Stefan Joos

Publications of Stefan Joos

• Tissue microarray analysis of RANKL in cutaneous lupus erythematosus and psoriasis.

  Authors: Ferdinand Toberer, Jaromir Sykora, Daniel Göttel, Vincent Ruland, Wolfgang Hartschuh, Alexander Enk, Thomas A Luger, Stefan Beissert, Karin Loser, Stefan Joos, Peter H Krammer, Annegret Kuhn

  Experimental dermatology. 07/2011; 20(7):600-2.

  Recently, it was discovered that the receptor activator of nuclear factor κB (RANK)/RANK ligand (RANKL) is part of an important signal transduction pathway for tissue homoeostasis. Therefore, we wereRecently, it was discovered that the receptor activator of nuclear factor κB (RANK)/RANK ligand (RANKL) is part of an important signal transduction pathway for tissue homoeostasis. Therefore, we were interested in investigating RANKL expression in the epidermis of skin lesions from patients with different subtypes of cutaneous lupus erythematosus (CLE) and psoriasis as well as normal healthy donors. Using the tissue microarray technique, skin biopsy specimens were evaluated by immunohistochemistry. RANKL showed a significantly increased expression in the epidermis of skin biopsy specimens from patients with psoriasis (median: 4, range: 0-5) compared to patients with CLE (median: 0, range: 0-4) (P<0.001). No significant differences in epidermal RANKL expression between the CLE subtypes were detected. These data show a different expression of RANKL in the epidermis of skin lesions from patients with CLE compared to those with psoriasis suggesting that RANKL might play an important role in the pathogenesis of the disease.

• Comparative expressed sequence hybridization detects recurrent patterns of altered sequence expression in oral squamous cell carcinoma.

  Authors: Snjezana Janjetovic, Carsten Sticht, Karl Knoepfle, Stefan Joos, Christof Hofele, Peter Lichter, Kolja Freier

  Oncology reports. 08/2010; 24(2):369-74.

  Despite its common histology and presentation, oral squamous cell carcinoma (OSCC) is associated with widely varying clinical behaviour and response to therapy. To further elucidate the molecularDespite its common histology and presentation, oral squamous cell carcinoma (OSCC) is associated with widely varying clinical behaviour and response to therapy. To further elucidate the molecular basis of OSCC, an approach for gene expression analysis termed comparative expressed sequence hybridization (CESH) was used in the present study. This straightforward approach allows the rapid delineation of pathophysiologically interesting candidate chromosome regions by a direct detection of aberrant transcriptional activation. CESH profiling of OSCC specimens led to the identification of several novel chromosomal regions. Increased expression compared to a set of control mucosa specimens was found on 1q22-q23, 3q26.3-qter, 4q31.1-q32, 11q12-q13.2, 14q32, 18q12, 19q13.2-q13.3 and 22q13.1-q13.2. Decreased expression was found on 8p22-p23, 16p12 and 16q23-q24. Using CESH, common patterns of altered sequence expression in different OSCC samples were obtained. While some of these regions overlap with those known to be frequently altered in OSCC on the genomic level, this screen revealed novel chromosome subregions with increased transcriptional activity, which are probably independent of the genomic status of the tumor cells.

• 3D geometry-based quantification of colocalizations in multichannel 3D microscopy images of human soft tissue tumors.

  Authors: Stefan Wörz, Petra Sander, Martin Pfannmöller, Ralf J Rieker, Stefan Joos, Gunhild Mechtersheimer, Petra Boukamp, Peter Lichter, Karl Rohr

  IEEE transactions on medical imaging. 08/2010; 29(8):1474-84.

  We introduce a new model-based approach for automatic quantification of colocalizations in multichannel 3D microscopy images. The approach uses different 3D parametric intensity models in conjunctionWe introduce a new model-based approach for automatic quantification of colocalizations in multichannel 3D microscopy images. The approach uses different 3D parametric intensity models in conjunction with a model fitting scheme to localize and quantify subcellular structures with high accuracy. The central idea is to determine colocalizations between different channels based on the estimated geometry of the subcellular structures as well as to differentiate between different types of colocalizations. A statistical analysis was performed to assess the significance of the determined colocalizations. This approach was used to successfully analyze about 500 three-channel 3D microscopy images of human soft tissue tumors and controls.

• Genomic profiling reveals subsets of dedifferentiated liposarcoma to follow separate molecular pathways.

  Authors: Ralf J Rieker, Juergen Weitz, Burkhard Lehner, Gerlinde Egerer, Andrea Mueller, Bernd Kasper, Peter Schirmacher, Stefan Joos, Gunhild Mechtersheimer

  Virchows Archiv : an international journal of pathology. 03/2010; 456(3):277-85.

