Biomedical subjects

Martina Mirlacher

Publications and source records attributed to Martina Mirlacher.

16 recordsLinked to original sources

PubMed2005

Expression patterns of potential therapeutic targets in prostate cancer.

Androgen withdrawal is the only effective therapy for patients with advanced prostate cancer, but progression to androgen independence ultimately occurs in almost all patients. Novel therapeutic strategies targeting molecular mechanisms that mediate resistance to hormonal and chemotherapeutic treatment are highly warranted. Here, we aimed to evaluate the expression of potential therapeutic targets in advanced prostate cancer. A tissue microarray (TMA) containing samples from 535 tissue blocks was constructed, including benign prostatic hyperplasia as controls (n = 65), prostatic intraepithelial neoplasia (PIN; n = 78), clinically localized prostate cancers (n = 181), as well as hormone-refractory local recurrences (n = 120) and distant metastases (n = 91). The expression of 13 different proteins was analyzed using immunohistochemistry (Bcl-2, p53, ILK, Syndecan-1, MUC-1, EGFR, HER2/neu, HSP-90, Ep-CAM, MMP-2, CD-10, CD-117 and Ki67). Significant overexpression in hormone-refractory prostate cancer and metastatic tissue compared to localized prostate cancer was found for Ki67 (64% vs. 9%), Bcl-2 (11% vs. 1%), p53 (35% vs. 4%), Syndecan-1 (38% vs. 3%), EGFR (16% vs. 1%) and HER2/neu (16% vs. 0%). Overexpression of CD-117 was restricted to 1 single metastasis. All other markers did not show relevant differences in expression between subgroups. Taken together, p53, Bcl-2, Syndecan-1, EGFR and HER2/neu are preferentially expressed in hormone-refractory and metastatic prostate cancer. Selected inhibition of these targets might offer a strategy to treat advanced tumors and prevent further progression. Treatment decisions should not be based on findings in primary tumors but rather on tissues from recurrent or metastatic lesions.

Adenocarcinoma↗

PubMed2004

Arterial neovascularization and inflammation in vulnerable patients: early and late signs of symptomatic atherosclerosis.

BACKGROUND: Atherosclerosis is complicated by cardiovascular events such as myocardial infarction, stroke, or peripheral arterial occlusive disease. Inflammation and pathological neovascularization are thought to precipitate plaque rupture or erosion, both causes of arterial thrombosis and cardiovascular events. We tested the hypothesis that arterial inflammation and angiogenic events are increased throughout the arterial tree in vulnerable patients, ie, in patients who suffered from cardiovascular events, compared with patients who never suffered from complications of atherosclerosis. METHODS AND RESULTS: In a postmortem study, we quantified the inflammatory infiltrate and microvascular network in the arterial wall of iliac, carotid, and renal arteries. Tissue microarray technology was adapted to investigate full-thickness arterial sectors. We compared 22 patients with symptomatic atherosclerosis with 27 patients who never had suffered from any cardiovascular event. The absolute intimal macrophage content was 2- to 4-fold higher in vulnerable patients at all 3 arterial sites analyzed (P<0.05). Patients with symptomatic atherosclerosis had a denser network of vasa vasorum than patients with asymptomatic disease (33+/-2 versus 25+/-2 adventitial microvessels per 1 mm2; P=0.008). Hyperplasia of vasa vasorum was an early and macrophage infiltration was a late sign of symptomatic atherosclerosis. CONCLUSIONS: High intimal macrophage content and a hyperplastic network of vasa vasorum characterize vulnerable patients suffering from symptomatic atherosclerosis. These changes are uniformly present in different arterial beds and support the concept of symptomatic atherosclerosis as a panarterial disease.

Aged↗

PubMed2004

Impaired expression of the cell cycle regulator BTG2 is common in clear cell renal cell carcinoma.

