Spindle cell tumors are clinically heterogeneous but morphologically similar neoplasms that can occur anywhere, mostly in adult patients. They are treated primarily with surgery to which is often added adjuvant or neoadjuvant radiation. Sub-classification of spindle cell sarcomas requires integration of histology, clinicopathological parameters, immunohistochemistry, cytogenetics (including fluorescence in situ hybridization) and/or molecular genetics. Some of the tumor subtypes are characterized by the presence of distinct chromosomal translocations and fusion genes. When no signs of differentiation are seen, the diagnosis by exclusion becomes undifferentiated spindle cell sarcoma. Cytogenetic, RNA sequencing and RT-PCR analyses were performed on a case of spindle cell sarcoma. The karyotype of the primary tumor was 46,X,del(X)(p?11p?22), der(12)(12pter?12q?22::12q?15?q?22::16p11?16pter),-16,+r(12). MDM2 was found amplified in both the primary tumor and a meta-stasis. RNA-Seq of the primary tumor identified four fusion genes, PTGES3-PTPRB, HMGA2-DYRK2, TMBIM4-MSRB3 and USP15-CNTN1, in which all the partner genes map to the q arm of chromosome 12. In material from the metastasis, RT-PCR detected the PTGES3-PTPRB, HMGA2-DYRK2 and TMBIM4-MSRB3 whereas no USP15-CNTN1 fusion transcript was found. Because MDM2 amplification and the fusion transcripts PTGES3-PTPRB, HMGA2-DYRK2 and TMBIM4-MSRB3 were found both in the primary tumor and in the metastasis, they are components of the same clone and may be involved both in initiation and progression of the tumor. Which of them is pathogenetically primary remains unknown.
The objective of this work was to investigate whether previous disposal practices in four metal finishing facilities, located at Asopos river basin (East-Central Greece), have caused any potential serious contamination of soils. The study focused mainly on Cr and Ni, which are the primary elements of concern in the area. To estimate the natural geochemical levels of Cr and Ni, thirty soil samples were collected from locations that were not suspected of any contamination. In this group of samples, Cr concentration varied between 60 and 418mg/kg, and Ni concentrations varied from 91 to 1200mg/kg. The second group of samples consisted of more than 100 drill cores and surface soil samples, potentially affected by the disposal of effluents and/or the drainage of runoff water from the industrial facilities. According to the findings of the study, the disposal of treated effluents in absorption type sinks resulted occasionally in the contamination of a thin layer of soil just at the bottom of the sinks, but there was no indication of downward migration, since Cr and Ni concentrations in the lower soil layers were similar to those of the reference soils.
The identification of recurrent gene fusions in common epithelial cancers--for example, TMPRSS2/ERG in prostate cancer and EML4/ALK in nonsmall cell lung carcinomas--has raised the question of whether fusion genes are pathogenetically important also in ovarian carcinomas. The first recurrent fusion transcript in serous ovarian carcinomas was reported by Salzman et al. in 2011, who used deep paired-end sequencing to detect the fusion gene ESRRA-C11orf20 in 10 out of 67 (15%) serous ovarian carcinomas examined, a finding that holds great promise for our understanding of ovarian tumorigenesis as well as, potentially, for new treatment strategies. We wanted to test how frequent the ESRRA/C11orf20 fusion is in ovarian carcinomas of all subtypes, and therefore examined a series of 230 ovarian carcinomas of which 197 were of the serous subtype and 163 of the 197 were of stages III and IV--that is, the very same carcinoma subset where the fusion transcript had been found. We performed PCR and high-throughput sequencing analyses in search of the fusion transcript. We used the same primers described previously for the detection of the fusion and the same primer combination, but found no ESRRA/C11orf20 fusion in our series. A synthetic DNA plasmid containing the reported ESRRA/C11orf20 fusion was included as a positive control for our PCR experiments. Data from high-throughput sequencing of 23 ovarian carcinomas were screened in search of alternative partner(s) for the ESRRA and/or C11orf20 gene, but none was found. We conclude that the frequency of the ESRRA/C11orf20 gene fusion in serous ovarian carcinomas of stages III and IV must be considerable less than that reported previously (0/163 in our experience compared with 10/67 in the previous study). At the very least, it seems clear that the said fusion cannot be a common pathogenetic event in this tumor type.
