Frank Wiesmann

University Hospital RWTH Aachen, Aachen, North Rhine-Westphalia, Germany

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Publications (13)50.59 Total impact

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    ABSTRACT: In the range of clinical decision points for response-guided therapy of HCV, there is still insufficient data concerning the conformity of quantification results obtained by different assays and their correlation with the HPS/CTM v2 assay which was used for initial clinical studies. In a head-to-head comparison, assay accuracy and detection rates of six quantitative assays [artus HCV QS-RGQ, COBAS Ampliprep/COBAS TaqMan HCV v1/v2, High Pure System/COBAS TaqMan (HPS), RealTime HCV, and Versant HCV1.0] were assessed by measuring WHO and PEI standards at dilution steps near clinical decision points. Detection rates and mean differences between assays were evaluated by analyzing twenty clinical samples at 10, 100, and 1,000 IU/mL. Ten replicates from specimens with different HCV genotypes were used to analyze pan-genotypic intra-assay variation. At ≤25 IU/mL, RealTime demonstrated the highest detection rates. With 0.1 log difference when testing clinical samples, results obtained from the Versant and RealTime assays matched best with results from HPS. Mean difference analysis across all assay results revealed wide differences between 0.01 and 0.75 log IU/mL. RealTime showed the lowest intra-assay variation across genotypes 1-4 (25, 100, 1,000 IU/mL). There are substantial analytical differences between viral load assays clinicians should be aware of. These variations may have impact on clinical decisions for patients on HCV triple therapy and may argue for assay-specific decision points equivalent to reference values established in studies using HPS. A comparison of quantification is recommended prior to a switch of assays during ongoing therapy.
    Medical microbiology and immunology. 11/2014;
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    ABSTRACT: Introduction: An association of persistent low level viremia (LLV) below 500 copies/mL and a higher risk of therapy failure is still point of controversial discussion. Furthermore, it seems that LLV occurs more frequently in patients with protease-inhibitor regimens than in NNRTI- / or integrase-inhibitor containing therapies. The focus of this work was to assess the prevalence of LLV (50-200 copies/mL) and weak viremia (201-500 copies/mL) in firstline-treated patients according to their therapy regimen. Methods: A total of 832 and 944 patients from 23 German centres were under firstline therapy in 2012 and 2013, respectively. All patients received their therapy for more than 24 weeks. VL data was related to clinical data retrospectively including ART-composition, subdivided into NNRTIs (Efavirenz, Nevirapine), PIs (Atazanavir, Darunavir, Lopinavir) and INIs (Raltegravir). Low viremic patients were classified into two arms of 50-200 copies/mL (group A) and 201-500 copies/mL (group B). Results: Success of therapy was defined as <50 copies/mL and was observed in 90.0% and 91.1% (2012/2013), respectively. An additional 2.0% and 2.3% had LLV. The amount of viremic patients with VLs <500 copies/mL differed significantly between NNRTI-based firstline regimens 1.7% and 2.5% and PI-based regimens 4.8% and 5.7% (2012/2013), respectively. LLV was clearly less often observed in EFV-based- (1.6% and 1.1% [group A] / 0.4% and 0.4% [group B]) or NVP-based firstline therapies (1.0% and 3.6% [group A] + 0% and 0% [group B]) than in ATV-based- (7.5% and 3.8% [group A] + 1.5% and 2.5% [group B]), DRV-based- (2.9% and 3.0% [group A] + 2.2% and 0% [group B]) or LPV-based firstline therapies (1.6% and 3.3% [group A] + 0.8% and 2.5% [group B]) and also in parts for RAL-based regimens (0% and 3.7% [group A] + 0% and 1.9% [group B]). Conclusions: LLV is more often observed under PI-based firstline than under NNRTI-regimens. Only one NNRTI-patient of group B remained on therapy. A possible explanation for this discrepancy might be the fact that physicians seem to tolerate LLV more often in PI-regimens than in NNRTI-regimens due to a higher genetic barrier against resistance and it remains a point of discussion if constant LLV does affect immune recovery and risk of therapy failure.
