Silver in situ hybridization (SISH) for determination of HER2 gene status in breast carcinoma: comparison with FISH and assessment of interobserver reproducibility.

The importance of HER2 status in breast cancer management has focused attention on the ability of clinical assays to correctly assign HER2 amplification status. There is no consensus as to the best method for assessing HER2 status. Disadvantages of fluorescence in situ hybridization (FISH) testing include longer time required for staining and scoring slides, requirements for specialized training and fluorescence microscopy, and loss of the signal due to quenching of the fluorescent dye. Silver-enhanced in situ hybridization (SISH) is a rapid fully automated assay providing permanently stained slides that are interpreted by conventional bright field microscopy which enables pathologists to evaluate slides within the context of tissue morphology. This study evaluates the concordance between SISH and FISH assays in determining the status of HER2 gene amplification in a cohort of 298 primary invasive breast carcinomas. Furthermore, we assessed in detail the variables contributing to interobserver interpretive reproducibility of HER2 SISH among 10 pathologists. HER2 was quantified using the ratio of HER2 to CHR17 signals using the conventional historical interpretation scale and also by the American Society of Clinical Oncology/College of American Pathologists reporting scheme. For SISH status determined by consensus among 10 pathologists, overall concordance between SISH and FISH was identified in 288 of 298 cases (96.6%) using the conventional Food and Drug Administration approved criteria. Overall agreement was observed in 282 of 285 cases (98.9%) using the American Society of Clinical Oncology/College of American Pathologists result reporting scheme (with equivocal cases removed). In conclusion, SISH represents a novel approach for the determination of HER2 status in breast cancer. The overall concordance between SISH and FISH is excellent, and the interpretation of SISH results by pathologists is most reproducible using the HER2/CHR17 ratio.

Variation of monosomy 3 status within uveal melanoma.

CONTEXT: Determining the most significant prognostic variables in uveal melanoma is important for stratifying patients for metastasis surveillance and possible initiation of chemotherapy or immunotherapy. Monosomy 3, one such variable, can be determined using fluorescence in situ hybridization, either on enucleated samples, fine-needle aspiration biopsy, or tumor sample obtained by vitrector. OBJECTIVE: To evaluate possible regional discordance in chromosome 3 by sites likely to be sampled by different biopsy methods. DESIGN: Eighteen consecutive patients with uveal melanoma who underwent primary enucleation were studied. Representative paraffin blocks were selected based on review of hematoxylin-eosin stained sections, and the apex and base of each tumor was demarcated. Unstained paraffin sections, 4 mum in thickness, were prepared, and fluorescence in situ hybridization, looking for monosomy 3, was performed. The chromosomal analysis was also correlated with histologic evaluation for melanoma cell type (spindle vs epithelioid cell), ciliary body involvement, presence of positive periodic acid-Schiff vascular mimicry patterns, scleral or extrascleral spread and size. One case was excluded because of necrosis. RESULTS: Ten of the 17 remaining cases (59%) demonstrated monosomy 3 (in either the base or both base and apex of the tumor) with 7 cases (41%) showing disomy. Seven cases (70%) with monosomy 3 demonstrated this in both the apex and the base locations, whereas 3 cases (30%) showed monosomy in one location only (always at the base). Fourteen of the 17 cases (82%) revealed concordance in chromosome 3-monosomy 3 (7 of 14, 50%) or chromosome 3-disomy 3 (7 of 14, 50%). All 3 discordant cases demonstrated the monosomy 3 at the base with disomy at the apex. Lack of concordance between the base and apex did not correlate with melanoma cell type. CONCLUSIONS: Prognostic variables are important in management of neoplasms, and this study points out that the site of tissue biopsy for prognostication in uveal melanoma could affect the results obtained, at least for the presence of monosomy 3.

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 hybridization (FISH).

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.

Fluorescence in situ hybridization (FISH) as primary methodology for the assessment of HER2 Status in adenocarcinoma of the breast: a single institution experience.

