German Cancer Consortium (DKTK) - A national consortium for translational cancer research.

The German Cancer Consortium ('Deutsches Konsortium für Translationale Krebsforschung', DKTK) is a long-term cancer consortium, bringing together the German Cancer Research Center (DKFZ), Germany's largest life science research center, and the leading University Medical Center-based Comprehensive Cancer Centers (CCCs) at seven sites across Germany. DKTK was founded in 2012 following international peer review and has positioned itself since then as the leading network for translational cancer research in Germany. DKTK is long term funded by the German Ministry of Research and Education and the federal states of each DKTK partner site. DKTK acts at the interface between basic and clinical cancer research, one major focus being to generate suitable multisite cooperation structures and provide the basis for including higher numbers of patients and facilitate effective collaborative forward and reverse translational cancer research. The consortium addresses areas of high scientific and medical relevance and develops critical infrastructures, for example, for omics technologies, clinical and research big data exchange and analysis, imaging, and clinical grade drug manufacturing. Moreover, DKTK provides a very attractive environment for interdisciplinary and interinstitutional training and career development for clinician and medical scientists.

FAM96A is a novel pro-apoptotic tumor suppressor in gastrointestinal stromal tumors.

The ability to escape apoptosis is a hallmark of cancer-initiating cells and a key factor of resistance to oncolytic therapy. Here, we identify FAM96A as a ubiquitous, evolutionarily conserved apoptosome-activating protein and investigate its potential pro-apoptotic tumor suppressor function in gastrointestinal stromal tumors (GISTs). Interaction between FAM96A and apoptotic peptidase activating factor 1 (APAF1) was identified in yeast two-hybrid screen and further studied by deletion mutants, glutathione-S-transferase pull-down, co-immunoprecipitation and immunofluorescence. Effects of FAM96A overexpression and knock-down on apoptosis sensitivity were examined in cancer cells and zebrafish embryos. Expression of FAM96A in GISTs and histogenetically related cells including interstitial cells of Cajal (ICCs), "fibroblast-like cells" (FLCs) and ICC stem cells (ICC-SCs) was investigated by Northern blotting, reverse transcription-polymerase chain reaction, immunohistochemistry and Western immunoblotting. Tumorigenicity of GIST cells and transformed murine ICC-SCs stably transduced to re-express FAM96A was studied by xeno- and allografting into immunocompromised mice. FAM96A was found to bind APAF1 and to enhance the induction of mitochondrial apoptosis. FAM96A protein or mRNA was dramatically reduced or lost in 106 of 108 GIST samples representing three independent patient cohorts. Whereas ICCs, ICC-SCs and FLCs, the presumed normal counterparts of GIST, were found to robustly express FAM96A protein and mRNA, FAM96A expression was much reduced in tumorigenic ICC-SCs. Re-expression of FAM96A in GIST cells and transformed ICC-SCs increased apoptosis sensitivity and diminished tumorigenicity. Our data suggest FAM96A is a novel pro-apoptotic tumor suppressor that is lost during GIST tumorigenesis.

Apoptotic signal molecules in skin biopsies of cutaneous lupus erythematosus: analysis using tissue microarray.

Cutaneous lupus erythematosus (CLE) is a heterogeneous autoimmune disease. Different pathogenetic mechanisms, including the accumulation of apoptotic keratinocytes in CLE, have been reported. Therefore, we investigated whether CLE and other inflammatory skin diseases differ with regard to the epidermal expression of molecules that are crucial for the initiation and regulation of apoptosis. In this study, 241 skin biopsies from patients with CLE, psoriasis (PSO), lichen planus (LP) and healthy controls (HCs) were analysed immunohistochemically using the tissue microarray (TMA) technique. The TUNEL assay and anti-activated caspase-3 antibodies revealed a significant increase of apoptotic keratinocytes in CLE lesions compared with HCs. Furthermore, we detected a significant increase in the epidermal expression of CD95 in CLE specimens compared with PSO, LP and HCs. These data suggest that the accumulation of apoptotic keratinocytes in CLE might be due to the increased epidermal expression of CD95, resulting in increased activity of the extrinsic apoptotic pathway in the disease.

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

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 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.

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 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.

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 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.

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

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. 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.

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

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 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.

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

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 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.

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

UNLABELLED: 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 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.

Gene deregulation and spatial genome reorganization near breakpoints prior to formation of translocations in anaplastic large cell lymphoma.

Although the identification and characterization of translocations have rapidly increased, little is known about the mechanisms of how translocations occur in vivo. We used anaplastic large cell lymphoma (ALCL) with and without the characteristic t(2;5)(p23;q35) translocation to study the mechanisms of formation of translocations and of ALCL transformation. We report deregulation of several genes located near the ALCL translocation breakpoint, regardless of whether the tumor contains the t(2;5). The affected genes include the oncogenic transcription factor Fra2 (located on 2p23), the HLH protein Id2 (2p25), and the oncogenic tyrosine kinase CSF1-receptor (5q33.1). Their up-regulation promotes cell survival and repression of T cell-specific gene expression programs that are characteristic for ALCL. The deregulated genes are in spatial proximity within the nuclear space of t(2;5)-negative ALCL cells, facilitating their translocation on induction of double-strand breaks. These data suggest that deregulation of breakpoint-proximal genes occurs before the formation of translocations, and that aberrant transcriptional activity of genomic regions is linked to their propensity to undergo chromosomal translocations. Also, our data demonstrate that deregulation of breakpoint-proximal genes has a key role in ALCL.

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

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 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.

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

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 35,035 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.

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 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.

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

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 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.

Cytogenetic and molecular genetic analyses of giant cell glioblastoma multiforme reveal distinct profiles in giant cell and non-giant cell subpopulations.

We have comparatively analyzed mechanisms associated with chromosomal and microsatellite instability in giant cell glioblastoma multiforme (gcGBM) and classic GBM. This included microsatellite instability (MSI), loss of expression of four major mismatch repair (MMR) proteins, aberrations of five chromosomes, EGFR copy number, and TP53 mutations. MSI was more frequent among gcGBM (30 vs. 7.8%, P = 0.054). TP53 mutations were more commonly observed in gcGBM (83.3%), whereas EGFR was amplified in just one gcGBM (8.3%). By tumor cell phenotype-specific cytogenetic analysis of gcGBM, increased chromosome copy numbers were identified in 72-84% of giant cells but in only 4-14% of nongiant cells; in classic GBM, intermediate frequencies were noted (11-49%). Chromosome 10 deletions were found in nongiant cells of all gcGBM cases but in only approximately 45% of the cell population in classic GBM. The present study shows a distinct pattern of cytogenetic alterations in nongiant and giant cell phenotypes in gcGBM and suggests that multinuclear giant cells evolve from nongiant tumor cells at an early tumor stage. Furthermore, the data point to differences in the profile of chromosomal and microsatellite instability in gcGBM and classic GBM that might underscore the distinct pathological features of both tumor subtypes.

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

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 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.

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

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.

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

Oral 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.

COX-2 upregulation in thymomas and thymic carcinomas.

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 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.