Comparison of dual-color in-situ hybridization and fluorescence in-situ hybridization in HER2 gene amplification in breast cancer

Background

HER2 is a prognostic factor in breast cancer, and is predictive of the effects of HER2-targeted drugs. HER2 tests are essential in invasive and metastatic breast cancer. Dual-color in-situ hybridization (DISH) is a novel genetic test, and we investigated its utility in HER2 testing in breast cancer.

Methods

Using DISH and two FISH methods (FISH method 1, FISH method 2) with representative slices of surgical specimens from 134 invasive breast cancer patients, we performed HER2 gene testing and compared the results for HER2 gene/CEP17 signal ratio and HER2 gene diagnosis.

Results

Of 134 patients, either the HER2 gene or the CEP17 signal could not be counted in 2 patients by DISH, in 1 patient by FISH method 1, and in 1 patient by FISH method 2. HER2 gene/CEP17 signal ratios were strongly correlated in DISH and FISH method 1 (R = 0.85, P < 0.05). Agreement of DISH and FISH method 1 for HER2 gene diagnosis was 98.5 % for all patients, irrespective of gene amplification (κ = 0.97). HER2 gene/CEP17 signal ratios were strongly correlated in DISH and FISH method 2 (R = 0.87, P < 0.05). Agreement of DISH and FISH method 2 for HER2 gene diagnosis was 94.1 % for gene amplification patients, 98.4 % for gene non-amplification patients, and 96.2 % for all patients (κ = 0.92).

Conclusions

DISH is useful for HER2 gene testing in breast cancer, and is recommended as a new option for assessing HER2 status.     

Comparison of HER2 gene amplification assessed by fluorescence in situ hybridization and HER2 protein expression assessed by immunohistochemistry in gastric cancer

A monoclonal antibody to HER2 protein is widely used in the treatment of patients with HER2-overexpressing breast cancer and has also been found to exhibit antitumor activity in human gastric cancer cells that overexpress HER2. The purpose of this study was to evaluate the frequency of HER2 overexpression and concordance between the results for protein expression and gene amplification in both surgical and biopsy specimens of gastric cancer as assessed with two commercial kits, one for immunohistochemistry (IHC) and the other for fluorescence in situ hybridization (FISH). The specimens consisted of formalin-fixed, paraffin-embedded sections of biopsy specimens and surgically resected tumors from 200 cases of invasive gastric cancer that had been treated surgically at the National Cancer Center Hospital East. The lesions were analyzed with the IHC kit, and expression was graded by the United States Food and Drug Administration (FDA)-approved grading system. Gene amplification was evaluated by FISH. IHC revealed HER2 overexpression in 46 of the 200 (23%) cases. The FISH assay was technically successful in 199 cases (99.5%), and gene amplification was observed in 54 cases (27.1%). The concordance rate between the results obtained by IHC and FISH was 86.9%. The concordance rate between the findings in the surgically resected tumors and the 200 pre-treatment biopsy specimens was 88.7%. HER2 expression can be assessed in gastric cancer with a commercial kit as previously reported in breast cancer. Even small biopsy specimens were found to be suitable for evaluating gastric cancer for HER2 overexpression.     

HER2 amplification ratios by fluorescence in situ hybridization and correlation with immunohistochemistry in a cohort of 6556 breast cancer tissues

To analyze HER2 amplification in a large cohort of diagnostic breast cancer specimens, fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) were performed on the same specimens with use of Food and Drug Administration&approved products. Procedures were standardized following the manufacturers' recommendations. Of 116,736 IHC specimens, 20% were positive for HER2. In 16,092 FISH specimens, 22.7% showed HER2 amplification. In the subset of 6556 tissues analyzed with IHC and FISH, however, 59% were positive on IHC and 23.6% were amplified on FISH. The increased frequency of positive test results is skewed by more frequent reflex FISH testing. In general, expression and amplification trended together, with the least amplification (4.1%) seen in IHC-negative cases, 7.4% amplification seen in IHC 1+ cases, 23.3% amplification seen in IHC 2+ cases, and 91.7% amplification seen in IHC 3+ cases. When FISH amplification ratios were stratified, the low FISH ratios (2.0-2.2) were most frequently seen in specimens with negative IHC results, high ratios (>5.0) were seen in IHC 3+ specimens, and intermediate levels of amplification were similar for all levels of IHC. The effect of changing the cutoff point was analyzed: removing cases with a ratio of exactly 2.0 decreased the FISH positivity rate to 22.2% in the combined IHC and FISH cohort. Sequentially moving the cutoff point to 2.2 and 2.5 affected cases at all IHC expression levels. Each change removed approximately 2% from the apparent positivity. This large database provides the distribution frequency of HER2 protein expression and gene amplification in invasive ductal and lobular breast cancer. The relationship between level of HER2 amplification and clinical outcome will require reanalysis of pivotal trial data.     

