Publications
We maintain this section to inform interested users about independent scientific studies conducted on MetaSystems products. We assume no responsibility or liability regarding the accuracy or correct use of the information or statements provided by external authors. The conclusions or statements expressed in the publications listed are those of the external authors or researchers. The publications may involve user-specific adaptations of MetaSystems products. They are not intended for diagnostic use. For publications covered by the Intended Purpose of Metafer or Ikaros, please refer to the respective instructions for use (IFU).
Increased efficiency of detecting genetically aberrant cells by UroVysiontest on voided urine specimens using automated immunophenotypicalpreselection of uroepithelial cells.
<p>There is a steady search for procedure which could replace or at least reduce the frequency of the invasive cystoscopy in the surveillance of heterogeneous superficial transitional cell carcinoma (TCC) of the bladder. Recently, UroVysion FISH assay has been shown to provide with better sensitivity than the urine cytology except for the lowest stage pTa and grade I-II TCCs. Data indicate that this failure of the sensitive FISH might be due to mistargeting. Therefore, our aim was to elaborate a procedure enabling FISH analysis in phenotypically preselected urothelial cells, only. Cytokeratin 7 (CK-7) chromogenic immunolabeling was applied to various mixtures of negative and positive control cells as well as voided urine specimens. Cellular targets and CK-7 positive cells were identified by morphometric and pixel intensity indices using an automated microscope workstation. UroVysion FISH pattern was analyzed only in the subsequently relocalized CK-7 positive events. Automated phenotypical preselection of urothelial cells proved to have 97.3% sensitivity, 96.1% specificity, and 99.0% accuracy, whereas combined pheno- and genotyping revealed 93.3% sensitivity and 99.8% specificity, respectively. In clinical samples, the overall 20.4% FISH positivity gained by traditional target identification contrasted with the 55.6% positivity obtained by the combined method, by which the efficiency of identifying chromosomally aberrant cells proved to be two to threefold higher even in grade I lesions. FISH analysis of phenotypically preselected urothelial cells might represent a reliable asset in surveillance of low stage-low grade TCCs.</p>
Increased levels of numerical chromosome aberrations after in vitroexposure of human peripheral blood lymphocytes to radiofrequencyelectromagnetic fields for 72 hours.
Mazor, R., Korenstein-Ilan, A., Barbul, A., Eshet, Y., Shahadi, A., Jerby, E. and Korenstein, R. Increased Levels of Numerical Chromosome Aberrations after In Vitro Exposure of Human Peripheral Blood Lymphocytes to Radiofrequency Electromagnetic Fields for 72 Hours. Radiat. Res. 169, 28-37 (2008). We investigated the effects of 72 h in vitro exposure of 10 human lymphocyte samples to radiofrequency electromagnetic fields (800 MHz, continuous wave) on genomic instability. The lymphyocytes were exposed in a specially designed waveguide resonator at specific absorption rates (SARs) of 2.9 and 4.1 W/kg in a temperature range of 36-37 degrees C. The induced aneuploidy of chromosomes 1, 10, 11 and 17 was determined by interphase FISH using semi-automated image analysis. We observed increased levels of aneuploidy depending on the chromosome studied as well as on the level of exposure. In chromosomes 1 and 10, there was increased aneuploidy at the higher SAR, while for chromosomes 11 and 17, the increases were observed only for the lower SAR. Multisomy (chromosomal gains) appeared to be the primary contributor to the increased aneuploidy. The effect of temperature on the level of aneuploidy was examined over the range of 33.5-40 degrees C for 72 h with no statistically significant difference in the level of aneuploidy compared to 37 degrees C. These findings suggest the possible existence of an athermal effect of RF radiation that causes increased levels of aneuploidy. These results contribute to the assessment of potential health risks after continuous chronic exposure to RF radiation at SARs close to the current levels set by ICNIRP guidelines.
Automated FISH analysis using dual-fusion and break-apart probes on paraffin-embedded tissue sections.
