TAF15

Gene Summary

Gene:TAF15; TAF15 RNA polymerase II, TATA box binding protein (TBP)-associated factor, 68kDa
Aliases: Npl3, RBP56, TAF2N, TAFII68
Location:17q11.1-q11.2
Summary:This gene encodes a member of the TET family of RNA-binding proteins. The encoded protein plays a role in RNA polymerase II gene transcription as a component of a distinct subset of multi-subunit transcription initiation factor TFIID complexes. Translocations involving this gene play a role in acute leukemia and extraskeletal myxoid chondrosarcoma, and mutations in this gene may play a role in amyotrophic lateral sclerosis. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, May 2012]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:TATA-binding protein-associated factor 2N
HPRD
Source:NCBIAccessed: 17 August, 2015

Ontology:

What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 17 August 2015 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 17 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: TAF15 (cancer-related)

Campos-Melo D, Droppelmann CA, Volkening K, Strong MJ
RNA-binding proteins as molecular links between cancer and neurodegeneration.
Biogerontology. 2014; 15(6):587-610 [PubMed] Related Publications
For many years, epidemiological studies have suggested an association between cancer and neurodegenerative disorders-two disease processes that seemingly have little in common. Although these two disease processes share disruptions in a wide range of cellular pathways, including cell survival, cell death and the cell cycle, the end result is very divergent: uncontrolled cell survival and proliferation in cancer and progressive neuronal cell death in neurodegeneration. Despite the clinical data connecting these two disease processes, little is known about the molecular links between them. Among the mechanisms affected in cancer and neurodegenerative diseases, alterations in RNA metabolism are obtaining significant attention given the critical role for RNA transcription, maturation, transport, stability, degradation and translation in normal cellular function. RNA-binding proteins (RBPs) are integral to each stage of RNA metabolism through their participation in the formation of ribonucleoprotein complexes (RNPs). RBPs have a broad range of functions including posttranscriptional regulation of mRNA stability, splicing, editing and translation, mRNA export and localization, mRNA polyadenylation and miRNA biogenesis, ultimately impacting the expression of every single gene in the cell. In this review, we examine the evidence for RBPs as being key a molecular linkages between cancer and neurodegeneration.

Broehm CJ, Wu J, Gullapalli RR, Bocklage T
Extraskeletal myxoid chondrosarcoma with a t(9;16)(q22;p11.2) resulting in a NR4A3-FUS fusion.
Cancer Genet. 2014; 207(6):276-80 [PubMed] Related Publications
Extraskeletal myxoid chondrosarcoma (EMC) is a rare neoplasm characterized by rearrangement of NR4A3. A t(9;22)(q22;q12), creating a fusion protein of EWSR1 and NR4A3, has been reported as a unique, recurring translocation in most cases. Reported variant translocations have resulted in fusion of NR4A3 with three other genes: TAF15, TCF12, and TFG. We report a case of EMC in a 59-year-old man who presented with a 6-month history of an enlarging mass in the proximal right thigh. The karyotype of fresh tissue from tumor taken at incisional biopsy revealed a t(9;16)(q22;p11.2). There was no evidence of an EWSR1 rearrangement by dual-color break-apart fluorescence in situ hybridization (FISH). Dual-color FISH probes revealed fusion of NR4A3 and FUS, a member of the TET family of genes, which includes EWSR1 and TAF15. Break-apart FISH probe results confirmed rearrangement of FUS. These findings show that a fusion product of FUS and NR4A3 may be an additional pathway to development of EMC.

Agaram NP, Zhang L, Sung YS, et al.
Extraskeletal myxoid chondrosarcoma with non-EWSR1-NR4A3 variant fusions correlate with rhabdoid phenotype and high-grade morphology.
Hum Pathol. 2014; 45(5):1084-91 [PubMed] Free Access to Full Article Related Publications
Extraskeletal myxoid chondrosarcomas (EMC) are rare soft tissue sarcomas with distinctive histology and uncertain histogenesis, characterized by Ewing sarcoma breakpoint region 1-nuclear receptor subfamily 4, group A, member 3 (EWSR1-NR4A3) fusion in 75% of the cases. A smaller proportion of cases show NR4A3 fused to other gene partners including TATA binding protein-associated factor 15 (TAF15), transcription factor 12 (TCF12), and TRK-fused gene (TFG). The impact of various gene fusions on morphology and outcome has not been previously evaluated. We investigated 26 consecutive EMCs and correlated the genetic findings with morphology and clinical outcome. There were 5 females and 21 males (median age, 49.5 years). Mean size of the tumors was 11 cm. Fluorescence in situ hybridization analysis showed EWSR1-NR4A3 gene fusion in 16 cases (62%), TAF15-NR4A3 gene fusion in 7 cases (27%), and TCF12-NR4A3 gene fusion in 1 case (4%). Two cases showed only NR4A3 gene rearrangements. Morphologically, most EWSR1-rearranged tumors (10/16) showed low cellularity, minimal cytologic atypia, and low mitotic counts. In contrast, 80% of EMCs with variant (non-EWSR1) NR4A3 gene fusions (TAF15, TCF12) had high-grade morphology with increased cellularity, proliferation, and cytologic atypia, showing a plasmacytoid/rhabdoid morphology in half the cases. Follow-up showed that only 1 of 16 patients with EWSR1-rearranged tumors died of disease, in contrast to 3 (43%) of 7 TAF15-rearranged tumors. In conclusion, EMCs with variant NR4A3 gene fusions show a higher incidence of rhabdoid phenotype, high-grade morphology, and a more aggressive outcome compared with the EWSR1-NR4A3 positive tumors. Furthermore, fluorescence in situ hybridization assay for NR4A3, along with EWSR1, may be an additional ancillary test to confirm diagnosis of EMCs.

