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Ronald Simon

Publications and source records attributed to Ronald Simon.

52 records · Page 3Linked to original sources
PubMed2004

Loss of SFRP1 is associated with breast cancer progression and poor prognosis in early stage tumors.

Aberrant activation of the Wnt signaling pathway plays an important role in the development of solid tumors such as breast and colon cancer. Secreted Frizzled-related protein 1 (SFRP1) is a negative regulator of the Wnt pathway. It has been described that SFRP1 mRNA is strongly down-regulated in breast cancer and a putative tumor suppressor function has been postulated. We have generated and characterized an SFRP1 specific antibody to analyze its expression on protein level and to investigate the association of SFRP1 expression with clinicopathological parameters and patient survival. Analysis of >2000 invasive breast tumors and 56 carcinoma in situ revealed similar frequencies of SFRP1 loss in these tumors (46% and 43% respectively). Therefore, we propose that loss of SFRP1 expression is an early event in breast tumorigenesis. SFRP1 expression was inversely correlated with tumor stage (p<0.001) but not with tumor grade (p=0.14) or lymph node status (p=0.84). Performing a multivariate analysis we could confirm the association between tumor stage and SFRP1 expression (p=0.029). In particular, loss of SFRP1 expression in early stage breast tumors (pT1) was associated with poor prognosis (p=0.04). In conclusion, expression of SFRP1 is commonly lost in breast cancer. SFRP1 expression might be useful as a novel prognostic marker in early stage breast cancer.

Biomarkers, Tumor↗
PubMed2004

HER2 analysis in breast cancer: reduced immunoreactivity in FISH non-informative cancer biopsies.

Due to the central role in predicting response to herceptin and possibly also other anticancer drugs, accurate and reproducible detection of the HER2 status is important. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) are the most commonly used methods for HER2 analysis. It is a disadvantage of FISH that a fraction of cases remain not interpretable probably due to suboptimal tissue handling before analysis. To investigate a possible influence of tissue damage on the results of HER2 IHC we compared the HER2 IHC results obtained in tumors with and without interpretable FISH in a breast cancer tissue microarray. The HER2 IHC results differed greatly between 1551 tumors with interpretable HER2 FISH signals and 405 breast cancers showing no FISH signals. FISH informative tumors had an IHC score of 3+ in 12.6%, 2+ in 3% and 1+ in 9.2% of cases. FISH non-informative tumors showed significantly lower IHC scores (p < 0.0001). They were IHC 3+ in 3.9%, 2+ in 3.7% and 1+ in 4.4% of cases. Overall, the data show that not only FISH but also IHC results are dependent on good tissue quality for successful analysis. Poor tissue quality can be easily identified in FISH analyses because of a lack of hybridization signals. Inappropriate tissue handling is more dangerous in IHC because an artificial lack of staining can be regarded as 'negative' result.

Adult↗
PubMed2003

HER-2 and TOP2A coamplification in urinary bladder cancer.

HER-2/NEU is one of the most frequently amplified oncogenes and a potential therapeutic target in bladder cancer. In breast cancer, the adjacent TOP2A gene, the molecular target for several anticancer drugs, is frequently coamplified together with HER-2. To study the amplification and expression of TOP2A and HER-2 and associations with tumor phenotype and clinical outcome in bladder cancer, a tissue microarray containing 2,317 bladder tumor samples was analyzed by FISH and immunohistochemistry. Overall amplification frequencies were 6.3% for HER-2 and 1.5% for TOP2A. Amplifications were most frequently seen in advanced-stage (pT2-4) tumors (HER-2 13.8%, TOP2A 3.4%). Of HER-2-amplified tumors, 56% also had alterations of TOP2A, including 14.7% coamplifications, 33.3% gains and 8% deletions. Only 17.6% of TOP2A amplifications occurred independently of HER-2 alterations. Both HER-2 and TOP2A amplifications were significantly associated with advanced tumor stage (HER-2 p < 0.0001, TOP2A p = 0.0218), high grade (p < 0.0001 for both) and protein overexpression (p < 0.0001 for both). TOP2A amplification and overexpression were linked to shortened survival in muscle-invasive tumors (p = 0.0042 and 0.0077, respectively). In summary, our data suggest that HER-2 amplifications are frequently linked to alterations of the TOP2A gene in bladder cancer. The anatomy of the 17q12-q21 amplicon may be important for response to therapies targeting HER-2 or TOP2A.

