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 translocation t(X;18)(p11;q11) is seen in > 80% of synovial sarcomas (SS) with informative karyotypes. The breakpoints of the t(X;18) have been cloned and shown to involve two novel genes, SSX (at Xp11) and SYT (at 18q11), which produce a chimeric SYT-SSX transcript as a result of the translocation. Recently, SSX has been shown to be duplicated, with both copies, SSX1 and SSX2, located within distinct subregions of Xp11. We performed a reverse transcriptase polymerase chain reaction (RT-PCR) assay for both chimeric SYT-SSX transcripts in a series of 35 SS (29 monophasic, 6 biphasic) to assess its usefulness in molecular diagnosis and to evaluate the incidence of molecular variants. Of the 35 cases, 29 (83%) showed a specific SYT-SSX RT-PCR product, using a consensus primer for SSX1 and SSX2 Upon excluding three negative cases that had poor quality RNA, the proportion of positives rose to 91% (29/32). The 29 positive cases were further studied using primers specific for either SSX1 or SSX2; 19 cases were positive for SYT-SSX1 and 10 for SYT-SSX2. The relationship of histological subtype (monophasic versus biphasic) to SSX1 or SSX2 involvement was not statistically significant. In a single histologically unremarkable monophasic SS, a slightly larger SYT-SSX2 RT-PCR product was observed. Sequencing of this novel variant showed a 129-bp segment inserted between the usual SYT and SSX2 fusion points, of which 126 bp were derived from a more proximal (5') portion of SSX2 The 3 bp immediately 5' to the fusion point could not be assigned to either SYT or SSX2 and may represent an insertion-deletion or a cryptic splicing event. This fragment maintains the reading frame of the chimeric product and encodes a predicted protein larger by 43 amino acids, which nevertheless replaces the region homologous to the transcriptional repression domain Kruppel-associated box, recently recognized in the 5' portion of the SSX genes, with all but the 3' end of the SYT transcript. Thus, a diagnosis of SS may be confirmed in > 90% of cases using RT-PCR detection of the chimeric transcript resulting from the t(X;18), and the incidence of molecular variants appears low.
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PMID:Molecular diagnosis of synovial sarcoma and characterization of a variant SYT-SSX2 fusion transcript. 749 84

The chimeric transcript SYT-SSX is generated as a result of reciprocal translocation t(X;18), which is the primary cytogenetic abnormality found in, and appears to be specific for, synovial sarcoma. We performed a reverse transcriptase-polymerase chain reaction (RT-PCR) for SYT-SSX transcripts in a series of 84 tumors (61 soft tissue tumors and 23 bone tumors), including a variety of histologic types, to assess its usefulness in molecular diagnosis. Ten synovial sarcomas, three tumors initially unclassified, and one malignant peripheral nerve sheath tumor contained the chimeric transcripts. A review of the original slides and additional examination showed that a diagnosis of synovial sarcoma was appropriate for these cases. Additionally, in situ hybridization with an SSX1 probe indicated that the chimeric transcripts exist not only in the cells of special components but also in cells showing a variety of histologic patterns. Therefore, RT-PCR can be considered a useful molecular biological technique that can provide objective evidence for diagnosis of synovial sarcoma. Northern blot analysis with an SSX1 probe also detected chimeric SYT-SSX transcripts in the synovial sarcoma cases. The additional smaller bands, however, were also detected in six peripheral primitive neuroectodermal tumors (pPNETs) and one embryonal rhabdomyosarcoma. In five of these pPNETs, other bands ranging in size from 2.0 to 2.2 kb were also found, and it seems possible that these bands might represent novel karyotypic aberrations and/or splicing variants of SSX.
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PMID:Diagnosis of synovial sarcoma with the reverse transcriptase-polymerase chain reaction: analyses of 84 soft tissue and bone tumors. 978 9

