HNF4A expression as a potential diagnostic tool to discriminate primary gastric cancer from breast cancer metastasis in a Brazilian cohort

HER2 assessment in biopsy specimens of gastric cancer (GC) is challenging because of the intratumoral heterogeneity. False negative results may be get because of limited biopsy material. The aim of this study is to explore how tumor-containing fragment number and biopsy specimen number affect HER2 immunohistochemistry (IHC) positive rate. Eight hundred and ninety biopsy specimens and 459 paired resected specimens were collected. IHC staining of HER2 was performed. HER2 IHC positive (scored 3+) rate was compared based on tumor-containing fragment number, biopsy specimen number, average size and tumor tissue proportion of tumor-containing fragments. The positive predictability of biopsy specimens to resected specimens was analyzed based on tumor fragment number. HER2 IHC positive rates were 2.0, 3.5, 7.0, 13.2, 17.1, and 15.9% when tumor fragment numbers were 1, 2, 3, 4, 5 and 6 respectively. The rate rose with the increase of tumor fragment number (P = 0.004). ROC curve analysis showed that biopsy specimens exhibited positive predictability when tumor fragment number reached 3, but showed better performance when the number was ≥4 (P < 0.05). After fragment number reached 4, no statistic differences were reached in either HER2 IHC positive rate or positive predictability with further increase of the number (P > 0.05). HER2 IHC positive rate was not associated with biopsy number (P = 0.127), average size of tumor fragments (P = 0.397), and tumor tissue proportion of tumor fragments (P = 0.825) directly. The number of tumor-containing fragments influences HER2 IHC positive (scored 3+) rate. Greater than or equal to 4 (≥4) tumor fragments give better results in the positive rate as well as positive predictability. We recommend the number of tumor containing fragments be described in the HER2 IHC pathology reports for clinical reference in endoscopic biopsy specimens of GC.     

The Reliability of Endoscopic Biopsies in Assessing HER2 Status in Gastric and Gastroesophageal Junction Cancer: A Study Comparing Biopsies with Surgical Samples

AIM: The aim of this study is to validate the accuracy of HER2 assessment on biopsies by comparing matched biopsy/surgical material from the same patients. METHODS: HER2 status was evaluated by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in 103 cases of gastric and gastroesophageal junction cancers in coupled biopsy and surgical material. RESULT: Complete concordance between IHC and FISH results on biopsy versus surgical samples was noted in 80% and 95% of cases, respectively. At comprehensive comparison, including IHC and FISH data on biopsy and surgical samples, 89% of biopsies were predictive of HER2 status in surgical samples, whereas 11% showed variable inconsistencies. The majority of these (10 of 12 cases) showed IHC score 0/1+ on biopsy but were all IHC positive and amplified at surgery; in particular, three (3 of 35; 8.5%) IHC score 0 and four (4 of 16; 25%) IHC score 1+ cases were FISH amplified on biopsy material also, whereas the remaining three cases were FISH non-amplified on biopsy. The percentage of cases, which were FISH amplified with IHC score 1+ or 2+ on biopsies, were similar (25% and 33%, respectively) and they also shared a similar grade of amplification. These data suggest that both IHC score 1+ and 2+ on biopsy material represent “equivocal cases” that may merit further investigation. CONCLUSIONS: The predictive value of HER2 IHC in biopsies is high. FISH analysis should be considered for IHC score 2+ and 1+ biopsy cases. Approximately 8% of cases will not be accurately predicted by biopsy evaluation.     

High MET copy number and MET overexpression: poor outcome in non-small cell lung cancer patients