  With the aim to provide more insight into their biology, a series of 79 liposarcomas (LS) representative of all main subtypes was analysed for chromosomal imbalances using comparative genomicWith the aim to provide more insight into their biology, a series of 79 liposarcomas (LS) representative of all main subtypes was analysed for chromosomal imbalances using comparative genomic hybridization. Based on the genetic data, unsupervised hierarchical clustering unveiled two main LS clusters, each with two subclusters, one comprising three subsets. The first main cluster consisted of one larger subcluster, being characterised by gains/high-level amplifications of chromosomal subregions 12q13-q15, and exclusively included well-differentiated and dedifferentiated LS. A smaller subcluster was set apart on the basis of recurrent gains of 20q13 and 8q24, and mainly comprised pleomorphic and myxoid/round cell LS. The larger subcluster was subdivided into three subsets, one with nearly exclusive overrepresentations of 12q13-q15, the second with additional frequent gains of 1q21-q24, and the third with further recurrent overrepresentations of 6q22-q24, 20q13, and 12q24 and frequent losses of 13q14-q21 and 11q22-q23. While the first subset comprised both well-differentiated and dedifferentiated LS, the second and third subsets entirely included dedifferentiated LS. The second main cluster was characterised by recurrent overrepresentations of 5p13-p15, 1q21-q24, 1p12-p21, and 17p11.2-p12 and essentially comprised pleomorphic and myxoid/round cell LS. A separation of this second main cluster into two subclusters was based on additional gains on 22q13 and losses on 1q42-q43. Genomic profiling reveals genetically distinct subsets of dedifferentiated LS, which are clearly different from pleomorphic, myxoid/round cell, and, for some subsets, from well-differentiated LS. These data indicate that dedifferentiated LS follow separate tumourigenic pathways and that genetic analysis is important to unravel these differences.

• Epigenetic downregulation of mitogen-activated protein kinase phosphatase MKP-2 relieves its growth suppressive activity in glioma cells.

  Authors: Anke Waha, Jörg Felsberg, Wolfgang Hartmann, Anna von dem Knesebeck, Thomas Mikeska, Stefan Joos, Marietta Wolter, Arend Koch, Pearlly S Yan, Elmar Endl, Otmar D Wiestler, Guido Reifenberger, Torsten Pietsch, Andreas Waha

  Cancer research. 02/2010; 70(4):1689-99.

  Critical tumor suppression pathways in brain tumors have yet to be fully defined. Along with mutational analyses, genome-wide epigenetic investigations may reveal novel suppressor elements. UsingCritical tumor suppression pathways in brain tumors have yet to be fully defined. Along with mutational analyses, genome-wide epigenetic investigations may reveal novel suppressor elements. Using differential methylation hybridization, we identified a CpG-rich region of the promoter of the dual-specificity mitogen-activated protein kinase phosphatase-2 gene (DUSP4/MKP-2) that is hypermethylated in gliomas. In 83 astrocytic gliomas and 5 glioma cell lines examined, hypermethylation of the MKP-2 promoter was found to occur relatively more frequently in diffuse or anaplastic astrocytomas and secondary glioblastomas relative to primary glioblastomas. MKP-2 hypermethylation was associated with mutations in TP53 and IDH1, exclusive of EGFR amplification, and with prolonged survival of patients with primary glioblastoma. Expression analysis established that promoter hypermethylation correlated with reduced expression of MKP-2 mRNA and protein. Consistent with a regulatory role, reversing promoter hypermethylation by treating cells with 5-aza-2'-deoxycytidine increased MKP-2 mRNA levels. Furthermore, we found that glioblastoma cell growth was inhibited by overexpression of exogenous MKP-2. Our findings reveal MKP-2 as a common epigenetically silenced gene in glioma, the inactivation of which may play a significant role in glioma development.

• 3D Geometry-Based Quantification of Colocalizations in Multichannel 3D Microscopy Images of Human Soft Tissue Tumors.

  Authors: Stefan Wörz, Petra Sander, Martin Pfannmoller, Ralf J. Rieker, Stefan Joos, Gunhild Mechtersheimer, Petra Boukamp, Peter Lichter, Karl Rohr

  IEEE Trans. Med. Imaging. 01/2010; 29:1474-1484.

• Recurrent copy number gain of transcription factor SOX2 and corresponding high protein expression in oral squamous cell carcinoma.