HER-2/neu gene amplification by fluorescence in situ hybridization allows risk-group assessment in node-negative breast cancer

In a collective of 112 node-negative breast cancer patients, we compared the prognostic impact of HER-2/neu gene amplification (AMP) determined by fluorescence in situ hybridization (FISH) and HER-2/neu protein overexpression (EXP) measured by immunohistochemistry (IHC) with traditional prognostic factors (tumor size, grade, steroid hormone receptor status, menopausal status) and tumor invasion markers uPA (urokinase-type plasminogen activator) and its inhibitor PAI-1 determined by enzyme immunoassay (ELISA). Median follow-up in patients still alive at time of analysis was 7 years. Automated FISH and IHC were performed on parallel-cut formalin-fixed paraffin-embedded tissue sections. HER-2/neu AMP was detected by FISH in 31% and HER-2/neu EXP was measured by IHC in 41% of the cases. In 13% of the tumors, both AMP and EXP were found. FISH and IHC results were concordant in 56% of all analyzed cases. In univariate analysis, HER-2/neu AMP significantly predicted both disease-free (DFS) and overall survival (OS). HER-2/neu EXP was significant for OS, only. In multivariate analysis of all analyzed prognostic factors, HER-2/neu AMP was the only independent predictive factor for both DFS and OS. CART analysis revealed that HER-2/neu AMP together with the combination uPA/PAI-1 allowed optimal risk-group assessment after a 7-year median follow-up: patients with low levels of both uPA and PAI-1 and no HER-2/neu AMP had a significantly lower relapse rate (4.6%) than the remaining patients (32%). In conclusion, HER-2/neu gene AMP determined by FISH allowed a more accurate risk-group assessment than HER-2/neu protein EXP measured by IHC. Combining the HER-2/neu gene status measured by FISH with levels of tumor invasion markers uPA and PAI-1 improves clinically relevant risk-group assessment. In addition to its prognostic strength, the significant impact of HER-2/neu AMP on OS may reflect its ability to predict resistance to systemic therapy.     

荧光原位杂交技术检测乳腺癌HER-2基因扩增实验方法的比较

目的:探讨荧光原位杂交(FISH)技术检测乳腺癌HER-2基因的最佳实验方法.方法:应用FISH技术检测55例乳腺癌组织标本的HER-2基因,分别采用水浴法和直接消化法,甲酰胺法和共变性法,检测HER-2基因表达成功率,对比实验方法的最佳结果.结果:两种消化法中,水浴法和直接法杂交成功率分别为86.21%(25/29)和88.46%(23/26),差异无统计学意义(P>0.05),杂信号比分别为17.24%(5/29)和46.15%(12/26),差异有统计学意义(P<0.05).两种变性法中甲酰胺法和共变性法杂交成功率分别为73.08%(19/26)和93.10%(27/29),差异有统计学意义(P<0.05).结论:FISH检测乳腺癌HER-2基因,以水浴法和共变性法杂交成功率最高.     

Detection of Her2/neu, c-MYC and ZNF217 gene amplification during breast cancer progression using fluorescence in situ hybridization

The deletion of tumor suppressor genes and amplification of activating oncogenes appear to be critical events in tumorigenesis. We carried out fluorescence in situ hybridization (FISH) analysis of the breast cancer cell line MCF7 and clinically obtained cancer tissue sections on the basis of which we suggest a breast cancer development model. We selected 28 genes for FISH probes from breast cancer patients. Of the 28 genes studied, 14 were shown to be consistently amplified in the breast cancer cell line MCF7. We selected three genes from clinical tumor samples on the basis of results from MCF7 analysis. The amplification of Her2/neu or ZNF217 is closely associated with the stages of breast cancer. The frequency of amplification of Her2/neu increased notably in patients at stages later than IIB based on TNM staging, whereas the amplification of ZNF217 correlated with T2N1M0 at stage IIB and later stages. c-MYC amplification was not related to the stage. Her2/neu, ZNF217 and c-MYC were found to have a significantly increased copy number in breast cancer cells. In breast cancer progression, c-MYC amplification is an early event, while ZNF217 and Her2/neu amplification may play a role in the later stage of tumor development.     