The prognosis of patients with renal cell carcinoma (RCC) is poor. A full understanding of the molecular genetics and signaling pathways involved in renal cancer development and in the metastatic process is of central importance for developing innovative and novel treatment options. In this study, BD Atlas Human Cancer 1.2 cDNA microarrays were used to identify genes involved in renal tumorigenesis. By analyzing gene expression patterns of four clear cell RCC (cRCC) cell lines and normal renal tissue, 25 genes were found differentially expressed. To determine the relevance of these genes, RNA in situ hybridization was performed on a tissue microarray generated from 61 snap-frozen primary renal cell carcinomas and 12 normal renal cortex biopsies. B-cell translocation gene 2 (BTG2), a negative cell cycle regulator, which was expressed in normal renal tissue but down-regulated in cRCC cell lines and primary cRCCs, was selected for additional experiments. Quantitative BTG2 mRNA expression analysis in 42 primary cRCCs and 18 normal renal cortex biopsies revealed up to 44-fold reduced expression in the tumor tissues. Decrease of BTG2 expression was not associated with tumor stage, grade, and survival. Cell culture experiments demonstrated that BTG2 expression was weakly inducible by the phorbolester 12-O-tetradecanoylphorbol-13-acetate in one of four cRCC cell lines. In contrast, increasing cell density led to elevated BTG2 mRNA expression in three of four cRCC cell lines. In both experiments, BTG2 mRNA levels did not reach values observed in normal renal tissue. These data suggest that down-regulation of BTG2 is an important step in renal cancer development.

Adenocarcinoma, Clear Cell↗

PubMed2004

KIT (CD117)-positive breast cancers are infrequent and lack KIT gene mutations.

PURPOSE: KIT (CD117) is a transmembrane tyrosine kinase representing a target for STI571 (Glivec) therapy. Some KIT-overexpressing solid tumors have responded favorably to STI571, potentially because of the presence of KIT-activating mutations. EXPERIMENTAL DESIGN: To investigate the epidemiology of KIT overexpression and mutations, we investigated a series of 1654 breast cancers. All tumors were analyzed by immunohistochemistry in a tissue microarray format. RESULTS: KIT expression was always present in normal breast epithelium. However, cancer analysis revealed the only 43 of 1654 (2.6%) tumors were KIT-positive. KIT expression was more frequent in medullary cancer (9 of 47 positive; 19.1%) than in any other histological tumor subtype (P < 0.001). KIT expression was significantly associated with high tumor grade (P < 0.0001) but unrelated to pT and pN categories or patient survival. Mutation analysis of exons 2, 8, 9, 11, 13, and 17 was negative in 10 KIT-positive tumors. CONCLUSIONS: Overall, our data show that a high level of KIT expression occurs infrequently in breast cancer. KIT-positive breast cancers may not reflect "KIT up-regulation" because KIT is also expressed in normal breast epithelium. The lack of KIT mutations also argues against the therapeutic efficacy of STI571 in breast cancer.

Adult↗

PubMed2004

Frequent EpCam protein expression in human carcinomas.

Expression of the transmembrane glycoprotein EpCam (epithelial cellular adhesion molecule) occurs in normal epithelium of different organs and was described in carcinomas of various sites. Specific anti-EpCam therapies are now being used in clinical trials. Thus, it is of interest to know which tumor types express or overexpress this protein, and in what frequency. We therefore analyzed EpCam expression by immunohistochemistry on a tissue microarray containing 3900 tissue samples of 134 different histological tumor types and subtypes. EpCam expression was detected in 98 of 131 tumor categories. At least a weak EpCam expression in >10% of tumors was observed in 87 of 131 different tumor categories. Adenocarcinomas of the colon (81%) and pancreas (78%), as well as hormone-refractory adenocarcinomas of the prostate (71%), were identified as particularly promising therapy targets with a high fraction of strongly positive tumors. Most soft-tissue tumors and all lymphomas were EpCam negative. It is concluded that anti-EpCam therapies, if proven to be successful, will have broad applications in a wide variety of carcinomas.

Adenocarcinoma↗

PubMed2004

TRIO amplification and abundant mRNA expression is associated with invasive tumor growth and rapid tumor cell proliferation in urinary bladder cancer.