The demand for both reflexed and primary fluorescence in-situ hybridization (FISH) testing in the clinical setting is increasing. Relevant literature has reported the incidence of HER2 overexpression in 20% to 30% of cases, but some reports suggest that HER2 gene amplification rates are substantially lower. Published data, however, on primary FISH assessment from a single institution is limited, especially information about the frequency of the anomalous genotypes defined by FISH. We report our experience with primary FISH testing in 742 consecutive cases of breast cancer, in the calendar year 2006. Eighty percent (595/742) of the breast cancer cases were not amplified for HER2 (HER2/CEP17=0.8-1.9), whereas 19% (142/742) of cases were HER2 amplified (HER2/CEP17>or=2.0). Among the HER2-amplified cases, 3% (19/742) were low-level amplified (HER2/CEP17 ratio=2.0-2.5). Genotypic heterogeneity, defined as >5% but <50% of the tumor cells demonstrating HER2 gene amplification, was observed in 5% (40/7242) of the cases. HER2 monoallelic deletion (HER2/CEP1780% of tumor cells) was observed in 2% (13/742). Polysomy, if defined as CEP17 spot count 3.0 or more in at least 80% of tumor cells, was observed in 3% (20/742) of the cases. These data may be helpful as benchmarks for other institutions initiating primary FISH analysis for HER2 genotyping.

Metallographic in situ hybridization.

Metallographic methods, in which a target is visualized using a probe or antibody that deposits metal selectively at its binding site, offers many advantages for bright-field in situ hybridization (ISH) detection as well as for other labeling and detection methods. Autometallographically enhanced gold labeling procedures have demonstrated higher sensitivity than conventional enzyme chromogens. Enzyme metallography, a novel procedure in which an enzymatic probe is used to deposit metal directly from solution, has been used to develop bright-field ISH methods for HER2 gene determination in breast cancer and other biopsy specimens. It provides the highest level of sensitivity and resolution, both for visualizing endogenous gene copies in nonamplified tissues and for resolving multiple gene copies to allow copy enumeration in amplified tissues without the need for oil immersion or fluorescence optics. An automated enzyme metallography procedure, silver ISH, has been developed for use in slide-staining instruments. Metallographic staining also provides excellent results for immunohistochemistry and may be combined with other staining procedures for the simultaneous detection of more than one gene or combinations of genes and proteins.

A new rabbit monoclonal antibody (4B5) for the immunohistochemical (IHC) determination of the HER2 status in breast cancer: comparison with CB11, fluorescence in situ hybridization (FISH), and interlaboratory reproducibility.

The 2 methodologies in current clinical use to assess HER2 status in breast cancer are: fluorescence in situ hybridization (FISH) (gene amplification) and immunohistochemistry (protein over-expression). A consistent finding has been that 3% to 15% of breast cancers over-express HER2 protein without evidence for gene amplification. Accurate determination of the HER2 status has implications for selecting patients most likely to respond to trastuzumab. We report here our preliminary experience with a new anti-HER2 rabbit monoclonal antibody, 4B5. The evaluation of HER2 status in 2 different cohorts of breast cancer cases (Single Institution (SI) and Multinational (MN)) with a total of 322 breast cancer cases was performed on an automated staining system (Ventana Medical Systems, Inc, Tucson, AZ) and scored by 3 pathologists (0-3+), for comparison with CB11 staining results (PATHWAY) and FISH (PathVysion). Interlaboratory reproducibility of automated staining results and interpretation was determined on a subset of the SI cohort at 3 separate laboratories. Rabbit monoclonal 4B5 demonstrated sharper membrane staining with less cytoplasmic and stromal background staining than CB11. In the SI cohort, the staining results for 4B5 were highly comparable with those obtained for CB11 with an overall concordance of 93.3%. In the multinational cohort, the overall concordance with CB11 was 84.7%. This lower level of concordance was associated with a much higher overall agreement of 4B5 with FISH (89.5%), compared with agreement of CB11 with FISH (81.2%). The difference in the performance of CB11 in the MN cohort versus the SI cohort may be due to differences in tissue fixation and processing in a centralized, high volume laboratory in an academic medical center versus multiple sites in the international community with potentially nonstandardized techniques. The staining results with 4B5 indicate that it has a more robust performance than CB11 because the correlation of 4B5 with FISH was nearly equivalent (88.2% MN; 89.3% SI) in both cohorts. Interlaboratory reproducibility was also excellent (kappa 1.0). RMoAb 4B5 provides excellent sensitivity, specificity, and interlaboratory reproducibility for the detection of HER2 status in breast cancer.

The expression of the cytoskeletal focal adhesion protein paxillin in breast cancer correlates with HER2 overexpression and may help predict response to chemotherapy: a retrospective immunohistochemical study.

