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  • 1
    Keywords: SUSCEPTIBILITY ; ABSORPTION ; SINGLE-NUCLEOTIDE POLYMORPHISMS ; GUT ; INDIVIDUAL-DIFFERENCES ; 6-N-PROPYLTHIOURACIL ; ALPHA-GUSTDUCIN ; BITTER TASTE RECEPTORS ; PERCEPTION ; RAT SMALL-INTESTINE
    Abstract: Molecular sensing in the lingual mucosa and in the gastro-intestinal tract play a role in the detection of ingested harmful drugs and toxins. Therefore, genetic polymorphisms affecting the capability of initiating these responses may be critical for the subsequent efficiency of avoiding and/or eliminating possible threats to the organism. By using a tagging approach in the region of Taste Receptor 2R38 (TAS2R38) gene, we investigated all the common genetic variation of this gene region in relation to colorectal cancer risk with a case-control study in a German population (709 controls and 602 cases) and in a Czech population (623 controls and 601 cases). We found that there were no significant associations between individual SNPs of the TAS2R38 gene and colorectal cancer in the Czech or in the German population, nor in the joint analysis. However, when we analyzed the diplotypes and the phenotypes we found that the non-taster group had an increased risk of colorectal cancer in comparison to the taster group. This association was borderline significant in the Czech population, (OR = 1.28, 95% CI 0.99-1.67; P-value = 0.058) and statistically significant in the German population (OR = 1.36, 95% CI 1.06-1.75; P-value = 0.016) and in the joint analysis (OR = 1.34, 95% CI 1.12-1.61; P-value = 0.001). In conclusion, we found a suggestive association between the human bitter tasting phenotype and the risk of CRC in two different populations of Caucasian origin
    Type of Publication: Journal article published
    PubMed ID: 21674048
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  • 2
    Keywords: DIAGNOSIS ; IDENTIFICATION ; immunohistochemistry ; microsatellite instability ; CARRIERS ; NONPOLYPOSIS COLORECTAL-CANCER ; HNPCC ; MLH1 ; MSH2 ; REVISED BETHESDA GUIDELINES
    Abstract: Carriers of mismatch repair (MMR) gene mutations have a high lifetime risk for colorectal and endometrial cancers, as well as other malignancies. As mutation analysis to detect these patients is expensive and time-consuming, clinical criteria and tumor-tissue analysis are widely used as pre-screening methods. The aim of our study was to evaluate the performance of commonly applied clinical criteria (the Amsterdam I and II Criteria, and the original and revised Bethesda Guidelines) and the results of tumor-tissue analysis in predicting MMR gene mutations. We analyzed 3,671 families from the German HNPCC Registry and divided them into nine mutually exclusive groups with different clinical criteria. A total of 680 families (18.5%) were found to have a pathogenic MMR gene mutation. Among all 1,284 families with microsatellite instability-high (MSI-H) colorectal cancer, the overall mutation detection rate was 53.0%. Mutation frequencies and their distribution between the four MMR genes differed significantly between clinical groups (p 〈 0.001). The highest frequencies were found in families fulfilling the Amsterdam Criteria (46.4%). Families with loss of MSH2 expression had higher mutation detection rates (69.5%) than families with loss of MLH1 expression (43.1%). MMR mutations were found significantly more often in families with at least one MSI-H small-bowel cancer (p 〈 0.001). No MMR mutations were found among patients under 40-years-old with only colorectal adenoma. Familial clustering of Lynch syndrome-related tumors, early age of onset, and familial occurrence of small-bowel cancer were clinically relevant predictors for Lynch syndrome.
    Type of Publication: Journal article published
    PubMed ID: 24493211
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  • 3
    Keywords: GENE ; immunohistochemistry ; FUSION ; INSIGHTS ; pleura ; NAB2
    Abstract: Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms, displaying variable morphological and clinicopathological features. Supportive immunohistochemical markers such as CD34, CD99, BCL2 and LSD1 are commonly applied in the differential diagnosis of SFTs, although none is sufficiently sensitive or specific enough. The aim of the present study was to examine the most differential markers for the reliable distinction of SFTs from histological mimics. We investigated the expression of STAT6, NAB2, ALDH1, GRIA2 and IGF2 in 454 comprehensive soft tissue tumors, comprising formalin-fixed paraffin-embedded (FFPE) tissue samples from 80 SFTs and 374 other mesenchymal tumors. The Duolink in situ proximity ligation assay (PLA) was adopted for the detection of NAB2-STAT6 fusion proteins. STAT6 was expressed in all 80 SFT cases with a moderate-strong nuclear staining intensity. In contrast, only 4/374 (1%) non-SFT mesenchymal tumors showed a nuclear STAT6 staining pattern. Strong expression of NAB2 and IGF2 was detected in SFT and non-SFT cases. Positive GRIA2 immunoreactivity was found in 64% (SFT) and 8% (non-SFT), respectively. Expression of ALDH1 was moderate-strong in 76% (SFT), whereas only 2 non-SFT lesions showed positive ALDH1 immunoreactivity. Moreover, the presence of NAB2STAT6 fusion proteins was indicated in 71/78 (91%) SFT cases by PLA. Nuclear STAT6 and cytoplasmic ALDH1 expression are the most sensitive and specific markers in the differential diagnosis of SFTs. Furthermore, application of Duolink in situ proximity ligation assay can be helpful to detect the NAB2-STAT6 fusion protein in the majority of SFTs.