  Authors: Kolja Freier, Karl Knoepfle, Christa Flechtenmacher, Susanne Pungs, Frauke Devens, Grischa Toedt, Christof Hofele, Stefan Joos, Peter Lichter, Bernhard Radlwimmer

  Genes, chromosomes & cancer. 09/2009;

  Gene copy number aberrations are involved in oral squamous cell carcinoma (OSCC) development. To delineate candidate genes inside critical chromosomal regions, array-CGH was applied to 40 OSCCGene copy number aberrations are involved in oral squamous cell carcinoma (OSCC) development. To delineate candidate genes inside critical chromosomal regions, array-CGH was applied to 40 OSCC specimens using a microarray covering the whole human genome with an average resolution of 1 Mb. Gene copy number gains were predominantly found at 1q23 (9 cases), 3q26 (11), 5p15 (13), 7p11 (7), 8q24 (17), 11q13 (15), 14q32 (8), 19p13 (8), 19q12 (7), 19q13 (8), and 20q13 (9), whereas gene copy number losses were detected at 3p21-3p12 (15), 8p32 (11), 10p12 (8), and 18q21-q23 (10). Subsequent mRNA expression analyses by quantitative real time polymerase chain reaction found high mRNA expression of candidate genes SOX2 in 3q26.33, FSLT3 in 19p13.3, and CCNE1 in 19q12. Tissue microarray (TMA) analyses in a representative OSCC collection found gene copy number gain for SOX2 in 52% (115/223) and for CCNE1 in 31% (72/233) of the tumors. Immunohistochemical analyses on TMA sections of the corresponding proteins detected high expression of SOX2 in 18.1% (49/271) and of CyclinE1 in 23.3% (64/275) of tumors analyzed. These findings indicate that SOX2 and CCNE1 might be activated via gene copy number gain and participate in oral carcinogenesis. The combination of array-CGH with TMA analyses allows rapid pinpointing of novel promising candidate genes, which might be used as therapeutic stratification markers or target molecules for therapeutic interference. (c) 2009 Wiley-Liss, Inc.

• Overexpression of the far upstream element binding protein 1 in hepatocellular carcinoma is required for tumor growth.

  Authors: Uta Rabenhorst, Rasa Beinoraviciute-Kellner, Marie-Luise Brezniceanu, Stefan Joos, Frauke Devens, Peter Lichter, Ralf J Rieker, Jörg Trojan, Hye-Jung Chung, David L Levens, Martin Zörnig

  Hepatology (Baltimore, Md.). 06/2009;

  We identified the far upstream element binding protein 1 (FBP1), an activator of transcription of the proto-oncogene c-myc, in a functional yeast survival screen for tumor-related antiapoptoticWe identified the far upstream element binding protein 1 (FBP1), an activator of transcription of the proto-oncogene c-myc, in a functional yeast survival screen for tumor-related antiapoptotic proteins and demonstrated strong overexpression of FBP1 in human hepatocellular carcinoma (HCC). Knockdown of the protein in HCC cells resulted in increased sensitivity to apoptotic stimuli, reduced cell proliferation, and impaired tumor formation in a mouse xenograft transplantation model. Interestingly, analysis of gene regulation in these cells revealed that c-myc levels were not influenced by FBP1 in HCC cells. Instead, we identified the cell cycle inhibitor p21 as a direct target gene repressed by FBP1, and in addition, expression levels of the proapoptotic genes tumor necrosis factor alpha, tumor necrosis factor-related apoptosis-inducing ligand, Noxa, and Bik were elevated in the absence of FBP1. Conclusion: Our data establish FBP1 as an important oncoprotein overexpressed in HCC that induces tumor propagation through direct or indirect repression of cell cycle inhibitors and proapoptotic target genes. (HEPATOLOGY 2009.).

• Outcome prediction in pediatric medulloblastoma based on DNA copy-number aberrations of chromosomes 6q and 17q and the MYC and MYCN loci.

  Authors: Stefan Pfister, Marc Remke, Axel Benner, Frank Mendrzyk, Grischa Toedt, Jörg Felsberg, Andrea Wittmann, Frauke Devens, Nicolas U Gerber, Stefan Joos, Andreas Kulozik, Guido Reifenberger, Stefan Rutkowski, Otmar D Wiestler, Bernhard Radlwimmer, Wolfram Scheurlen, Peter Lichter, Andrey Korshunov

  Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 05/2009; 27(10):1627-36.