Detecting balanced translocations using tissue sections plays an important diagnostic role in cases of hematological malignancies. Manual scoring is often problematic due to truncation and overlapping of nuclei. Reports have described automated analysis using primarily tile sampling. The aim of this study was to investigate an automated fluorescent in situ hybridization analysis method using grid sampling on tissue sections, and compare the performance of dual-fusion (DF) and break-apart (BA) probes in this setting. Ten follicular, 10 mantle cell lymphoma, and 10 translocation-negative samples were used to set the threshold of false positivity using IGH/CCND1, IGH/BCL-2 DF, and IGH BA probes. The cut-off distances of red and green signals to define fusion signals were 0.5, 1.0, and 1.2 mum for the IGH/CCND1, IGH/BCL-2 DF, and IGH BA probes, respectively. The mean false positivity of grid units was 5.3, 11.4, and 28.1%, respectively. Ten to 14 additional samples analyzed blindly and were correctly classified using each probe. Discriminating positive and negative samples using automated analysis and grid sampling was possible with each probe, although different definitions of fusion signals were required due to the different physical distances between the DNA probes. Using the DF probes resulted in lower false positivity, which was less affected by signal numbers per grid units.
Use of automated imaging and analysis technology for the detection of aneuploidy in human sperm
OBJECTIVE: To determine the precision and accuracy of an automated cell counting system when applied to counting aneuploidies in sperm samples. DESIGN: Prospective pilot study. SETTING: Andrology clinic and research laboratory in a university teaching hospital. PATIENT(S): Ten anonymous sperm donors of known fertility and two patients seeking infertility treatment. INTERVENTION(S): Semen samples were processed for detection of aneuploidies for chromosomes 13, 18, 21, X, and Y with use of fluorescent in situ hybridization. The detection of chromosome aneuploidy was performed both by manual counting and by the use of an automated cell counting system with manual review of aneuploid sperm. MAIN OUTCOME MEASURE(S): Semen samples were judged for the percent aneuploidy for chromosomes 13, 18, 21, X, and Y when counted manually or with the use of the automated cell counting system and review by a technician. RESULT(S): The sperm aneuploidy rates determined by the automated cell counting system and careful review were comparable with those obtained by manual counting by a trained technician. CONCLUSION(S): These preliminary data demonstrate that automated cell counting devices may be useful in increasing productivity in aneuploidy detection in sperm and may become an alternative to the labor-intensive manual counting by technicians.
The clinical implementation of sperm chromosome aneuploidy testing:pitfalls and promises.
Severe male infertility has been shown to be associated with improper meiotic recombination and elevated sperm chromosome aneuploidy. Elevated sperm aneuploidy increases the risk of embryo lethality or fetal anomalies. Although difficulties in interpreting aneuploidy data still exist, advances in fluorescent in situ hybridization (FISH) technology have facilitated the study of sperm from patients with severe spermatogenesis defects, which has demonstrated the prudence of evaluating sperm chromosome aneuploidy in men with severe male factor infertility, such as nonobstructive azoospermia or severe ultrastructure defects, especially in cases of previous repeated in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) failure. Testing is also advisable in men with chromosome translocations and unexplained recurrent pregnancy loss, and it may be beneficial in patients with unexplained, repeated IVF failure. Automated FISH imaging and analysis technology is now available and is beneficial in reducing technician time analyzing sperm aneuploidy. Emerging technologies, such comparative genomic hybridization, may be beneficial in further improving the quality of data derived from aneuploidy analysis and reducing the cost of the assay.