    Journal of the International AIDS Society 01/2014; 17(4(Suppl 3)):19828. · 3.94 Impact Factor
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    ABSTRACT: The goal of antiretroviral therapy is reduction in morbidity and mortality via suppression of human immunodeficiency virus (HIV) viral load (VL) to undetectable levels. VL assay sensitivity has improved over time, but the reproducibility and clinical importance of VL results marginally higher than the limit of detection (LoD) are uncertain. We assessed the reproducibility and concordance of low VL results obtained with the Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 version 2.0 (CAP-CTM) and the Abbott RealTime (m2000) HIV-1 assays, using longitudinal specimens from HIV-1-infected patients with low VL (<300 copies/ml) and stable CD4+ cell counts. Based on replicate testing of 3 specimens, coefficients of variation for log-transformed VL results were 5-8 % for m2000 and 9-10 % for CAP-CTM. The concordance between assays in specimens from patients with previously undetectable, detectable but not quantifiable VL, or variable (undetectable/detectable but not quantifiable VL) results over time was 90, 56, and 56 %, respectively. Correlation between results for specimens with quantifiable VL (initially 40-300 copies/ml) was moderate (R (2) = 0.48) with significantly higher results for CAP-CTM and a mean difference (CAP-CTM minus m2000) of 0.10 log(10) copies/ml. T-cell activation (CD8+/CD38+ percentage) in patients with low VL was initially higher than in patients with undetectable VL, and then decreased to equivalent levels over time. These results indicate that residual viremia at levels slightly above the LoD have no negative effect on T-cell activation.
    Medical Microbiology and Immunology 06/2012; · 3.55 Impact Factor
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    ABSTRACT: Although being considered as a rarely observed HIV-1 protease mutation in clinical isolates, the L76V-prevalence increased 1998-2008 in some European countries most likely due to the approval of Lopinavir, Amprenavir and Darunavir which can select L76V. Beside an enhancement of resistance, L76V is also discussed to confer hypersusceptibility to the drugs Atazanavir and Saquinavir which might enable new treatment strategies by trying to take advantage of particular mutations. Based on a cohort of 47 L76V-positive patients, we examined if there might exist a clinical advantage for L76V-positive patients concerning long-term success of PI-containing regimens in patients with limited therapy options.Genotypic- and phenotypic HIV-resistance tests from 47 mostly multi-resistant, L76V-positive patients throughout Germany were accomplished retrospectively 1999-2009. Five genotype-based drug-susceptibility predictions received from online interpretation-tools for Atazanavir, Saquinavir, Amprenavir and Lopinavir, were compared to phenotype-based predictions that were determined by using a recombinant virus assay along with a Virtual Phenotype™(Virco). The clinical outcome of the L76V-adapted follow-up therapy was determined by monitoring viral load for 96 weeks. In this analysis, the mostly used interpretation systems overestimated the L76V-mutation concerning Atazanavir- and SQV resistance. In fact, a clear benefit in drug susceptibility for these drugs was observed in phenotype analysis after establishment of L76V. More importantly, long-term therapy success was significantly higher in patients receiving Atazanavir and/or Saquinavir plus one L76V-selecting drug compared to patients without L76V-selecting agents (p = 0.002).In case of L76V-occurrence ATV and/or SQV may represent encouraging options for patients in deep salvage situations.
    AIDS Research and Therapy 02/2011; 8:7. · 2.54 Impact Factor
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    ABSTRACT: Y-box binding protein-1 (YB-1) is the prototypic member of the cold shock protein family that fulfills numerous cellular functions. In the nucleus YB-1 protein orchestrates transcription of proliferation-related genes, whereas in the cytoplasm it associates with mRNA and directs translation. In human tumor entities, such as breast, lung and prostate cancer, cellular YB-1 expression indicates poor clinical outcome, suggesting that YB-1 is an attractive marker to predict patients' prognosis and, potentially, is suitable to individualize treatment protocols. Given these predictive qualities of YB-1 detection we sought to establish a highly specific monoclonal antibody (Mab) for diagnostic testing and its characterization towards outcome prediction (relapse-free and overall survival). Hybridoma cell generation was carried out with recombinant YB-1 protein as immunogen and Mab characterization was performed using immunoblotting and ELISA with recombinant and tagged YB-1 proteins, as well as immunohistochemistry of healthy and breast cancer specimens. Breast tumor tissue array staining results were analyzed for correlations with receptor expression and outcome parameters. YB-1-specific Mab F-E2G5 associates with conformational binding epitopes mapping to two domains within the N-terminal half of the protein and detects nuclear YB-1 protein by immunohistochemistry in paraffin-embedded breast cancer tissues. Prognostic evaluation of Mab F-E2G5 was performed by immunohistochemistry of a human breast cancer tissue microarray comprising 179 invasive breast cancers, 8 ductal carcinoma in situ and 37 normal breast tissue samples. Nuclear YB-1 detection in human breast cancer cells was associated with poor overall survival (p = 0.0046). We observed a close correlation between nuclear YB-1 detection and absence of progesterone receptor expression (p = 0.002), indicating that nuclear YB-1 detection marks a specific subgroup of breast cancer. Likely due to limitation of sample size Cox regression models failed to demonstrate significance for nuclear YB-1 detection as independent prognostic marker. Monoclonal YB-1 antibody F-E2G5 should be of great value for prospective studies to validate YB-1 as a novel biomarker suitable to optimize breast cancer treatment.