Mesenchymal chondrosarcomas are fast-growing tumors that account for 2-10% of primary chondrosarcomas. Cytogenetic information is restricted to 12 cases that did not show a specific aberration pattern. Recently, two fusion genes were described in mesenchymal chondrosarcomas: a recurrent HEY1-NCOA2 found in tumors that had not been cytogenetically characterized and an IRF2BP2-CDX1 found in a tumor carrying a t(1;5)(q42;q32) translocation as the sole chromosomal abnormality. Here, we present the cytogenetic and molecular genetic analysis of a mesenchymal chondrosarcoma in which the patient had two histologically indistinguishable tumor lesions, one in the neck and one in the thigh. An abnormal clone with the G-banding karyotype 46,XX,add(6)(q23),add(8)(p23),del(10)(p11),+12,-15 was found in the neck tumor whereas a normal karyotype, 46,XX, was found in the tumor of the thigh. RT-PCR and Sanger sequencing showed that exon 4 of HEY1 was fused to exon 13 of NCOA2 in the sample from the thigh lesion; we did not have spare material to perform a similar analysis of the neck tumor. Examining the published karyotypes we observed numerical or structural aberrations of chromosome 8 in the majority of the karyotyped mesenchymal chondrosarcomas. Chromosome 8 was also structurally affected in the present study. The pathogenetic mechanisms behind this nonrandom involvement are unknown, but the presence on 8q of two genes, HEY1 and NCOA2, now known to be involved in mesenchymal chondrosarcoma tumorigenesis is, of course, suggestive.
The chimeric transcripts described in endometrial stromal sarcomas (ESS) are JAZF1/SUZ12, YWHAE/FAM22, ZC3H7/BCOR, MBTD1/CXorf67, and recombinations of PHF1 with JAZF1, EPC1, and MEAF6. The MEAF6/PHF1 fusion had hitherto been identified in only one tumor. We present two more ESS with MEAF6/PHF1 detected by transcriptome sequencing (case 1) and RT-PCR (case 2), proving that this fusion is recurrent in ESS. The transcript of both cases was an in-frame fusion between exon 5 of MEAF6 and exon 2 of PHF1. Both genes are involved in epigenetic modification, and this may well be their main pathogenetic theme also in ESS tumorigenesis.
Cancer-specific fusion genes are often caused by cytogenetically visible chromosomal rearrangements such as translocations, inversions, deletions or insertions, they can be the targets of molecular therapy, they play a key role in the accurate diagnosis and classification of neoplasms, and they are of prognostic impact. The identification of novel fusion genes in various neoplasms therefore not only has obvious research importance, but is also potentially of major clinical significance. The "traditional" methodology to detect them began with cytogenetic analysis to find the chromosomal rearrangement, followed by utilization of fluorescence in situ hybridization techniques to find the probe which spans the chromosomal breakpoint, and finally molecular cloning to localize the breakpoint more precisely and identify the genes fused by the chromosomal rearrangement. Although laborious, the above-mentioned sequential approach is robust and reliable and a number of fusion genes have been cloned by such means. Next generation sequencing (NGS), mainly RNA sequencing (RNA-Seq), has opened up new possibilities to detect fusion genes even when cytogenetic aberrations are cryptic or information about them is unknown. However, NGS suffers from the shortcoming of identifying as "fusion genes" also many technical, biological and, perhaps in particular, clinical "false positives," thus making the assessment of which fusions are important and which are noise extremely difficult. The best way to overcome this risk of information overflow is, whenever reliable cytogenetic information is at hand, to compare karyotyping and sequencing data and concentrate exclusively on those suggested fusion genes that are found in chromosomal breakpoints. This article is part of a Directed Issue entitled: Rare Cancers.
RNA-sequencing was performed on three tenosynovial giant cell tumors (TSGCT) in an attempt to elicit more information on the mechanisms of CSF1 expression in this tumor type. A novel CSF1-S100A10 fusion gene was found in a TSGCT that carried the translocation t(1;1)(q21;p11) as the sole karyotypic abnormality. In this fusion gene, the part of CSF1 coding for the CSF1 protein (exons 1-8 in sequences with accession nos. NM_000757 and NM_172212) is fused to the 3'-part of S100A10. Since the stop codon TAG of CSF1 is present in it, the CSF1-S100A10 fusion gene's predominant consequence seems to be the replacement of the 3'-untranslated region (UTR) of CSF1 (exon 9; nt 2092-4234 in sequence with accession no. NM_000757 or nt 2092-2772 in NM_172212) by the 3'-end of S100A10 (exon 3; nt 641-1055 in sequence with accession no. NM_002966). In the other two TSGCT, a novel CSF1 transcript was detected, the same in both tumors. Similar to the occurrence in the CSF1-S100A10 fusion gene, the novel CSF1 transcript 3'-UTR is replaced by a new exon located ~48 kb downstream of CSF1 and 11 kb upstream of AHCYL1. Although only 3 TSGCT were available for study, the finding in all of them of a novel CSF1-S100A10 fusion gene or CSF1 transcript indicates the existence of a common pathogenetic theme in this tumor type: the replacement of the 3'-UTR of CSF1 with other sequences.