Stacchiotti S, Pantaleo MA, Astolfi A, et al.
Activity of sunitinib in extraskeletal myxoid chondrosarcoma.
Eur J Cancer. 2014; 50(9):1657-64 [PubMed] Related Publications
BACKGROUND: Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma, marked by NR4A3 rearrangement. Herein we report on the activity of sunitinib in a series of 10 patients, strengthening what initially observed in two cases.
PATIENTS AND METHODS: From July 2011, 10 patients with progressive metastatic translocated EMC have been consecutively treated with sunitinib 37.5mg/day, on a named-use basis. In an attempt to interpret the activity of sunitinib in EMC, genotype/phenotype correlations were carried out by fluorescence in situ hybridization (FISH) analyses. Moreover, transcriptome, immunohistochemical and biochemical analyses of a limited set of samples were performed focusing on some putative targets of sunitinib.
RESULTS: Eight of 10 patients are still on therapy. Six patients had a Response Evaluation Criteria in Solid Tumours (RECIST) partial response (PR), two were stable, two progressed. Positron emission tomography (PET) was consistent in 6/6 evaluable cases. One patient underwent surgery after sunitinib, with evidence of a pathologic response. At a median follow-up of 8.5 months (range 2-28), no secondary resistance was detected. Median progression free survival (PFS) has not been reached. Interestingly, all responsive cases turned out to express the typical EWSR1-NR4A3 fusion, while refractory cases carried the alternative TAF15-NR4A3 fusion. Among putative sunitinib targets, only RET was expressed and activated in analysed samples.
CONCLUSIONS: This report confirms the therapeutic activity of sunitinib in EMC. Genotype/phenotype analyses support a correlation between response and EWSR1-NR4A3 fusion. Involvement of RET deserves further investigation.

Benini S, Cocchi S, Gamberi G, et al.
Diagnostic utility of molecular investigation in extraskeletal myxoid chondrosarcoma.
J Mol Diagn. 2014; 16(3):314-23 [PubMed] Related Publications
Extraskeletal myxoid chondrosarcoma is characterized by the reciprocal chromosomal translocation t(9;22) and the resultant fused gene EWS RNA-binding protein 1 and nuclear receptor subfamily 4, group A, member 3 (EWSR1-NR4A3). A second cytogenetic rearrangement t(9;17) involves the genes NR4A3 and TAF 15 RNA polymerase II, TATA box binding protein (TBP)-associated factor (TAF15). Less frequent fusion transcript variants of the NR4A3 gene, transcription factor 12 (TCF12)-NR4A3 and TRK-fused gene (TFG)-NR4A3, are associated with t(9;15) and t(9;3) respectively. The samples from 42 patients with extraskeletal myxoid chondrosarcoma were examined for the presence of EWSR1-NR4A3, TAF15-NR4A3, TCF12-NR4A3, and TFG-NR4A3 fusion transcripts by using RT-PCR. Fluorescence in situ hybridization was performed to analyze the status of EWSR1 and NR4A3 genes. The fusion transcripts were detected in 34 of 42 samples (81%); the presence of an EWSR1 or NR4A3 gene rearrangements were detected in 8 of 42 samples (19%) which had tested negative for all fusion transcripts detected by RT-PCR. Of the 34 samples evaluable for fusion transcripts, 23 yielded positive results for EWSR1-NR4A3, 10 for TAF15-NR4A3, and 1 for TCF12-NR4A3. The combination of RT-PCR and fluorescence in situ hybridization on frozen and paraffin-embedded tissue is a sensitive and specific method for molecular detection of recurrent translocations and is an important ancillary method to establish the diagnosis of extraskeletal myxoid chondrosarcoma.

Bidkhori G, Narimani Z, Hosseini Ashtiani S, et al.
Reconstruction of an integrated genome-scale co-expression network reveals key modules involved in lung adenocarcinoma.
PLoS One. 2013; 8(7):e67552 [PubMed] Free Access to Full Article Related Publications
Our goal of this study was to reconstruct a "genome-scale co-expression network" and find important modules in lung adenocarcinoma so that we could identify the genes involved in lung adenocarcinoma. We integrated gene mutation, GWAS, CGH, array-CGH and SNP array data in order to identify important genes and loci in genome-scale. Afterwards, on the basis of the identified genes a co-expression network was reconstructed from the co-expression data. The reconstructed network was named "genome-scale co-expression network". As the next step, 23 key modules were disclosed through clustering. In this study a number of genes have been identified for the first time to be implicated in lung adenocarcinoma by analyzing the modules. The genes EGFR, PIK3CA, TAF15, XIAP, VAPB, Appl1, Rab5a, ARF4, CLPTM1L, SP4, ZNF124, LPP, FOXP1, SOX18, MSX2, NFE2L2, SMARCC1, TRA2B, CBX3, PRPF6, ATP6V1C1, MYBBP1A, MACF1, GRM2, TBXA2R, PRKAR2A, PTK2, PGF and MYO10 are among the genes that belong to modules 1 and 22. All these genes, being implicated in at least one of the phenomena, namely cell survival, proliferation and metastasis, have an over-expression pattern similar to that of EGFR. In few modules, the genes such as CCNA2 (Cyclin A2), CCNB2 (Cyclin B2), CDK1, CDK5, CDC27, CDCA5, CDCA8, ASPM, BUB1, KIF15, KIF2C, NEK2, NUSAP1, PRC1, SMC4, SYCE2, TFDP1, CDC42 and ARHGEF9 are present that play a crucial role in cell cycle progression. In addition to the mentioned genes, there are some other genes (i.e. DLGAP5, BIRC5, PSMD2, Src, TTK, SENP2, PSMD2, DOK2, FUS and etc.) in the modules.

