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)

We report 15 primary renal neoplasms with morphologic, immunohistochemical, and molecular features identical to those of synovial sarcoma. These tumors form a distinct subset of the entity previously designated as embryonal sarcoma of the kidney. Most were diagnosed between the ages of 20 and 50 years. On gross examination, tumors are large, partially necrotic, and usually contain smooth-walled cysts. Microscopically, tumors are characterized by mitotically active, monomorphic plump spindle cells with indistinct cell borders growing in short, intersecting fascicles. Grossly identified cysts are lined by mitotically inactive polygonal eosinophilic cells with apically oriented nuclei ("hobnailed epithelium"). The spindle cells are immunoreactive for vimentin, often immunoreactive for EMA, but typically non-immunoreactive for desmin, actin, S100, or cytokeratins, whereas the cyst epithelium is cytokeratin-positive. These findings are consistent with monophasic, spindled synovial sarcoma encircling dilated native renal collecting ducts. The presence of an SYT-SSX gene fusion resulting from the t(X;18) characteristic of synovial sarcoma was demonstrated by reverse transcriptase polymerase chain reaction in three of three tumors in which adequate RNA could be obtained from paraffin blocks. An additional case demonstrated the characteristic t(X; 18) translocation on cytogenetic analysis, but adequate material to perform molecular studies was not available in this case or the remaining 11 cases. Primary renal synovial sarcoma is a distinctive clinicopathologic entity confirmed by molecular detection of SYT-SSX fusion transcripts.
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PMID:Primary renal synovial sarcoma: molecular and morphologic delineation of an entity previously included among embryonal sarcomas of the kidney. 1093 49

We investigated the expression of several candidate gene markers: MAGE-1, MAGE-3, cytokeratin-20 (CK-20), and alpha-fetoprotein (AFP) in tumor tissue and blood specimens from patients with hepatocellular carcinoma to develop a multiple marker reverse transcriptase-polymerase chain reaction (RT-PCR) assay for detection of micrometastasis in circulation. In 24 tumor specimens, the positivity for MAGE-1, MAGE-3, AFP, and CK-20 genes was 71, 67, 88, and 79% respectively, and all specimens expressed at least one marker. Although AFP and CK-20 transcripts were also detected in corresponding noncancerous liver specimens, none of the 22 corresponding normal specimens or seven normal livers were positive for MAGE-1 or MAGE-3 transcripts. In addition, MAGE-1 and MAGE-3 gene transcripts were not detected in any peripheral blood specimens from 31 normal healthy volunteers. MAGE-1, MAGE-3, and AFP transcripts were detected in 9 (12.7%), 3 (4.8%), and 10 (15.9%) of 71 blood specimens from 11 hepatocellular carcinoma patients, respectively, while 19 specimens (26.8%) were positive for at least one marker. Our results indicate that a multimarker RT-PCR assay with cancer-specific markers such as MAGE-1 and MAGE-3 in combination with a liver-specific AFP marker may be a promising diagnostic tool for monitoring hepatocellular carcinoma patients with better sensitivity and specificity.
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PMID:Development of a multiple-marker RT-PCR assay for detection of micrometastases of hepatocellular carcinoma. 1096 17

Primary malignant neuroepithelial tumors of the kidney (NETKs) comprise a group of primitive, highly malignant neoplasms that histologically and clinically are not well characterized. A large cohort of 146 of these tumors, occurring in adults and children, has been collected at a single depository site, the National Wilms' Tumor Study Group (NWTSG) Pathology Center. The authors undertook a systematic retrospective review of the histologic, ultrastructural, and clinical features of these tumors, based on materials collected by the NWTSG and the consultation files of one of the authors (J.B.B.). Histologic features were generally those of primitive neural tumors with varying amounts of rosettes and neuropil; however, a large proportion of cases displayed unusual features such as spindle cells, ganglion cells, clear cell sarcoma-like foci, rhabdoid cells, epithelioid cells, and organoid foci. CD99 staining had been performed on 69 cases and showed membranous staining in 65. The NETKs were present in patients with a wide age spectrum, ranging from 1 month to 72 years (median, 18 years). EWS/FLI1 fusion analysis using reverse transcriptase-polymerase chain reaction and immunohistochemical stains for cytokeratin, chromogranin, and epithelial membrane antigen were performed successfully on a subset of 45 cases with available paraffin blocks. Only 13 of the 45 were fusion-positive, and there was no correlation between fusion status and histology, presence of rosettes, ultrastructural features, or cytokeratin positivity. CD99-negative cases were usually fusion-negative (six of seven cases), and all three chromogranin-positive cases were fusion-negative. Tumor staging, performed on 72 clearly defined and quantifiable cases by using NWTSG criteria, indicated that these are aggressive tumors, because only six were Stage 1, compared with 16 Stage 2, 31 Stage 3, and 19 Stage 4 lesions. The authors conclude that NETKs are a somewhat diverse group of generally aggressive, high-grade lesions that may present in a wide age range and are difficult to characterize without immunohistochemistry and cytogenetics/molecular biology.
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PMID:Primary malignant neuroepithelial tumors of the kidney: a clinicopathologic analysis of 146 adult and pediatric cases from the National Wilms' Tumor Study Group Pathology Center. 1117 62