    Type of Publication: Journal article published
    PubMed ID: 25901508
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  • 4
    Keywords: GENE ; neuroblastoma ; ENHANCERS ; LANDSCAPE ; TERT REARRANGEMENTS
    Abstract: Neuroblastoma is a malignant paediatric tumour of the sympathetic nervous system. Roughly half of these tumours regress spontaneously or are cured by limited therapy. By contrast, high-risk neuroblastomas have an unfavourable clinical course despite intensive multimodal treatment, and their molecular basis has remained largely elusive. Here we have performed whole-genome sequencing of 56 neuroblastomas (high-risk, n = 39; low-risk, n = 17) and discovered recurrent genomic rearrangements affecting a chromosomal region at 5p15.33 proximal of the telomerase reverse transcriptase gene (TERT). These rearrangements occurred only in high-risk neuroblastomas (12/39, 31%) in a mutually exclusive fashion with MYCN amplifications and ATRX mutations, which are known genetic events in this tumour type. In an extended case series (n = 217), TERT rearrangements defined a subgroup of high-risk tumours with particularly poor outcome. Despite a large structural diversity of these rearrangements, they all induced massive transcriptional upregulation of TERT. In the remaining high-risk tumours, TERT expression was also elevated in MYCN-amplified tumours, whereas alternative lengthening of telomeres was present in neuroblastomas without TERT or MYCN alterations, suggesting that telomere lengthening represents a central mechanism defining this subtype. The 5p15.33 rearrangements juxtapose the TERT coding sequence to strong enhancer elements, resulting in massive chromatin remodelling and DNA methylation of the affected region. Supporting a functional role of TERT, neuroblastoma cell lines bearing rearrangements or amplified MYCN exhibited both upregulated TERT expression and enzymatic telomerase activity. In summary, our findings show that remodelling of the genomic context abrogates transcriptional silencing of TERT in high-risk neuroblastoma and places telomerase activation in the centre of transformation in a large fraction of these tumours.
    Type of Publication: Journal article published
    PubMed ID: 26466568
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  • 5
    Abstract: Purpose: Programmed death ligand-1 (PD-L1), encoded by the CD274 gene, is a target for immune checkpoint blockade; however, little is known about genomic CD274 alterations. A subset of small-cell lung cancer (SCLC) exhibits increased copy number of chromosome 9p24, on which CD274 resides; however, most SCLCs show low expression of PD-L1. We therefore examined whether CD274 is a target of recurrent genomic alterations.Experimental Design: We examined somatic copy number alterations in two patient cohorts by quantitative real-time PCR in 72 human SCLC cases (cohort 1) and SNP array analysis in 138 human SCLC cases (cohort 2). Whole-genome sequencing revealed the detailed genomic structure underlying focal amplification. PD-L1 expression in amplified cases from cohorts 1 and 2 was further examined by transcriptome sequencing and immunohistochemical (IHC) staining.Results: By examining somatic copy number alterations in two cohorts of primary human SCLC specimens, we observed 9p24 copy number gains (where CD274 resides) and focal, high-level amplification of CD274 We found evidence for genomic targeting of CD274, suggesting selection during oncogenic transformation. CD274 amplification was caused by genomic rearrangements not affecting the open reading frame, thus leading to massively increased CD274 transcripts and high level expression of PD-L1.Conclusions: A subset (4/210, 1.9%) of human SCLC patient cases exhibits massive expression of PD-L1 caused by focal amplification of CD274 Such tumors may be particularly susceptible to immune checkpoint blockade. Clin Cancer Res; 23(5); 1220-6. (c)2016 AACR.