Ballarino M, Jobert L, Dembélé D, et al.
TAF15 is important for cellular proliferation and regulates the expression of a subset of cell cycle genes through miRNAs.
Oncogene. 2013; 32(39):4646-55 [PubMed] Related Publications
TAF15 (formerly TAFII68) is a member of the FET (FUS, EWS, TAF15) family of RNA- and DNA-binding proteins whose genes are frequently translocated in sarcomas. By performing global gene expression profiling, we found that TAF15 knockdown affects the expression of a large subset of genes, of which a significant percentage is involved in cell cycle and cell death. In agreement, TAF15 depletion had a growth-inhibitory effect and resulted in increased apoptosis. Among the TAF15-regulated genes, targets of microRNAs (miRNAs) generated from the onco-miR-17 locus were overrepresented, with CDKN1A/p21 being the top miRNAs-targeted gene. Interestingly, the levels of onco-miR-17 locus coded miRNAs (miR-17-5p and miR-20a) were decreased upon TAF15 depletion and shown to affect the post-transcriptional regulation of TAF15-dependent genes, such as CDKN1A/p21. Thus, our results demonstrate that TAF15 is required to regulate gene expression of cell cycle regulatory genes post-transcriptionally through a pathway involving miRNAs. The findings that high TAF15 levels are needed for rapid cellular proliferation and that endogenous TAF15 levels decrease during differentiation strongly suggest that TAF15 is a key regulator of maintaining a highly proliferative rate of cellular homeostasis.

Thorsen J, Micci F, Heim S
Identification of chromosomal breakpoints of cancer-specific translocations by rolling circle amplification and long-distance inverse PCR.
Cancer Genet. 2011; 204(8):458-61 [PubMed] Related Publications
We describe the use of rolling circle amplification and long-distance inverse polymerase chain reaction (LD-PCR) to identify chromosomal breakpoints and fusion genes in cancer cells carrying acquired translocations. This approach produced enough template for 100 inverse PCR reaction from as little as 20 ng of patient DNA, consequently enabling the use of up to 500 times less patient DNA compared to standard inverse PCR. The method is based on identifying restriction sites in a putative breakpoint area in a cancer-specific translocation, followed by circularization and amplification of the restriction DNA products by using T4 DNA ligase and Phi29 enzyme, respectively. The amplified DNA thus obtained is used as a template in long-distance inverse PCR to amplify and detect the precise breakpoint of the chromosomal rearrangements in question by sequencing of the obtained PCR products. We demonstrate the feasibility of this approach by identifying fusion genes TAF15-ZNF384 (brought about by a (12;17)(p13;q21) translocation) and BCR-ABL1 (produced by a (9:22)(q34;q11.2) translocation) in five leukemia samples. The application of rolling circle amplification before inverse PCR may be particularly useful in the search for chromosomal breakpoints and fusion genes brought about by new translocations when only minute amounts of DNA are available from the sampled malignant lesion.

Sankar S, Lessnick SL
Promiscuous partnerships in Ewing's sarcoma.
Cancer Genet. 2011; 204(7):351-65 [PubMed] Free Access to Full Article Related Publications
Ewing's sarcoma is a highly aggressive bone and soft tissue tumor of children and young adults. At the molecular genetic level Ewing's sarcoma is characterized by a balanced reciprocal translocation, t(11;22)(q24;q12), which encodes an oncogenic fusion protein and transcription factor EWS/FLI. This tumor-specific chimeric fusion retains the amino terminus of EWS, a member of the TET (TLS/EWS/TAF15) family of RNA-binding proteins, and the carboxy terminus of FLI, a member of the ETS family of transcription factors. In addition to EWS/FLI, variant translocation fusions belonging to the TET/ETS family have been identified in Ewing's sarcoma. These studies solidified the importance of TET/ETS fusions in the pathogenesis of Ewing's sarcoma and have since been used as diagnostic markers for the disease. EWS fusions with non-ETS transcription factor family members have been described in sarcomas that are clearly distinct from Ewing's sarcoma. However, in recent years there have been reports of rare fusions in "Ewing's-like tumors" that harbor the amino-terminus of EWS fused to the carboxy-terminal DNA or chromatin-interacting domains contributed by non-ETS proteins. This review aims to summarize the growing list of fusion oncogenes that characterize Ewing's sarcoma and Ewing's-like tumors and highlights important questions that need to be answered to further support the existing concept that Ewing's sarcoma is strictly a "TET/ETS" fusion-driven malignancy. Understanding the molecular mechanisms of action of the various different fusion oncogenes will provide better insights into the biology underlying this rare but important solid tumor.

Nyquist KB, Thorsen J, Zeller B, et al.
Identification of the TAF15-ZNF384 fusion gene in two new cases of acute lymphoblastic leukemia with a t(12;17)(p13;q12).
Cancer Genet. 2011; 204(3):147-52 [PubMed] Related Publications
We report the clinical, cytogenetic, and molecular data of two patients diagnosed with acute lymphoblastic leukemia characterized by the rare translocation t(12;17)(p13;q12). This translocation has been reported in 25 cases and its putative molecular consequence, the formation of a TAF15-ZNF384 fusion gene, in only six cases. We used fluorescence in situ hybridization followed by long-range polymerase chain reaction to find the translocation breakpoints. A fusion between TAF15 and ZNF384 was identified and confirmed by nucleotide sequencing. Our results confirm that the t(12;17)(p13;q12) leading to a TAF15-ZNF384 fusion gene characterizes a specific subgroup of acute lymphoblastic leukemia and suggest that two different breakpoints in TAF15 may be involved. Whether the two variants of the TAF15-ZNF384 fusion that these correspond to are in any way hematologically or prognostically different, is unknown.

Spitzer JI, Ugras S, Runge S, et al.
mRNA and protein levels of FUS, EWSR1, and TAF15 are upregulated in liposarcoma.
Genes Chromosomes Cancer. 2011; 50(5):338-47 [PubMed] Free Access to Full Article Related Publications
Translocations or mutations of FUS, EWSR1, and TAF15 (FET) result in distinct genetic diseases. N-terminal translocations of any FET protein to a series of transcription factors yields chimeric proteins that contribute to sarcomagenesis, whereas mutations in the conserved COOH-terminal domain of wild-type FUS were recently shown to cause familial amyotrophic lateral sclerosis. We thus investigated whether the loss of one FUS allele by translocation in liposarcoma may be followed by mutations in either the remaining FUS allele or the paralogous EWSR1. Furthermore, we investigated the strength of the FET promoters and their contributions to sarcomagenesis given the proteins' frequent involvement in oncogenic translocations. We sequenced the respective genomic regions of both FUS and EWSR1 in 96 liposarcoma samples. Additionally, we determined FET transcript and protein levels in several liposarcoma cell lines. We did not observe sequence variations in either FUS or EWSR1. However, protein copy numbers reached an impressive 0.9 and 5.5 Mio of FUS and EWSR1 per tumor cell, respectively. Compared with adipose-derived stem cells, FUS and EWSR1 protein expression levels were elevated on average 28.6-fold and 7.3-fold, respectively. TAF15 mRNA levels were elevated on average 3.9-fold, although with a larger variation between samples. Interestingly, elevated TAF15 mRNA levels did not translate to strongly elevated protein levels, consistent with its infrequent occurrence as translocation partner in tumors. These results suggest that the powerful promoters of FET genes are predominantly responsible for the oncogenic effect of transcription factor translocations in sarcomas.