    BMC Cancer 11/2009; 9:410. · 3.33 Impact Factor
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    ABSTRACT: Endothelin (EDN) signalling plays a crucial role in cell differentiation, proliferation and migration processes. There is compelling evidence that altered EDN signalling is involved in carcinogenesis by modulating cell survival and promoting invasiveness. To date, most reports have focused on the oncogenic potential of EDN1 and EDN2, both of which are overexpressed in various tumour entities. Here, we aimed at a first comprehensive analysis on EDN3 expression and its implication in human breast cancer. EDN3 mRNA expression was assessed by Northern blotting in normal human tissues (n = 9) as well as in matched pairs of normal and tumourous tissues from breast specimens (n = 50). EDN3 mRNA expression in breast cancer was further validated by real-time polymerase chain reaction (PCR) (n = 77). A tissue microarray was used to study EDN3 protein expression in breast carcinoma (n = 150) and normal breast epithelium (n = 44). EDN3 promoter methylation was analysed by methylation-specific PCR in breast cell lines (n = 6) before and after demethylating treatment, normal breast tissues (n = 17) and primary breast carcinomas (n = 128). EDN3 expression and methylation data were statistically correlated with clinical patient characteristics and patient outcome. Loss of EDN3 mRNA expression in breast cancer, as initially detected by array-based expression profiling, could be confirmed by Northern blot analysis (> 2-fold loss in 96%) and real-time PCR (> 2-fold loss in 78%). Attenuated EDN3 expression in breast carcinoma was also evident at the protein level (45%) in association with adverse patient outcome in univariate (P = 0.022) and multivariate (hazard ratio 2.0; P = 0.025) analyses. Hypermethylation of the EDN3 promoter could be identified as the predominant mechanism leading to gene silencing. Reversion of the epigenetic lock by 5-aza-2'-deoxycytidine and trichostatin A resulted in EDN3 mRNA re-expression in vitro. Furthermore, EDN3 promoter hypermethylation was detected in 70% of primary breast carcinomas with significant association to loss of EDN3 mRNA expression (P = 0.005), whilst normal matched breast tissues revealed no EDN3 promoter methylation. EDN3 is a frequent target of epigenetic inactivation in human breast cancer, potentially contributing to imbalanced EDN signalling commonly found in this disease. The clinical implication supports the view that EDN3, in contrast to EDN1 and EDN2, may act as natural tumour suppressor in the human mammary gland.
    Breast cancer research: BCR 07/2009; 11(3):R34. · 5.87 Impact Factor
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    ABSTRACT: EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1) was recently described as an antagonist of angiogenesis. Motivated by a strong dependence of tumor growth and metastasis on angiogenesis, we investigated the role of EFEMP1 in human breast cancer. We applied RNA microarray expression analysis and quantitative real-time PCR (QRT) in a total of 45 sporadic breast cancer tissues and found EFEMP1 down-regulation in 59% and 61% of the analyzed tissues, respectively. This down-regulation was confirmed on protein level. Immunohistochemistry in 211 breast cancer tissues resulted in reduced or even abolished EFEMP1 expression in 57-62.5% of the tumors. Bisulphite genomic sequencing in breast cancer cell lines and primary breast cancer tissues revealed promoter methylation as the major cause of this down-regulation. Furthermore, analysis of 203 clinically well characterized primary breast cancers displayed a significant correlation of reduced EFEMP1 protein expression with poor disease-free (p = 0.037) and overall survival (p = 0.032), particularly in those node-positive patients who received adjuvant anthracycline-based chemotherapy, but not in those treated by either cyclophosphamide-methotrexate-5-fluorouracil (CMF) or Tamoxifen. In summary, the presented data demonstrate for the first time the reduced EFEMP1 expression on RNA and protein level in a substantial number of sporadic breast carcinomas and its correlation with epigenetic alterations. Furthermore, these data point towards a possible predictive impact of EFEMP1 expression in primary breast cancer.