For the advanced study of the cell and molecular biology of middle ear mucosa, an in vitro cell culture system is required. Although middle ear epithelial cells have been cultured from various species of laboratory animal, there have been no reports concerning a serial subculture system of human middle ear epithelial cells. In this paper, we describe the establishment of a primary culture system of human middle ear epithelial cells using a serum-free conditioned medium and the characterization of these cells by the expression of phenotypic characteristics of epithelial cells and mucin genes. Cultured cells were anchorage-dependent in terms of growth and showed a polygonal cobblestone-like appearance: desmosomes in the cell junction were observed by electron microscopy. In the immunocytochemical study, cytokeratin (epithelial cell marker) was expressed in all cultured cells. but von Willebrand factor (endothelial cell marker) was not. Unexpectedly, vimentin (fibroblast marker) was locally expressed, and a double stain showed the co-expression of both cytokeratin and vimentin in the same cell. The products of reverse transcriptase polymerase chain reaction from cultured cells yielded distinct bands compatible with the expected sizes of the MUC1, MUC2, MUC5AC and MUC5B genes. This culture system will allow us to prepare the cell line and to perform advanced studies of human middle ear mucosal biology.
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PMID:Mucin gene expression in cultured human middle ear epithelial cells. 1120 May 87

Axillary lymph node status is the single most important predictor of overall survival in patients with breast cancer. Standard histopathologic examination of regional lymph nodes relies on one microscopic section of each node to detect metastatic disease. The spectrum of metastatic disease in a lymph node ranges from complete replacement of the node by tumor to isolated nests of tumor cells in the subcapsular sinus. The clinical significance of micrometastases in axillary lymph nodes has changed over time. Micrometastases are defined by the American Joint Committee on Cancer as tumor foci less than or equal to 2 mm in greatest dimension. Retrospective studies of node-negative breast cancer patients employing intensive histopathologic examination of the axillary lymph nodes consistently show that up to a third of these patients are actually node positive. Studies published through the mid-1980s failed to show any significant effect of these micrometastases on survival. More recent studies (mid-1980s-1997) with more than 10 years of clinical follow-up have come to a different conclusion. It now appears that micrometastases are associated with a small, but statistically significant, decrease in tumor-free survival and overall survival, as compared with truly node-negative breast cancer patients. Additional slides stained with hematoxylin and eosin ("levels"), immunohistochemistry for cytokeratin proteins (found only in epithelial cells), and reverse transcriptase polymerase chain reaction for cytokeratin protein mRNA have all been used to detect micrometastases in recently published studies. The methodology utilized to detect micrometastases clearly affects the sensitivity of their detection. The current issue is the most appropriate method of detection of these small foci of tumor, given technical and cost considerations. The clinical significance of single malignant cells in the subcapsular sinus of lymph nodes, identified only by immunohistochemistry or molecular techniques, remains unclear.
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PMID:Axillary Node Micrometastases: Detection and Biologic Significance. 1134 9