Whole transcriptome sequencing was used to study a small round cell tumor in which a t(4;19)(q35;q13) was part of the complex karyotype but where the initial reverse transcriptase PCR (RT-PCR) examination did not detect a CIC-DUX4 fusion transcript previously described as the crucial gene-level outcome of this specific translocation. The RNA sequencing data were analysed using the FusionMap, FusionFinder, and ChimeraScan programs which are specifically designed to identify fusion genes. FusionMap, FusionFinder, and ChimeraScan identified 1017, 102, and 101 fusion transcripts, respectively, but CIC-DUX4 was not among them. Since the RNA sequencing data are in the fastq text-based format, we searched the files using the "grep" command-line utility. The "grep" command searches the text for specific expressions and displays, by default, the lines where matches occur. The "specific expression" was a sequence of 20 nucleotides from the coding part of the last exon 20 of CIC (Reference Sequence: NM_015125.3) chosen since all the so far reported CIC breakpoints have occurred here. Fifteen chimeric CIC-DUX4 cDNA sequences were captured and the fusion between the CIC and DUX4 genes was mapped precisely. New primer combinations were constructed based on these findings and were used together with a polymerase suitable for amplification of GC-rich DNA templates to amplify CIC-DUX4 cDNA fragments which had the same fusion point found with "grep". In conclusion, FusionMap, FusionFinder, and ChimeraScan generated a plethora of fusion transcripts but did not detect the biologically important CIC-DUX4 chimeric transcript; they are generally useful but evidently suffer from imperfect both sensitivity and specificity. The "grep" command is an excellent tool to capture chimeric transcripts from RNA sequencing data when the pathological and/or cytogenetic information strongly indicates the presence of a specific fusion gene.
An acute myeloid leukemia was suspected of having a t(8;16)(p11;p13) resulting in a KAT6A-CREBBP fusion because the bone marrow was packed with monoblasts showing marked erythrophagocytosis. The diagnostic karyotype was 46,XY,add(1)(p13),t(8;21)(p11;q22),der(16)t(1;16)(p13;p13)/46,XY; thus, no direct confirmation of the suspicion could be given although both 8p11 and 16p13 seemed to be rearranged. The leukemic cells were examined in two ways to find out whether a cryptic KAT6A-CREBBP was present. The first was the "conventional" approach: G-banding was followed by fluorescence in situ hybridization (FISH) and reverse transcription PCR (RT-PCR). The second was RNA-Seq followed by data analysis using FusionMap and FusionFinder programs with special emphasis on candidates located in the 1p13, 8p11, 16p13, and 21q22 breakpoints. FISH analysis indicated the presence of a KAT6A/CREBBP chimera. RT-PCR followed by Sanger sequencing of the amplified product showed that a chimeric KAT6A-CREBBP transcript was present in the patients bone marrow. Surprisingly, however, KATA6A-CREBBP was not among the 874 and 35 fusion transcripts identified by the FusionMap and FusionFinder programs, respectively, although 11 sequences of the raw RNA-sequencing data were KATA6A-CREBBP fragments. This illustrates that although many fusion transcripts can be found by RNA-Seq combined with FusionMap and FusionFinder, the pathogenetically essential fusion is not always picked up by the bioinformatic algorithms behind these programs. The present study not only illustrates potential pitfalls of current data analysis programs of whole transcriptome sequences which make them less useful as stand-alone techniques, but also that leukemia diagnosis still relies on integration of clinical, hematologic, and genetic disease features of which the former two by no means have become superfluous.