HER-2/neu amplification detected by fluorescence in situ hybridization in fine needle aspirates from primary breast cancer.

BACKGROUND: The HER-2/neu gene is amplified in 20-30% of human breast cancers and has been shown to have prognostic and predictive value for treatment with chemotherapy, hormone therapy and antibodies against the HER-2/neu domain (trastuzumab). The aim of our study was to evaluate the reliability of HER-2/neu determination by fluorescence in situ hybridization (FISH) on fine-needle aspirates (FNAs) from primary breast cancer patients by comparison with the results obtained by FISH and immunohistochemistry (IHC) on the corresponding histological sections. MATERIALS AND METHODS: HER-2/neu amplification was determined by FISH on 66 breast cancer FNAs. Twenty-three and 36 corresponding formalin-fixed, paraffin-embedded sections were assayed by FISH and by IHC, respectively, in order to detect HER-2/neu amplification and HER-2/neu protein expression. RESULTS: Twenty-seven per cent (18/66) of breast cancer FNAs showed amplification of HER-2/neu by FISH. Paired results by FISH cytology and FISH histology were available in 22 cases. Concordance was 91% (20/22). Paired results by FISH cytology and IHC were available in 36 cases. Concordance was 92% (33/36). Eighteen of 66 breast cancer FNAs were also submitted to flow cytometric DNA analysis. None of the diploid cases showed HER-2/neu amplification by FISH. Six out of the eight aneuploid cases were amplified and two were polysomic. CONCLUSIONS: HER-2/neu gene amplification can be reliably estimated by FISH on breast cancer FNAs and a good correlation has been found between FISH and IHC results from the corresponding histological sections.     

Monosomy of chromosome 17 in breast cancer during interpretation of HER2 gene amplification

Monosomy of chromosome 17 may affect the assessment of HER2 amplification. Notably, the prevalence ranges from 1% up to 49% due to lack of consensus in recognition. We sought to investigate the impact of monosomy of chromosome 17 to interpretation of HER2 gene status. 201 breast carcinoma were reviewed for HER2 gene amplification and chromosome 17 status. FISH analysis was performed by using double probes (LSI/CEP). Absolute gene copy number was also scored per each probe. HER2 FISH test was repeated on serial tissue sections, ranging in thickness from 3 to 20 µm. Ratio was scored and subsequently corrected by monosomy after gold control test using the aCGH method to overcome false interpretation due to artefactual nuclear truncation. HER2 immunotests was performed on all cases. 26/201 cases were amplified (13%). Single signals per CEP17 were revealed in 7/201 (3.5%) cases. Five out of 7 cases appeared monosomic with aCGH (overall, 5/201, 2.5%) and evidenced single signals in >60% of nuclei after second-look on FISH when matching both techniques. Among 5, one case showed amplification with a pattern 7/1 (HER2/CEP17>2) of copies (3+ at immunotest); three cases revealed single signals per both probes (LSI/CEP=1) and one case revealed a 3:1 ratio; all last 4 cases showed 0/1+ immunoscore. We concluded that: 1) monosomy of chromosome 17 may be observed in 2.5% of breast carcinoma; 2) monosomy of chromosome 17 due to biological reasons rather than nuclear truncation was observed when using the cut-off of 60% of nuclei harboring single signals; 3) the skewing of the ratio due to single centromeric 17 probe may lead to false positive evaluation; 4) breast carcinomas showing a 3:1 ratio (HER2/CEP17) usually show negative 0/1+ immunoscore and <6 gene copy number at FISH.     