Studies by comparative genome hybridization have suggested that 5p amplification is related to tumor progression in urinary bladder cancer. In this study seven genes (TAS2R, ADCY2, DNAH5, CTNND2, TRIO, ANKH, and MYO10) located to 5p15.31-5p15.1 were analyzed by fluorescence in situ hybridization using a tissue microarray containing samples from tumors and cell lines with known 5p amplification by comparative genome hybridization. Amplification frequency was highest for TRIO, which maps to 5p15.2 and encodes a protein with a putative role in cell-cycle regulation. To further investigate the role of TRIO amplification in bladder cancer, a tissue microarray containing samples from 2317 bladder tumors was used for fluorescence in situ hybridization analysis. TRIO amplification was strongly associated with invasive tumor phenotype, high tumor grade, and rapid tumor cell proliferation (Ki67 LI) (P < 0.0001 each). Only 7 of 456 pTaG1/G2 tumors (1.5%) but 62 of 485 pT1-4 carcinomas (12.8%) had TRIO amplification. TRIO amplification was not associated with poor prognosis. Using a frozen bladder tumor tissue microarray RNA in situ hybridization confirmed that TRIO is up-regulated in amplified tumors. It is concluded that TRIO up-regulation through amplification has a potential role in bladder cancer progression.

Carcinoma↗

PubMed2004

The homeobox intestinal differentiation factor CDX2 is selectively expressed in gastrointestinal adenocarcinomas.

CDX2 is a homeobox domain-containing transcription factor that is important in the development and differentiation of the intestines. Based on recent studies, CDX2 expression is immunohistochemically detectable in normal colonic enterocytes and is retained in most, but not all, colorectal adenocarcinomas. CDX2 expression has also been documented in a subset of adenocarcinomas arising in the stomach, esophagus and ovary. In this study, we examined CDX2 expression in a series of large tissue microarrays representing 4652 samples of normal and neoplastic tissues. Strong nuclear staining for CDX2 was observed in 97.9% of 140 colonic adenomas, 85.7% of 1109 colonic adenocarcinomas overall and 81.8% of 55 mucinous variants. There was no significant difference in the staining of well-differentiated (96%) and moderately differentiated tumors (90.8%, P=0.18), but poorly differentiated tumors showed reduced overall expression (56.0%, P<0.000001). Correspondingly, there was an inverse correlation between CDX2 expression and tumor stage, with a significant decrease in staining between pT2 and pT3 tumors (95.8 vs 89.0%, P<0.012), and between pT3 and pT4 tumors (89.0 vs 79.8%, P<0.016). Analysis of 140 locally advanced, CDX2-positive colorectal adenocarcinomas coarrayed with their matching lymph node metastases revealed that expression of this marker was retained in 82.1% of the metastases. Consistent with previous reports, CDX2 staining was observed in gastric adenocarcinomas (n=71), more commonly in the intestinal-type than the diffuse-type (28.9 vs 11.5%, P<0.05). Occasional ovarian carcinomas were positive for CDX2, including mucinous (10.5%), endometrioid (9.3%) and serous variants (2%), but expression was either very rare or absent in primary carcinomas of the lung, breast, thyroid, pancreas, liver, gallbladder, kidney, endometrium and urinary bladder. A low frequency of CDX2 expression in pancreatic and biliary carcinomas observed on the microarrays was pursued further by comparing these tumors with ampullary adenocarcinomas on conventional sections. Ampullary adenocarcinomas were more commonly positive for CDX2 (19/24, 79%) than cholangiocarcinomas (1/11, 9%) and pancreatic carcinomas (3/20, 15%). In summary, CDX2 is a sensitive and specific marker for colorectal adenocarcinoma, although its expression is decreased among higher grade and stage tumors, and it is not invariably present in metastases from positive primaries. CDX2 may also be helpful in distinguishing adenocarcinomas of the ampulla from those arising in the pancreas and biliary tree.

Adenocarcinoma↗

PubMed2004

Influence of slide aging on results of translational research studies using immunohistochemistry.