The aim of this study was to evaluate the prevalence and prognostic role of increased gene copy number and protein expression of MET and EGFR in non-small cell lung cancer (NSCLC) patients. Samples were collected from 380 patients with surgically resected NSCLC, and fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC) were performed. EGFR amplification and high polysomy (EGFR FISH-positive) were observed in 9.7% and 17.4% of the patients, respectively. EGFR was overexpressed (EGFR IHC-positive) in 19.2% of the patients. Neither EGFR FISH-positive nor EGFR IHC-positive status affected survival after resection. Increased MET copy number (MET FISH-positive by University of Colorado Cancer Center criteria) was observed in 11.1% of the patients (high polysomy, 8.7%; gene amplification, 2.4%). According to the Cappuzzo system, 7.1% of the patients were MET FISH-positive. MET FISH positivity was a negative prognostic factor, especially in patients with adenocarcinoma histology (p=0.040), female gender (p=0.010), old age (p=0.084), and EGFR FISH negativity (p=0.020) at the univariate level but not at the multivariate level. MET was overexpressed (MET IHC-positive) in 13.7% of the patients and associated with shorter overall and disease-free survival (p=0.010 and p=0.056, respectively). Multivariate analysis revealed that MET IHC-positive patients had a significantly increased risk of death (hazard ratio, 1.618; 95% confidence interval, 1.066-2.456; p=0.024). Increased MET copy number and MET overexpression are negative prognostic factors for surgically resected NSCLCs.     

Accurate Identification of ALK Positive Lung Carcinoma Patients: Novel FDA-Cleared Automated Fluorescence In Situ Hybridization Scanning System and Ultrasensitive Immunohistochemistry

Background

Based on the excellent results of the clinical trials with ALK-inhibitors, the importance of accurately identifying ALK positive lung cancer has never been greater. However, there are increasing number of recent publications addressing discordances between FISH and IHC. The controversy is further fuelled by the different regulatory approvals. This situation prompted us to investigate two ALK IHC antibodies (using a novel ultrasensitive detection-amplification kit) and an automated ALK FISH scanning system (FDA-cleared) in a series of non-small cell lung cancer tumor samples.

Methods

Forty-seven ALK FISH-positive and 56 ALK FISH-negative NSCLC samples were studied. All specimens were screened for ALK expression by two IHC antibodies (clone 5A4 from Novocastra and clone D5F3 from Ventana) and for ALK rearrangement by FISH (Vysis ALK FISH break-apart kit), which was automatically captured and scored by using Bioview''s automated scanning system.

Results

All positive cases with the IHC antibodies were FISH-positive. There was only one IHC-negative case with both antibodies which showed a FISH-positive result. The overall sensitivity and specificity of the IHC in comparison with FISH were 98% and 100%, respectively.

Conclusions

The specificity of these ultrasensitive IHC assays may obviate the need for FISH confirmation in positive IHC cases. However, the likelihood of false negative IHC results strengthens the case for FISH testing, at least in some situations.     

Assessment of HER2 Status Using Immunohistochemistry (IHC) and Fluorescence In Situ Hybridization (FISH) Techniques in Mucinous Epithelial Ovarian Cancer: A Comprehensive Comparison between ToGA Biopsy Method and ToGA Surgical Specimen Method

We aimed to compare the assay performance characteristics of HER2 status in mucinous epithelial ovarian cancer (EOC) by ToGA (Trastuzumab for Gastric Cancer) biopsy versus ToGA surgical specimen methods. Forty-nine tissue microarray (TMA) samples of mucinous EOC from Asian women were analyzed by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) tests using ToGA trial HER2 scoring methods. The overall concordance between IHC and FISH by the ToGA surgical specimen method is 97.56% and by the ToGA biopsy specimen method is 97.14%. The agreements of HER2 IHC results under both biopsy and surgical specimen methods were nearly perfect (weighted kappa = 0.845). Additionally, the percentage of Her2 FISH amplification showed increasing trend with increasing HER2 IHC ordinals (negative, equivocal, positive) by both TOGA biopsy (P<0.001) and surgical specimen method (P<0.001). After excluding equivocal cases, the sensitivity (100%), PPV (88.89%) and NPV (100%) of HER2 IHC were unchanged under either surgical specimen method or biopsy method. However, the specificity (96.97%) and accuracy (97.56%) of HER2 IHC was slightly higher under the surgical specimen method than those (specificity 96.30%, accuracy 97.14%) under the biopsy method. Of the total 49 cases, the number (n = 14) of HER2 IHC equivocal results under the ToGA biopsy method was 1.75-fold higher than those (n = 8) under the ToGA surgical specimen method (28.57% vs. 16.32%). Therefore, compared to ToGA surgery specimen method, the ToGA biopsy method caused more equivocal IHC cases to be referred to FISH testing and did not increase the detection rates of Her2 FISH amplification.     