Sequential combination of cytogenetics and RNA-sequencing (RNA-Seq) has been shown to be an efficient approach to detect pathogenetically important fusion genes in neoplasms carrying only one or a few chromosomal rearrangements. We performed RNA-Seq on an acute myeloid leukemia in a 2-year-old girl with the karyotype 46,XX,add(1)(p36), der(2)t(2;3)(q21;q21),del(3)(q21),der(10)t(1;10)(q32;q24),der(16)(2qter-->2q21::16p11-->16q24::16p11-->16pter)/46,XX and identified a cryptic FUS/ERG fusion gene. PCR and direct sequencing verified the presence of the FUS-ERG chimeric transcript in which exon 7 of FUS from 16p11 (nt 904 in sequence with accession number NM_004960 version 3) was fused in frame to exon 8 of ERG from sub-band 21q22.2 (nt 967 in NM_004449 version 4). The FUS-ERG transcript found here has been reported in only two other cases of childhood leukemia, in a 1-year-old boy and an 8-month-old boy, both diagnosed with precursor B cell ALL. The fusion transcript codes for a 497 amino acid residues FUS-ERG protein and, similar to other AML-related FUS-ERG fusion proteins, contains both functional domains (TR1 and TR2) of the transactivation domain of FUS and the ETS domain of ERG. The clinical significance, if any, of the amino acid residues which are coded by the exons 8, 9 and 10 of ERG in the fusion FUS-ERG proteins, remains unclear.
The rare but recurrent RUNX1-USP42 fusion gene is the result of a t(7;21)(p22;q22) chromosomal translocation and has been described in 6 cases of acute myeloid leukemia (AML) and one case of refractory anemia with excess of blast. In the present study, we present the molecular genetic analysis and the clinical features of a t(7;21)(p22;q22)-positive AML case. PCR amplified two RUNX1-USP42 cDNA fragments but no reciprocal USP42-RUNX1 fragment indicating that the RUNX1-USP42 is the leukemogenic fusion gene. Sequencing of the two amplified fragments showed that exon 6 or exon 7 of RUNX1 (accession number NM_001754 version 3) was fused to exon 3 of USP42 (accession number NM_032172 version 2). The predicted RUNX1-USP42 fusion protein would contain the Runt homology domain (RHD), which is responsible for heterodimerization with CBFB and for DNA binding, and the catalytic UCH (ubiquitin carboxyl terminal hydroxylase) domain of the USP42 protein. The bone marrow cells in the present case also had a 5q deletion, and it was revealed that 5 out of the 8 reported cases (including the present case) with t(7;21)(p22;q22)/RUNX1-USP42 also had cytogenetic abnormalities of 5q. The fact that t(7;21) and 5q- occur together much more often than chance would allow seems to be unquestionable, although the pathogenetic connection between the two aberrations remains unknown.
Mesothelioma is a rare but very aggressive tumor derived from mesothelial cells. A number of often complex but nonrandom cytogenetic abnormalities have been found in these tumors, resulting in loss of chromosome bands 14q32 and 22q12 in more than 35% of the cases. In this study, we used RNA sequencing to search for fusion transcripts in a mesothelioma carrying a t(14;22)(q32;q12) as the sole chromosomal aberration and found an EWSR1-YY1 and its reciprocal YY1-EWSR1 fusion transcript. Screening 15 additional cases of mesothelioma from which we had RNA but no cytogenetic information, we identified one more tumor carrying an EWSR1-YY1 fusion gene but not the reciprocal YY1-EWSR1 transcript. RT-polymerase chain reaction and sequencing showed that in both cases exon 8 of EWSR1 (nucleotide 1,139, accession number NM_013986 version 3, former exon 7 in sequence with accession number X66899) was fused to exon 2 of YY1 (nucleotide 1,160, accession number NM_003403 version 3). The EWSR1 breakpoint in exon 8 in the EWSR1-YY1 chimeric transcript is similar to what is found in other fusions involving EWSR1 such as EWSR1-FLI1, EWSR1-DDIT3, and EWSR1-ATF1. The EWSR1-YY1-encoded protein is an abnormal transcription factor with the transactivation domain of EWSR1 and the DNA-binding domain of YY1. This is the first study to detect a specific fusion gene in mesothelioma (the reason how frequent the EWSR1-YY1 fusion is remains uncertain) and also the first time that direct involvement of YY1 in oncogenesis has been demonstrated.