Cytogenetically, most synovial sarcomas are characterised by a specific chromosomal translocation [(X;18) (p11.2;q11.2)], which results in the generation of fusion transcripts comprising SYT (18q11) and either SSX1 or SSX2 (Xp11) sequences. By using a sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) protocol, specific SYT-SSX1/2 fusion transcripts were detected in 10 histopathologically confirmed synovial sarcomas. Control tumours with morphological spindle cell patterns mimicking monophasic synovial sarcoma tested negative (18/19) in the RT-PCR protocol, with the exception of one spindle cell sarcoma originally classified as a fibrosarcoma. Furthermore, the established RT-PCR protocol was used to evaluate the feasibility of SYT-SSX1/2 fusion transcript detection for minimal residual disease analysis. Analyses of surgical margins revealed a fusion transcript in two of four operations for synovial sarcoma analysed, one of which was diagnosed with tumour free margins by conventional histopathology. These data suggest that the RT-PCR amplification of SYT-SSX1/2 fusion transcripts is a valuable tool in the differentiation of synovial sarcomas, especially in cases of equivocal morphology. Additionally, the RT-PCR approach may be used for the detection of residual tumour cells in synovial sarcoma patients.
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PMID:Detection of SYT-SSX1/2 fusion transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) is a valuable diagnostic tool in synovial sarcoma. 1007 Mar 16

Synovial sarcomas are rather common among soft-tissue tumors, occurring at any age but affecting mainly young adults. The vast majority of synovial sarcomas carries a t(X;18)(p11.2;q11.2) chromosomal translocation, in about one-third of the cases as the sole cytogenetic anomaly. Several studies have indicated that the t(X;18) translocation arises exclusively in synovial sarcomas, therefore being an excellent tool to diagnose this malignancy. The breakpoint-associated genes were recently isolated: SYT, from chromosome 18, and SSX1 and SSX2, both from the X chromosome. This discovery enabled the detection of SYT-SSX fusion transcripts by specific reverse transcriptase-polymerase chain reactions. This molecular genetics methodology has now been applied to numerous tumor samples and has led to the finding that, in contrast to tumors carrying SYT-SSX2 fusions, SYT-SSX1-positive tumors more often exhibit a biphasic histology, show a higher proliferation rate, and are associated with a poorer clinical outcome. It has also been shown that the SYT and SSX proteins are localized in the nucleus, where they appear to play a role in transcriptional regulation, SYT as an activator of transcription and the SSX proteins as transcriptional repressors. It was also found that SYT interacts and colocalizes in the nucleus with the BRM protein, a transcriptional coactivator, and that the SSX proteins colocalize in the nucleus with polycomb group proteins, which are transcriptional corepressors. Together, these studies have provided mechanistic clues about how the SYT-SSX fusion proteins may trigger synovial sarcoma development.
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PMID:Molecular mechanisms underlying human synovial sarcoma development. 1110 70

Synovial sarcomas are high-grade malignant mesenchymal tumors carrying a pathognomonic cytogenetic alteration t(X;18) involving the SYT gene on chromosome 18 and either SSX1 or SSX2 on chromosome X. Morphologically, biphasic (BSS) and monophasic (MSS) variants can be distinguished. Cancer/testis (CT) antigens are expressed in a variety of malignant tumors, but not in normal tissues except in germ cells, primarily of the testis. Anti-MAGE monoclonal antibody (mAb) 57B previously showed a high incidence and homogenous reactivity pattern in a preliminary analysis of synovial sarcomas. This study was performed to analyze the expression of MAGE by immunohistochemistry with mAb 57B in 25 synovial sarcomas (12 monophasic, 13 biphasic), which were typed for the t(X;18)-derived fusion transcript by reverse transcriptase polymerase chain reaction (19 SYT-SSX1, 6 SYT-SSX2). 57B immunoreactivity was present in 22 of 25 (88%) cases, and antigen expression was homogeneous in 14 of 22 57B-positive cases. Both morphological variants and both translocation types were immunoreactive; three SYT-SSX1 tumors (one MSS, two BSS) were 57B negative. Our study demonstrates that MAGE is frequently and homogeneously expressed in synovial sarcomas of both morphological variants and both translocation types, making these tumors an attractive target for MAGE antigen-based immunotherapy.
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PMID:MAGE antigen expression in monophasic and biphasic synovial sarcoma. 1195 49