Atypical primary biliary cholangitis results in vanishing bile duct syndrome with cutaneous xanthomas: a case report

Former single center studies indicated that HER2 assessment with two primary tumor blocks (dual block HER2 assessment) could be an efficient and practical approach to overcome the adverse impact of heterogeneity and acquire a HER2 positive rate in gastric cancer (GC). This multicenter prospective clinical trial (NCT 02843412) was launched to verify its value and generality. A total of 3806 participants with primary GCs have been enrolled from 8 hospitals in China. Two primary tumor blocks were selected and recorded as block 1 and block 2 after histological evaluation. An HER2 (4B5) rabbit monoclonal antibody was used for the immunohistochemistry (IHC) analysis. In total patients, HER2 IHC positive (3+) rate with dual block assessment (9.4%) was higher than that with single block assessment (block 1: 7.8%, block 2: 7.8%) (P < 0.001). Compared with single-block assessment, dual-block assessment increased the positive rate by approximate 20%. Similarly, HER2 equivocal (2+) rate was increased in dual block assessment (25.8%), which was higher than that in single block assessment (block 1: 20.3%, block 2: 20.9%) (P < 0.001). Conversely, dual block assessment demonstrated a lower HER2 negative (0/1+) rate (64.8%) than single block assessment (block1: 71.9%, block 2: 71.3%) (P < 0.001). These findings were also confirmed in individual hospitals. Dual block HER2 assessment effectively increased HER2 IHC positive rate in resected specimens of GC. We recommended dual block HER2 assessment be promoted in routine clinical practice in GC. ClinicalTrials.gov, NCT 02843412 . Registered 1 July 2016 - Retrospectively registered.     

Impact of Modified 2013 ASCO/CAP Guidelines on HER2 Testing in Breast Cancer. One Year Experience

Introduction

The latest guidelines of the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) to test Human Epidermal Growth Factor Receptor 2 (HER2) in breast cancer after being revised in 2008 underwent a second modification in October 2013. The modification includes changes in cut-offs: 10% strong membranous staining for score 3+ on immunohistochemistry (IHC) (previously 30%) and using the ratio of >2 or absolute gene-copy-number (6 or more) alone or in combination with each other by in-situ-hybridisation technology (previously >2.2 and average copy-number of 6 or more). Hereby we addressed the question, which impact the modified cut-offs had on overall HER2-positivity in a single institution.

Methods

We prospectively analysed 617 consecutive diagnostic breast-cancer cases which underwent double HER2 testing by immunohistochemistry and fluorescent in-situ hybridisation (FISH), using the modified 2013 ASCO/CAP-guidelines for one year (October 2013–October 2014). Results were compared with HER2-test results on 1,528 consecutive diagnostic breast-cancer cases from two previous years (2011–2012), using the 2008 ASCO/CAP guidelines, also tested with IHC and FISH in each case.

Results

Between October 2013 and October 2014, overall HER2-positivity was 15.8% (98 of 617 cases were either IHC 3+ or FISH amplified). 79 of 617 cases (13%) were IHC 3+, 96 of 617 cases (15.5%) were FISH amplified. Equivocal cases were seen in 25 of 617 cases (4.1%). 22 of 25 equivocal cases (88%) in 2013–2014 were IHC 1+ or 2+. In 13 equivocal cases, there was a repeated IHC/FISH testing: 2 of 13 cases (15%) became FISH amplified, 1 of 13 cases (7.5%) became IHC 3+. In 2011–2012, overall HER2-positivity (IHC/FISH) was 13.8% (211 of 1,528 cases). 185 of 1,528 cases (12%) were 3+ on IHC, 181 of 1,522 cases (12%) were amplified by FISH. Six of 1,528 cases were equivocal by FISH, and interpreted as non-amplified (0.3%).

Conclusions

Applying the modified ASCO/CAP guidelines from 2013 resulted in an increase (2%) in overall HER2-positivity rate compared to overall-HER2-positivity rate using the 2008 ASCO/CAP guidelines. The increased positivity rate was mainly due to more FISH-positive cases (3.5% more than until 2013). The high rate of equivocal cases (4.1%) did not contribute to increase in overall HER2-positivity, but resulted in delay in definitive HER2-status.     

