow up of his acute lymphoblastic leukemia. Ultrasonography and computed tomography revealed a 1-cm sized intravesical tumor. The tumor was transurethrally resected with no residual tumor at the margin. Histopathologic analyses revealed a small round blue cell tumor with positive staining for CD99 antibody. EWS-FLI1 fusion transcripts were detected in the tumor tissue by reverse transcriptase polymerase chain reaction. These findings support the diagnosis of Ewing sarcoma family of tumor. After adjuvant multidrug chemotherapy, the patient has shown no evidence of disease for more than 2 years.
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PMID:A case of a ewing sarcoma family tumor in the urinary bladder after treatment for acute lymphoblastic leukemia. 1809 Sep 34

Sarcomas constitute a heterogeneous group of rare tumors that in recent years have been shown by cytogenetic analysis to have a remarkably high incidence of specific and primary alterations. These genetic alterations not only have guided molecular studies in establishing the underlying genes involved, thereby yielding important pathogenetic information, but have also provided clinicians with a valuable tool to add to their diagnostic armamentarium. The addition of molecular cytogenetic (fluorescence in situ hybridization [FISH]) and molecular approaches (reverse transcriptase-polymerase chain reaction [RT-PCR]) has further enhanced the sensitivity and accuracy of detecting nonrandom chromosomal imbalances and/or structural rearrangements in sarcomas, including assessment in formalin-fixed, paraffin-embedded tissues. Poorly differentiated sarcomas represent a significant challenge to the pathologist as these neoplasms lack an identifiable hematoxylin and eosin-stained phenotype and often have lost diagnostic immunohistochemical or ultrastructural features as well. In contrast, primary cytogenetic changes and associated molecular events such as the 11;22 translocation in Ewing sarcoma are retained as a given tumor metastasizes or becomes less differentiated, as their presence appears to be vital for sustaining neoplastic transformation. Consequently, demonstration of characteristic, tumor-specific chromosomal aberrations is especially useful in the management of poorly differentiated sarcomas.
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PMID:Contribution of cytogenetics to the management of poorly differentiated sarcomas. 1844 69

Superficial primitive Ewing's sarcomas are rare and have been reported to be of favorable prognosis compared to conventional deep-seated tumors. In the skin and subcutis, the diagnosis is often difficult, and performing molecular cytogenetic techniques may be helpful. We performed a retrospective analysis of 14 cases of superficial Ewing's sarcomas, all confirmed by molecular cytogenetics. Clinical, histological, immunohistochemical, molecular cytogenetic, therapeutic, and follow-up data are reported. There were 11 female and 3 male patients aged from 12 to 77 years (median: 17 years). Seven tumors occurred in the extremities, five in the trunk wall, and two in the head. Tumor size ranged from 1 to 5 cm (median, 3 cm). They were all small round-cell proliferations with a strong membranous positivity for CD99. Ewing's sarcoma translocations/fusion gene transcripts were detected in eight cases, both by FISH and reverse transcriptase (RT)-PCR. Four tumors were positive by RT-PCR alone (FISH not done in three cases and not interpretable in one case), and two cases were positive by FISH alone (RT-PCR not done). Surgical resection was performed in all patients. Chemotherapy was given in ten patients and radiotherapy in six. At last medical examination (median follow-up, 47 months), two patients who underwent surgical resection alone had died from the tumor. Our results confirm that superficial Ewing's sarcomas are of good prognosis. Given the difficulty of the diagnosis and the importance of an adapted treatment, a confirmation of the diagnosis by molecular or cytogenetic techniques is recommended when dealing with a superficial tumor.
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PMID:Superficial primitive Ewing's sarcoma: a clinicopathologic and molecular cytogenetic analysis of 14 cases. 1882 Jun 60

We evaluated the feasibility and usefulness of reverse transcriptase-polymerase chain reaction (RT-PCR) on fine-needle aspirates for categorization of small blue round cell tumors (SBRCTs). A total of 51 cases, including 25 Ewing sarcoma/peripheral primitive neuroectodermal tumors (PNETs), 11 rhabdomyosarcomas, 13 neuroblastomas, and 2 desmoplastic small round cell tumors (DSRCTs) were analyzed. The detection of the EWS-FLI1 (20/25) and EWS-ERG (4/25) fusion transcripts resolved 24 of 25 cases of Ewing sarcoma/PNET. The PAX3/7-FKHR fusion transcript was detected in 2 of 4 cases of alveolar rhabdomyosarcoma and the EWS-WT1 transcript in both cases of DSRCT. Tyrosine hydroxylase and 3,4-dihydroxyphenylalanine (dopa) decarboxylase transcripts were demonstrated in 10 of 13 cases of neuroblastoma. In comparison, immunocytochemical analysis resolved 19 (76%) of 25 Ewing sarcomas, 9 (82%) of 11 rhabdomyosarcomas, 6 (46%) of 13 neuroblastomas, and 1 (50%) of 2 DSRCTs. Overall, RT-PCR resolved 38 (86%) of 44 vs 35 (69%) of 51 cases by immunocytochemical analysis. RT-PCR is easily applied to fine-needle aspirates of SBRCT and greatly facilitates accurate tumor typing.
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PMID:Reverse transcriptase-polymerase chain reaction as an ancillary molecular technique in the diagnosis of small blue round cell tumors by fine-needle aspiration cytology. 2023 17


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