High concordance between immunohistochemistry and fluorescence in situ hybridization testing for HER2 status in breast cancer requires a normalized IHC scoring system
The American Society of Clinical Oncologists and College of American Pathologists have recently released new guidelines for laboratory testing of HER2 status in breast cancer, which require high levels (95%) of concordance between immunohistochemistry positive (3+) and fluorescence in situ hybridization-amplified cases, and between immunohistochemistry negative (0/1+) and fluorescence in situ hybridization-nonamplified cases; these required levels of concordance are significantly higher than those found in most published studies. We tested the hypothesis that a modification of the HER2 immunohistochemistry scoring system could significantly improve immunohistochemistry and fluorescence in situ hybridization concordance. A total of 6604 breast cancer specimens were evaluated for HER2 status by both immunohistochemistry and fluorescence in situ hybridization using standard methodologies. Results were compared when the standard immunohistochemistry scoring system was replaced by a normalized scoring system in which the HER2 score was derived by subtracting the score on the non-neoplastic breast epithelium from that on the tumor cells. Among the 6604 tumors, using a non-normalized immunohistochemistry scoring system, 267/872 (30.6%) of the immunohistochemistry 3+ cases proved to be fluorescence in situ hybridization nonamplified, whereas using the normalized scoring system only 30/562 (5.3%) of immunohistochemistry 3+ cases proved to be 'false positive'. The concordance rate between immunohistochemistry 3+ and fluorescence in situ hybridization-amplified cases using the normalized scoring method was 94.7%, whereas the concordance using the non-normalized method was only 69.4%. Extremely high concordance between immunohistochemistry and fluorescence in situ hybridization assessment of HER2 status in breast cancer is achievable, but to attain this high level of concordance, modification of the FDA-approved immunohistochemistry scoring system is required.
New cutpoints to identify increased HER2 copy number: analysis of a large, population-based cohort with long-term follow-up
BACKGROUND: HER2 gene amplification and/or protein overexpression in breast cancer is associated with a poor prognosis and predicts response to anti-HER2 therapy. We examine the natural history of breast cancers in relationship to increased HER2 copy numbers in a large population-based study. PATIENTS AND METHODS: HER2 status was measured by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in approximately 1,400 breast cancer cases with greater than 15 years of follow-up. Protein expression was evaluated with two different commercially-available antibodies. RESULTS: We looked for subgroups of breast cancer with different clinical outcomes, based on HER2 FISH amplification ratio. The current HER2 ratio cut point for classifying HER2 positive and negative cases is 2.2. However, we found an increased risk of disease-specific death associated with FISH ratios of >1.5. An 'intermediate' group of cases with HER2 ratios between 1.5 and 2.2 was found to have a significantly better outcome than the conventional 'amplified' group (HER2 ratio >2.2) but a significantly worse outcome than groups with FISH ratios less than 1.5. CONCLUSION: Breast cancers with increased HER2 copy numbers (low level HER2 amplification), below the currently accepted positive threshold ratio of 2.2, showed a distinct, intermediate outcome when compared to HER2 unamplified tumors and tumors with HER2 ratios greater than 2.2. These findings suggest that a new cut point to determine HER2 positivity, at a ratio of 1.5 (well below the current recommended cut point of 2.2), should be evaluated.
Entamoeba histolytica encodes unique formins, a subset of which regulates DNA content and cell division.
The formin family of proteins mediates dynamic changes in actin assembly in eukaryotes, and therefore it is important to understand the function of these proteins in Entamoeba histolytica, where actin forms the major cytoskeletal network. In this study we have identified the formin homologs encoded in the E. histolytica genome based on sequence analysis. Using multiple tools, we have analyzed the primary sequences of the eight E. histolytica formins and discovered three subsets: (i) E. histolytica formin-1 to -3 (Ehformin-1 to -3), (ii) Ehformin-4, and (iii) Ehformin-5 to -8. Two of these subsets (Ehformin-1 to -3 and Ehformin-4) showed significant sequence differences from their closest homologs, while Ehformin-5 to -8 were unique among all known formins. Since Ehformin-1 to -3 showed important sequence differences from Diaphanous-related formins (DRFs), we have studied the functions of Ehformin-1 and -2 in E. histolytica transformants. Like other DRFs, Ehformin-1 and -2 associated with F-actin in response to serum factors, in pseudopodia, in pinocytic and phagocytic vesicles, and at cell division sites. Ehformin-1 and -2 also localized with the microtubular assembly in the nucleus, indicating their involvement in genome segregation. While increased expression of Ehformin-1 and -2 did not affect phagocytosis or motility, it clearly showed an increase in the number of binucleated cells, the number of nuclei in multinucleated cells, and the average DNA content of each nucleus, suggesting that these proteins regulate both mitosis and cytokinesis in E. histolytica.
Assessing Candidate Gene nsSNPs for Phenotypic Differences in Double-StrandBreak Repair Using Radiation-Induced gammaH2A.X Foci.