Endometrial stromal sarcomas (ESS) are genetically heterogeneous uterine tumors in which a JAZF1-SUZ12 chimeric gene resulting from the chromosomal translocation t(7;17)(p15;q21) as well as PHF1 rearrangements (in chromosomal band 6p21) with formation of JAZF1-PHF1, EPC1-PHF1, and MEAF6-PHF1 chimeras have been described. Here, we investigated two ESS characterized cytogenetically by the presence of a der(22)t(X;22)(p11;q13). Whole transcriptome sequencing one of the tumors identified a ZC3H7-BCOR chimeric transcript. Reverse transciptase-PCR with the ZC3H7B forward and BCOR reverse primer combinations confirmed the presence of a ZC3H7-BCOR chimeric transcript in both ESS carrying a der(22)t(X;22) but not in a control ESS with t(1;6) and the MEAF6-PHF1 fusion. Sequencing of the amplified cDNA fragments showed that in both cases ESS exon 10 of ZC3H7B (from 22q13; accession number NM_017590 version 4) was fused to exon 8 of BCOR (from Xp11; accession number NM_001123385 version 1). Reciprocal multiple BCOR-ZC3H7B cDNA fragments were amplified in only one case suggesting that ZC3H7B-BCOR, on the der(22)t(X;22), is the pathogenetically important fusion gene. The putative ZC3H7B-BCOR protein would contain the tetratricopeptide repeats and LD motif from ZC3H7B and the AF9 binding site (1093-1233aa), the 3 ankyrin repeats (1410-1509 aa), and the NSPC1 binding site of BCOR. Although the presence of these motifs suggests various functions of the chimeric protein, it is possible that its most important role may be in epigenetic regulation. Whether or not the (patho)genetic subsets JAZF1-SUZ12, PHF1 rearrangements, and ZC3H7B-BCOR correspond to any phenotypic, let alone clinically important, differences in ESS remain unknown.
Little is known about the genomic abnormalities of squamous cell carcinomas (SCC) of the vulva and how they correlate with gene expression. We determined the genomic and expression profiles of 15 such SCC using karyotyping, DNA ploidy analysis, arrayCGH, and expression arrays. Four of the five cases with clonal chromosomal aberrations found by G-banding showed highly abnormal karyotypes with multiple rearrangements. The imbalances scored by arrayCGH mapped to different chromosomes with losses being more common than gains. Frequent losses were scored from 3p and 8p whereas gains were frequent from 3q and 8q (loss of 8p with concomitant gain of 8q mostly occurred via 8q isochromosome formation). This is the first study of vulvar tumors using arrayCGH, and some frequent imbalances could be defined precisely. Of particular note were the sometimes large, sometimes small deletions of 3p and 9p which had minute areas in 3p14 and 9p23 as minimal commonly deleted regions. FHIT (3p14) and PTPRD (9p23) are the only genes here. They were both lost in seven cases, including homozygous losses of PTPRD in four tumors. Using qPCR we could demonstrate deregulation of the FHIT gene in tumor cells. Hence, this gene is likely to play a pathogenetic role in vulvar SCC tumorigenesis. Expression array analyses also identified a number of other genes whose expression profile was altered. Notable among the downregulated genes were MAL (in 2q11), KRT4 (in 12q13), and OLFM4 (in 13q14), whereas upregulated genes included SPRR2G (in 1q21.3) and S100A7A (in 1q21.3).
Acute erythroid leukemia was diagnosed in a 4-month-old boy. Cytogenetic analysis of bone marrow (BM) cells showed a t(11;20)(p11;q11) translocation. RNA extracted from the BM was sequenced and analyzed for fusion transcripts using the software FusionMap. A ZMYND8-RELA fusion was ranked first. RT-PCR and direct sequencing verified the presence of an in frame ZMYND8-RELA chimeric transcript. Fluorescence in situ hybridization showed that the ZMYND8-RELA was located on the p12 band of der(11); therefore a cytogenetically invisible pericentric inversion in chromosome 11 must have taken place besides the translocation. The putative ZMYND8-RELA fusion protein contains the Zinc-PHD finger domain, a bromodomain, a PWWP domain, a MYND type of zinc finger of ZMYND8, and the entire RELA protein, indicating that it might act leukemogenically by influencing several cellular processes including the NF-kappa-B pathway.
