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)

Differentiating desmoplastic small round cell tumor (DSRCT) from another similar small round cell tumor of childhood, the Ewing sarcoma/primitive neuroectodermal tumor (EWS/PNET), can be difficult because morphologic and immunohistochemical features overlap. We studied the predictive value of immunohistochemistry with an antibody to the C-terminal region of the Wilms tumor (WT1) protein for differentiating DSRCT from EWS/PNET in 24 malignant small round cell tumors that had been previously diagnosed as DSRCT or EWS/PNET by standard methods. We performed reverse transcriptase-polymerase chain reaction (RT-PCR) analysis in cases with available tissue as a confirmatory measure: 6 of 13 DSRCTs were informative by RT-PCR, and 6 of 6 showed an EWS-WT1 fusion; all 13 DSRCTs showed strong, definitive nuclear staining with the WT1 antibody. All 11 EWS/PNETs were WT1 antibody negative; 7 of 11 cases classified as EWS/PNET were informative by RT-PCR, and 7 of 7 showed an EWS-FLI-1 fusion. For cases in which the morphologic and immunohistochemical features are consistent with a diagnosis of DSRCT, WT1 antibody staining predicts the EWS-WT1 translocation with high sensitivity and specificity and is, therefore, useful for differentiating DSRCT from EWS/PNET when genetic information is unavailable.
...
PMID:WT1 staining reliably differentiates desmoplastic small round cell tumor from Ewing sarcoma/primitive neuroectodermal tumor. An immunohistochemical and molecular diagnostic study. 1098 34

Primitive neuroectodermal tumor (PNET) is a small round cell sarcoma that mainly develops in the central nervous system and soft tissues of childhood; however recently, primary occurrence of this tumor in the kidney has been reported. We experienced one case of PNET primarily arose in the kidney without metastasis. The patient was a 28-year-old man whose chief complaint was abdominal pain, especially on exercise. On computed tomography scan and magnetic resonance imaging, a solid lesion was found in the left kidney, and a left nephrectomy was performed based on the diagnosis of a tumor in the left kidney. The tumor was within the parenchyma of lower end of left kidney protruding into the abdominal cavity. Histologically, diffuse proliferation of primitive small round cells with rosette formation was found. Immunohistochemically, MIC2 gene product, neuron-specific enolase and S-100 protein were positive. No metastasis to the regional lymph nodes was found. From these observations, the tumor was diagnosed as PNET primarily arising in the left kidney. Although chromosome analysis was not performed, EWS-FLI1 chimera gene was identified by reverse transcriptase-polymerase chain reaction on the freshly frozen specimen and fluorescence in situ hybridization on paraffin sections.
...
PMID:Primary primitive neuroectodermal tumor of the kidney. 1112 63

We describe a rare case of a primary primitive neuroectodermal tumor (PNET) in the lung of a 17-year-old girl. Grossly, the tumor, located in the right lower lobe, was relatively well-circumscribed and whitish to yellowish in color with scattered hemorrhagic necrosis. Microscopically, the tumor was composed of ovoid to polygonal cells with a high nuclear to cytoplasmic ratio and relatively scant cytoplasm, arranged in solid sheets with intervening fine fibrovascular stroma. Immunohistochemically, the tumor was positive for the MIC2 gene product, whereas AE1/AE3, CAM5.2, and a variety of neuroendocrine markers such as chromogranin A, synaptophysin, and ProGRP, were negative. Three months after the lobectomy, recurrent tumors were noted in the mediastinum and right thoracic wall, and she died despite combined chemotherapy and radiation therapy. In this case cytogenetic analysis showed a hypertriploid karyotype with multiple numerical and structural chromosomal aberrations, but failed to disclose distinct evidence of translocation between chromosome 11 and 22. However, the reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated EWS/FLI-1 fusion transcripts, confirming the histopathologic diagnosis of PNET. This case indicates that the primary pulmonary PNET is a highly aggressive neoplasm occurring at a young age, and should prompt combined systemic chemotherapy, even though it is organ-confined.
...
PMID:Primary pulmonary primitive neuroectodermal tumor (PNET). A case report. 1126 15