Göransson M, Andersson MK, Forni C, et al.
The myxoid liposarcoma FUS-DDIT3 fusion oncoprotein deregulates NF-kappaB target genes by interaction with NFKBIZ.
Oncogene. 2009; 28(2):270-8 [PubMed] Related Publications
FUS (also called TLS), EWSR1 and TAF15 (also called TAF2N) are related genes involved in tumor type-specific fusion oncogenes in human malignancies. The FUS-DDIT3 fusion oncogene results from a t(12;16)(q13;p11) chromosome translocation and has a causative role in the initiation of myxoid/round cell liposarcomas (MLS/RCLS). The FUS-DDIT3 protein induces increased expression of the CAAT/enhancer-binding protein (C/EBP) and nuclear factor-kappaB (NF-kappaB)-controlled gene IL8, and the N-terminal FUS part is required for this activation. Chromatin immunoprecipitation analysis showed that FUS-DDIT3 binds the IL8 promoter. Expression studies of the IL8 promoter harboring a C/EBP-NF-kappaB composite site pinpointed the importance of NF-kappaB for IL8 expression in FUS-DDIT3-expressing cells. We therefore probed for possible interaction of FUS-DDIT3 with members of the NF-kappaB family. The nuclear factor NFKBIZ colocalizes with FUS-DDIT3 in nuclear structures, and immunoprecipitation experiments showed that FUS-DDIT3 binds the C-terminal of NFKBIZ. We also report that additional NF-kappaB-controlled genes are upregulated at the mRNA level in FUS-DDIT3-expressing cell lines and they can be induced by NFKBIZ. Taken together, the results indicate that FUS-DDIT3 deregulates some NF-kappaB-controlled genes through interactions with NFKBIZ. Similar mechanisms may be a part of the transformation process in other tumor types carrying FUS, EWSR1 and TAF15 containing fusion oncogenes.

Kim S, Lee HJ, Jun HJ, Kim J
The hTAF II 68-TEC fusion protein functions as a strong transcriptional activator.
Int J Cancer. 2008; 122(11):2446-53 [PubMed] Related Publications
Human extraskeletal myxoid chondrosarcoma (EMC) is caused by a chromosomal translocation that involves TEC (translocated in extraskeletal myxoid chondrosarcoma), and either EWS (Ewing's sarcoma) or hTAF(II)68 (human TATA-binding protein-associated factor II 68), which generates EWS-TEC or hTAF(II)68-TEC fusion proteins, respectively. Although there has been a great deal of progress in characterizing EWS-TEC, there is relatively little known about the biological function of hTAF(II)68-TEC. We have examined the functional consequences of the fusion of the amino terminal domain (NTD) of hTAF(II)68 to TEC in EMC. The chimeric gene encodes a nuclear protein that binds DNA with the same sequence specificity as parental TEC. Nuclear localization of hTAF(II)68-TEC was dependent on the DNA binding domain, and we identified a cluster of basic amino acids in the DNA binding domain, KRRR, that specifically mediate the nuclear localization of hTAF(II)68-TEC. The transactivation activity of hTAF(II)68-TEC was higher than TEC towards a known target promoter that contained several TEC binding sites. Finally, deletion analysis of hTAF(II)68-TEC indicated that the hTAF(II)68 NTD, and the AF1 and AF2 domains of hTAF(II)68-TEC are necessary for full transactivation potential. These results suggest that the oncogenic effect of the t(9;17) translocation may be due to the hTAF(II)68-TEC chimeric protein and that fusion of the hTAF(II)68 NTD to the TEC protein produces a gain of function chimeric product.

Riggi N, Cironi L, Suvà ML, Stamenkovic I
Sarcomas: genetics, signalling, and cellular origins. Part 1: The fellowship of TET.
J Pathol. 2007; 213(1):4-20 [PubMed] Related Publications
Sarcomas comprise some of the most aggressive solid tumours that, for the most part, respond poorly to chemo- and radiation therapy and are associated with a sombre prognosis when surgical removal cannot be performed or is incomplete. Partly because of their lower frequency, sarcomas have not been studied as intensively as carcinomas and haematopoietic malignancies, and the molecular mechanisms that underlie their pathogenesis are only beginning to be understood. Even more enigmatic is the identity of the primary cells from which these tumours originate. Over the past 25 years, however, several non-random chromosomal translocations have been found to be associated with defined sarcomas. Each of these translocations generates a fusion gene believed to be directly related to the pathogenesis of the sarcoma in which it is expressed. The corresponding fusion proteins provide a unique tool not only to study the process of sarcoma development, but also to identify cells that are permissive for their putative oncogenic properties. This is the first of two reviews that cover the mechanisms whereby specific fusion/mutant gene products participate in sarcoma development and the cellular context that may provide the necessary permissiveness for their expression and oncogenicity. Part 1 of the review focuses on sarcomas that express fusion genes containing TET gene family products, including EWSR1, TLS/FUS, and TAFII68. Part 2 (J Pathol 2007; DOI: 10.1002/path.2008) summarizes our current understanding of the genetic and cellular origins of sarcomas expressing fusion genes exclusive of TET family members; it also covers soft tissue malignancies harbouring specific mutations in RTK-encoding genes, the prototype of which are gastrointestinal stromal tumours (GIST).