Synovial sarcoma is the most common nonrhabdomyosarcomatous soft tissue sarcoma in children and adolescents and is characterized by a reciprocal t(X;18)(p11;q11) which results in the fusion of the SYT gene on chromosome 18q11 to either of two closely related genes, SSX1 (Xp11.23) or SSX2 (Xp11.21). Detection of this translocation or its resultant gene fusion by molecular methods is helpful in the pathologic diagnosis of synovial sarcoma, especially in poorly differentiated tumors. This study was designed to evaluate the utility of a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay to detect and distinguish SYT-SSX1 and SYT-SSX2 fusions in fresh and archival specimens of synovial sarcoma in pediatric patients seen at St. Jude Children's Research Hospital. In addition, the clinicopathologic features of the tumors with SYT-SSX1 vs. SYT-SSX2 fusions were compared. The 25 patients studied had a median age of 13 years 9 months (range 5 to 19 years). Estimates of survival and event-free survival at 5 years were 78.7 +/- 10.5% and 56.2 +/- 13.2%, respectively. Seventeen (68%) tumors were monophasic, eight (32%) were biphasic. Seven tumors contained poorly differentiated areas. Positive results for either SYT-SSX1 or SYT-SSX2 were obtained in 21/25 (84%) cases. Three cases did not have a detectable gene fusion and one had no amplifiable RNA. SYT-SSX1 transcripts were found in 18/24 (75%) of the tumors while SYT-SSX2 transcripts were identified in 3/24 (12.5%). All of the poorly differentiated tumors and seven out of eight tumors from patients who developed lung metastases had an SYT-SSX1 fusion transcript. Real-time PCR is useful in detecting and distinguishing SYT-SSX1 from SYT-SSX2 gene fusions in synovial sarcoma. Valuable aspects of this methodology are the applicability to both frozen and formalin-fixed samples, decreased labor costs, and the rapidity of results. In addition, distinguishing SYT-SSX1 from SYT-SSX2 fusions with these methods allow for prospective collection of information that may clarify issues of prognostic relevance.
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PMID:Real-time polymerase chain reaction as an aid for the detection of SYT-SSX1 and SYT-SSX2 transcripts in fresh and archival pediatric synovial sarcoma specimens: report of 25 cases from St. Jude Children's Research Hospital. 1246 33

Synovial sarcomas are aggressive tumors of adolescent and young adults that account for up to 10% of soft tissue sarcomas. Cytogenetically, they are characterized by translocation t(X;18), which is found in more than 95% of tumors. In most cases, it results in fusion of the SYT gene with the SSX1 or SSX2 gene, thus creating SYT-SSX1 or SYT-SSX2 rearrangement. The 2 types of gene fusion have been correlated with histologic variants and prognosis of synovial sarcomas. In this study, we developed a simple and rapid method for the simultaneous detection of SYT-SSX1 and SYT-SSX2 rearrangements by using a LightCycler real-time one-step reverse transcriptase polymerase chain reaction (RT-PCR) technology (Roche). Oligonucleotide probes were designed so that the donor probe would span a fusion point and the acceptor probe would be complementary to the SSX1 sequence but have 2 nucleotide mismatches with SSX2 sequence. Such a design allows simultaneous amplification of 2 types of rearrangement in the same reaction but distinguishes them based on differences in melting temperature detected by melting curve analysis after PCR. With this method, 27 tumors (9 synovial sarcomas and 18 nonsynovial sarcomas) were studied and showed SYT-SSX1 rearrangement in 6 cases and SYT-SSX2 in 3 cases. These results had complete correlation with the finding of conventional RT-PCR and direct sequencing. In conclusion, we have developed a fast, accurate, and simple method for the detection of 2 major types of SYT-SSX rearrangement by using LightCycler RT-PCR and melting curve analysis.
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PMID:Detection of SYT-SSX rearrangements in synovial sarcomas by real-time one-step RT-PCR. 1574 98