  PURPOSE: Medulloblastoma is the most common malignant brain tumor in children. Current treatment decisions are based on clinical variables. Novel tumor-derived biomarkers may improve the riskPURPOSE: Medulloblastoma is the most common malignant brain tumor in children. Current treatment decisions are based on clinical variables. Novel tumor-derived biomarkers may improve the risk stratification of medulloblastoma patients. PATIENTS AND METHODS: A model for the molecular risk stratification was proposed from an array-based comparative genomic hybridization (array-CGH) screen (n = 80). Fluorescence in situ hybridization (FISH) analyses for chromosome arms 6q, 17p, and 17q and the MYC and MYCN loci were performed in an independent validation set (n = 260). Copy number aberrations were correlated with clinical, histologic, and survival data. RESULTS: Gain of 6q and 17q and genomic amplification of MYC or MYCN were each associated with poor outcome in the array-CGH study (n = 80). In contrast, all patients with 6q-deleted tumors survived. Given these findings, the following hierarchical molecular staging system was defined: (1) MYC/MYCN amplification, (2) 6q gain, (3) 17q gain, (4) 6q and 17q balanced, and (5) 6q deletion. The prognostic value of this staging system was investigated by FISH analysis (n = 260). The addition of molecular markers to clinical risk factors resulted in the identification of a large proportion of patients (72 of 260 patients; 30%) at high risk for relapse and death who would be considered standard risk by application of clinical variables alone. CONCLUSION: Genomic aberrations in medulloblastoma are powerful independent markers of disease progression and survival. By adding genomic markers to established clinical and histologic variables, outcome prediction can be substantially improved. Because the analyses can be conducted on routine paraffin-embedded material, it will be especially feasible to use this novel molecular staging system in large multicenter clinical trials.

• Troglitazone-mediated sensitization to TRAIL-induced apoptosis is regulated by proteasome-dependent degradation of FLIP and ERK1/2-dependent phosphorylation of BAD.

  Authors: Kerstin Grund, Rezvan Ahmadi, Fortunata Jung, Verena Funke, Georg Gdynia, Axel Benner, Jaromir Sykora, Henning Walczak, Stefan Joos, Jörg Felsberg, Guido Reifenberger, Otmar Wiestler, Christel Herold-Mende, Wilfried Roth

  Cancer biology & therapy. 01/2009; 7(12).

  Resistance to apoptosis is one reason for the poor response of malignant brain tumors to therapy. The PPARgamma-modulating drug Troglitazone downregulates the anti-apoptotic FLIP protein andResistance to apoptosis is one reason for the poor response of malignant brain tumors to therapy. The PPARgamma-modulating drug Troglitazone downregulates the anti-apoptotic FLIP protein and sensitizes glioblastoma cells to apoptosis induced by the death ligand TRAIL. To investigate the molecular basis of an experimental combination therapy for malignant gliomas with TRAIL and Troglitazone, we investigated the Troglitazone-induced signaling cascades and the expression of TRAIL receptors and FLIP in malignant gliomas. Troglitazone downregulated the FLIP protein through accelerated ubiquitin/proteasome-dependent degradation, which might be mediated by a Troglitazone-induced increase in reactive oxygen species. Moreover, Troglitazone induced the phosphorylation of the MAP kinase ERK1/2 as well as of the BAD protein. Inhibition of either PPARgamma or MEK1/2 blocked the Troglitazone-mediated phosphorylation of BAD and further increased the synergistic induction of glioma cell death by TRAIL and Troglitazone. Immunohistochemical analysis demonstrated that FLIP and TRAIL-R2 were significantly higher expressed in anaplastic (WHO grade III) than in diffuse (WHO grade II) gliomas. High FLIP and low TRAIL-R2 expression levels were associated with a poor prognosis of patients. Our findings warrant a further pre-clinical evaluation of an experimental anti-glioma therapy with TRAIL and Troglitazone, potentially in conjunction with a MAP kinase inhibitor.

• Activation of MAP kinase signaling through ERK5 but not ERK1 expression is associated with lymph node metastases in oral squamous cell carcinoma (OSCC).

  Authors: Carsten Sticht, Kolja Freier, Karl Knöpfle, Christa Flechtenmacher, Susanne Pungs, Christof Hofele, Meinhard Hahn, Stefan Joos, Peter Lichter

  Neoplasia (New York, N.Y.). 06/2008; 10(5):462-70.

  In an attempt to further elucidate the pathomechanisms in oral squamous cell carcinoma (OSCC), gene expression profiling was performed using a whole-transcriptome chip that contains 35,035In an attempt to further elucidate the pathomechanisms in oral squamous cell carcinoma (OSCC), gene expression profiling was performed using a whole-transcriptome chip that contains 35,035 gene-specific 70 mere oligonucleotides (Human OligoSet 4.0; Operon, Cologne, Germany) to a set of 35 primary OSCCs. Altogether, 7390 genes were found differentially expressed between OSCC tumor samples and oral mucosa. To characterize the major biologic processes in this tumor collection, MAPPFinder, a component of GenMAPP version 2.1, was applied to this data set to generate a statistically ranked list of molecular signaling pathways. Among others, cancer-related pathways, such as mitogen-activated protein (MAP) kinase signaling (z score = 4.6, P < .001), transforming growth factor-beta signaling (z score = 3.0, P = .015), and signaling pathways involved in apoptosis (z score = 2.1, P = .037), were found deregulated in the OSCC collection analyzed. Focusing on the MAP kinase signaling pathway, subsequent tissue microarray analyses by immunohistochemistry revealed an increase in protein expression of MAP kinase-related proteins ERK1 in 22.8% (48 of 209) and ERK5 in 27.4% (76 of 277), respectively. An association of high ERK5 but not of high ERK1 expression with advanced tumor stage and the presence of lymph node metastases was found (P = .008 and P = .016, respectively). Our analysis demonstrates the reliability of the combined approach of gene expression profiling, signaling pathway analyses, and tissue microarray analysis to detect novel distinct molecular aberrations in OSCC.

