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)

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

Alveolar soft part sarcoma (ASPS) is a distinct, rare soft tissue tumor with an unknown histogenesis and a tendency for late widespread metastases to lung, bone, and brain. It is now clear that they are caused by a specific unbalanced translocation, der(17)t(X;17)(p11;q25), which results in the formation of an ASPSCR1-TFE3 (alias ASPL-TFE3) fusion gene. The rearrangement results in the expression of chimeric transcripts, which can be identified by means of reverse transcriptase-polymerase chain reaction (RT-PCR). We investigated the histogenesis of ASPS and attempted to detect circulating ASPS tumor cells in peripheral blood. The immunohistochemical and genetic details of four cases and one cell line of ASPS were examined. An immunohistochemical analysis and RT-PCR did not detect myogenic differentiation gene MYOD1. The sensitivity of nested RT-PCR for detection of circulating ASPS cells was assessed by demonstrating that the tumor cell-associated gene translocation could be detected in 50 tumor cells/2 mL of blood. Clinically, it was detectable in a peripheral blood sample (2 mL) of ASPS patient with distant metastases. The findings suggest that ASPS is not of skeletal muscle origin. ASPS tumor cells in the peripheral blood could be monitored by RT-PCR.
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PMID:Molecular analyses of cell origin and detection of circulating tumor cells in the peripheral blood in alveolar soft part sarcoma. 1938 23

Alveolar soft part sarcoma (ASPS) is a rare soft tissue sarcoma which is characterized by the presence of a specific chromosomal translocation encoding the chimeric transcription factor (ASPL-TFE3) that activates expression of MET. We reviewed the clinical features and treatment outcome of 12 ASPS patients. The presence of ASPL-TFE3 fusion transcripts was assessed by reverse transcriptase polymerase chain reaction. In addition, we performed immunohistochemical studies for MET, TFE3, Ki-67, and EGFR expression. Lower extremity was the most commonly affected primary site (2 thigh, 3 lower leg, and 1 foot). Of four patients who received primary cytotoxic chemotherapy, no patient demonstrated treatment response. With follow-up duration of 94.4 months, median overall survival was 53.2 (95% C.I. 40.9-65.5) months. The immunohistochemical staining demonstrated 100% TFE3 positivity (8 of 8), 75% MET positivity (6 of 8) with a strong association between TFE3 expression and MET positivity with correlation coefficient of 0.808 (P = 0.02). The high expression of MET in ASPL-TFE3 (+) ASPS may further support the potential role of targeted agents against MET in this rare, chemoresistant tumor.
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PMID:Expression of MET in alveolar soft part sarcoma. 1947 90

The diagnosis of Xp11.2 translocation renal cell carcinoma (tRCC), which relies on morphology and immunohistochemistry (IHC), is often either missed in the diagnosis or misdiagnosed. To improve the accuracy of diagnosis of Xp11.2 tRCC and ASPL-TFE3 renal cell carcinoma (RCC), we investigated newly designed fluorescence in situ hybridization (FISH) probes (diagnostic accuracy study).Based on the genetic characteristics of Xp11.2 tRCC and the ASPL-TFE3 RCC, a new break-apart TFE3 FISH probe and an ASPL-TFE3 dual-fusion FISH probe were designed and applied to 65 patients with RCC who were <45 years old or showed suspicious microscopic features of Xp11.2 tRCC in our hospital. To test the accuracy of the probes, we further performed reverse transcriptase-polymerase chain reaction (PCR) on 8 cases for which frozen tissues were available.Among the 65 cases diagnosed with RCC, TFE3 IHC was positive in 24 cases. Twenty-two cases were confirmed as Xp11.2 tRCC by break-apart TFE3 FISH, and 6 of these cases were further diagnosed as ASPL-TFE3 RCC by ASPL-TFE3 dual-fusion FISH detection. Importantly, reverse transcriptase-PCR showed concordant results with the results of FISH assay in the 8 available frozen cases.The break-apart and ASPL-TFE3 dual-fusion FISH assay can accurately detect the translocation of the TFE3 gene and ASPL-TFE3 fusion gene and can thus serve as a valid complementary method for diagnosing Xp11.2 tRCC and ASPL-TFE3 RCC.
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PMID:Newly designed break-apart and ASPL-TFE3 dual-fusion FISH assay are useful in diagnosing Xp11.2 translocation renal cell carcinoma and ASPL-TFE3 renal cell carcinoma: a STARD-compliant article. 2598 79

Alveolar soft part sarcoma (ASPS) is a rare soft tissue sarcoma, but it's easily misdiagnosed in rare locations. The derivation of ASPS is still uncertain, therefore we conducted this study to explore the histogenesis of ASPS by analyzing stem cell markers (ALDH1, CD29, CD133 and Nestin). Protein TFE3 and fusion gene ASPS-TFE3 were tested in paraffin to explore diagnostic strategy and molecular pathological features. In this study, nine cases of ASPS were immunostained with stem cell surface markers (ALDH1, CD29, CD133 and Nestin) and protein TFE3. Seven cases of ASPS mRNA were successfully extracted from nine paraffin-embedded tissues. The expression of fusion gene ASPL-TFE3 was examined by reverse transcriptase-polymerase chain reaction. The immunohistochemical staining of nine patients showed that CD29 and Nestin were negative in all nine cases (0/9). CD133 was weakly positive in one cases (1/9) and ALDH1 was weakly positive in one cases (1/9). TFE3 was positive in nine cases (9/9). Seven paraffin tissues could be successfully extracted with mRNA in nine cases. The results of Reverse Transcription Polymerase Chain Reaction (RT-PCR) showed that ASPL-TFE3 fusion transcripts could be tested in the seven cases (four cases being type 2 and three cases being type 1). The positive rate of CD133 and ALDH1 were less than 1% and the expression of CD29 and Nestin were negative in ASPS. Immunohistochemistry results indicated that the histogenesis of ASPS maybe not derive from mesenchymal stem cells. Immunohistochemistry staining showed that TFE3 protein expression was highly sensitive in ASPS. Furthermore, RT-PCR results showed that fusion gene ASPL-TFE3 (ASPL-TFE3 type 1 and ASPL-TFE3 type 2) was expressed in ASPS, which could provide information for clinical molecular pathological diagnosis and improve the diagnosis rate of rare atypical ASPS.
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PMID:Exploring the Histogenesis and Diagnostic Strategy Using Immunoassay and RT-PCR in Alveolar Soft Part Sarcoma. 2876 50