    Type of Publication: Journal article published
    PubMed ID: 27620277
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  • 6
    Keywords: CANCER ; EXPRESSION ; tumor ; carcinoma ; Germany ; human ; GENE ; GENES ; TUMORS ; PATIENT ; DNA ; prognosis ; ANTIGEN ; ANTIGENS ; DOWN-REGULATION ; FREQUENCY ; FREQUENCIES ; NO ; STAGE ; PROGRESSION ; MUTATION ; REPAIR ; METASTASIS ; colorectal cancer ; COLORECTAL-CANCER ; metastases ; LINE ; DISPLAY ; INSTABILITY ; microsatellite instability ; MUTATIONS ; BETA ; antigen presentation ; MHC CLASS-I ; PHENOTYPE ; CARCINOMAS ; HLA ; PREVALENCE ; germline mutations ; HIGH-LEVEL ; ONCOLOGY ; INFILTRATION ; DEFECTS ; development ; LEVEL ; USA ; LOSSES ; CANCERS ; DEFECT ; colorectal ; CLASS-I EXPRESSION ; colorectal adenoma ; COLORECTAL TUMORS ; hereditary norpolyposis colorectal cancer ; immune selection ; tumor immune evasion
    Abstract: Defects of DNA mismatch repair (MMR) cause the high level microsatellite instability (MSI-H) phenotype. MSI-H cancers may develop either sporadically or in the context of the hereditary non-polyposis colorectal cancer (HNPCC) syndrome that is caused by germline mutations of MMR genes. In colorectal cancer (CRC), MSI-H is characterized by a dense lymphocytic infiltration, reflecting a high immunogenicity of these cancers. As a consequence of immunoselection, MSI-H CRCs frequently display a loss of human leukocyte antigen (HLA) class I antigen presentation caused by mutations of the beta 2-microglobulin (beta 2m) gene. To examine the implications of beta 2m mutations during MSI-H colorectal tumor development, we analyzed the prevalence of beta 2m mutations in MSI-H colorectal adenomas (n = 38) and carcinomas (n = 104) of different stages. Mutations were observed in 6/38 (15.8%) MSI-H adenomas and 29/104 (27.9%) MSI-H CRCs. A higher frequency of beta 2m mutations was observed in MSI-H CRC patients with germline mutations of MMR genes MLH1 or MSH2 (36.4%) compared with patients without germline mutations (15.4%). The high frequency of beta 2m mutations in HNPCC-associated MSI-H CRCs is in line with the hypothesis that immunoselection may be particularly pronounced in HNPCC patients with inherited predisposition to develop MSI-H cancers. beta 2m mutations were positively related to stage in tumors without distant metastases (UICC I-III), suggesting that loss of beta 2m expression may promote local progression of colorectal MSI-H tumors. However, no beta 2m mutations were observed in metastasized CRCs (UICC stage IV, p = 0.04). These results suggest that functional beta 2m may be necessary for distant metastasis formation in CRC patients. (C) 2007 Wiley-Liss, Inc
    Type of Publication: Journal article published
    PubMed ID: 17373663
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  • 7
    Keywords: RECEPTOR ; CANCER ; POPULATION ; RISK ; ASSOCIATION ; POLYMORPHISMS ; OBESITY ; COLON-CANCER ; FOOD-INTAKE ; insulin ; PHYSICAL-ACTIVITY ; metabolic syndrome ; WOMEN UNITED-STATES ; DES-ACYL GHRELIN ; VISCERAL FAT ACCUMULATION
    Abstract: Background: Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor (GHSR), has two major functions: the stimulation of the growth hormone production and the stimulation of food intake. Accumulating evidence also indicates a role of ghrelin in cancer development. Methods: We conducted a case-control study to examine the association of common genetic variants in the genes coding for ghrelin (GHRL) and its receptor (GHSR) with colorectal cancer risk. Pairwise tagging was used to select the 11 polymorphisms included in the study. The selected polymorphisms were genotyped in 680 cases and 593 controls from the Czech Republic. Results: We found two SNPs associated with lower risk of colorectal cancer, namely SNPs rs27647 and rs35683. We replicated the two hits, in additional 569 cases and 726 controls from Germany. Conclusion: A joint analysis of the two populations indicated that the T allele of rs27647 SNP exerted a protective borderline effect (P-trend = 0.004)
    Type of Publication: Journal article published
    PubMed ID: 20920174
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  • 8
    Abstract: BACKGROUND: High-grade soft tissue sarcomas are a heterogeneous, complex group of aggressive malignant tumors showing mesenchymal differentiation. Recently, soft tissue sarcomas have increasingly been classified on the basis of underlying genetic alterations; however, the role of aberrant DNA methylation in these tumors is not well understood and, consequently, the usefulness of methylation-based classification is unclear. RESULTS: We used the Infinium HumanMethylation27 platform to profile DNA methylation in 80 primary, untreated high-grade soft tissue sarcomas, representing eight relevant subtypes, two non-neoplastic fat samples and 14 representative sarcoma cell lines. The primary samples were partitioned into seven stable clusters. A classification algorithm identified 216 CpG sites, mapping to 246 genes, showing different degrees of DNA methylation between these seven groups. The differences between the clusters were best represented by a set of eight CpG sites located in the genes SPEG, NNAT, FBLN2, PYROXD2, ZNF217, COL14A1, DMRT2 and CDKN2A. By integrating DNA methylation and mRNA expression data, we identified 27 genes showing negative and three genes showing positive correlation. Compared with non-neoplastic fat, NNAT showed DNA hypomethylation and inverse gene expression in myxoid liposarcomas, and DNA hypermethylation and inverse gene expression in dedifferentiated and pleomorphic liposarcomas. Recovery of NNAT in a hypermethylated myxoid liposarcoma cell line decreased cell migration and viability. CONCLUSIONS: Our analysis represents the first comprehensive integration of DNA methylation and transcriptional data in primary high-grade soft tissue sarcomas. We propose novel biomarkers and genes relevant for pathogenesis, including NNAT as a potential tumor suppressor in myxoid liposarcomas.