Metaplastic breast carcinomas exhibit EGFR, but not HER2, gene amplification and overexpression: immunohistochemical and chromogenic in situ hybridization analysis

Introduction

Metaplastic breast carcinomas constitute a heterogeneous group of neoplasms, accounting for less than 1% of all invasive mammary carcinomas. Approximately 70–80% of metaplastic breast carcinomas overexpress the epidermal growth factor receptor (EGFR). Human epidermal growth factor receptor (HER)2 and EGFR have attracted much attention in the medical literature over the past few years owing to the fact that humanized monoclonal antibodies against HER2 and therapies directed against the extracellular ligand-binding domain or the intracellular tyrosine kinase domain of EGFR have proven successful in treating certain types of human cancer. We investigated whether HER2 and EGFR overexpression was present and evaluated gene amplification in a series of metaplastic breast carcinomas.

Method

Twenty-five metaplastic breast carcinomas were immunohistochemically analyzed using a monoclonal antibody (31G7) for EGFR and two antibodies for HER2 (Herceptest and CB11) and scored using the Herceptest scoring system. Gene amplification was evaluated by chromogenic in situ hybridization using Zymed Spot-Light EGFR and HER2 amplification probe. The results were evaluated by bright field microscopy under 40× and 63× objective lenses.

Results

Nineteen (76%) metaplastic breast carcinomas exhibited EGFR ovexpression, and among these EGFR amplification (defined either by large gene clusters or >5 signals/nucleus in >50% of neoplastic cells) was detected in seven cases (37%): three carcinomas with squamous differentiation and four spindle cell carcinomas. One case exhibited HER2 overexpression of grade 2+ (>10% of cells with weak to moderate complete membrane staining), but HER2 gene amplification was not detected.

Conclusion

Metaplastic breast carcinomas frequently overexpressed EGFR, which was associated with EGFR gene amplification in one-third of cases. Our findings suggest that some patients with metaplastic breast carcinomas might benefit from novel therapies targeting EGFR. Because most metaplastic breast carcinomas overexpress EGFR without gene amplification, further studies to evaluate EGFR activating mutations are warranted.     

FISH检测乳腺癌HER-2基因扩增及17号染色体多体状况及其临床病理学意义的分析

目的:总结分析临床应用荧光原位杂交(FISH)技术检测诊断乳腺癌大样本的经验和临床病理学意义。方法:用FISH技术诊断1 699例乳腺浸润性导管癌HER-2基因扩增和17号染色体多体状态,并分析HER-2基因扩增与其他重要生物指标及临床病理的关系。结果:乳腺癌HER-2基因扩增阳性率为52.6%(894/1 699);乳腺癌17号染色体多体阳性率为12.7%(216/1 699)。HER-2基因扩增与HER-2表达状况和17号染色体多体呈正相关,P值分别为0.000 1和0.009;乳腺癌HER-2基因扩增与肿瘤大小(P=0.008)、病理学分级(P=0.025)、淋巴结转移(P=0.015)和Ki-67(P=0.004)呈正相关,与ER(P=0.002)、PR(P=0.001)和Bcl-2(P=0.028)呈负相关。HER-2基因扩增的乳腺癌赫赛汀用药组预后明显优于未用药组(Log-rank=38.5;P=0.000 1);17号染色体多体的乳腺癌赫赛汀用药组患者较未用药组复发率低(P=0.022)。结论:临床应用FISH技术诊断HER-2基因扩增靶标来指导乳腺癌的分子靶向治疗可以明显改善患者的预后,值得进一步推广应用。     

Comparison of MET gene amplification analysis by next-generation sequencing and fluorescence in situ hybridization

MET gene alterations are known to be involved in acquired resistance to epidermal growth factor receptor inhibition. MET amplifications present a potential therapeutic target in non-small cell lung cancer. Although next-generation sequencing (NGS) and fluorescence in situ hybridization (FISH) are conventionally used to assess MET amplifications, there are currently no clinically defined cut-off values for NGS, with FISH still being the gold standard. A collective of 20 formalin-fixed paraffin-embedded lung cancer tissue samples (mean age 64 years) were selected based on increased MET gene copy number (CNV) status or the presence of mutations detected by NGS (GeneReader, QIAGEN) and were further assessed by FISH (MET/CEN7, Zytomed). Of these, 17 tumor samples were MET-amplified and one patient was found to have a MET rearrangement by NGS, while two samples had no MET gene alteration. In contrast to the NGS result, FISH analysis showed only one highly amplified sample and 19 negative samples. The single highly amplified case detected by FISH was also positive by NGS with a fold change (FC) of 3.18 and a mean copy number (CN_{MV 10−100%}) of 20.5. Therefore, for the assessment of MET amplifications using the QIAGEN NGS workflow, we suggest detecting amplified cases with an FC value of ≥ 3.0 and a CN_{MV 10−100%} value of ≥ 20.0 by FISH. In summary, NGS allows for DNA- and RNA-based analysis of specific MET gene amplifications, point mutations or rearrangements.     