• BRAF gene duplication constitutes a mechanism of MAPK pathway activation in low-grade astrocytomas.

  Authors: Stefan Pfister, Wibke G Janzarik, Marc Remke, Aurélie Ernst, Wiebke Werft, Natalia Becker, Grischa Toedt, Andrea Wittmann, Christian Kratz, Heike Olbrich [......] Bernhard Radlwimmer, Andreas Kulozik, Torsten Pietsch, Christel Herold-Mende, Astrid Gnekow, Guido Reifenberger, Andrey Korshunov, Wolfram Scheurlen, Heymut Omran, Peter Lichter

  The Journal of clinical investigation. 06/2008; 118(5):1739-49.

  The molecular pathogenesis of pediatric astrocytomas is still poorly understood. To further understand the genetic abnormalities associated with these tumors, we performed a genome-wide analysis ofThe molecular pathogenesis of pediatric astrocytomas is still poorly understood. To further understand the genetic abnormalities associated with these tumors, we performed a genome-wide analysis of DNA copy number aberrations in pediatric low-grade astrocytomas by using array-based comparative genomic hybridization. Duplication of the BRAF protooncogene was the most frequent genomic aberration, and tumors with BRAF duplication showed significantly increased mRNA levels of BRAF and a downstream target, CCND1, as compared with tumors without duplication. Furthermore, denaturing HPLC showed that activating BRAF mutations were detected in some of the tumors without BRAF duplication. Similarly, a marked proportion of low-grade astrocytomas from adult patients also had BRAF duplication. Both the stable silencing of BRAF through shRNA lentiviral transduction and pharmacological inhibition of MEK1/2, the immediate downstream phosphorylation target of BRAF, blocked the proliferation and arrested the growth of cultured tumor cells derived from low-grade gliomas. Our findings implicate aberrant activation of the MAPK pathway due to gene duplication or mutation of BRAF as a molecular mechanism of pathogenesis in low-grade astrocytomas and suggest inhibition of the MAPK pathway as a potential treatment.

• Frequent high telomerase reverse transcriptase expression in primary oral squamous cell carcinoma.

  Authors: Kolja Freier, Susanne Pungs, Christa Flechtenmacher, Franz X Bosch, Peter Lichter, Stefan Joos, Christof Hofele

  Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology. 05/2007; 36(5):267-72.

  BACKGROUND: Gene copy number gain of chromosomal arm 5p is frequently found in oral squamous cell carcinoma (OSCC) suggesting the activation of proto-oncogenes. TERT is a candidate gene encoding forBACKGROUND: Gene copy number gain of chromosomal arm 5p is frequently found in oral squamous cell carcinoma (OSCC) suggesting the activation of proto-oncogenes. TERT is a candidate gene encoding for human telomerase reverse transcriptase (hTERT). The aim of the present study was to elucidate the relevance of TERT copy number gain and high hTERT expression in OSCC. METHODS: Fluorescence in situ hybridization (FISH) for TERT and immunohistochemistry (IHC) for hTERT were performed to analyze TERT copy numbers and hTERT expression, respectively, on tissue microarray (TMA) sections including n = 247 OSCC and n = 105 pharyngeal and laryngeal squamous cell carcinomas (PSCC/LSCC). RESULTS: Increased hTERT protein expression was more frequently found in OSCC (71.1%, 155/218) than in PSCC/LSCC (36.0%, 35/89) (P < 0.001). By contrast, specific TERT amplifications were less common in OSCC (2.1%, 4/191) compared with PSCC/LSCC (9.9%, 8/81) (P = 0.047). CONCLUSIONS: High hTERT expression is a frequent finding in OSCC. It might be a promising target for the development of specific anti-neoplastic therapy approaches.

• High survivin expression is associated with favorable outcome in advanced primary oral squamous cell carcinoma after radiation therapy.

  Authors: Kolja Freier, Susanne Pungs, Carsten Sticht, Christa Flechtenmacher, Peter Lichter, Stefan Joos, Christof Hofele

  International journal of cancer. Journal international du cancer. 02/2007; 120(4):942-6.