Immunotherapies using cancer-testis (CT) antigens as targets represent a potentially useful treatment in patients with multiple myeloma (MM) who commonly show recurrent disease following chemotherapy. We analyzed the expression of 11 CT antigens in bone marrow samples from patients with MM (n=55) and healthy donors (n=32) using reverse transcriptase-polymerase chain reaction (RT-PCR). CT antigens were frequently expressed in MM with 56% (MAGEC2), 55% (MAGEA3), 35% (SSX1), 20% (SSX4, SSX5), 16% (SSX2), 15% (BAGE), 7% (NY-ESO-1), and 6% (ADAM2, LIPI) expressing the given antigen. Importantly, CT antigens were not expressed in healthy bone marrow. Analyzing patients with MM (n=66) for antibody responses against MAGEA3, SSX2, and NY-ESO-1, we found strong antibody responses against CT antigens preferentially in patients who had received allogeneic stem cell transplantation (alloSCT). Antibody responses against NY-ESO-1 correlated with NY-ESO-1-specific CD4+ and CD8+ T-cell responses against peptide NY-ESO-1(51-62) and CD4+ responses against NY-ESO-1(121-140) in 1 of these patients. These allogeneic immune responses were not detectable in pretransplantation samples and in the patients' stem cell donors, indicating that CT antigens might indeed represent natural targets for graft-versus-myeloma effects. Immune responses induced by alloSCT could be boosted by active CT antigen-specific immunotherapy, which might help to achieve long-lasting remissions in patients with MM.
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PMID:Cancer-testis antigens are commonly expressed in multiple myeloma and induce systemic immunity following allogeneic stem cell transplantation. 1702 85

Synovial Sarcoma consistently harbors t(X;18) resulting in SS18-SSX1, SS18-SSX2 and rarely SS18-SSX4 fusion transcripts. Of 328 cases included in our study, synovial sarcoma was either the primary diagnosis or was very high in the differential diagnosis in 134 cases: of these, amplifiable cDNA was obtained from 131. SS18-SSX fusion products were found in 126 (96%) cases (74 SS18-SSX1, 52 SS18-SSX2), using quantitative and 120 by conventional reverse transcriptase-polymerase chain reaction (RT-PCR). One hundred and one cases in a tissue microarray, analyzed by fluorescence in situ hybridization (FISH), revealed that 87 (86%) showed SS18 rearrangement: four RT-PCR positive cases, reported as negative for FISH, showed loss of one spectrum green signal, and 15 cases had multiple copies of the SS18 gene: both findings are potentially problematic when interpreting results. One of three cases, not analyzed by RT-PCR reaction owing to poor quality RNA, was positive by FISH. SS18-SSX1 was present in 56 monophasic and 18 biphasic synovial sarcoma: SS18-SSX2 was detected in 41 monophasic and 11 biphasic synovial sarcoma. Poorly differentiated areas were identified in 44 cases (31%). There was no statistically significant association between biphasic, monophasic and fusion type. Five cases were negative for SS18 rearrangement by all methods, three of which were pleural-sited neoplasms. Following clinical input, a diagnosis of mesothelioma was favored in one case, a sarcoma, not otherwise specified in another and a solitary fibrous tumor in the third case. The possibility of a malignant peripheral nerve sheath tumor could not be excluded in the other two cases. We concluded that the employment of a combination of molecular approaches is a powerful aid to diagnosing synovial sarcoma giving at least 96% sensitivity and 100% specificity but results must be interpreted in the light of other modalities such as clinical findings and immunohistochemical data.
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PMID:Detection of SS18-SSX fusion transcripts in formalin-fixed paraffin-embedded neoplasms: analysis of conventional RT-PCR, qRT-PCR and dual color FISH as diagnostic tools for synovial sarcoma. 1733 49

With synovial sarcoma (SS) of the thorax, being exceptionally rare, its definite diagnosis is difficult, and the optimal therapy has not yet been established. An examination of our patient, a 64-year-old man with SS using a chest roentgenogram showed a large mass with homogeneous density in the lower two-thirds of the left hemithorax. A computed tomographic image of the chest revealed a large, heterogeneous, enhanced mass in the left hemithorax. Histologic examination of the resected tumor tissues suggested monophasic fibrous SS. A fragment of the SYT-SSX1 fusion transcript, which was smaller than the control, was amplified with reverse transcriptase polymerase chain reaction. Direct sequence analyses revealed the fusion between exon 9 of SYT and exon 5 of SSX1 instead of fusion between exon 10 of SYT and exon 6 of SSX1, which is found in most cases. Although the biological and clinical significance of this rare variant is not yet known, our data present another example of the usefulness of molecular analyses for making a definite diagnosis of SS in unusual sites.
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PMID:A case of primary synovial sarcoma of the thorax with a variant SYT-SSX1 fusion transcript. 1955 55


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