Paxillin, a cytoskeletal focal adhesion adaptor protein, has been shown to be transcriptionally up-regulated and phosphorylated by human epidermal growth factor receptor-2 (HER2) signaling in vitro. Paxillin expression may also correlate with HER2 amplification in breast cancer patients. In the current study, we sought to explore the relationship further between paxillin expression and clinicopathologic features and clinical outcome in breast cancer. A total of 314 primary invasive breast carcinomas were assessed for paxillin expression via immunohistochemistry. Paxillin immunoreactivity was compared with estrogen receptor/progesterone receptor status, HER2 status by silver in situ hybridization, age, tumor size, stage, Bloom-Richardson grade, nodal status, disease-free survival (DFS), and overall survival (OS). Paxillin expression was identified in 27.7% of breast carcinomas as diffuse cytoplasmic staining and the expression correlated with HER2 overexpression (p < 0.001). The influence of paxillin on clinical outcome, in particular the response to chemotherapy, appeared to differ depending on the HER2 status of the tumor. For the subset of HER2 nonamplified cases treated with chemotherapy, patients whose tumor showed a loss of paxillin expression demonstrated a significantly lengthened DFS and OS. In contrast, loss of paxillin expression in the HER2 amplified subset of patients who received chemotherapy correlated with a significantly worse outcome. These data suggest that paxillin up-regulation may be a part of the HER2 pathway in some breast cancers and, furthermore, paxillin expression may also influence the clinical response to chemotherapy, depending upon the HER2 status of a given patient's tumor. Further study of a role for paxillin expression in predicting response to cytotoxic regimens or targeted treatments is warranted.

An approach to the validation of novel molecular markers of breast cancer via TMA-based FISH scanning.

Tissue microarrays (TMA) are valuable tools for validating results of array-based comparative genomic hybridization (ACGH) and other translational research applications requiring independent verification of genomic gains and losses by fluorescence in situ hybridization (FISH). However, spatial orientation and accurate manual tracking of the TMA cores is challenging and prone to error. Image analysis combined with core tracking software, implemented via an automated FISH scanning workstation, represents a new approach to FISH and TMA-based validation of novel genomic changes discovered by ACGH in breast and other cancers. Automated large-scale tissue microarray validation FISH studies of genomic gains and losses identified by ACGH for breast cancer are feasible using an automated imaging scanner and tracking/classifying software. Furthermore, by leveraging the bifunctional fluorescent and chromogenic properties of the alkaline phosphatase chromogen fast red K and combining the technology with FISH, correlative and simultaneous phenotype/genotype studies may be enabled.

Genotyping of phenotypically defined cells in neoplasia: enhanced immunoFISH via tyramide signal amplification (TSA) segregates immunophenotypically-defined cell populations for gated genotyping.

Molecular morphologic tools exist for simultaneously visualizing immunophenotype and genotype of tumors, but are frequently hampered by a delicate balance between removing sufficient amount of the protein blocking full access of the probe to hybridize to target nucleic acids while still preserving sufficient target antigen for immunophenotyping. The result is often suboptimal, with either insufficiently visualized gene deletions and amplifications due to masking protein, or overdigestion of the protein target. Our purpose was to design and validate a gated genotyping assay that enables optimal and concomitant detection of both gene and protein. Using the proliferating endothelial cell compartment within gliomas organized in a tissue microarray (TMA), we tested the hypothesis that tyramide signal amplification (TSA) with deposition of a fluorochrome could be used during immunophenotyping, permitting sufficient protein digestion while insuring probe accessibility to nucleic acid target. The method was successfully validated using a TMA containing 38 glioma cases previously genotyped for EGFR amplification. CD31 positive endothelial cells were segregated via TSA-based Alexa-Fluor 647 immunofluorescence for analysis of EGFR amplification of the gliomas organized in the TMA. Enhanced immunoFISH (TSA) successfully segregates immunophenotypically-defined cell populations for gated genotyping.

The specificity of interphase FISH translocation probes in formalin fixed paraffin embedded tissue sections is readily assessed using automated staining and scoring of tissue microarrays constructed from murine xenografts.