Extraskeletal Ewing sarcoma (EES) is a rare soft tissue tumor that is morphologically indistinguishable from Ewing sarcoma of bone. It is usually found in young people, but several cases have occurred in patients older than 50 years. The differential diagnoses include other small, blue round cell tumors (SBRCTs) and other members of the Ewing family of tumors such as the primitive neuroectodermal tumor. We present a case of EES in the left inguinal region of a 77-year-old woman. The tumor was distinguished from other SBRCTs by lack of immunoreactivity for epithelial, lymphoid, vascular, neuroendocrine, neural, histiocytic, and muscle markers. Primitive neuroectodermal tumor was excluded because of the lack of neural differentiation by histologic analysis, immunohistochemistry, and electron microscopy. Extraskeletal Ewing sarcoma was confirmed by characteristic features on histologic analysis, histochemistry, immunohistochemistry, and electron microscopy and by the presence of the t(11;22)(q24;q12) fusion transcript detected by reverse transcriptase-polymerase chain reaction. This case serves to remind the reader that EES is not a tumor that occurs exclusively in young patients.
...
PMID:Extraskeletal Ewing sarcoma in a 77-year-old woman. 1157 Sep 16

We describe two cases of peripheral primitive neuroectodermal tumor-Ewing's sarcoma (PNET-ES) arising intracranially in the leptomeninges. Both tumors exhibited a primitive undifferentiated round-cell morphology. Immunohistochemical stains revealed strong membrane expression of CD99 in both cases. A t(11;22)(q24;q12) could be demonstrated with reverse transcriptase-polymerase chain reaction in one case, whereas fluorescence in situ hybridization analysis performed in the second case showed a rearrangement of the EWS gene. The occurrence of PNET-ES at this site is very unusual. Immunophenotypical as well as genetic analysis play a key role in the diagnosis and the distinction from central PNET.
...
PMID:Primary peripheral PNET/Ewing's sarcoma of the dura: a clinicopathologic entity distinct from central PNET. 1206 82

We report a case of primitive neuroectodermal tumor (PNET) arising from the meninges in a 30-yr-old female patient whose clinical and radiological features were consistent with meningioma. The neoplasm was composed of primitive small, round cells, growing in sheets and nests in continuity with meningeal layers. Ultrastructurally, the neoplastic cells were characterized by large and regular nuclei, primitive cytoplasm with pools of glycogen, and lack of dense core granules. The neuroectodermal nature of the tumor was confirmed by positive immunostaining for vimentin, neurofilaments, neuron specific enolase (NSE), and 013 (an antibody raised against MIC2 antigen). Further support to the diagnosis was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR) detection of Chromogranin A and Secretogranin II genes. t(1 1;22) translocation was also observed by RT-PCR, a finding that was not recorded in previously described intracranial PNET. The tumor followed a malignant course, recurring and spreading to chest wall and sacroiliac region over a 10-yr period. The meningeal location enlarges the topographic spectrum of intracranial PNET, and this tumor has to be considered in the differential diagnosis with meningioma.
...
PMID:Primitive Neuroectodermal Tumor of the Meninges: An Histological, Immunohistochemical, Ultrastructural, and Cytogenetic Study. 1211 19

We report a case of primitive neuroectodermal tumor (PNET) arising in the transverse colonic mesentery. A 24-year-old Japanese woman was admitted to Kagoshima City Hospital with complaints of abdominal pain and sensations of abdominal fullness of 5 months' duration. On palpation, a mass the size of an infant's head was noted in the right flank. Abdominal computed tomography (CT) and ultrasonography showed a huge mass that consisted of multiple cystic components. On arteriography, a slight tumor stain appeared, with stretched and displaced tributaries of the right colic and middle colic arteries. Barium swallow examination demonstrated that the ascending colon was shifted to the right and small intestine to the left. We performed an en-bloc resection of the tumor in the transverse colonic mesentery, including the ascending colon, proximal jejunum (20 cm in length), and greater omentum. The resected tumor was 12 x 10 x 7 cm in size, 590g in weight, elastic soft in consistency, and multicystic. Histologically, the specimens showed a sheet-like proliferation of spindle-to-polygonal cells, and focally, the tumor formed rosette structures. Immunohistochemically, the tumor cells were positive for neuron-specific enolase (NSE) and mic-2. EWS-FLI1 chimeric mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Based on the above findings, we finally diagnosed the tumor as PNET of the colonic mesentery. There has been no recurrence for 20 months after operation. PNET arising in the mesentery is very rare, and we distinguished PNET from other tumors by immunohistochemical examination and by demonstration of the presence of EWS-FLI1 chimeric mRNA in the tumor.
...
PMID:Primitive neuroectodermal tumor of the transverse colonic mesentery defined by the presence of EWS-FLI1 chimeric mRNA in a Japanese woman. 1216 13