The unbalanced translocation, der(17)t(X;17)(p11.2;q25), is characteristic of alveolar soft part sarcoma (ASPS). We have recently shown that this translocation fuses the TFE3 transcription factor gene at Xp11.2 to ASPL, a novel gene at 17q25. We describe herein eight morphologically distinctive renal tumors occurring in young people that bear the identical ASPL-TFE3 fusion transcript as ASPS, with the distinction that the t(X;17) translocation is cytogenetically balanced in these renal tumors. A relationship between these renal tumors and ASPS was initially suggested by the cytogenetic finding of a balanced t(X;17)(p11.2;q25) in two of the cases, and the ASPL-TFE3 fusion transcripts were then confirmed by reverse transcriptase-polymerase chain reaction. The morphology of these eight ASPL-TFE3 fusion-positive renal tumors, although overlapping in some aspects that of classic ASPS, more closely resembles renal cell carcinoma (RCC), which was the a priori diagnosis in all cases. These tumors demonstrate nested and pseudopapillary patterns of growth, psammomatous calcifications, and epithelioid cells with abundant clear cytoplasm and well-defined cell borders. By immunohistochemistry, four tumors were negative for all epithelial markers tested, whereas four were focally positive for cytokeratin and two were reactive for epithelial membrane antigen (EMA) (one diffusely, one focally). Electron microscopy of six tumors demonstrated a combination of ASPS-like features (dense granules in four cases, rhomboid crystals in two cases) and epithelial features (cell junctions in six cases, microvilli and true glandular lumens in three cases). Overall, although seven of eight tumors demonstrated at least focal epithelial features by electron microscopy or immunohistochemistry, the degree and extent of epithelial differentiation was notably less than expected for typical RCC. We confirmed the balanced nature of the t(X;17) translocation by fluorescence in situ hybridization in all seven renal tumors thus analyzed, which contrasts sharply with the unbalanced nature of the translocation in ASPS. In summary, a subset of tumors previously considered to be RCC in young people are in fact genetically related to ASPS, although their distinctive morphological and genetic features justify their classification as a distinctive neoplastic entity. Finally, the finding of distinctive tumors being associated with balanced and unbalanced forms of the same translocation is to our knowledge, unprecedented.
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PMID:Primary renal neoplasms with the ASPL-TFE3 gene fusion of alveolar soft part sarcoma: a distinctive tumor entity previously included among renal cell carcinomas of children and adolescents. 1143 65

Primary cultures of intrahepatic bile duct epithelial (IBDE) cells isolated from duckling livers were successfully grown for studies of duck hepatitis B virus (DHBV). The primary IBDE cells were characterized by immunohistochemistry using CAM 5.2, a cytokeratin marker which was shown to react specifically to IBDE cells in duck liver tissue sections and in primary cultures of total duck liver cells. Immunofluorescence assay using anti-duck albumin, a marker for hepatocytes, revealed that these IBDE cultures did not appear to contain hepatocytes. A striking feature of these cultures was the duct-like structures present within each cell colony of multilayered IBDE cells. Normal duck serum in the growth medium was found to be essential for the development of these cells into duct-like structures. When the primary cultures of duck IBDE cells were acutely infected with DHBV, dual-labeled confocal microscopy using a combination of anti-DHBV core proteins and CAM 5.2 or a combination of anti-pre-S1 proteins and CAM 5.2 revealed that the IBDE cell colonies contained DHBV proteins. Immunoblot analysis of these cells showed that the DHBV pre-S1 and core proteins were similar to their counterparts in infected primary duck hepatocyte cultures. Southern blot analysis of infected IBDE preparations using a digoxigenin-labeled positive-sense DHBV riboprobe revealed the presence of hepadnavirus covalently closed circular (CCC) DNA, minus-sense single-stranded (SS) DNA, double-stranded linear DNA, and relaxed circular DNA. The presence of minus-sense SS DNA in the acutely infected IBDE cultures is indicative of DHBV reverse transcriptase activity, while the establishment of a pool of viral CCC DNA reveals the ability of these cells to maintain persistent infection. Taken collectively, the results from this study demonstrated that primary duck IBDE cells supported hepadnavirus replication as shown by the de novo synthesis of DHBV proteins and DNA replicative intermediates.
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PMID:Duck hepatitis B virus replication in primary bile duct epithelial cells. 1146 37