Implementation of interphase fluorescence in situ hybridization (FISH) assays in the clinical laboratory requires validation against established methods. Validation tools in common use include exchange of consecutive sections with another institution that has already established the FISH assay, comparison with conventional banded metaphase cytogenetics, confirmation of specificity using probed normal metaphases, consecutive paraffin sections of a validation set tested by a reference laboratory, and specificity assessment against well characterized cell lines. We have investigated the feasibility of using tissue microarrays (TMA) constructed from murine xenografts as a preliminary specificity-screening tool for validation of interphase FISH assays. Cell lines currently in use for FISH controls are used to generate xenografts in SCID mice which are fixed in formalin and paraffin embedded. A TMA is constructed using duplicate donor cores from the xenograft blocks. Xenografts used represent a wide range of translocations used routinely for formalin fixed paraffin embedded sections evaluated by FISH. Probe cocktails (Abbott-Vysis), for several non-random translocations associated with hematologic neoplasms and soft tissue sarcomas have been used in this manner. On-line deparaffinization, cell conditioning, and prehybridization steps are automated using a staining workstation (Ventana Discovery XT); hybridization and stringency washes are performed manually offline. FISH-probed TMAs are tracked using a Metasystems image scanner and analyzed using classifiers specifically developed for each molecular abnormality. FISH results for each xenograft in the TMA correspond exactly to the genotype previously established for the parent cell line from which the xenograft was prepared. Moderate complexity tissue microarrays constructed from murine xenografts are excellent validation tools for initial assessment of interphase FISH probe specificity.

Automation of manual components and image quantification of direct dual label fluorescence in situ hybridization (FISH) for HER2 gene amplification: A feasibility study.

Determination of HER2 status by fluorescence in situ hybridization (FISH) in breast carcinoma correlates well with response to targeted therapy and prognosis. However, manual time consuming methods and quantification aspects of the procedure may be challenging for some laboratories. We examined the feasibility of automating these components of the FISH assay using a tissue microarray (TMA-118 clinically annotated cases) and a series of 41 whole sections. An in situ hybridization automated staining workstation was used to automate a programmed overnight start, on line baking, deparaffinization, cell conditioning, protease digestion, and prehybridization buffer washing. Dual label probe/target codenaturation/hybridization and stringency washing were done off line. The HER2 and CEP17 spot counts were quantified, and the HER2/CEP17 ratio calculated, via an imaging workstation. Results were benchmarked against manual counts for whole sections, and bright field in situ hybridization [silver in situ hybridization (SISH)] for the TMA. Automated FISH results using whole sections correlated well with manual results: HER2/CEP17 ratio correlation coefficient r = 0.9154, r = 0.8380, P < 0.0001. Correlation between automated and manual TMA FISH results was also excellent, and disease-free survival was significantly shorter (P < 0.001) for the HER2 amplified cases. Automation of the laborious manual prehybridization and image quantification components of FISH using directly labeled probes is feasible. Operational gains and enhanced consistency are inherent in this automated approach to HER2 clinical FISH testing.

Fluorescence in situ hybridization analysis of immunoglobulin heavy chain translocations in plasma cell myeloma using intact paraffin sections and simultaneous CD138 immunofluorescence.

Fluorescence in situ hybridization (FISH) studies are much more sensitive than classical cytogenetics for identification of karyotypic abnormalities in plasma cell myeloma. However, FISH analysis of bone marrow samples is often challenging because of a large number of admixed non-neoplastic hematopoietic elements. In this report, we describe a novel method using FISH analysis of intact paraffin sections of formalin-fixed, bone marrow clot preparations with simultaneous CD138 tyramine signal amplification (TSA)-mediated immunofluorescence. We studied 22 cases of plasma cell myeloma for translocations involving the immunoglobulin heavy chain locus that are of known diagnostic and/or prognostic significance. All cases were analyzed using dual color, break-apart immunoglobulin heavy chain probe and dual color, dual fusion probes for t(11;14)(q13;q32) and t(4;14)(p16;q32). TSA-mediated fluorochrome deposition in CD138+ cells was unaltered by protease pretreatment. Translocations were identified in 10 cases, including five with t(11;14)(q13;q32) and three with t(4;14)(p16.3;q32). When present, abnormalities were identified in a large percentage of CD138+ cells (47 to 93%, median 84%). This technique allows for efficient molecular cytogenetic analysis of plasma cell myeloma using routinely archived paraffin-embedded material.

JC virus chromogenic in situ hybridization in brain biopsies from patients with and without PML.