Un F
G1 arrest induction represents a critical determinant for cisplatin cytotoxicity in G1 checkpoint-retaining human cancers.
Anticancer Drugs. 2007; 18(4):411-7 [PubMed] Related Publications
Cisplatin has been used effectively to treat various human cancer types; yet, the precise mechanism underlying its cytotoxicity remains unknown. In eukaryotes, progression through G1 is monitored by a checkpoint, which executes G1 arrest in the event of DNA damage to allow time for repair before initiating DNA replication. The retinoblastoma tumor suppressor gene is an integral component of the mammalian G1 checkpoint. The utility of the retinoblastoma gene as a therapeutic for human cancers has been investigated. Intriguingly, the cytotoxicity profile of the retinoblastoma gene therapy closely parallels the clinical targets of cisplatin. It prompted an investigation into the potential role of the checkpoint-induced G1 arrest in cisplatin cytotoxicity. Here, the evidence that G1 arrest induction represents a critical step in cisplatin-induced lytic path is presented. First, cisplatin-treated human cancer cells undergo a prolonged G1 arrest before dying. Second, triggering G1 arrest via infection with a recombinant adenovirus expressing the human retinoblastoma gene is sufficient to potentiate lethality in the absence of cisplatin. Third, the extent of the lethality induced correlates with the G1-arresting potential of the ectopically expressed human retinoblastoma polypeptide. Fourth, human cancer cells resistant to cisplatin do not undergo G1 arrest despite cisplatin treatment. The above mechanism may be exploited to develop therapeutics that preserve the efficacy of cisplatin yet bypass its mutagenicity associated with the formation of secondary tumors.

Law WJ, Cann KL, Hicks GG
TLS, EWS and TAF15: a model for transcriptional integration of gene expression.
Brief Funct Genomic Proteomic. 2006; 5(1):8-14 [PubMed] Related Publications
Multifunctional proteins are demonstrating that gene expression is not a series of compartmentalized events beginning with transcription and culminating in delivery of mature mRNA into the cytoplasm, but an integrated pathway of transcription, splicing, RNA metabolism and subcellular targeting of translation. One such multifunctional family is made up of the RNA-binding proteins TLS, EWS and TAF15. These three proteins each contribute a potent transcriptional activation domain to oncogenic fusion proteins, and the formation of these fusion genes are thought to be the primary causes of their associated cancers. Wild-type TLS, EWS and TAF15 can function as classical transcription factors in addition to their better-known functions in splicing and mRNA transport. The interaction between TLS and the stress-response protein YB-1 is an example of how these proteins can induce a multi-faceted change in gene expression, as they can interact to induce changes in both transcription and splicing of target genes. Investigating the multiple functions of TLS, EWS and TAF15 will enhance our understanding of gene expression as a whole, and also allow us to better understand how these proteins may be contributing to the oncogenic pathways the associated fusion proteins initiate.

Tateishi U, Hasegawa T, Nojima T, et al.
MRI features of extraskeletal myxoid chondrosarcoma.
Skeletal Radiol. 2006; 35(1):27-33 [PubMed] Related Publications
OBJECTIVE: To describe the MRI features of extraskeletal myxoid chondrosarcoma in comparison with clinicopathologic findings.
DESIGN AND PATIENTS: The study comprised 12 male subjects and seven female subjects with a mean age of 53 years (range 16-76 years). MRI findings, evaluated by two radiologists with agreement by consensus, were compared for histopathologic features.
RESULTS: The tumor size ranged from 2.0 cm to 20.0 cm (mean 8.9 cm). Fusion gene transcripts could be detected in 13 (68%) of the 19 cases: EWS-CHN in nine cases, TAF2N-CHN in three, and TFG-TCH in one. There were six fusion-negative cases. Signal characteristics on T1-weighted and T2-weighted MR images were non-specific with regard to each cytogenetic variant. Peripheral enhancement was seen more frequently in tumors with the EWS-CHN variant than in those with other cytogenetic variants. The characteristic pattern of enhancement corresponded to the presence of fibrous septa and peripheral areas of high cellularity within lobules, by correlation with pathologic findings. All cases with TAF2N-CHN or TFG-TCH variants showed invasion of extracompartmental structure, bone, or vessels.
CONCLUSION: Extraskeletal myxoid chondrosarcoma is an uncommon soft-tissue malignancy that may be recognized by MRI features of multi-lobular soft-tissue mass often invading extracompartmental, bony, and vascular structures.

Hisaoka M, Okamoto S, Yokoyama K, Hashimoto H
Coexpression of NOR1 and SIX3 proteins in extraskeletal myxoid chondrosarcomas without detectable NR4A3 fusion genes.
Cancer Genet Cytogenet. 2004; 152(2):101-7 [PubMed] Related Publications
Extraskeletal myxoid chondrosarcoma (EMC) is a rare mesenchymal tumor cytogenetically characterized by reciprocal translocations, such as t(9;22)(q22;q12) and t(9;17)(q22;q11), which result in EWSR1/NR4A3 and TAF15/NR4A3 fusion genes (alias EWS/NOR1, TAF2N/NOR1), respectively. NOR1 is an orphan nuclear receptor and acts as a transcription factor that can bind to its putative coactivator, SIX3. Although the NOR1 fusion protein has been implicated in oncogenesis of EMC, a small fraction of EMC lacks detectable rearrangements of the NR4A3 gene or 9q22. We report a case of EMC with no detectable NR4A3 gene alterations, as assessed with various molecular techniques including reverse transcription-polymerase chain reaction (RT-PCR), Southern blotting, interphase fluorescence in situ hybridization, and PCR single-strand conformation polymorphism-but with coexpression of native NOR1 and SIX3. In our survey of another 18 EMCs, we identified one more case expressing both NOR1 and SIX3 but lacking NR4A3 fusion. Fourteen tumors with detectable NR4A3 fusion genes (EWSR1-NR4A3; TAF15-NR4A3) expressed neither native NOR1 nor SIX3. SIX3 expression is normally confined specifically to the developing eye and fetal forebrain, although the expression of NR4A3 is largely ubiquitous. Our data suggest that aberrant coexpression of NOR1 and SIX3 is a potential alternative mechanism underlying the development of EMC.