The histological diagnosis of hepatocellular carcinoma (HCC) can be complicated by difficulty in differentiation from cholangiocarcinoma and metastatic carcinoma. Immunohistochemical stains currently in use are suboptimal in terms of specificity and sensitivity. Using cDNA array analysis for differential gene expression, we demonstrated a significant increase in mRNA expression level of CD10/CALLA, a type 2 cell-surface metalloproteinase, in HCC, which was subsequently confirmed by reverse transcriptase-polymerase chain reaction and Western blotting analysis. To test the possibility of using CD10/CALLA as a diagnostic marker for HCC, various intrahepatic tumors were studied immunohistochemically using a monoclonal antibody for CD10. A characteristic canalicular-staining pattern was observed in normal hepatocytes and at the apical surface of bile duct epithelial cells. The canalicular expression of CD10 was identified in 9 of 15 HCCs examined (60%), whereas 10 cholangiocarcinomas and 8 of 9 metastatic carcinomas lacked this staining. In three of the six HCCs negative for CD10, the surrounding nonneoplastic liver tissue was also negative, suggesting fixation-associated loss of immunoreactivity. Six HCCs had stronger CD10 staining in tumor cells when compared to the surrounding nonneoplastic tissue. Three cases of benign bile duct adenomas also expressed CD10 at the luminal aspect. One of the MCs showed a diffuse, cytoplasmic staining for CD10, a pattern readily distinguishable from that of HCC. A panel of other immunohistochemical markers were also studied for comparison, including polyclonal anti-carcinoembryonic antigen, cytokeratin (CK) 7, CK20, and alpha-fetoprotein. Our results demonstrate that cDNA arrays can be effectively used to identify new diagnostic markers, and that CD10 is a reliable marker for identifying HCC, particularly when used in conjunction with a panel of immunohistochemical markers (polyclonal anti-carcinoembryonic antigen, CK7, CK20, and alpha-fetoprotein) and in the distinction from cholangiocarcinoma.
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PMID:cDNA arrays and immunohistochemistry identification of CD10/CALLA expression in hepatocellular carcinoma. 1158 69

The suitability of "real-time" quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for the detection of isolated carcinoma cells in bone marrow was investigated by evaluating the expression of cytokeratin (CK)7, CK8, CK18, CK19, and CK20 in 17 gastrointestinal cancer cell lines, 64 control bone marrow specimens from noncancer patients, and 30 bone marrow specimens from patients with gastric or colorectal cancer. RT-PCR products for CK8 and CK18 were detected in all cancer cell lines, but only 16, 5, and 11 cell lines provided evidence for CK19, CK7, and CK20 transcription. Variable numbers of bone marrow specimens from noncancer patients demonstrated background transcription of CK8 (78.1%), CK18 (95.3%), CK19 (35.9%), CK20 (29.6%), and CK7 (16.7%). Maximal background transcription for CK8, CK18, and CK19 ranged from 52.2 to 56.1 copies/10(3) copies glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the corresponding values of 0.06 and 0.76 copies for CK7 and CK20 being distinctly lower. When maximal background values were used as a threshold value to define positivity in tumor cell dilution experiments, sensitivity levels of one tumor cell in 10(4) bone marrow cells were determined for CK7 and CK20 RT-PCR assays. Maximal background expression values of the different CKs as obtained in the control series were exceeded once (CK20), twice (CK18 and CK19), and 18 times (CK7) in bone marrow specimens from cancer patients, with none of these specimens exceeding the maximal background expression value of CK8. We conclude that RT-PCR for CK8, CK18, and CK19 cannot be recommended for the detection of isolated tumor cells in bone marrow of cancer patients. On the other side, the limited number of gastric and colorectal cancer cell lines expressing CK7 and CK20 indicates that assay sensitivity for these CKs might be limited because of their selective expression by carcinoma cells.
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PMID:Transcription of cytokeratins 8, 18, and 19 in bone marrow and limited expression of cytokeratins 7 and 20 by carcinoma cells: inherent limitations for RT-PCR in the detection of isolated tumor cells. 1159 48

Anaplastic thyroid carcinoma is a rapidly growing, aggressive neoplasm affecting the elderly which does not respond to most of the therapies. We established cultured cell lines from four untreated tumors. The cultures grew in a monolayer of spindle-shaped cells in three cell lines and of small polygonal cells in one line, having relatively long doubling times and chromosomal abnormalities. The xenotransplantation of the lines in athymic nude mice produced tumors with a histology similar to the original tumors. The immunocytochemical staining showed the expression of PCNA, HLA-class 1, cytokeratin, vimentin and FAS (fatty acid synthase) but not CEA, desmin or P-glycoprotein. The lines secreted TPA, IL-6, IL-8 and few or no thyroid-related hormones in the culture supernatant. One cell line produced G-CSF. The chemosensitivity assay revealed intrinsic drug resistance to nine out of 11 antineoplastic agents. The reverse transcriptase-polymerase chain reaction (RT-PCR) detected MRP (multidrug resistance-associated protein) mRNA but not mdr (multidrug resistance protein)-1 and mdr-3 mRNAs. This finding indicates that the multidrug resistance of these lines is mediated by a P-glycoprotein-unrelated mechanism. The RT-PCR also presented FAS mRNA in all the lines, and IL-6 and IL-8 mRNAs in some of the lines.
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PMID:Biological characteristics and chemosensitivity profile of four human anaplastic thyroid carcinoma cell lines. 1168 81


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