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by the JC polyoma virus. Electron microscopy and immunohistochemistry are the traditional methods of confirming the presence of the virus in brain biopsies from these patients. We studied the brain biopsies from 7 patients with PML and 6 patients without PML with chromogenic in situ hybridization (CISH) for the JC polyoma virus using a commercially available probe. The biopsies from the patients with the PML cases were proven to contain the JC polyoma virus by traditional and molecular methods. The CISH findings were compared with the known state of infection. All (7/7) of the biopsies from patients with PML were positive for the presence of polyoma virus by CISH, whereas the biopsies from patients without PML were uniformly negative. CISH seems to be a useful tool for the detection of the JC virus in brain biopsies from patients with PML, and is more accessible because a commercial probe is available.

High-resolution immunophenotyping of subcellular compartments in tissue microarrays by enzyme metallography.

Ultrasensitive bright field in situ hybridization assays using enzyme metallography (EnzMet) have been developed and validated, but little is known regarding the applicability of EnzMet for immunophenotypic detection of protein via IHC. Superior resolution via discrete metallographic deposits offers the potential for enhancing high-resolution immunophenotyping. Using high-complexity tissue microarrays (TMAs), 88 common solid tumors were evaluated by automated EnzMet (Nanoprobes and Ventana). Targets were chosen to assess the ability of EnzMet to specifically localize encoded antigens in the nucleus (estrogen receptor), cytoplasm (cytokeratins), and cytoplasmic membrane (HER2) in TMAs. Results were compared with conventional IHC diaminobenzidine (DAB) immunostaining. There was full concordance between the EnzMet and conventional IHC results. Furthermore, the EnzMet reaction products did not appreciably diffuse, were dense and sharply defined, and provided excellent high-resolution differentiation of cellular compartments in paraffin sections for the nuclear, cytoplasmic, and cell membrane-localized antigens evaluated. The higher density of elemental silver deposited during enzyme metallography permitted evaluation of core immunophenotypes at a relatively low magnification, allowing more tissue to be screened in an efficient manner. This preliminary study shows the utility of using enzyme metallography for high-resolution immunophenotyping in TMAs.

Analytical validation and interobserver reproducibility of EnzMet GenePro: a second-generation bright-field metallography assay for concomitant detection of HER2 gene status and protein expression in invasive carcinoma of the breast.

Fluorescence in situ hybridization (FISH) has both excellent sensitivity and specificity in detecting HER2 gene amplification in invasive breast carcinoma. FISH has not been widely implemented in clinical practice because of reagent costs and the special instrumentation and expertise required to perform and integrate the assay. Immunohistochemistry (IHC) for HER2 protein is widely used, but false-positive and false-negative results are problematic. We developed a bright-field assay to visualize HER2 gene amplification and concomitant HER2 protein expression (EnzMet GenePro). This assay detects HER2 gene amplification via deposition of metallic silver by enzyme metallographytrade mark (EnzMettrade mark, Nanoprobes, Yaphank, NY) combined with HER2 protein detection by IHC using alkaline phosphatase and fast red K substrate visualization (CB11;Ventana, Tucson, AZ). The assay was performed on 94 invasive breast carcinomas, for which FISH (PathVysiontrade mark, Vysis, Downer's Grove, IL), conventional IHC (CB11), and enzyme metallography (EnzMettrade mark) results were known. The EnzMettrade mark component of the assay was scored as either HER2 gene amplified, polysomic, or nonamplified. The IHC component was scored using the conventional FDA scale of 0 to 3+. Concordance of the EnzMet component of the assay versus FISH was assessed and showed an excellent correlation (Pearson coefficient of 0.95; P < 0.001). The combination of gene and protein detection (EnzMet GenePro) displayed a specificity of 100% and an accuracy of 92.6% (95% confidence interval 85.3-97.0), facilitated recognition of gene/protein discordances, and allowed for efficient interpretation of the slide by conventional light microscopy. The interobserver kappa for each component was excellent (IHC, kappa = 0.94; and EnzMettrade mark, kappa = 0.96). EnzMet is the first bright-field ISH assay in our experience that routinely and nonambiguously detects endogenous HER2 signals, essential for a reliable clinical HER2 assay, and in combination with HER2 protein enables improved diagnosis in borderline cases.

The incidence of topoisomerase II-alpha genomic alterations in adenocarcinoma of the breast and their relationship to human epidermal growth factor receptor-2 gene amplification: a fluorescence in situ hybridization study.