  Oral squamous cell carcinoma (OSCC) is a solid neoplasm exhibiting aggressive tumor phenotypes with unpredictable biological behavior. Recent studies suggested that high expression of theOral squamous cell carcinoma (OSCC) is a solid neoplasm exhibiting aggressive tumor phenotypes with unpredictable biological behavior. Recent studies suggested that high expression of the antiapoptotic protein survivin might be associated with adverse outcome in oral cancer patients. To investigate, whether increased copy numbers of the survivin-encoding gene BIRC5 results in elevated survivin levels and whether BIRC5 and survivin could serve as progression markers in the clinical course of OSCC, tumor tissue microarray analysis was performed applying fluorescence in situ hybridization and immunohistochemistry to 296 OSCC specimens. Gene copy number gain of BIRC5 was detected in 33.9% (150/227) of cases, which correlated significantly with high UICC stage and the presence of lymph node metastases (p = 0.003 and p = 0.001, respectively), but not with unfavorable patients' outcome (p > 0.05) in multivariate analysis. High survivin expression was found in 67.3% (169/251) of cases to predict increased 5- and 10-year overall survival of patients in a multivariate model including UICC stage and age as covariables (p = 0.035 and p = 0.026, respectively). Within a subgroup of patients, who received radiation therapy (n = 121), high survivin expression was found to be the only predictor of favorable 3-, 5- and 10-year overall survival in a multivariate cox regression analysis including UICC stage and age as covariables (p = 0.001, p = 0.004 and p = 0.006, respectively). In conclusion, high survivin expression might be useful to identify OSCC patients, who would benefit from radiotherapy.

• Recurrent FGFR1 amplification and high FGFR1 protein expression in oral squamous cell carcinoma (OSCC).

  Authors: Kolja Freier, Carsten Schwaenen, Carsten Sticht, Christa Flechtenmacher, Joachim Mühling, Christof Hofele, Bernhard Radlwimmer, Peter Lichter, Stefan Joos

  Oral oncology. 02/2007; 43(1):60-6.

  Chromosomal aberrations are known to have an impact on the initiation and progression of oral squamous cell carcinoma (OSCC), but individual genes involved in OSCC pathogenesis are poorly described.Chromosomal aberrations are known to have an impact on the initiation and progression of oral squamous cell carcinoma (OSCC), but individual genes involved in OSCC pathogenesis are poorly described. To elucidate the molecular events underlying oral carcinogenesis, a set of primary OSCC were screened for distinct genetic imbalances by means of array-based comparative genomic hybridisation. For this, a DNA array was used containing 812 genomic targets including oncogenes, tumour-suppressor genes and chromosomal regions frequently altered in human neoplasms. The most frequent aberrations were amplification of MYC, EGFR, CCND1 and PIK3CA, whereas deletions affected TRAILR1 and ATM. Furthermore, a distinct high-level amplification of the fibroblast growth factor receptor 1 (FGFR1) locus was detected in two cases. Detailed FISH analysis on OSCC tissue microarray sections revealed amplification prevalence for FGFR1 of 17.4% (16/92). Furthermore, FGFR1 protein analysis by immunohistochemistry on a TMA containing 178 OSCC found a high FGFR1 expression in tumours of early t-stadium and UICC stage (T1/2 vs. T3/4: p=0.002; SI-II vs. S III-IV: p=0.048). Our results indicate that an increase in FGFR1 expression contributes to oral carcinogenesis at an early stage of development.

• COX-2 upregulation in thymomas and thymic carcinomas.

  Authors: Ralf J Rieker, Stefan Joos, Gunhild Mechtersheimer, Hendrik Blaeker, Philipp A Schnabel, Alicia Morresi-Hauf, Erich Hecker, Michael Thomas, Hendrik Dienemann, Peter Schirmacher, Michael A Kern

  International journal of cancer. Journal international du cancer. 12/2006; 119(9):2063-70.