Nonsynonymous SNPs (nsSNPs) in DNA repair genes may be important determinants of DNA damage and cancer risk. We applied a set of screening criteria to a large number of nsSNPs and selected a subset of SNPs that were likely candidates for phenotypic effects on DNA double-strand break repair (DSBR). In order to induce and follow DSBR, we exposed panels of cell lines to gamma irradiation and followed the formation and disappearance of gammaH2A.X foci over time. All panels of cell lines showed significant increases in number, intensity, and area of foci at both the 1-hour and 3-hour time points. Twenty four hours following exposure, the number of foci returned to preexposure levels in all cell lines, whereas the size and intensity of foci remained significantly elevated. We saw no significant difference in gammaH2A.X foci between controls and any of the panels of cell lines representing the different nsSNPs.
An Evaluation of the Effectiveness of a Semi-automatic MetaphaseLocating and On-screen Karyotyping System.
Karyotyping is currently the #gold##standard# test for the detection of human chromosome abnormalities. Over the past 40 years, changes in techniques have improved the band definition of chromosomes; however, very little has changed with respect to improvements through automation. In this study, we compare chromosome analysis by traditional microscopy with semi-automatic karyotyping using robotic equipment from MetaSystems (Altlussheim, Germany). Analysis using MetaSystems was significantly quicker than using the microscope with an average reduction in analysis time of 26.5 minutes; for the average analyst, this equates to a reduction of 27 percent. Analysis checking times using MetaSystems showed even greater improvement with an average reduction in checking time of 11.4 minutes; for the average checker, this equates to a reduction of 48 percent. The MetaSystems semi-automatic karyotyping equipment offers increased throughput of cases for karyotype analysis while maintaining accuracy.
Development of automated brightfield double In Situ hybridization (BDISH) application for HER2 gene and chromosome 17 centromere (CEN 17) for breast carcinomas and an assay performance comparison to manual dual color HER2 fluorescence In Situ hybridizatio
BACKGROUND: Human epidermal growth factor receptor 2 (HER2) fluorescence in situ hybridization (FISH) is a quantitative assay for selecting breast cancer patients for trastuzumab therapy. However, current HER2 FISH procedures are labor intensive, manual methods that require skilled technologists and specialized fluorescence microscopy. Furthermore, FISH slides cannot be archived for long term storage and review. Our objective was to develop an automated brightfield double in situ hybridization (BDISH) application for HER2 gene and chromosome 17 centromere (CEN 17) and test the assay performance with dual color HER2 FISH evaluated breast carcinomas. METHODS: The BDISH assay was developed with the nick translated dinitrophenyl (DNP)-labeled HER2 DNA probe and DNP-labeled CEN 17 oligoprobe on the Ventana BenchMark(R) XT slide processing system. Detection of HER2 and CEN 17 signals was accomplished with the silver acetate, hydroquinone, and H2O2 reaction with horseradish peroxidase (HRP) and the fast red and naphthol phosphate reaction with alkaline phosphatase (AP), respectively. The BDISH specificity was optimized with formalin-fixed, paraffin-embedded xenograft tumors, MCF7 (non-amplified HER2 gene) and BT-474 (amplified HER2 gene). Then, the BDISH performance was evaluated with 94 routinely processed breast cancer tissues. Interpretation of HER2 and CEN 17 BDISH slides was conducted by 4 observers using a conventional brightfield microscope without oil immersion objectives. RESULTS: Sequential hybridization and signal detection for HER2 and CEN 17 ISH demonstrated both DNA targets in the same cells. HER2 signals were visualized as discrete black metallic silver dots while CEN 17 signals were detected as slightly larger red dots. Our study demonstrated a high consensus concordance between HER2 FISH and BDISH results of clinical breast carcinoma cases based on the historical scoring method (98.9%, Simple Kappa = 0.9736, 95% CI = 0.9222 - 1.0000) and the ASCO/CAP scoring method with the FISH equivocal cases (95.7%, Simple Kappa = 0.8993%, 95% CI = 0.8068 - 0.9919) and without the FISH equivocal cases (100%, Simple Kappa = 1.0000%, 95% CI = 1.0000 - 1.0000). CONCLUSION: Automated BDISH applications for HER2 and CEN 17 targets were successfully developed and it might be able to replace manual two-color HER2 FISH methods. The application also has the potential to be used for other gene targets. The use of BDISH technology allows the simultaneous analyses of two DNA targets within the context of tissue morphological observation.