Clinical and in vitro evidence supports the concept that human epidermal growth factor receptor-2 ( HER2 ) gene amplification prediction of response to anthracycline-based chemotherapy in breast cancer is not a direct effect of HER2 overexpression, but the result of coamplification of topoisomerase II-alpha ( TOP2A ). We investigated the relationship of TOP2A to HER2 genomic alterations by fluorescence in situ hybridization (FISH) and the correlations with polysomic states for chromosome 17 (CEP17). One hundred thirty-eight cases of breast cancer HER2 gene amplified by 2-color FISH ( HER2 /CEP17) were reevaluated with a 3-color probe set ( HER2 /CEP17/ TOP2A ) to investigate the frequency of coamplification and deletion of TOP2A . TOP2A was never amplified in the absence of HER2 amplification and was coamplified with HER2 in 68 (50%) of 137 cases; HER2 gene copy number was higher than the TOP2A copy number ( P < .01). Of the 137 cases with HER2 amplification, 23 (16%) showed a monoallelic deletion of TOP2A . Of the 43 cases not amplified for HER2 , 27 (63%) were CEP17 eusomic, 13 (30%) polysomic, and 3 (7%) monosomic. Of the HER2 nonamplified cases, 2 (5%) showed monoallelic deletion of both the HER2 and TOP2A . The current study demonstrates the complex interrelationship between the HER2 and TOP2A genes in breast cancer. The clinical implications of TOP2A amplification and deletion in breast cancer need to be further defined. If TOP2A gene dosage can be confirmed to correlate with tumor responsiveness to anthracycline-based therapy in the clinical setting, FISH testing for TOP2A status may be warranted to aid in the selection of the most appropriate therapy.

Novel bright field molecular morphology methods for detection of HER2 gene amplification.

Profiling the amplification and over-expression of the HER2 gene is a key component for defining the prognosis and management of invasive breast carcinoma. Clinical laboratory testing for HER2 gene amplification and over expression has been complicated by an unacceptably high rate of false positive immunohistochemistry (IHC) results, poor reproducibility for the '2+' category of IHC scoring, and reluctant acceptance of alternative testing by fluorescence in situ hybridization (FISH) by the diagnostic pathology community. Novel chromogenic in situ hybridization (CISH) assays have been developed that utilize bright field microscopy and a conventional light microscope for interpretation, but the analytical sensitivity of first generation CISH systems has been problematic. Novel second generation in situ hybridization detection methods based upon polymerized lg detection chemistry, autometallography or enzyme metallography, have been developed that routinely detect endogenous HER2 signals in normal cells (on slide hybridization control) and HER2 signals in both non-amplified and amplified patterns of HER2 genomic signatures. By combining the strength of polymerized peroxidase-labeled antibodies and metallography for gene amplification, with the detection of expression of HER2 encoded protein by IHC on the same slide, both HER2 gene amplification and protein over-expression can be simultaneously evaluated on a cell-by-cell basis in each microscopic field of carcinoma.

In situ hybridization in the pathology laboratory: general principles, automation, and emerging research applications for tissue-based studies of gene expression.

Diagnostic anatomic pathologists play an important role in the care of patients through their careful evaluation of morphological features in routinely prepared histological sections stained with Hematoxylin and Eosin. Morphological assessment of tissue sections, backed by over one hundred years of experience is powerful and allows for the accurate classification and diagnosis of the majority of disease states within pathologically altered tissues. However, the appearance of cells and their architectural arrangement within a morphologically complex tissue represents only a fraction of the information, which is contained within a histological section. These tissues also contain all of the cellular proteins and expressed genes, which help to ultimately determine the biological behavior of cells, as well as provide clues to the origins and pathogenesis of disease states. Technical and theoretical advances in our understanding of cellular biology have provided pathologists with powerful tools to probe beyond pure morphology into the abnormalities in both protein and gene expression that underlie human disease. These tools, which include immunohistochemistry and in situ hybridization, are playing an increasingly important role in diagnostic pathology, as well as in translational research. This review will focus on the emerging role of in situ hybridization within clinical and research laboratories, and will highlight a number of technical advances that have expanded the application of this technology.

Latent membrane protein 1, tumor necrosis factor receptor-associated factor (TRAF) 1, TRAF-2, TRAF-3, and nuclear factor kappa B expression in posttransplantation lymphoproliferative disorders.