Pediatric small round cell tumors still pose tremendous diagnostic problems. In difficult cases, the ability to detect tumor-specific gene fusion transcripts for several of these neoplasms, including Ewing sarcoma/peripheral primitive neuroectodermal tumor (ES/PNET), synovial sarcoma (SS), alveolar rhabdomyosarcoma (ARMS), and desmoplastic small round cell tumor (DSRCT) using reverse transcriptase-polymerase chain reaction (RT-PCR), can be extremely helpful. Few studies to date, however, have systematically examined several different tumor types for the presence of multiple different fusion transcripts in order to determine the specificity and sensitivity of the RT-PCR method, and no study has addressed this issue for formalin-fixed material. The objectives of this study were to address the specificity, sensitivity, and practicality of such an assay applied strictly to formalin-fixed tissue blocks. Our results demonstrate that, for these tumors, the overall sensitivity for detecting each fusion transcript is similar to that reported in the literature for RT-PCR on fresh or formalin-fixed tissues. The specificity of the assay is very high, being essentially 100% for each primer pair when interpreting the results from visual inspection of agarose gels. However, when these same agarose gels were examined using Southern blotting, a small number of tumors also yielded reproducibly detectable weak signals for unexpected fusion products, in addition to a strong signal for the expected fusion product. Fluorescence in situ hybridization (FISH) studies in one such case indicated that a rearrangement that would account for the unexpected fusion was not present, while another case was equivocal. The overall specificity for each primer pair used in this assay ranged from 94 to 100%. Therefore, RT-PCR using formalin-fixed paraffin-embedded tissue sections can be used to detect chimeric transcripts as a reliable, highly sensitive, and highly specific diagnostic assay. However, we strongly suggest that the final interpretation of the results from this assay be viewed in light of the other features of the case, including clinical history, histology, and immunohistochemistry, by the diagnostic pathologist. Additional studies such as FISH may be useful in clarifying the nature of equivocal or unexpected results.
...
PMID:Performance characteristics of a reverse transcriptase-polymerase chain reaction assay for the detection of tumor-specific fusion transcripts from archival tissue. 1237 29

Ewing family of tumors is a group of highly aggressive neoplasias that occur most commonly in the first two decades of life. These tumors are most frequently localized in bones, less frequently in soft tissues. They usually appear as undifferentiated small round-cell tumors. With current treatment regiments, 5-year disease-free survival rates exceed 60% in patients with a localized disease. Patients with metastatic disease at the time of their first presentation have a poor prognosis. We describe a rare case of visceral primitive neuroectodermal tumor with the involvement of the kidney in a 9-year-old girl. The tumor was studied with immunohistochemistry, cytogenetics, and molecular biology methods. Strong expression of protein MIC(2) by immunochemistry (antibody HBA 71) with subsequent demonstration of a translocation consistent with t(11;22)(q24;q12) using cytogenetic and reverse transcriptase polymerase chain reaction (RT-PCR) confirmed the histopathological diagnosis of peripheral primitive neuroectodermal tumor. We detected minimal residual disease in bone marrow using RT-PCR.
...
PMID:Malignant peripheral primitive neuroectodermal tumor of the kidney. 1254 63

Primitive neuroectodermal tumors (PNETs), including medulloblastoma (PNET/MB) and supratentorial PNET (sPNET), are the most common malignant brain tumors of childhood. The stabilization of telomere lengths by telomerase activation is an important step in carcinogenesis and cell immortalization. Epigallocatechin gallate (EGCG), the major polyphenol in green tea, is a telomerase inhibitor with antiproliferative and anticarcinogenic effects against different types of cancer. In this study, we used real-time reverse transcriptase-polymerase chain reaction to measure the mRNA expression of the human telomerase reverse transcriptase (hTERT) in 50 primary PNET samples (43 PNET/MB, 7 sPNET), 14 normal human brain samples, and 6 human PNET cell lines. Compared to normal human cerebellum, 38/50 (76%) primary PNET samples had >or= 5-fold upregulated hTERT mRNA expression. We then examined PNET cell lines for telomerase activity using a quantitative telomeric repeat amplification protocol (TRAP), and for telomere length using terminal restriction fragment analysis. While a positive correlation between hTERT mRNA expression and telomerase activity was detected in PNET cell lines, no correlation was found between telomerase activity and telomere length. Treatment of PNET cell lines with EGCG resulted in a dose-dependent inhibition of telomerase activity at micromolar levels. Although EGCG displayed strong proliferation inhibitory effects against TRAP-positive PNET cell lines, it had no significant effect against TRAP-negative D425 cells. These results provide evidence for a possible role of telomerase in the pathogenesis of most PNETs and indicate that subsets of PNETs maintain telomere length by alternative mechanisms. Inhibition of telomerase function represents a novel experimental therapeutic strategy in childhood PNETs that warrants further investigation.
...
PMID:Telomere maintenance in childhood primitive neuroectodermal brain tumors. 1476 33


<< Previous 1 2 3 Next >>

---