  The treatment of advanced stage thymomas and thymic carcinomas is a multimodal therapy. New therapeutic targets are currently under investigation, including the epidermal growth factor receptorThe treatment of advanced stage thymomas and thymic carcinomas is a multimodal therapy. New therapeutic targets are currently under investigation, including the epidermal growth factor receptor (EGFR) as well as KIT. A number of studies have shown protumorigenic potential of Cyclooxygenase-2 (COX-2) in a variety of human malignancies, but so far it is unknown whether COX-2 is expressed in primary malignancies of the thymus. Using tissue microarrays, the expression of COX-2, microsomal-PGES-1 and -PGES-2 (mPGES-1 and mPGES-2), as well as EGFR was evaluated in different subtypes of thymoma and thymic carcinomas. COX-2 was expressed in all subtypes as determined by immunohistochemistry. Some cases of type B2 and thymic carcinomas had COX-2 staining levels classified as mild to moderate. However, when measuring the optical color intensity, no significant differences could be detected. Concerning the expression levels, a weak correlation between the expression of COX-2, mPGES-1 and mPGES-2 as well as EGFR was found. Furthermore, additional cases of thymomas and thymic carcinomas were analyzed by COX-2 Western immunoblot analysis and were compared to normal thymi. The analysis showed that thymomas and thymic carcinomas had a significantly stronger COX-2 expression than that of the normal thymi (p < 0.04). In summary, COX-2 is expressed in all subtypes of thymomas and thymic carcinomas and thus represents, in addition to EGFR and KIT, a potential therapeutic target. Further studies are needed in order to determine whether a combined therapy using COX-2 inhibitors in addition to the evolving anti-EGFR antibody therapy may be considered as a treatment option.

• Frequent amplifications and abundant expression of TRIO, NKD2, and IRX2 in soft tissue sarcomas.

  Authors: Martyna Adamowicz, Bernhard Radlwimmer, Ralf J Rieker, Daniel Mertens, Matthias Schwarzbach, Peter Schraml, Axel Benner, Peter Lichter, Gunhild Mechtersheimer, Stefan Joos

  Genes, chromosomes & cancer. 10/2006; 45(9):829-38.

  Copy number gains and high-level amplifications of the short arm of chromosome 5 are frequently observed in soft tissue sarcomas. To identify genes from this region possibly involved in tumorCopy number gains and high-level amplifications of the short arm of chromosome 5 are frequently observed in soft tissue sarcomas. To identify genes from this region possibly involved in tumor progression, we analyzed 34 soft tissue sarcomas (10 pleomorphic and 8 dedifferentiated liposarcomas, 6 malignant fibrous histiocytomas, and 10 malignant peripheral nerve sheath tumors (MPNST)) using a DNA microarray including 418 BAC clones representing 99% of chromosome arm 5p. In seven tumors, distinct high-level amplifications were identified affecting four different subregions. From these regions, genes TERT, TRIO, SKP2, FBXO32, NKD2, SLC6A3, IRX2, POLS, FYB, PTGER4, and FGF10 were selected for detailed quantitative expression analysis (RQ-PCR) based on their potential tumorigenic function. Of these, TRIO, coding for a guanidine nucleotide exchange factor, was consistently overexpressed in all cases, while IRX2 and NKD2, both involved in the regulation of developmental processes via the WNT pathway, showed a characteristic expression only in MPNSTs. Detailed nonparametric multidimensional scaling analysis further showed that the expression of TRIO, IRX2, and NKD2 strongly correlated with the gene copy number. In conclusion, we found TRIO, IRX2, and NKD2 frequently affected by high-level amplifications as well as up-regulated in a gene-dosage dependent manner. Thus, these genes represent candidate targets of 5p amplifications in soft tissue sarcomas and might play a crucial role during the progression of this disease.

• Recurrent NMYC copy number gain and high protein expression in basal cell carcinoma.

  Authors: Kolja Freier, Christa Flechtenmacher, Frauke Devens, Wolfgang Hartschuh, Christof Hofele, Peter Lichter, Stefan Joos

  Oncology reports. 06/2006; 15(5):1141-5.

  Formation of basal cell carcinoma (BCC) has been linked to deregulation in the sonic hedgehogh (Shh) signalling pathway. Though mutations of the genes, PTCH1 and SMO, are known to be involved inFormation of basal cell carcinoma (BCC) has been linked to deregulation in the sonic hedgehogh (Shh) signalling pathway. Though mutations of the genes, PTCH1 and SMO, are known to be involved in aberrant Shh signalling, the distinct downstream effectors of these genes are poorly described. Studies have indicated that the NMYC oncogene is a potential Shh downstream effector. To assess the expression of Nmyc protein and gene copy numbers of the NMYC gene locus in a representative BCC tumour collection, immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH) were performed on 273 BCC specimens of different growth patterns and anatomic localisations on tissue microarray (TMA) sections. High Nmyc protein expression was detected in 72.7% (160/220) of all BCC specimens. Strong Nmyc immunopositivity was more frequently found in infiltrative BCCs compared to nodular/superficial BCCs (p=0.005), and in BCCs of the head compared to BCCs of other anatomic localisations (p=0.021). The prevalence of NMYC copy number gains was 17.5% (37/211), including three tumours with nodular differentiation that exhibited a distinct high-level amplification of the NMYC locus. These data indicate that high expression of the Shh downstream mediator, Nmyc, is a frequent event in BCC, predominantly in more aggressive subtypes. Although the NMYC copy number gain found in a subset of cases might contribute to this aberrant Nmyc protein expression by a gene dosage effect, our data suggests that Nmyc protein can also be induced by aberrant Shh signalling, acting as an effector molecule of the Shh pathway. Novel systemic anti-sense NMYC inhibition strategies could be a promising option for therapy-refractory BCC.