    International Journal of Cancer 11/2008; 124(7):1727-35. · 6.20 Impact Factor
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    Journal of the International AIDS Society 01/2008; 11. · 3.94 Impact Factor
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    Patrick Braun, Frank Wiesmann
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    ABSTRACT: Coreceptor tropism antagonists represent a new class of antiretrovirals for the treatment of HIV infection. The knowledge of patients' viral population tropism before the initiation of and during therapy with such compounds may be critical in order to optimize treatment strategies. In this review we focus on the characteristics of phenotypic assays for the determination of HIV coreceptor tropism. Beside traditional phenotypic assays, there are at least four phenotypic recombinant virus assays (RVA) available to predict coreceptor usage: Trofile (Monogram Biosciences), Phenoscript (VIRalliance), XtrackC/ PhenX-R (inPheno) and a platform developed by Virco. Trofile and Phenoscript represent single-cycle assays and are able to determine coreceptor tropism without cocultivation of HIV particles in cell culture. Trofile offers the most clinically validated data with currently about 25,000 analysed samples. The detection of minority variants is a limitation of all population-based assays and varies between 1 and 10%, depending on the assay used. XtrackC/PhenX-R and Virco's platform combine genotypic and phenotypic assays to analyze a patient's sample for tropism. Although all assays are validated for the assessment of coreceptor tropism in different HIV-1 subtypes, there is still a need for further evaluations. Furthermore, the establishment of cut-offs for X4 minority species will be difficult, and is affected by many factors like patient sample quality, the input volume, viral load, the detection limits and PCR variations. Overall, RVAs confirm efficiency and accuracy thus making them suitable for the clinical management of HIV infected individuals treated with coreceptor antagonists.
    European journal of medical research 11/2007; 12(9):463-72. · 1.10 Impact Factor
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    ABSTRACT: Oncogenic wingless-related mouse mammary tumour virus (Wnt) signalling, caused by epigenetic inactivation of specific pathway regulators like the putative tumour suppressor secreted frizzled-related protein 1 (SFRP1), may be causally involved in the carcinogenesis of many human solid tumours including breast, colon and kidney cancer. To evaluate the incidence of SFRP1 deficiency in human tumours, we performed a large-scale SFRP1 expression analysis using immunohistochemistry on a comprehensive tissue microarray (TMA) comprising 3448 tumours from 36 organs. This TMA contained 132 different tumour subtypes as well as 26 different normal tissues. Although tumour precursor stages of, for example kidney, colon, endometrium or adrenal gland still exhibited moderate to abundant SFRP1 expression, this expression was frequently lost in the corresponding genuine tumours. We defined nine novel tumour entities with apparent loss of SFRP1 expression, i.e., cancers of the kidney, stomach, small intestine, pancreas, parathyroid, adrenal gland, gall bladder, endometrium and testis. Renal cell carcinoma (RCC) exhibited the highest frequency of SFRP1 loss (89% on mRNA level; 75% on protein level) and was selected for further analysis to investigate the cause of SFRP1 loss in human tumours. We performed expression, mutation and methylation analysis in RCC and their matching normal kidney tissues. SFRP1 promoter methylation was frequently found in RCC (68%, n=38) and was correlated with loss of SFRP1 mRNA expression (p<0.05). Although loss of heterozygosity was found in 16% of RCC, structural mutations in the coding or promoter region of the SFRP1 gene were not observed. Our results indicate that loss of SFRP1 expression is a very common event in human cancer, arguing for a fundamental role of aberrant Wnt signalling in the development of solid tumours. In RCC, promoter hypermethylation seems to be the predominant mechanism of SFRP1 gene silencing and may contribute to initiation and progression of this disease.