Potential for molecular targeted therapy of HER-2/neu for invasive bladder cancer: examination of gene amplification by fluorescence in situ hybridization

Analysis of HER-2/neu gene amplification by fluorescence in situ hybridization was performed in 40 patients with invasive bladder cancer in order to evaluate the potential for molecular targeted therapy of HER-2 as a tailor-made treatment for patients with invasive bladder cancer. This study included 40 patients seen at the Aichi Medical University Hospital from January 2001 to December 2004 and were pathologically diagnosed with invasive transitional cell carcinoma of the bladder (pT2-pT4). The PathVysion kit was used to evaluate the status of HER-2/neu gene amplification, and a signal ratio > or =2.0 was considered positive for HER-2/neu gene amplification. In primary foci 5 patients (12.5%) were positive for HER-2/neu gene amplification. According to the classification of grade and stage, no statistically significant difference was observed. Lymph node metastasis was found in 10 patients, and 3 patients (30%) were positive for HER-2/neu gene amplification. In the patients with HER-2/neu gene-amplified metastatic lymph nodes, primary foci were also positive for gene amplification, showing a statistically significant difference. This study indicates that 12.5% of patients with invasive bladder cancer may benefit from molecular targeted therapy of HER-2, and that molecular targeted therapy can be expected to be effective even for patients with lymph node metastases as long as their primary foci are positive for HER-2/neu gene amplification.     

Importance of formalin fixing conditions for HER2 testing in gastric cancer: immunohistochemical staining and fluorescence in situ hybridization

Background

Accurate and reliable assessment of human epidermal growth factor receptor type 2 (HER2) status is important for selecting patients with gastric cancer who may benefit from trastuzumab treatment. Here we examined the impact of formalin fixing conditions on HER2 immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in xenografted tumor tissues.

Methods

Xenografted tumor tissues of the human gastric cancer cell lines NCI-N87, SCH, and SNU-16 were collected and kept at room temperature for 0, 6, or 24 h before being fixed with 10 % neutral buffered formalin (NBF) for 24 h or 5, 7, or 10 days and embedded in paraffin. Use of 10 % NBF, 20 % NBF, or nonbuffered formalin as fixative was investigated.

Results

The HER2 IHC scores for NCI-N87, SCH, and SNU-16 tumors were 3+, 2+, and 1+, respectively, when specimens were fixed with 10 % NBF for 24 h immediately after resection of the tumors. Specimens left for longer than 6 h before fixation had shrinkage of the tumor periphery and decreased immunostaining intensity in this region in all specimens. In SCH and SNU-16 specimens, starting fixation 24 h after tumor tissue collection induced autolysis and reduction of the number of stained cells, and 10-day-fixation lowered the HER2 score. Prolongation of fixation time did not affect FISH results, but if samples were left for more than 6 h before fixation, the FISH score was strongly reduced in SCH specimens (2.3 to 1.3). Reduced IHC staining intensity was observed with 20 % NBF and nonbuffered formalin compared to 10 % NBF.

Conclusions

The time to and length of fixation of tumor specimens can affect HER2 IHC and FISH scores. The fixative used can affect IHC results.     

Detection and quantitation by fluorescence in situ hybridization (FISH) and image analysis of HER-2/neu gene amplification in breast cancer fine-needle samples.