Antigens, Neoplasm↗
PubMed2003

Tissue microarray (TMA) applications: implications for molecular medicine.

Modern expression-screening platforms such as complementary DNA (cDNA) arrays allow for high-throughput lead discovery in cancer and other diseases. For evaluation of promising candidate genes, however, in situ analysis of high numbers of clinical tissues samples--for example, by immunohistochemistry or fluorescence in situ hybridisation--is mandatory. Tissue microarray (TMA) technology greatly facilitates such analysis. Minute tissue cores (diameter 0.6 mm) are removed from up to a thousand different conventional paraffin blocks and re-assembled in a single empty paraffin block at predefined positions. Sections of the resulting TMA can be utilised for the range of research applicable to conventional tissue sections. Important advantages of the TMA technology are speed (parallel analysis of up to a thousand tissues), cost efficiency (the same amount of reagents required for a single large-section analysis is sufficient for a thousand samples), and standardisation (the same experimental conditions are applied to all samples). Because of the high numbers of samples usually included in TMAs, they are optimally suited to detect genotype-phenotype associations with high statistical power. Thus, TMA technology will markedly accelerate the transition from basic research to clinical applications.

Automation↗
PubMed2003

Sequence analysis and high-throughput immunohistochemical profiling of KIT (CD 117) expression in uveal melanoma using tissue microarrays.

We aimed to immunohistochemically examine the expression of KIT (CD 117) in human posterior uveal melanoma and to analyze KIT-positive tumors for gene mutations. Brought into a tissue microarray (TMA) format were 101 formalin-fixed, paraffin-embedded posterior uveal melanomas. Immunohistochemistry was performed using the polyclonal anti-CD117 antibody from Dako (A4502). In ten selected KIT-positive tumors, exons 2, 8, 9, 11, 13 and 17 were sequenced. Of the 101 cases, 89 (88%) could be evaluated on the TMAs. Immunohistochemistry for CD 117 was weakly positive in 5 cases (6%), moderately positive in 10 cases (12%) and strongly positive in 57 cases (69%). No KIT mutations were detected in the analyzed exons. In conclusion, human posterior uveal melanoma frequently expresses CD117 at high levels. Although KIT mutations could not be found, it appears justified to investigate the utility of imatinib mesylate in the treatment of these patients.

Adult↗
PubMed2003

High-throughput tissue microarray analysis of 11q13 gene amplification (CCND1, FGF3, FGF4, EMS1) in urinary bladder cancer.

Gene amplification is a common mechanism for oncogene overexpression. High-level amplifications at 11q13 have been repeatedly found in bladder cancer by comparative genomic hybridization (CGH) and other techniques. Putative candidate oncogenes located in this region are CCND1 (PRAD1, bcl-1), EMS1, FGF3 (Int-2), and FGF4 (hst1, hstf1). To evaluate the involvement of these genes in bladder cancer, a tissue microarray (TMA) containing 2317 samples was screened by fluorescence in situ hybridization (FISH). The frequency of gains and amplifications of all genes increased significantly from stage pTa to pT1-4 and from low to high grade. In addition, amplification was associated with patient survival and progression of pT1 tumours. Among 123 tumours with amplifications, 68.3% showed amplification of all four genes; 19.5% amplification of CCND1, FGF4, and FGF3; and 0.8% co-amplification of FGF4, FGF3, and EMS1. Amplification of CCND1 alone was found in 9% of the tumours, while EMS1 alone was amplified in 1.6% and FGF4 in 0.8%. Overall, the amplification frequency decreased with increasing genomic distance from CCND1, suggesting that, among the genes examined, CCND1 is the major target gene in the 11q13 amplicon in bladder cancer.

Adenocarcinoma↗
PubMed2003

Tissue microarrays in cancer diagnosis.

New molecular techniques such as cDNA, protein or antibody arrays allow for high-throughput identification of thousands of potentially disease-related markers on the genome, transcriptome and proteome level. Major disadvantages of such studies are the enormous costs and the need for unfixed tissues, disallowing comprehensive large-scale studies. Consequently, validation studies including large sets of clinically well-defined tissue samples are now necessary to identify those genes or proteins with true impact on the course of disease which will eventually lead to therapeutic applications. Tissue microarray technology overcomes the bottleneck of traditional tissue analysis and allows it to catch up with the rapid advances in lead discovery. Current applications and the future potential of tissue microarray technology in cancer research and diagnosis are discussed.