CREB3L2, a member of the CREB3 family of transcription factors, spans >120 kbp and is composed of 12 exons. We characterized a widely expressed transcript of CREB3L2 generated by an intronic polyadenylation site in intron 4 of the gene. It could be translated to a CREB3L2 variant which is localized both in the nucleus and the endoplasmatic reticulum. The protein retains the N-terminal transactivation domain but lacks the DNA-binding domain, the transmembrane domain and the C-terminal part. Experiments using a GAL4 DNA-binding domain fusion model showed that the transcript is a transactivator but it cannot exert its function through the CRE and ATF6 binding sites and has little effect on the GRP78 promoter. Whether this transcript has a cellular function or is targeted for degradation by nonsense-mediated RNA decay system of RNA surveillance is currently unknown.
Bordetella holmesii is a fastidious Gram-negative rod that was initially identified in 1995. It causes bacteremia, predominantly among patients with anatomical or functional asplenia. We report four cases of B. holmesii bacteremia in asplenic children occurring within the last 4 years. In all cases, B. holmesii was misidentified by an automated system as Acinetobacter lwoffii.
Endometrial stromal sarcomas are rare malignancies, accounting for less than 10% of uterine sarcomas. The most characteristic chromosomal aberration of this tumor type is the translocation t(7;17)(p15-p21;q12-q21) leading to the fusion of two zinc finger genes, JAZF1 and SUZ12. Recently, the presence of the neoplastic JAZF1/SUZ12 fusion transcript was reported in normal cells of human endometrium. One of the positive samples for the JAZF1/SUZ12 transcript was the immortalized T HESCs cell line. This cell line was derived from the stromal cells obtained from an adult female with myomas and immortalized by transfection of a human telomerase gene. Since T HESCs has a normal karyotype and no fusion of the two genes occurs at the genomic level, the JAZF1/SUZ12 transcript was proposed to be generated by regulated trans-splicing between precursor RNAs for JAZF1 and SUZ12. However, no confirmatory reports currently exist. To determine whether the results could be reproduced, the T HESCs cell line was subjected to three different RT-PCR amplifications for the JAZF1/SUZ12 fusion transcript. RT-PCR assays did not amplify JUZF1/SUZ12 cDNA fragments in the T HESCs cell line, whereas the same assays easily generated JUZF1/SUZ12-amplified transcripts in an endometrial stromal cell sarcoma carrying the t(7;17) chromosomal aberration. Thus, the presence, if any, of a JUZF1/SUZ12 chimeric transcript in the immortalized normal T HESCs is not a constant, reproducible result.
Neuroendocrine (NE) differentiation in prostate cancer has been correlated with a poor prognosis and hormone refractory disease. In a previous report, we demonstrated the presence of immunoreactive cytoplasmic hypoxia inducible factor 1alpha (HIF1alpha), in both benign and malignant NE prostate cells. HIF1alpha and HIF1beta are two subunits of HIF1, a transcription factor important for angiogenesis. The aim of this study was to elucidate whether the cytoplasmic stabilization of HIF1alpha in androgen independent NE differentiated prostate cancer is due to the presence of certain HIF1alpha isoforms.
Myoepithelial neoplasms of soft tissue have only recently been acknowledged as a separate diagnostic entity. To know based on histological appearance whether these tumors are benign or malignant is often difficult, and their tumorigenic mechanisms remain poorly understood. We report a myoepithelial carcinoma with an aberrant near-diploid karyotype, 43 approximately 47,XX,add(1)(p34)x2,add(3)(q27)x2,del(12)(q22),+add(18)(p11)x2,del(22)(q11),+r, found in cells cultured from a lung metastasis. The deletion in 22q led us to search by molecular cytogenetic means for possible EWSR1 rearrangements, and eventually a novel chimeric gene consisting of the 5-end of EWSR1 (22q12) and the 3-end of ZNF444 (19q13) was found. How the new fusion gene contributes to tumorigenesis is unknown, but the finding of an EWSR1 rearrangement suggests that this, possibly even the EWSR1-ZNF444, is a defining pathogenetic feature of at least a subset of these tumors.
The HMGA2 gene encodes a protein that alters chromatin structure. Deregulation, typically through chromosomal rearrangements, of HMGA2 has an important role in the development of several mesenchymal neoplasms. These rearrangements result in the expression of a truncated protein lacking the acidic C-terminus, a fusion protein consisting of the AT-hook domains encoded by exons 1-3 and parts from another gene, or a full-length protein; loss of binding sites for regulatory microRNA molecules from the 3 untranslated region (UTR) of HMGA2 has been suggested to be a common denominator.