Several reports have shown that a long delay between cutting sections and immunohistochemical (IHC) staining can decrease the IHC reaction intensity. However, systematic large-scale studies to investigate to what extent this problem may influence the outcome of translational research studies are lacking. In this study, we used a tissue microarray (TMA) approach to investigate the influence of slide age on comparisons between the results of IHC analyses for estrogen receptor (ER), progesterone receptor (PR), cyclin D1, HER2 (HercepTest), and E-cadherin and clinical outcome in a series of 522 breast cancer patients. Old TMA sections stored for 6 months at 4 degrees C and freshly cut sections were analyzed under exactly identical experimental conditions. As compared to results obtained on freshly cut sections, the frequency of positivity on old sections decreased from 65 to 46% for ER (P<0.0001), from 33 to 18.5% for PR (P<0.0001), from 16.3 to 9.6% for HER2 (P=0.0047), from 45.1 to 37.7% for cyclin D1 (P=0.10), and from 58.9 to 32.9% for E-cadherin (P<0.0001). Despite the lower fraction of positive cases, most associations between IHC data and tumor phenotype that were observed in fresh section analysis were also found when old section data were analyzed. The results confirm that slide aging has a great influence on the intensity of IHC staining in individual cases, but they also suggest that many clinicopathological associations can be detected if suboptimally processed sections are used for IHC.

Biomarkers, Tumor↗

PubMed2004

Hepatocyte paraffin 1 expression in human normal and neoplastic tissues: tissue microarray analysis on 3,940 tissue samples.

Hepatocyte paraffin 1 (Hep Par 1) is a monoclonal antibody developed from hepatic tissue from a failed liver allograft. Several studies have shown that Hep Par 1 is a useful marker to differentiate hepatocellular carcinoma (HCC) from other types of adenocarcinoma metastatic to the liver. The aim of our study was the systematic investigation of the epidemiology of Hep Par 1 expression in 3,940 tissue samples using the tissue microarray technique. Strong Hep Par 1 expression was found most frequently in 35 (73%) of 48 HCCs. In nonhepatic tumors, strong Hep Par 1 expression was detected in adenocarcinoma of the lung (2/50), gallbladder (3/31), pancreas (2/48), stomach (3/74), small intestine (1/11), adenoma of the colon with high-grade dysplasia (1/49), adrenal gland carcinoma (1/6), paraganglioma (1/9), and malignant melanoma (2/48). Our data suggest that Hep Par 1 is a highly specific marker for HCC, although several nonhepatic tumors occasionally can show some Hep Par 1 positivity.

Adenocarcinoma↗

PubMed2004

Tissue microarrays.

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Gene Expression Profiling↗

PubMed2004

Tissue microarrays.

The identification of disease-related genes is a major focus of modern biomedical research. Recent techniques, including array-based platforms for molecular profiling of disease tissues such as DNA arrays for expression profiling or matrix comparative genomic hybridization, allow for the comprehensive screening of the whole genome in a single experiment. Consequently, thousands of candidate genes have already been identified that may be linked to disease development and progression, and the process of lead discovery continues unimpeded. The evaluation of the clinical value of such leads is challenging because thousands of well-characterized tissue specimens must be analyzed. Tissue microarray (TMA) technology enables high-throughput tissue analyses to keep pace with the rapid process of lead discovery. With this technique, up to 1000 minute tissue samples are brought into an array format and analyzed simultaneously. The TMA technology is a fast, cost-effective, and statistically powerful method that will substantially facilitate translational research.

Animals↗

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

Tissue microarray analysis reveals prognostic significance of syndecan-1 expression in prostate cancer.

BACKGROUND: Tissue microarrays (TMA) have recently emerged as powerful tools to rapidly analyze the clinical significance of new molecular markers in human tumors. Here, we have tested several molecular markers on a prostate TMA containing 637 different specimens. METHODS: The specimens were from 551 patients with prostate cancer and long-term follow-up information on progression (median 5.3 years), tumor-specific and overall survival (median 5.9 years). Eighty-six specimens from benign prostatic hyperplasia were included as controls. Expression of Ki67, Bcl-2, p53, CD-10 (neutral endopeptidase), and syndecan-1 (CD-138) was analyzed by immunohistochemistry. RESULTS: Gleason grade and Ki67 Labeling Index (LI) were independent predictors of early recurrence and poor survival. Bcl-2 predicted early recurrence, whereas p53 was associated with poor survival. Syndecan-1 overexpression also predicted early recurrence and was significantly associated with tumor specific survival, high Gleason grade, Ki67 LI, and Bcl-2 overexpression. Neoadjuvant hormonal therapy was associated with overexpression of Bcl-2 and inhibition of Ki67 LI and CD-10, but did not affect the expression of the remaining markers. CONCLUSIONS: The results of this TMA study confirm a dominant prognostic significance of Gleason grading and Ki67 LI in prostate cancer, as compared to a less pronounced role of Bcl-2, and p53. We identified syndecan-1 as a new prognostic factor and provide evidence for an androgen-dependent regulation of CD-10 expression.