Histocytological Preparation Techniques↗
PubMed2002

Prognostic relevance of MAGE-A4 tumor antigen expression in transitional cell carcinoma of the urinary bladder: a tissue microarray study.

TAAs of the MAGE family are mostly studied as targets of specific immune responses. Their potential relevance as tumor markers has also been underlined. We used a MAb, 57B, recognizing MAGE-A4 protein in paraffin-embedded sections, to evaluate its expression in bladder cancers by employing TMA including 2,317 samples from 1,849 patients. In 2,090/2,317 cases (90.2%), immunostaining yielded interpretable results. Since for some patients more than 1 sample was available, only interpretable first biopsies (n = 1,628) were considered. MAGE-A4 protein was expressed at significantly (p < 0.001) higher frequency in squamous (25/55, 45.5%) than in adeno (4/15, 26.7%), sarcomatoid (4/14, 28.6%), small cell (5/20, 25%) or transitional cell (281/1,522, 18.5%) carcinomas. In TCCs, overall MAGE-A4 positivity was significantly correlated with invasive phenotype (p < 0.001) and high tumor grade (p < 0.0001). Clinical data from 908 TCC patients were retrospectively evaluated, revealing that strong 57B staining was highly significantly associated with decreased tumor-specific survival (p < 0.0001). These data suggest that evaluation of MAGE-A4 protein expression is useful in the identification of groups of TCCs characterized by severe prognosis, thus possibly providing indications for early MAGE TAA-targeted immunotherapy.

Antibodies, Monoclonal↗
PubMed2002

Amplification pattern of 12q13-q15 genes (MDM2, CDK4, GLI) in urinary bladder cancer.

The chromosomal region 12q13-q15 is recurrently amplified in bladder cancer. Putative target genes located in this region include MDM2, CDK4, and GLI. To evaluate the involvement of these genes in bladder cancer, we screened a tissue microarray (TMA) containing 2317 samples by fluorescence in situ hybridization (FISH). Amplification was found for MDM2 in 5.1%, for CDK4 in 1.1%, and for GLI in 0.4% of interpretable tumors. Among tumors having amplification of at least one of these 12q13-q15 genes, 76.6% had amplification of MDM2 alone and 6.4% had amplification of CDK4 alone. Coamplifications were seen of MDM2 and CDK4 in 10.6%, and of CDK4 and GLI in 6.4%. Neither coamplifications of all three genes nor isolated GLI amplifications were found. These data suggest a prominent role of MDM2 as a 12q13-q15 amplification target in bladder cancer. However, independent CDK4 amplifications do also occur suggesting either two non-overlapping amplification sites or else a minimal overlapping region between MDM2 and CDK4 perhaps containing another yet unknown oncogene. The frequency of amplification increased significantly from stage pTa to pT1-4 (P<0.04) and from low to high grade (P<0.005). These data are consistent with a high level of genetic instability in invasively growing and high-grade bladder tumors.

Chromosomes, Human, Pair 12↗
PubMed2002

Analysis of the progression of fibroepithelial tumours of the breast by PCR-based clonality assay.

Fibroadenoma and phyllodes tumour of the breast are both fibroepithelial tumours. Although progression to epithelial malignancy has been described, the behaviour of most fibroadenomas is benign. Phyllodes tumours, on the other hand, can display locally destructive growth and can even metastasize. A relationship between the two tumours has been suggested in the literature. This study investigated the clonality of both the stroma and the epithelium of these fibroepithelial tumours and attempted to construct a model in which fibroadenoma can progress in both an epithelial and a stromal direction. Fibroadenomas (n=25) and phyllodes tumours (n=12) were selected for analysis. Tissue was microdissected and analysed for clonality using a polymerase chain reaction (PCR)-based assay targeted at an X-linked polymorphic marker, the human androgen receptor gene (HUMARA). Nineteen fibroadenomas and nine phyllodes tumours could be analysed. Normal-appearing epithelium, hyperplastic epithelium, and stroma removed from fibroadenomas were polyclonal. As expected, carcinoma in situ (CIS) removed from four fibroadenomas was monoclonal. Three areas of apparent stromal expansion within fibroadenoma were monoclonal, suggesting stromal progression. Mostly, the stroma of phyllodes tumours was monoclonal and the epithelium polyclonal. In two cases, however, the epithelium seemed to be monoclonal, whereas in three other cases the stromal component was polyclonal. These findings indicate that fibroadenoma can progress in an epithelial direction to CIS and in a stromal direction to phyllodes tumour.