    Type of Publication: Journal article published
    PubMed ID: 24345474
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  • 9
    Abstract: BACKGROUND: The reliable identification of non-small cell lung cancers (NSCLC) with chromosomal breaks in the gene of the anaplastic lymphoma kinase (ALK) is crucial for the induction of therapy with ALK-inhibitors. In order to ensure a reliable detection of ALK-breaks by means of fluorescence in situ hybridization (FISH) testing, round robin tests are essential. In preparation of a nation (German)-wide round robin test we initiated a pre-testing phase involving 8 experts in FISH-diagnostics to identify NSCLC cases (n = 10) with a pre-tested ALK-status. In addition, ALK immunohistochemistry (IHC) was performed to assess ALK protein expression. MATERIAL AND METHODS: Sections derived from a tissue microarray, each consisting of 3 cores from 10 NSCLC cases, were independently tested for ALK protein expression by IHC and genomic ALK-breaks by FISH involving 8 institutes of pathology. Based on a pre-screening, 5 cases were identified to be clearly ALK-break negative, whereas the remaining 5 cases were ALK-break positive including one case with low percentage (20%) of positive cells. The latter had been additionally tested by RT-PCR. RESULTS: The 5 unequivocal ALK-break negative NSCLC were almost consistently scored negative by means of FISH and IHC by all 8 experts. Interestingly, 4 of the 5 cases with pre-defined ALK-breaks revealed homogenous FISH results whereas IHC for the detection of ALK protein expression showed heterogeneous results. The remaining case (low number of ALK-break positive cells) was scored negative by 3 experts and positive by the other 5. RT-PCR revealed the expression of an EML4-ALK fusion gene variant 1. CONCLUSION: ALK-break negative NSCLC cases revealed concordant homogeneous results by means of FISH and IHC (score 0-1) by all 8 experts. Discordant FISH results were raised in one ALK-break positive case with a low number of affected tumor cells. The remaining 4 ALK-break positive cases revealed concordant FISH data whereas the ALK-IHC revealed very diverse results. The cases with concordant FISH results provide an excellent basis for round robin ALK-FISH testing. As long as standardized ALK-IHC protocols are missing, ALK protein expression cannot by regarded as the method of choice for identification of patients eligible for treatment with ALK inhibitors.
    Type of Publication: Journal article published
    PubMed ID: 23669200
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  • 10
    Keywords: MODEL ; CELL-CYCLE ; REVEALS ; DNA-DAMAGE RESPONSE
    Abstract: KRAS is one of the most frequently mutated oncogenes in human cancer. Despite substantial efforts, no clinically applicable strategy has yet been developed to effectively treat KRAS-mutant tumors. Here, we perform a cell-line-based screen and identify strong synergistic interactions between cell-cycle checkpoint-abrogating Chk1- and MK2 inhibitors, specifically in KRAS- and BRAF-driven cells. Mechanistically, we show that KRAS-mutant cancer displays intrinsic genotoxic stress, leading to tonic Chk1- and MK2 activity. We demonstrate that simultaneous Chk1- and MK2 inhibition leads to mitotic catastrophe in KRAS-mutant cells. This actionable synergistic interaction is validated using xenograft models, as well as distinct Kras- or Braf-driven autochthonous murine cancer models. Lastly, we show that combined checkpoint inhibition induces apoptotic cell death in KRAS- or BRAF-mutant tumor cells directly isolated from patients. These results strongly recommend simultaneous Chk1- and MK2 inhibition as a therapeutic strategy for the treatment of KRAS- or BRAF-driven cancers.
    Type of Publication: Journal article published
    PubMed ID: 26140595
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