Hisaoka M, Ishida T, Imamura T, Hashimoto H
TFG is a novel fusion partner of NOR1 in extraskeletal myxoid chondrosarcoma.
Genes Chromosomes Cancer. 2004; 40(4):325-8 [PubMed] Related Publications
Extraskeletal myxoid chondrosarcoma (EMC) is characterized by recurrent chromosomal translocations resulting in fusions of the nuclear receptor gene NOR1 (also known as CHN or TEC) to various N-terminal partners, including EWS and TAF2N (or RBP56). Significant structural homology of EWS or TAF2N to TLS (or FUS) prompted us to investigate a potential novel gene fusion of NOR1 to TLS in EMCs without detectable known NOR1 fusions. In one of the EMCs examined, our reverse-transcription polymerase chain reaction using NOR1 and TLS primers unexpectedly amplified a cDNA sequence derived not from a TLS/NOR1 fusion but from a TFG/NOR1 fusion, a hitherto undescribed fusion type in EMC, probably a result of incidental misannealing by the TLS primer, which has a sequence partially identical to TFG. Encoding a protein with a putative coiled-coil structure, TFG previously was identified by a homology search in the Expressed Sequence Tag Database as having an SPYGQ-rich region similar to the N-terminal parts of EWS and TLS. TFG/NOR1 fusion appears to play an oncogenic role equivalent to those of other NOR1 fusions in EMC.

Sandberg AA
Genetics of chondrosarcoma and related tumors.
Curr Opin Oncol. 2004; 16(4):342-54 [PubMed] Related Publications
PURPOSE OF REVIEW: The burgeoning body of information on the genetic changes present in and underlying the development and biology of human cancers has carried implications regarding the possible genetic events that are responsible for not only the genesis of these cancers but also the hope of the cure for these cancers. Chondrosarcomas are a group of tumors that fall into this category. The purpose of this review is to summarize the genetic findings in these tumors.
RECENT FINDINGS: The histopathologic variability of chondrosarcomas is reflected in the complexity and lack of specificity of their cytogenetic and molecular genetic findings, except for extraskeletal myxoid chondrosarcomas. These are characterized in the preponderant number of cases by a translocation, t(9;22)(q22;q12), and in a small number of cases by variant translocations t(9;17)(q22;q11) and t(9;15)(q22;q21). These translocations lead to the formation of abnormal fusion genes and gene products (proteins). In each of these translocations, the CHN gene is involved, resulting in the chimeric fusion genes EWS/CHN, RBP56/CHN, and TCF12/CHN, respectively. The specific translocations and their associated molecular genetic changes are diagnostic of extraskeletal myxoid chondrosarcomas. The abnormal proteins resulting from these fusion genes aberrantly affect gene transcription and cellular signaling pathways thought to be responsible for initiating sarcoma formation. In skeletal (central) chondrosarcomas of varying histopathologic types, the cytogenetic and molecular genetic findings are variable, complex, and apparently lacking in specificity. These changes may reflect a stepwise process (or processes) of oncogenesis involving an array of genes.
SUMMARY: Although some cartilaginous tumors are characterized by specific or recurrent chromosome alterations and molecular genetic changes, much is yet to be learned about the nature and sequence of these genetics events and about their unique role in the stepwise process involved in the development and biology of each tumor type, both malignant and nonmalignant. Until such time, some of the genetic changes, particularly the presence of specific translocations, can be of definite diagnostic value.

Domanski HA, Carlén B, Mertens F, Akerman M
Extraskeletal myxoid chondrosarcoma with neuroendocrine differentiation: a case report with fine-needle aspiration biopsy, histopathology, electron microscopy, and cytogenetics.
Ultrastruct Pathol. 2003 Sep-Oct; 27(5):363-8 [PubMed] Related Publications
Although extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma, its morphological, ultrastructural, and cytogenetical features have been well investigated. The authors describe a very rare variant of EMC with neuroendocrine differentiation. A 49-year-old woman presented with an 11-cm, deep-seated, lobulated soft tissue mass in the left thigh and a lymph node metastasis in the left groin. Analysis of fine-needle aspiration biopsy (FNAB) smears and a cellblock prepared from FNAB material, as well as histological sections of the excised tumor, showed a neoplasm composed of rounded and elongated cells arranged in strands and cords in a myxoid background matrix. The nuclei were rounded and often eccentric. The immunohistochemical phenotype was S-100 protein -, neuron specific enolase +, and chromogranin A+. Electron microscopy showed tumor cells harboring numerous mitochondria, partial basal lamina, and unequivocal neuroendocrine granules. Molecular genetic analysis revealed a TAF15/NR4A3 fusion, a characteristic rearrangement occurring in about 25% of cytogenetically investigated EMC. A few cases of EMC with neuroendocrine differentiation have been reported. However, the only previously described case with genetic information also displayed the t(9;17) instead of the more common t(9;22), suggesting an association between type of primary chromosome abnormality and neuroendocrine differentiation.

Sjögren H, Meis-Kindblom JM, Orndal C, et al.
Studies on the molecular pathogenesis of extraskeletal myxoid chondrosarcoma-cytogenetic, molecular genetic, and cDNA microarray analyses.
Am J Pathol. 2003; 162(3):781-92 [PubMed] Free Access to Full Article Related Publications
Extraskeletal myxoid chondrosarcomas (EMCs) are characterized by recurrent chromosome translocations resulting in fusions of the nuclear receptor TEC to various NH(2)-terminal partners. Here we describe the phenotypic, cytogenetic, and molecular genetic characteristics of a series of 10 EMCs. Using spectral karyotyping and fluorescence in situ hybridization, clonal chromosome abnormalities were detected in all but one tumor. A t(9;22)(q22;q12) translocation was found in three cases; a del(22)(q12-13)in one case; and variant translocations, including t(9;17)(q22;q11-12), t(7;9;17)(q32;q22;q11), and t(9;15)(q22;q21), were detected in one case each. Recurrent, secondary abnormalities, including trisomy 1q, 7, 8, 12, and 19, were found in seven tumors. All tumors contained translocation-generated or cryptic gene fusions, including EWS-TEC (five cases, of which one was a novel fusion), TAF2N-TEC (four cases), and TCF12-TEC (one case). cDNA microarray analysis of the gene expression patterns of two EMCs and a myxoid liposarcoma reference tumor revealed a remarkably distinct and uniform expression profile in both EMCs despite the fact that they had different histologies and expressed different fusion transcripts. The most differentially expressed gene in both tumors was CHI3L1, which encodes a secreted glycoprotein (YKL-40) previously implicated in various pathological conditions of extracellular matrix degradation as well as in cancer. Our findings suggests that EMC exhibits a tumor-specific gene expression profile, including overexpression of several cancer-related genes as well as genes implicated in chondrogenesis and neural-neuroendocrine differentiation, thus distinguishing it from other soft tissue sarcomas.