Breast Neoplasms↗
PubMed2002

Patterns of chromosomal aberrations in urinary bladder tumours and adjacent urothelium.

Bladder cancer is often characterized by recurrent and multifocal growth, and tumours are frequently accompanied by precancerous alterations of the surrounding urothelium. These findings have led to the hypothesis that cells from areas of genetically aberrant but morphologically non-cancerous or even unremarkable mucosa may be the source of bladder carcinomas. Fluorescence in situ hybridization (FISH) was performed using ten probes targeting five different chromosomes that are known to be frequently altered in bladder cancer (centromere 1, 8, 9, 11, 17 and 1p36, 8p23, 9p21, 11q13, 17p13) on paraffin-embedded tissue sections of 11 superficial bladder cancers. Copy number changes of the tumours were compared to those in the urothelium adjacent to the tumour. Eleven of 11 (100%) tumours and eight of 11 (73%) samples of adjacent urothelium showed copy number changes of at least one chromosome. The occurrence of similar patterns of chromosomal aberrations in the tumours and their associated urothelium supports the hypothesis of a clonal relationship. It is concluded that FISH analysis targeting five different chromosomes is more sensitive than conventional histology for distinguishing between neoplastic and normal cells of the urothelium.

Carcinoma, Transitional Cell↗
PubMed2002

Food Allergy.

Although many emerging therapies demonstrate theoretical and practical promise, strict elimination of the allergenic food remains the only proven therapy for food hypersensitivity. Given such therapeutic limitations, accurate diagnosis and thorough patient education are critical for proper management. This is particularly important for individuals with anaphylactic potential, as food allergy is currently the single leading cause of anaphylaxis treated in hospital emergency departments.

Journal Article↗
PubMed2002

Tissue microarrays for miniaturized high-throughput molecular profiling of tumors.

New high-throughput screening technologies such as complementary (cDNA) microarrays allow identification of hundreds of candidate genes in one experiment. To prioritize the leads obtained in such studies, it is necessary to analyze a large number of tissues for candidate gene expression. Tissue microarray (TMA) technology greatly facilitates such analyses. In this method, hundreds of minute tissue samples (0.6-mm diameter) can be placed on one microscope glass slide. The TMA approach allows simultaneous analysis of all tissues with in situ methods (immunohistochemistry, fluorescence in situ hybridization, RNA in situ hybridization) of all tumors in one experiment under highly standardized conditions. TMAs are not restricted to solid tumors but can be manufactured from a variety of other sources, including cell lines, xenografts, and hematologic tissues. In addition to tumor type-specific applications that comprise large numbers of one particular tumor type with extensive histopathologic and clinical data, TMAs are well suited for large-scale molecular epidemiologic studies. For example, genes of interest can be analyzed in multitissue TMAs containing a variety of different human normal tissues and tumor entities. Once tumor types are identified, where a given molecular alteration plays a role, the clinical significance of this molecular alteration can be investigated on tumor-specific TMAs. Thus, TMA technology allows miniaturized high-throughput molecular epidemiologic studies. The TMA technique will markedly accelerate the transition from basic research to clinical applications.

Gene Expression Profiling↗
PubMedDate not supplied

Tissue microarrays for high-throughput molecular pathology.

Modern research technologies, including DNA, protein, and antibody microarrays identify a steadily growing number of clues that are useful in molecular disease classification, drug development, and the prediction of response to treatment. Subsequent validation of the clinical importance of such candidate genes or proteins requires large-scale analysis of human tissues. To date, this analysis constitutes an important bottleneck in the process of discovery because tissue analysis by the conventional slide-by-slide strategy is slow and expensive. To overcome these limitations, tissue microarray (TMA) technology has been developed. TMA allows for the simultaneous analysis of up to 1,000 tissue samples in a single experiment, using all types of in-situ analyses including immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and RNA in situ hybridization (RNA-ISH). TMA technology has the potential to greatly facilitate the translation of basic research into clinical practice. Potential applications include the establishment of associations between molecular changes and clinical endpoints, testing of potential therapeutic targets using tissue samples from specific cancer patients, standardization of molecular detection of targets, and rapid translation of results from cell lines and animal models to human cancer. Because of its beneficial economic aspects and ability to differentiate ethnic differences in tumor biology, TMA applications may become particularly important in developing countries.

Developing Countries↗