Both Xp11 translocation renal cell carcinomas and the corresponding mesenchymal neoplasms are characterized by a variety of gene fusions involving TFE3. It has been known that tumors with different gene fusions may have different clinicopathologic features; however, further in-depth investigations of subtyping Xp11 translocation-associated cancers are needed in order to explore more meaningful clinicopathologic correlations. A total of 22 unusual cases of Xp11 translocation-associated cancers were selected for the current study; 20 cases were further analyzed by RNA sequencing to explore their TFE3 gene fusion partners. RNA sequencing identified 17 of 20 cases (85%) with TFE3-associated gene fusions, including 4 ASPSCR1/ASPL-TFE3, 3 PRCC-TFE3, 3 SFPQ/PSF-TFE3, 1 NONO-TFE3, 4 MED15-TFE3, 1 MATR3-TFE3, and 1 FUBP1-TFE3. The results have been verified by fusion fluorescence in situ hybridization (FISH) assays or reverse transcriptase polymerase chain reaction (RT-PCR). The remaining 2 cases with specific pathologic features highly suggestive of MED15-TFE3 renal cell carcinoma were identified by fusion FISH assay. We provide the detailed morphologic and immunophenotypic description of the MED15-TFE3 renal cell carcinomas, which frequently demonstrate extensively cystic architecture, similar to multilocular cystic renal neoplasm of low malignant potential, and expressed cathepsin K and melanotic biomarker Melan A. This is the first time to correlate the MED15-TFE3 renal cell carcinoma with specific clinicopathologic features. We also report the first case of the corresponding mesenchymal neoplasm with MED15-TFE3 gene fusion. Additional novel TFE3 gene fusion partners, MATR3 and FUBP1, were identified. Cases with ASPSCR1-TFE3, SFPQ-TFE3, PRCC-TFE3, and NONO-TFE3 gene fusion showed a wide variability in morphologic features, including invasive tubulopapillary pattern simulating collecting duct carcinoma, extensive calcification and ossification, and overlapping and high columnar cells with nuclear grooves mimicking tall cell variant of papillary thyroid carcinoma. Furthermore, we respectively evaluated the ability of TFE3 immunohistochemistry, TFE3 FISH, RT-PCR, and RNA sequencing to subclassify Xp11 translocation-associated cancers. In summary, our study expands the list of TFE3 gene fusion partners and the clinicopathologic features of Xp11 translocation-associated cancers, and highlights the importance of subtyping Xp11 translocation-associated cancers combining morphology, immunohistochemistry, and multiple molecular techniques.
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PMID:RNA sequencing of Xp11 translocation-associated cancers reveals novel gene fusions and distinctive clinicopathologic correlations. 2971 41

The free fatty acid receptor G protein-coupled receptor 120 (GPR120) is expressed in pancreatic islets, but its specific cell distribution and function have not been fully established. In this study, a GPR120-IRES-EGFP knockin (KI) mouse was generated to identify GPR120-expressing cells with enhanced green fluorescence proteins (EGFP). EGFP-positive cells collected from KI mouse islets by flow cytometry had a significantly higher expression of pancreatic polypeptide (PP) evidenced by reverse transcriptase (RT)-quantitative polymerase chain reaction (qPCR). Single-cell RT-PCR and immunocytochemical double staining also demonstrated the coexpression of GPR120 with PP in mouse islets. The GPR120-specific agonist TUG-891 significantly increased plasma PP levels in mice. TUG-891 significantly increased PP levels in islet medium in vitro, which was markedly attenuated by GPR120 small interfering RNA treatment. TUG-891-stimulated PP secretion in islets was fully blocked by pretreatment with YM-254890 (a Gq protein inhibitor), U73122 (a phospholipase C inhibitor), or thapsigargin (an inducer of endoplasmic reticulum Ca2+ depletion), respectively. TUG-891 triggered the increase in intracellular free Ca2+ concentrations ([Ca2+]i) in PP cells, which was also eliminated by YM-254890, U73122, or thapsigargin. GPR120 gene expression was significantly reduced in islets of high-fat diet (HFD)-induced obese mice. TUG-891-stimulated PP secretion was also significantly diminished in vivo and in vitro in HFD-induced obese mice compared with that in normal-chow diet control mice. In summary, this study demonstrated that GPR120 is expressed in mouse islet PP cells and GPR120 activation stimulated PP secretion via the Gq/PLC-Ca2+ signaling pathway in normal-chow diet mice but with diminished effects in HFD-induced obese mice.
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PMID:GPR120 Regulates Pancreatic Polypeptide Secretion From Male Mouse Islets via PLC-Mediated Calcium Mobilization. 3287 13

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