Oct 3/4 (Octamer 3/4), a member of POU family has been considered as an important stem cell marker and essential transcription factor during human embryogenesis. In recent years, there have also been reports on presence of Oct 3/4 in differentiated benign and malignant human cells. The objective of this study was to investigate the transcription and the protein expression of Oct 3/4 isoforms in prostate cancer and benign prostate tissue.
EWSR1 is involved in chimeric proteins which play crucial roles in the development of a variety of bone and soft tissue tumors. Many of the chimeric genes involving EWSR1 have been extensively studied, whereas less is known about the wild-type (wt) gene and its regulation. As the expression of the chimeric gene is driven by the EWSR1 promoter, it is of importance to study the mechanisms regulating wt EWSR1 expression. We estimated the transcriptional activity of the EWSR1 promoter through deletion fragments driving reporter gene expression. This assay identified the 100-bp region immediately downstream of the EWSR1 transcriptional start site (+1) and the downstream region from +100 to +300 as important regions for transcriptional regulation. We also found that EWSR1 and RHBDD3, a gene located directly upstream of EWSR1 that is likely to share regulatory elements with EWSR1, were co-expressed in the tissue panels, Ewing tumor biopsies and cell lines. Thus, our results show that the EWSR1 promoter functions in a bidirectional manner, thereby regulating also RHBDD3, and identifies specific regions that strongly influence promoter activity.
CREB3L2 encodes a member of the CREB3 family of transcription factors. We characterized its promoter region, showing that it is asymmetrically bidirectional, also driving the expression of a variant of AKR1D1. It has a CRE binding site which is conserved among mammalians; removal or alteration of it resulted in reduced promoter activity. When transiently transfecting the HEK293 cell line with constructs with partially deleted promoter regions, 5 deletions beyond 1058-bp upstream of the transcription starting site resulted in successive reduction of the activity. The inclusion of the untranslated part of CREB3L2 exon 1 strongly inhibited the promoter activity. Forskolin resulted in a decreased reporter activity, whereas phorbol 12-myristate 13-acetate increased the promoter activity irrespective of the status of the CRE binding site. The presence of the CRE site indicates autoregulation of CREB3L2 and/or regulation via other members of the CREB3 family or a variety of bZIP transcription factors.
Myxoinflammatory fibroblastic sarcoma (MIFS) is a low-grade malignant neoplasm for which limited genetic information, including a t(1;10)(p22;q24) and amplification of chromosome 3 material, is available. To further characterize these aberrations, we have investigated eight soft tissue sarcomas diagnosed as MIFS, haemosiderotic fibrolipomatous tumour (HFT), myxoid spindle cell/pleomorphic sarcoma with MIFS features, and inflammatory malignant fibrous histiocytoma/undifferentiated pleomorphic sarcoma with prominent inflammation (IMFH) harbouring a t(1;10) or variants thereof and/or ring chromosomes with possible involvement of chromosome 3. Using chromosome banding, fluorescence in situ hybridization, array-based comparative genomic hybridization, global gene expression, and real-time quantitative PCR analyses, we identified the breakpoint regions on chromosomes 1 and 10, demonstrated and delineated the commonly amplified region on chromosome 3, and assessed the consequences of these alterations for gene expression. The breakpoints in the t(1;10) mapped to TGFBR3 in 1p22 and in or near MGEA5 in 10q24, resulting in transcriptional up-regulation of NPM3 and particularly FGF8, two consecutive genes located close to MGEA5. The ring chromosomes contained a commonly amplified 1.44 Mb region in 3p11-12, which was associated with increased expression of VGLL3 and CHMP2B. The identified genetic aberrations were not confined to MIFS; an identical t(1;10) was also found in a case of HFT and the amplicon in 3p was seen in an IMFH.
The analysis of a small number of patients with atypical chronic myeloid leukemia showing balanced chromosomal translocations has revealed diverse tyrosine kinase fusion genes, most commonly involving FGFR1, PDGFRA, PDGFRB, JAK2, and ABL. We present a case of aCML with a 3q22;21q22-translocation that led to truncation of the receptor-like tyrosine kinase (RYK) gene and its juxtaposition with sequences from chromosome 21 including the ATP5O gene coding for a mitochondrial ATP synthase. The resulting fusion was not in frame, however, which is why we speculate that an abrogated RYK gene product rather than a chimeric protein might be the leukemogenic result.