Panagopoulos I, Mertens F, Isaksson M, et al.
Molecular genetic characterization of the EWS/CHN and RBP56/CHN fusion genes in extraskeletal myxoid chondrosarcoma.
Genes Chromosomes Cancer. 2002; 35(4):340-52 [PubMed] Related Publications
Extraskeletal myxoid chondrosarcoma (EMC) is a soft-tissue neoplasm cytogenetically characterized by the translocations t(9;22)(q22;q11-12) or t(9;17)(q22;q11), generating EWS/CHN or RBP56/CHN fusion genes, respectively. In the present study, 18 EMCs were studied both cytogenetically and at the molecular level. Chromosomal aberrations were detected in 16 samples: 13 with involvement of 9q22 and 22q11-12, and three with rearrangements of 9q22 and 17q11. Fifteen cases had an EWS/CHN fusion transcript and three had an RBP56/CHN transcript. The most frequent EWS/CHN transcript (type 1; 10 tumors), involved fusion of EWS exon 12 with CHN exon 3, and the second most common (type 5; two cases) was fusion of EWS exon 13 with CHN exon 3. In all tumors with RBP56/CHN fusion, exon 6 of RBP56 was fused to exon 3 of CHN. By genomic XL PCR and sequence analyses, the breakpoints from 14 cases were mapped in the EWS, RBP56, and CHN genes. In CHN, 12 breakpoints were found in intron 2 and only two in intron 1. In EWS, the breaks occurred in introns 7 (one break), 12 (eight breaks), and 13 (one break), and in RBP56 in intron 6. Repetitive elements such as Alu and LINE sequences seem to have limited, if any, importance in the genesis of EWS/CHN and RBP56/CHN chimeras. Furthermore, there were no chi, chi-like, topoisomerase II, or translin consensus sequences in the introns harboring the translocation breakpoints, nor could the number of topo I sites in EWS, RBP56, and CHN introns explain the uneven distribution of the breakpoints among EWS or CHN introns. Additional genetic events, such as nucleotide insertions, homologies at the junction, deletions, duplications, and inversions, were found to accompany the translocations, indicating that the chromosomal translocations do not require sequence-specific recombinases or extensive homology between the recombined sequences.

Martini A, La Starza R, Janssen H, et al.
Recurrent rearrangement of the Ewing's sarcoma gene, EWSR1, or its homologue, TAF15, with the transcription factor CIZ/NMP4 in acute leukemia.
Cancer Res. 2002; 62(19):5408-12 [PubMed] Related Publications
Fusions of the TET-proteins (TLS/FUS, EWSR1, and TAF15/RBP56) to different transcription factors are involved in various malignancies including Ewing's sarcoma, primitive neuroectodermal tumors, and acute myeloid leukemia. These are thought to arise through transcriptional deregulation, with the transcription factor defining the tumor phenotype. We show that, as result of a t(12;17)(p13;q11) or its variant t(12;22)(p13;q12), the transcription factor gene CIZ/NMP4 is recurrently involved in acute leukemia through fusion with either EWSR1 or TAF15. The fusions possess transforming properties in NIH3T3 cells but do not affect the expression of CIZ target genes, suggesting a contribution to oncogenesis that is independent of the transactivating properties of the fusion protein. These results also extend the involvement of TET-protein fusions to acute lymphoblastic leukemia and suggest a role for CIZ/NMP4 in lymphoid and myeloid development.

Okamoto S, Hisaoka M, Ishida T, et al.
Extraskeletal myxoid chondrosarcoma: a clinicopathologic, immunohistochemical, and molecular analysis of 18 cases.
Hum Pathol. 2001; 32(10):1116-24 [PubMed] Related Publications
Extraskeletal myxoid chondrosarcoma (EMCS) is an uncommon clinicopathologically well-defined tumor, but its pathogenesis and biologic behavior are poorly understood. We reviewed 18 cases of EMCS to verify clinicopathologic features and immunohistochemical profiles together with molecular detection of the tumor-specific fusion genes. The tumors were located mainly in the proximal extremities and limb girdles (72%). Two tumors arose at unusual anatomic sites: the finger and the hip joint. Nine of the 17 followed-up patients were alive and disease free, 4 were alive with recurrences and/or metastases, and 4 died of the tumor. Fifteen tumors showed typical features of EMCS, and 3 had hypercellular areas in addition to conventional EMCS areas. The tumors were variably immunoreactive for S-100 protein (50%), NSE (89%), peripherin (60%), and synaptophysin (22%). Chromogranin A and some epithelial markers (AE1/AE3, CAM5.2, and epithelial membrane antigen) were entirely negative. Frequent expressions of the neural/neuroendocrine markers suggest possible neural/neuroendocrine differentiation in at least some EMCSs, in addition to chondroid differentiation. In a reverse-transcription polymerase chain reaction (RT-PCR) assay using paraffin-embedded specimens, EWS-CHN or TAF2N-CHN fusion gene transcripts characteristic of EMCS could be detected in 15 (83%) of the 18 cases: EWS-CHN type 1 in 11 cases, EWS-CHN type 2 in 1, and TAF2N-CHN in 3. Three fusion-negative cases included 2 conventional EMCSs and 1 considered a "cellular" variant of the tumor. None of 30 other soft tissue and bone tumors with myxoid or chondroid morphology that we examined contained these fusion genes. Thus, RT-PCR detection of EWS-CHN or TAF2N-CHN fusion gene using archival paraffin-embedded tissue is a feasible and useful ancillary technique for the diagnosis of EMCS.