Automated detection of irradiated food with the comet assay.
Food irradiation is the process of exposing food to ionising radiation in order to disinfect, sanitise, sterilise and preserve food or to provide insect disinfestation. Irradiated food should be adequately labelled according to international and national guidelines. In many countries, there are furthermore restrictions to the product-specific maximal dose that can be administered. Therefore, there is a need for methods that allow detection of irradiated food, as well as for methods that provide a reliable dose estimate. In recent years, the comet assay was proposed as a simple, rapid and inexpensive method to fulfil these goals, but further research is required to explore the full potential of this method. In this paper we describe the use of an automated image analysing system to measure DNA comets which allow the discrimination between irradiated and non-irradiated food as well as the set-up of standard dose-response curves, and hence a sufficiently accurate dose estimation.
Automated detection of residual leukemic cells by consecutive immunolabelingfor CD10 and fluorescence in situ hybridization for ETV6/RUNX1 rearrangementin childhood acute lymphoblastic leukemia.
<p>Among the various methods available for analyzing minimal residual disease, a new procedure for the cell-based approaches using consecutive phenotypic and genotypic analysis as revealed by immunofluorescent labeling and subsequent fluorescent in situ hybridization (FISH) has been developed. We are introducing a fluorescent microscopy-based technique by which not only cellular targets and immunological marker positivity, but also the FISH pattern was identified by automated scanning. For the latter one translocation-specific FISH pattern recognition was accomplished by using an automated scanning mode for the 3D determination of valid distances between FISH signals, to define the cutoff value for the shortest green-red spot distance differentiating positive cells from negative ones. The procedure was tested with CD10(+) acute lymphoblastic leukemia cell line harboring the t(12;21)(p13;q22) resulting in the ETV6/RUNX1 rearrangement (formerly TEL/AML1), as well as peripheral blood lymphocytes of healthy individuals. Using the combined, automated method, a sensitivity of 98.67% and a specificity of 99.97% were obtained. The mean false positivity + 2 standard deviations cutoff level (0.09%) allows detection of leukemic cells with high accuracy, even a bit below the tumor load dilution of 10(-3), a value reported to be critical in clinical decision making.</p>
Interleukin-6 gene amplification and shortened survival in glioblastomapatients.
Interleukin-6 (IL-6) is known to promote tumour growth and survival. We evaluated IL-6 gene amplification in tumours from 53 glioma patients using fluorescence in situ hybridisation. Amplification events were detected only in glioblastomas (15 out of 36 cases), the most malignant tumours, and were significantly associated with decreased patient survival.
Automated image analysis of micronuclei in binucleated human lymphocytes.
The lymphocyte micronucleus test is the most standardized of all cellular biomarkers for genotoxic effects. Until recently, the analysis of micronuclei was done exclusively by visual microscopical inspection but recently great progress has been made in automation. In this article we compare micronucleus data obtained by 'classical' visual scoring with those obtained by automated scoring using an image analysis system with micronucleus software. The results show that the use of automation is perfectly reliable for this task, especially after conducting limited post-analysis corrections.
Comprehensive assessment of TMPRSS2 and ETS family gene aberrations in clinically localized prostate cancer.