BACKGROUND: Fine-needle sampling, although a practical and noninvasive method of tissue acquisition, has rarely been used for HER-2/neu fluorescent in situ hybridization (FISH). To assess HER-2/neu gene amplification in mammary carcinoma, FISH signals on cytology and corresponding tissue biopsies were detected visually and measured by image analysis. The results were correlated with patient and tumor characteristics. METHODS: In situ HER-2/neu DNA probe hybridization was performed on 61 cytology specimens and on 47 corresponding frozen sections of breast carcinomas. Tumors were classified by visual evaluation as unamplified, moderately amplified, or highly amplified. Multiparametric image analysis was performed using the Discovery automated image analyzer (Becton Dickinson, Leiden, Netherlands). The integrated fluorescence ratio (IFR) was calculated for each sample as the integrated FISH fluorescence of the tumor cells divided by the integrated FISH fluorescence of internal control cells containing two spots. The percentage positive nuclear area (PPN), calculated as the area of FISH fluorescence divided by the area of nuclear DNA fluorescence, and the PPR, ratio of the PPN of the tumor cells divided by the control cells, were also calculated for each sample. RESULTS: Visual analysis yielded 46 unamplified and 15 (24.6%) amplified (seven moderately amplified and eight highly-amplified) tumors. Strong (P < 0.001) correlation between results on cytological and histological materials was obtained. The FISH spots on the cytological preparations were more easily visualized and scored than those on the corresponding tissue sections. Visual HER-2/neu signal scoring was strongly correlated with IFR (P = 0.0001) and PPR (P = 0.0001). Within the tumors classified as highly amplified by visual examination, quantitation of the degree of amplification fluorescence signal was possible using image analysis. CONCLUSIONS: Cytologic specimens were a suitable and representative source of materials for detection and quantitation of HER-2/neu gene amplification by FISH and image analysis. Cancer (Cancer Cytopathol) Copyright 1999 American Cancer Society.     

Chromosomal alterations in breast cancer revealed by multicolour fluorescence in situ hybridization

The aim of this study was to characterise cytogenetically, breast cancer cell lines and primary tumours to identify chromosomal regions of interest in breast cancer. Multicolour fluorescence in situ hybridization (MFISH) and comparative genomic hybridization (CGH) were used to karyotype five established breast cancer cell lines and two short-term primary tumour cultures. Chromosome 8 was identified as a frequent target for aberrations in all cell lines and one primary culture by MFISH and CGH. CGH identified frequent gains of 1q (all samples) and 14q (all cell lines) and deletion of 22q (all samples). MFISH revealed a t(9;17) translocation in both primary tumours and the T47D cell line. MFISH analysis of the cell lines revealed a significant number of translocations previously unidentified in other studies using similar techniques, highlighting the necessity of utilising data from both primary cultures and established cell lines when investigating complex cytogenetic aberrations using MFISH and CGH.     

Significance of HER2 low-level copy gain in Barrett's cancer: implications for fluorescence in situ hybridization testing in tissues.

PURPOSE: HER2 may be a relevant biomarker in Barrett's cancer. We compared three HER2 laboratory methods, standard fluorescence in situ hybridization (FISH), image-based three-dimensional FISH in thick (16 microm) sections, and immunohistochemistry, to predict patient outcome. EXPERIMENTAL DESIGN: Tissue microarray sections from 124 Barrett's cancer patients were analyzed by standard FISH on thin (4 microm) sections and by image-based three-dimensional FISH on thick (16 microm) sections for HER2 and chromosome-17, as well for p185(HER2) by immunohistochemistry. Correlations with clinical and follow-up data were examined. RESULTS: Only three-dimensional FISH on thick (16 microm) sections revealed HER2 gene copy gain to be associated with increased disease-specific mortality (relative risk, 2.1; 95% confidence interval, 1.06-4.26; P = 0.033). In contrast, standard FISH on thin (4 microm) sections and immunohistochemistry failed to predict clinical outcome. Low-level gain of HER2 occurred frequently in Barrett's cancer (>or=2.5-4.0 HER2 copies, 59.7%; HER2-to-chromosome-17 ratio, >or=1.1-2.0; 61.2%) and defined a subpopulation for patient outcome as unfavorable as HER2 gene amplification [disease-free survival, P = 0.017 (HER2 copies)]. This low-level group was neither definable by standard FISH nor immunohistochemistry. No prognostic significance was found for chromosome-17 aneusomy. CONCLUSIONS: Low-level copy gains of HER2 define a biologically distinct subpopulation of Barrett's cancer patients. Importantly, these subtle copy number changes are not reliably detected by standard FISH in thin (4 microm) tissue sections, highlighting a thus far unrecognized weakness in HER2 FISH testing. These results should be taken into account for accurate evaluation of biomarkers by FISH and for HER2 FISH testing in tissue sections.