• Isochromosome breakpoints on 17p in medulloblastoma are flanked by different classes of DNA sequence repeats.

  Authors: Frank Mendrzyk, Andrey Korshunov, Grischa Toedt, Frank Schwarz, Bernhard Korn, Stefan Joos, Andreas Hochhaus, Claudia Schoch, Peter Lichter, Bernhard Radlwimmer

  Genes, chromosomes & cancer. 05/2006; 45(4):401-10.

  Medulloblastoma is a highly malignant embryonal tumor of the cerebellum that accounts for 20%-25% of all intracranial pediatric tumors. The most frequent chromosomal rearrangement in medulloblastomaMedulloblastoma is a highly malignant embryonal tumor of the cerebellum that accounts for 20%-25% of all intracranial pediatric tumors. The most frequent chromosomal rearrangement in medulloblastoma is isochromosome 17, or i(17q). Its frequency suggests that it serves an important role in tumor pathogenesis, possibly mediated by the disruption or permanent activation of a gene at the breakpoint. To address this question, we performed a detailed analysis of chromosome 17 DNA copy number from 18 medulloblastomas previously shown to carry an apparent i(17q). We identified two breakpoint regions, one well within band 17p11.2 (n = 16) and a second within the pericentromeric region (n = 2). To map the breakpoints more precisely, we constructed a tiling-path matrix-CGH array covering chromosomal band 17p11.2 to the centromere and utilized it to delineate two small breakpoint intervals mapping at Mb 19.0 and 21.7 in seven of the medulloblastomas and in nine hematological neoplasias with i(17q). The former interval contains two breakpoint clusters that each colocalize with a pair of head-to-head inverted DNA sequence repeats, and the latter maps close to a region of alpha-satellite repeats. No consensus coding sequence localizes in these regions. Together, these data strongly suggest that the effects of i(17q) in medulloblastoma are mediated by gene-dosage effects of genes on 17p or 17q rather than by the disruption or deregulation of a "breakpoint" gene. Furthermore, we identified artifacts introduced in DNA copy number data by cross-hybridization of low-copy repeat sequences and discuss the challenge these can pose in the interpretation of diagnostic microarrays.

• Recurrent coamplification of cytoskeleton-associated genes EMS1 and SHANK2 with CCND1 in oral squamous cell carcinoma.

  Authors: Kolja Freier, Carsten Sticht, Christof Hofele, Christa Flechtenmacher, Daniel Stange, Laura Puccio, Grischa Toedt, Bernhard Radlwimmer, Peter Lichter, Stefan Joos

  Genes, chromosomes & cancer. 03/2006; 45(2):118-25.

  Chromosomal band 11q13 is frequently amplified in oral squamous cell carcinoma (OSCC) and assumed to be critically involved in tumor initiation and progression by proto-oncogene activation. ThoughChromosomal band 11q13 is frequently amplified in oral squamous cell carcinoma (OSCC) and assumed to be critically involved in tumor initiation and progression by proto-oncogene activation. Though cyclin D1 (CCND1) is supposed to be the most relevant oncogene, several additional putative candidate genes are inside this chromosomal region, for which their actual role in tumorigenesis still needs to be elucidated. To characterize the 11q13 amplicon in detail, 40 OSCCs were analyzed by comparative genomic hybridization to DNA microarrays (matrix-CGH) containing BAC clones derived from chromosomal band 11q13. This high-resolution approach revealed a consistent amplicon about 1.7 Mb in size including the CCND1 oncogene. Seven BAC clones covering FGF3, EMS1, and SHANK2 were shown to be frequently coamplified inside the CCND1 amplicon. Subsequent analysis of tissue microarrays by FISH revealed amplification frequencies of 36.8% (88/239) for CCND1, 34.3% (60/175) for FGF3, 37.4% (68/182) for EMS1, and 36.3% (61/168) for SHANK2. Finally, quantitative mRNA expression analysis demonstrated consistent overexpression of CCND1 in all tumors and of EMS1 and SHANK2 in a subset of specimens with 11q13 amplification, but no expression of FGF3 in any of the cases. Our study underlines the critical role of CCND1 in OSCC development and additionally points to the functionally related genes EMS1 and SHANK2, both encoding for cytoskeleton-associated proteins, which are frequently coamplified with CCND1 and therefore could cooperatively contribute to OSCC pathogenesis.