Novel recurrent gene fusions between the androgen-regulated gene TMPRSS2 and the ETS family members ERG, ETV1, or ETV4 have been recently identified as a common molecular event in prostate cancer development. We comprehensively analyzed the frequency and risk of disease progression for the TMPRSS2 and ETS family genes rearrangements in a cohort of 96 American men surgically treated for clinically localized prostate cancer. Using three break apart (TMPRSS2, ERG, ETV4) and one fusion (TMPRSS:ETV1) fluorescence in situ hybridization (FISH) assays, we identified rearrangements in TMPRSS2, ERG, ETV1, and ETV4 in 65, 55, 2, and 2% of cases, respectively. Overall, 54 and 2% of cases demonstrated TMPRSS2:ERG and TMPRSS2:ETV1 fusions, respectively. As intronic loss of genomic DNA between TMPRSS2 and ERG has been identified as a mechanism of TMPRSS2:ERG fusion, our assays allowed us to detect deletion of the 3' end of TMPRSS2 and the 5' end of ERG in 41 and 39% of cases rearranged for respective genes. Prostate cancers demonstrating TMPRSS2 gene rearrangement were associated with high pathologic stage (P=0.04). Our results confirm that recurrent chromosomal aberrations in TMPRSS2 and/or ETS family members are found in about 70% of prostate cancers. Importantly, we define a novel approach to study these gene fusions and identified cases where TMPRSS2 was rearranged without rearrangement of ERG, ETV1 or ETV4 and cases with ETS family gene rearrangement without TMPRSS2 rearrangement, suggesting that novel 5' and 3' partners may be involved in gene fusions in prostate cancer.
Assessment of potential cancer risk in children exposed to urban air pollution in Bangkok, Thailand.
Urban air pollution resulting from traffic is a major problem in many cities in Asia, including Bangkok, Thailand. This pollution originates mainly from incomplete fossil fuel combustion, e.g. transportation, and the composition of which is very complex. Some of the compounds are carcinogenic in experimental animals and in man. Polycyclic aromatic hydrocarbons (PAHs) and benzene are among the major carcinogenic compounds found in urban air pollution from motor vehicle emissions. In major cities in Asia, the levels of PAHs and benzene are relatively high compared with those in Europe or in the United States and thus people are exposed to higher levels. Biomarkers of exposure and early biological effects have been used to study the potential health effects of exposure to PAHs and benzene in air pollution in school children attending schools in inner-city Bangkok compared to those attending schools in rural areas. Bangkok school children are exposed to total PAHs at levels 3.5-fold higher than those in the rural area. Urinary 1-hydroxypyrene, a metabolite of PAH, was also significantly higher, while PAH-DNA adducts in lymphocytes were five-fold higher in Bangkok school children than rural school children. Benzene exposure in Bangkok school children was approximately two-fold higher than in rural school children. This is in agreement with the levels of biomarkers of internal benzene dose, i.e. blood benzene and urinary t,t-muconic acid. The potential health risks from exposure to genotoxic substances were assessed through DNA-damage levels and DNA repair capacity. DNA strand breaks were significantly higher, whereas DNA repair capacity was significantly reduced in Bangkok children. Genetic polymorphisms have been detected in glutathione-S-transferases (GSTs) and cytochrome P450 (CYP450) enzymes involved in the metabolism of benzene and PAHs, but these polymorphisms had no significant effects on the biomarkers of PAH exposure. Our results indicate that children living in a mega city such as Bangkok may have an increased health risk of the development of certain diseases due to exposure to genotoxic substances in air pollution compared to children living in suburban/rural areas.
Analysis of HER2 gene amplification using an automated fluorescence in situ hybridization signal enumeration system.
The HER2 gene, amplified in 10 to 35% of invasive human breast carcinomas, has prognostic and therapeutic implications. Fluorescent in situ hybridization is one method currently used for assessing HER2 status, but fluorescent in situ hybridization involves the time-consuming step of manual signal enumeration. To address this issue, Vysis has developed an automated signal enumeration system, Vysis AutoVysion. A multicenter, blinded study was conducted on 39 formalin-fixed, paraffin-embedded invasive breast carcinoma specimens, including 20 HER2 nonamplified and 19 HER2 amplified (weakly to highly amplified), provided in duplicate to each study site for analysis. Calculation of the HER2/CEP17 ratio and the hands-on time of both manual and automated enumeration approaches were compared. Overall agreement of HER2 classification results (positive and negative) was 92.5% (196 of 212). The Vysis AutoVysion System requires manual enumeration for cases with scanner results within the ratio range of 1.5 to 3.0. When the data in this range are excluded, the agreement between manual and scanner results is 98.8% (169 of 171). The average Vysis AutoVysion System hands-on time per slide was 4.59 versus 7.47 minutes for manual signal enumeration (savings of 2.88 minutes/slide). These data suggest that the Vysis AutoVysion System can correctly classify specimens and may increase the overall efficiency of HER2 testing.