CONTEXT: Most posttransplantation lymphoproliferative disorders (PTLDs) are associated with Epstein-Barr virus (EBV) infection. The EBV latent membrane protein 1 (LMP-1) is important in the transformation of B lymphocytes through its interaction with intracellular tumor necrosis factor receptor-associated factors (TRAFs) that, in turn, can activate transcription factors such as nuclear factor kappa B (NFkappaB) and Jun-N-kinase. Of the 6 members of the TRAF family, TRAF-1, TRAF-2, and TRAF-3 are most commonly associated with LMP-1. Recently, it has been suggested that LMP-1-induced TRAF activation is important in the pathogenesis of PTLDs. OBJECTIVE: To characterize the expression patterns of these proteins in PTLDs, we studied a series of well-characterized cases for expression of LMP-1, TRAF-1, TRAF-2, TRAF-3, and NFkappaB by immunohistochemical analysis. METHODS: A total of 27 specimens from 25 patients were analyzed for LMP-1, TRAF-1, TRAF-2, TRAF-3, and NFkappaB (active form) by immunohistochemical analysis. Expression of EBV-encoded RNA (EBER) was evaluated by in situ hybridization. Correlation between the expression of the different markers was performed using the Mantel-Haenszel chi(2) test. Cox proportional hazards analysis and Kaplan-Meier analysis with log-rank testing were used to analyze antigen expression and clinical outcome. RESULTS: Ninety-six percent of PTLDs expressed NFkappaB, 74% to 84% expressed TRAFs, 78% expressed EBER, and 77% expressed LMP-1. TRAF-1, TRAF-2, and TRAF-3 expression did not correlate with either EBER or LMP-1 expression. TRAF-2, but not TRAF-1 or TRAF-3, expression correlated with NFkappaB expression (P =.02). CONCLUSIONS: These results suggest that TRAF molecules and active NFkappaB are expressed in PTLDs regardless of EBV positivity. Given the association of TRAF-2 and active NFkappaB expression, TRAF-2 may play an important role in regulating this transcription factor in PTLD.

Multitarget fluorescence in situ hybridization assay detects transitional cell carcinoma in the majority of patients with bladder cancer and atypical or negative urine cytology.

PURPOSE: The multitarget fluorescence in situ hybridization (FISH) probe set UroVysion (Vysis, Downers Grove, Illinois), containing probes to chromosomes 3, 7 and 17, and to the 9p21 band, has been recently shown to have high sensitivity and specificity for detecting transitional cell carcinoma. In this study we retrospectively tested 120 urine samples from patients with atypical, suspicious and negative cytology for whom concurrent and followup bladder biopsy data were available. We evaluated the ability of FISH to identify malignant cells in cytologically equivocal or negative cases. MATERIALS AND METHODS: Archived slides from 120 voided (47) or instrumented (73) urine cytology specimens from patients with concurrent bladder biopsy and a minimum of 12 months of biopsy followup were subjected to hybridization with UroVysion. The cohort included patients with biopsy proven transitional cell carcinoma, which was grades 1 to 3 in 23, 35 and 24, respectively, and stages pTis in 3, pTa in 64, pT1 in 6, pT2 in 6 and pT4 in 3, while it showed negative histology in 38. Cytology findings were suspicious, atypical and negative for transitional cell carcinoma in 31, 49 and 40 cases, respectively. A positive FISH result was defined as 5 transitional cells or greater with a gain of 2 or more of chromosomes 3, 7 or 17, 12 cells or greater with 9p21 deletion, or 10% or greater of cells with isolated trisomy of 1 of chromosomes 3, 7 and 17. RESULTS: All except 12 of the 82 biopsy proven transitional cell carcinoma cases (11 pTa and 1 pT1 tumors) were positive by FISH (85% sensitivity). Sensitivity in patients with suspicious, atypical and negative cytology was 100%, 89% and 60%, respectively. Nine patients with atypical cytology had positive FISH in the setting of a negative concurrent bladder biopsy. However, 8 of these 9 patients (89%) had biopsy proven transitional cell carcinoma within 12 months following the date when the sample tested by FISH was obtained. The last of these patients with false-positive results had previously documented pTis disease, which was also present in the next bladder biopsy 15 months following the positive FISH result. The remaining 29 specimens from patients with negative biopsy and a negative 12-month followup tested negative by FISH (97% overall specificity). CONCLUSIONS: The UroVysion FISH assay provides high sensitivity and specificity to detect transitional cell carcinoma in cytologically equivocal and negative urine samples. These results emphasize the important role of this assay in the management of bladder cancer.