Studies on the molecular mechanisms behind soft tissue sarcoma development have disclosed that these malignancies are as genetically heterogeneous as they are clinically and morphologically diverse. Much of the genetic information on soft tissue sarcomas is still limited to the genomic level, as detected by chromosome banding analysis or comparative genomic hybridization. Based on the results of such studies, soft tissue sarcomas may be broadly dichotomized into one group, accounting for approximately 20% of the cases, characterized by specific balanced translocations, and one group typically showing massive chromosomal rearrangements leading to recurrent, but non-specific, structural and numerical rearrangements. As summarized in this review, the genomic characterization of soft tissue sarcomas has not only provided cell biologists with decisive information on the parts of the genome that may harbor genes that are essential for tumor development but also given the clinicians involved in the management of these patients a valuable diagnostic tool.
Mesenchymal chondrosarcomas (MCs) account for 3-10% of primary chondrosarcomas. The cytogenetic literature includes only ten such tumours with karyotypic information and no specific aberrations have been identified. Using a purely molecular genetic approach a HEY1-NCOA2 fusion gene was recently detected in 10 of 15 investigated MCs. The fusion probably arises through intrachromosomal rearrangement of chromosome arm 8 q. We report a new case of MC showing a t(1;5)(q42;q32) as the sole karyotypic aberration. Through FISH and whole transcriptome sequencing analysis we found a novel fusion between the IRF2BP2 gene and the transcription factor CDX1 gene arising from the translocation. The IRF2BP2-CDX1 has not formerly been described in human neoplasia. In our hospitals archives three more cases of MC were found, and we examined them looking for the supposedly more common HEY1-NCOA2 fusion, finding it in all three tumours but not in the case showing t(1;5) and IRF2BP2-CDX1 gene fusion. This demonstrates that genetic heterogeneity exists in mesenchymal chondrosarcoma.
A 10-year-old boy was admitted to the hospital because of anemia detected after a two week history of fatigue, dizziness, nausea, headaches, and weight loss. A bone marrow investigation confirmed a diagnosis of acute lymphoblastic leukemia of the B-cell precursor phenotype. Chromosome G-banding analysis yielded the karyotype 46,XY,t(17;19)(q22;p13), and fluorescence in situ hybridization (FISH) analysis showed rearrangement of the genes TCF3 (on 19p13; accession number NM_03200 version 3) and HLF (on 17q22; accession number NM_002126 version 4) with the generation of a TCF3-HLF chimera. Polymerase chain reaction and sequencing analyses demonstrated the presence of two in-frame chimeric TCF3-HLF transcripts. In the first one, which corresponds to a type 2 fusion, exon 15 of TCF3 is fused to exon 4 of HLF. In the second, described here for the first time and named type 3, exon 14 of TCF3 is fused to exon 4 of HLF. Whether the type 3 chimeric transcript has the same DNA binding and transcriptional regulatory effect as type 1 and type 2 TCF3-HLF chimeras remains to be seen.
Rearrangement of chromosome band 6p21 is recurrent in endometrial stromal sarcoma (ESS) and targets the PHF1 gene. So far, PHF1 was found to be the 3 partner in the JAZF1-PHF1 and EPC1-PHF1 chimeras but since the 6p21 rearrangements involve also other chromosomal translocation partners, other PHF1-fusions seem likely. Here, we show that PHF1 is recombined with a novel fusion partner, MEAF6 from 1p34, in an ESS carrying a t(1;6)(p34;p21) translocation as the sole karyotypic anomaly. 5-RACE, RT-PCR, and sequencing showed the presence of an MEAF6-PHF1 chimera in the tumor with exon 5 of MEAF6 being fused in-frame to exon 2 of PHF1 so that the entire PHF1 coding region becomes the 3 terminal part of the MEAF6-PHF1 fusion. The predicted fusion protein is composed of 750 amino acids and contains the histone acetyltransferase subunit NuA4 domain of MEAF6 and the tudor, PHD zinc finger, and MTF2 domains of PHF1. Although the specific functions of the MEAF6 and PHF1 proteins and why they are targeted by a neoplasia-specific gene fusion are not directly apparent, it seems that rearrangement of genes involved in acetylation (EPC1, MEAF6) and methylation (PHF1), resulting in aberrant gene expression, is a common theme in ESS pathogenesis.
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