    Oncogene 08/2007; 26(38):5680-91. · 8.56 Impact Factor
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    ABSTRACT: Quantification of viral load (VL) is standard for monitoring HIV-1 therapy and is crucial before deciding whether to switch or to continue a current antiretroviral regimen. We compared the performance of the four most widely used commercial viral-load assays, COBAS Amplicor Monitor v1.5, Versant HIV-1 RNA 3.0, Abbott RealTime HIV-1 and Cobas AmpliPrep/Cobas TaqMan HIV-1 (CAP/CTM), in terms of intra- and inter-assay variability, as well as hands-on-time, specificity and ability to quantify group M subtypes. Although linearity and correlation were confirmed for the assays and comparable sensitivity and specificity were verified for genetically diverse HIV-1 subtypes, demonstrating suitability for monitoring of HIV group M isolates, the viral loads obtained showed variations, with a mean difference of 0.1-0.4 log, depending on the system used. Although sensitivity and precision were confirmed for all the systems, differences between them should be taken into account when viral load monitoring of the same person is performed using different systems.
    Clinical Chemistry and Laboratory Medicine 02/2007; 45(1):93-9. · 3.01 Impact Factor
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    ABSTRACT: The canonical Wnt signalling pathway plays a key role during embryogenesis and defects in this pathway have been implicated in the pathogenesis of various types of tumours, including breast cancer. The gene for secreted frizzled-related protein 1 (SFRP1) encodes a soluble Wnt antagonist and is located in a chromosomal region (8p22-p12) that is often deleted in breast cancer. In colon, lung, bladder and ovarian cancer SFRP1 expression is frequently inactivated by promoter methylation. We have previously shown that loss of SFRP1 protein expression is a common event in breast tumours that is associated with poor overall survival in patients with early breast cancer. To investigate the cause of SFRP1 loss in breast cancer, we performed mutation, methylation and expression analysis in human primary breast tumours and breast cell lines. No SFRP1 gene mutations were detected. However, promoter methylation of SFRP1 was frequently observed in both primary breast cancer (61%, n=130) and cell lines analysed by methylation-specific polymerase chain reaction (MSP). We found a tight correlation (P<0.001) between methylation and loss of SFRP1 expression in primary breast cancer tissue. SFRP1 expression was restored after treatment of tumour cell lines with the demethylating agent 5-aza-2'-deoxycytidine. Most interestingly, SFRP1 promoter methylation was an independent factor for adverse patient survival in Kaplan-Meier analysis. Our results indicate that promoter hypermethylation is the predominant mechanism of SFRP1 gene silencing in human breast cancer and that SFRP1 gene inactivation in breast cancer is associated with unfavourable prognosis.
    Oncogene 06/2006; 25(24):3479-88. · 8.56 Impact Factor
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    ABSTRACT: The WNT signalling pathway plays a central role during embryonic development of multi-cellular organisms, especially for the temporal and spatial specification of organs (e.g. WNT4 in kidney development), a process called pattern formation. Interestingly, genes of the WNT pathway are deregulated in a variety of solid tumours, being considerably up- or down-regulated compared to their expression in the corresponding normal tissue. Some members like WNT1 have demonstrated oncogenic properties in animal models. The SFRP1 gene on chromosome 8 p12 is a negative regulator of the WNT pathway. SFRP1 protein is supposed to bind WNT1 molecules thereby inhibiting the activation of frizzled receptors and the WNT pathway. Characterising an SFRP1-specific antibody we could show that loss of SFRP1 is an extremely common event in breast cancer, i.e. SFRP1 was considerably down-regulated in 73% (n = 1967) of analysed invasive breast cancers. SFRP1 loss is associated with unfavourable prognosis in early breast cancer (pT1 tumours). To analyse the cause of SFRP1 inactivation in breast cancer we performed a parallel expression and promoter methylation analysis in human breast cancer and tumour cell lines. RT-PCR techniques and methylation-specific PCR (MSP) were applied. All tumorigenic cell lines analysed exhibited complete promoter methylation and did not express detectable amounts of SFRP1 mRNA. SFRP1 expression could be restored in these cell lines after treatment with 5-Aza-2'-deoxycytidine, a demethylating agent. Human primary breast cancer was methylated in nearly 75% of cases. Our results indicate that epigenetic inactivation by methylation is the predominant mechanism of SFRP1 gene silencing in breast cancer.
    Verhandlungen der Deutschen Gesellschaft für Pathologie 02/2005; 89:169-77.