Aged↗

PubMed2003

Calretinin expression in human normal and neoplastic tissues: a tissue microarray analysis on 5233 tissue samples.

Calretinin is a calcium-binding protein expressed in different normal and neoplastic tissues. Early studies suggested that calretinin is a useful marker to differentiate adenocarcinomas from malignant mesotheliomas of the lung, but subsequent work has shown that calretinin can be expressed in several other tumor types. To systematically investigate the epidemiology of calretinin expression in normal and neoplastic tissues, we used tissue microarrays (TMAs) to analyze the immunohistochemically detectable expression of calretinin in 5233 tissue samples from 128 different tumor categories and 76 different normal tissue types. At least 1 case with weak expression could be found in 74 of 128 (58%) different tumor types and 46 entities (36%) had at least 1 tumor with strong positivity. In normal tissues, a particularly strong expression was found in Leydig cells of the testis, neurons of the brain, theca-lutein and theca interna cells of the ovary, and mesothelium. In tumors, strong calretinin expression was most frequently found in malignant mesotheliomas (6 of 7), Leydig cell tumors of the testis (5 of 5), adenomas of adrenal gland (5 of 9), and adenomatoid tumors (4 of 9). In summary, calretinin is frequently expressed in many different tumor types. Metastases of various different origins must be included in the differential diagnosis of calretinin-positive pleura tumors.

Biomarkers↗

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

Tissue microarray evaluation of Melanoma antigen E (MAGE) tumor-associated antigen expression: potential indications for specific immunotherapy and prognostic relevance in squamous cell lung carcinoma.

OBJECTIVE: To evaluate MAGE tumor-associated antigen (TAA) expression in an extensive panel of normal and neoplastic tissues. SUMMARY BACKGROUND DATA: TAAs of the MAGE family represent targets of active specific immunotherapy. Limited-size studies indicate that they are expressed in normal testis and tumors of different histologies. High-throughput tissue microarray (TMA) technology and MAGE TAA-specific monoclonal antibodies now allow us to comprehensively evaluate their expression in large numbers of tissues and to address clinical correlations. METHODS: A TMA containing 3,520 samples from 197 different tissues and a non-small-cell lung cancer TMA including 301 specimens were stained using the MAGE TAA-specific monoclonal antibody 57B. For patients with squamous cell carcinoma of the lung, the dichotomous result (positive vs. negative) of MAGE TAA staining was used as a predictor variable along with other covariates in proportional hazard regression analysis of tumor-specific survival. RESULTS: MAGE TAAs are expressed with frequencies ranging between 22.7% (larynx) and 50% of cases (lung) in squamous cell carcinomas from different anatomic areas and in large cell carcinomas of the lung (37.9%). The authors provide here the first description of MAGE TAA expression in basalioma (48.1%). To investigate the clinical significance of MAGE expression in a frequently positive tumor type, a non-small-cell lung cancer, TMA was then studied. In this TMA 43.2% of tumors were 57B positive. In patients with squamous cell carcinoma, MAGE TAA positivity was significantly correlated with a shorter tumor-specific survival in the proportional hazard regression analysis model. CONCLUSIONS: These data suggest novel potential therapeutic indications in different types of cancers. In lung squamous cell carcinoma, the significant association of MAGE TAA expression with poor prognosis suggests that patients with 57B-positive tumors may benefit from early, specific immunotherapy procedures.

Adult↗