Sjögren H, Wedell B, Meis-Kindblom JM, et al.
Fusion of the NH2-terminal domain of the basic helix-loop-helix protein TCF12 to TEC in extraskeletal myxoid chondrosarcoma with translocation t(9;15)(q22;q21).
Cancer Res. 2000; 60(24):6832-5 [PubMed] Related Publications
Extraskeletal myxoid chondrosarcomas (EMCs) are characterized by recurrent t(9;22) or t(9;17) translocations resulting in fusions of the NH2-terminal transactivation domains of EWS or TAF2N to the entire TEC protein. We report here an EMC with a novel translocation t(9; 15)(q22;q21) and a third type of TEC-containing fusion gene. The chimeric transcript encodes a protein in which the first 108 amino acids of the NH2-terminus of the basic helix-loop-helix (bHLH) protein TCF12 is linked to the entire TEC protein. The translocation separates the NH2-terminal domain of TCF12 from the bHLH domain as well as from a potential leucine zipper domain located immediately downstream of the breakpoint. These results demonstrate that the NH2-terminal transactivation domains of EWS or TAF2N are not unique in their ability to convert the TEC protein into an oncogenically active fusion protein, and that they may be replaced by a domain from a bHLH protein that presumably endows the fusion protein with similar functions.

Harris M, Coyne J, Tariq M, et al.
Extraskeletal myxoid chondrosarcoma with neuroendocrine differentiation: a pathologic, cytogenetic, and molecular study of a case with a novel translocation t(9;17)(q22;q11.2).
Am J Surg Pathol. 2000; 24(7):1020-6 [PubMed] Related Publications
A case of extraskeletal myxoid chondrosarcoma (EMC) in which there was histochemical, immunohistochemical, and ultrastructural evidence of neuroendocrine differentiation is reported. Genetic investigations showed the recently described novel translocation t(9;17)(q22;q11.2) and associated fusion of the CHN and RBP56 genes, contrasting with the translocation t(9;22)(q22;q12) and EWS/CHN gene fusion found in the majority of EMCs.

Bertolotti A, Bell B, Tora L
The N-terminal domain of human TAFII68 displays transactivation and oncogenic properties.
Oncogene. 1999; 18(56):8000-10 [PubMed] Related Publications
In Ewing tumor, the (11;22) chromosomal translocation produces a chimeric molecule composed of the amino-terminal domain of EWS fused to the carboxyl-terminal DNA-binding domain of FLI-1. Previously, we have identified a novel protein TAFII68, which is highly similar to EWS and another closely related protein TLS (also called FUS). We demonstrate that the N-terminus of TAFII68 efficiently stimulates transcription when fused to two different DNA binding domains and that overexpression of TAFII68-FLI-1 chimeras in NIH3T3 cells leads to oncogenic transformation. We have also investigated the molecular mechanisms which could account for the transcriptional activation and the oncogenic transformation potential of the N-termini of TAFII68 and EWS. Thus, we have tested whether the artificial recruitment of components of the preinitiation complex (PIC) or a histone acetyltransferase (HAT) could bypass the requirement for the activation domains of either EWS or TAFII68. Recruitment of individual components of the transcription machinery or the GCN5 HAT is not sufficient to promote activation from FLI-1 responsive genes either in transfection experiments or in oncogenic transformation assays. These results suggest that the TAFII68 or EWS activation domains enhance a step after PIC formation in the transcriptional activation process.

Attwooll C, Tariq M, Harris M, et al.
Identification of a novel fusion gene involving hTAFII68 and CHN from a t(9;17)(q22;q11.2) translocation in an extraskeletal myxoid chondrosarcoma.
Oncogene. 1999; 18(52):7599-601 [PubMed] Related Publications
A proportion of extraskeletal myxoid chondrosarcomas (EMC) have been shown to have a characteristic translocation t(9;22)(q22;q12) involving the EWS gene at 22q12 and the CHN orphan nuclear receptor gene at 9q22. This translocation appears to be largely specific for EMC, but has not been detected in all such tumours. We report here a case of EMC with a t(9;17)(q22;q11.2) as the sole chromosome abnormality. We have determined that the translocation results in the fusion of the entire coding region of CHN to the N-terminal transactivation domain of RBP56/hTAFII68. This is the first report of a translocation involving RBP56/hTAFII 68, a protein with sequence homology to both EWS and TLS/FUS. The involvement of RBP56/hTAFII68 may explain some unusual features of the tumour.

Panagopoulos I, Mencinger M, Dietrich CU, et al.
Fusion of the RBP56 and CHN genes in extraskeletal myxoid chondrosarcomas with translocation t(9;17)(q22;q11).
Oncogene. 1999; 18(52):7594-8 [PubMed] Related Publications
Although most extraskeletal myxoid chondrosarcomas (EMC) are cytogenetically characterized by the translocation t(9;22)(q22;q12), another subset has recently been identified carrying a t(9;17)(q22;q11). Whereas the t(9;22) is known to result in fusion of the CHN (TEC) gene from 9q22 with the EWS gene from 22q12, creating a chimeric EWS/CHN, the genes involved in the t(9;17) of EMC are unknown. We examined two EMC with t(9;17)(q22;q11) and found that the CHN gene was recombined with the RBP56 gene from 17q11 to generate a chimeric RBP56/CHN. RBP56 has not previously been shown to be involved in tumorigenesis but it encodes a putative RNA-binding protein similar to the EWS and FUS (TLS) proteins known to play a pathogenetic role in several sarcomas. The presence of the RBP56/CHN chimeric gene in EMC with t(9;17)(q22;q11) shows that the N-terminal parts of EWS and RBP56 have similar oncogenic potential making them pathogenetically equivalent in oncoproteins arising from fusions with certain transcription factors.

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