Fully Automated Fluorescent in situ Hybridization (FISH) Staining and Digital Analysis of HER2 in Breast Cancer: A Validation Study

HER2 assessment is routinely used to select patients with invasive breast cancer that might benefit from HER2-targeted therapy. The aim of this study was to validate a fully automated in situ hybridization (ISH) procedure that combines the automated Leica HER2 fluorescent ISH system for Bond with supervised automated analysis with the Visia imaging D-Sight digital imaging platform. HER2 assessment was performed on 328 formalin-fixed/paraffin-embedded invasive breast cancer tumors on tissue microarrays (TMA) and 100 (50 selected IHC 2+ and 50 random IHC scores) full-sized slides of resections/biopsies obtained for diagnostic purposes previously. For digital analysis slides were pre-screened at 20x and 100x magnification for all fluorescent signals and supervised-automated scoring was performed on at least two pictures (in total at least 20 nuclei were counted) with the D-Sight HER2 FISH analysis module by two observers independently. Results were compared to data obtained previously with the manual Abbott FISH test. The overall agreement with Abbott FISH data among TMA samples and 50 selected IHC 2+ cases was 98.8% (κ = 0.94) and 93.8% (κ = 0.88), respectively. The results of 50 additionally tested unselected IHC cases were concordant with previously obtained IHC and/or FISH data. The combination of the Leica FISH system with the D-Sight digital imaging platform is a feasible method for HER2 assessment in routine clinical practice for patients with invasive breast cancer.     

Anaplastic Lymphoma Kinase Rearrangement in Digestive Tract Cancer: Implication for Targeted Therapy in Chinese Population

Background

Anaplastic lymphoma kinase (ALK) rearrangements define a subgroup of lung cancer which is eligible to targeted kinase inhibition. The aim of this study is to observe the incidence rate of ALK fusion in a large cohort of Chinese digestive tract cancer patients.

Patients and Methods

Tissue microarray (TMA) was constructed from 808 digestive tract cancer cases, including 169 esophageal squamous cell carcinoma, 182 gastric cancer and 457 colorectal cancer (CRC) cases. We tested all cases for ALK expression via a fully automated immunohistochemistry (IHC) assay. The IHC-positive cases were subjected to fluorescence in situ hybridization (FISH), real-time polymerase chain reaction (qRT-PCR), target gene enrichment and sequencing for confirmation of ALK gene rearrangement and discovery of novel fusion partner.

Results

Among the tested cases, 2 (0.44%) CRC cases showed positive both by IHC and FISH. By qRT-PCR, EML4–ALK fusion was found in one IHC-positive CRC case. In another IHC-positive CRC case, target gene enrichment and sequencing revealed ALK was fused to a novel partner, spectrin beta non-erythrocytic 1 (SPTBN1). One gastric cancer case showed partially positive IHC result, but no fusion was found by FISH and gene sequencing.

Conclusions

The incidence rate of ALK gene fusion in Chinese CRC patients was 0.44%,but not detectable in gastric and esophageal cancers. The novel SPTBN1 -ALK fusion, together with other ALK fusion genes, may become a potential target for anti-ALK therapy.     

HER2 Status in Gastric and Gastroesophageal Junction Cancer Assessed by Local and Central Laboratories: Chinese Results of the HER-EAGLE Study

Trastuzumab has been approved for human epidermal growth factor receptor 2 (HER2)-positive advanced gastric and gastroesophageal junction cancers (GC and GJC) in combination with chemotherapy. The aim of this HER2 early/advanced gastric epidemiology (HER-EAGLE) study was to evaluate the frequency of HER2 over-expression and to evaluate agreement on HER2 status assessment in GC and GJC patients in local laboratories versus a central laboratory in China. Tumor samples from 734 GC or GJC patients who were enrolled at 11 different hospitals in China were examined. HER2 status was assessed by immunohistochemistry (IHC), and followed by dual-color silver-enhanced in Situ hybridization (DSISH) in IHC 2+ cases. Clinicopathologic characteristics were collected from all of the patients. HER2-positive tumors were identified in 12.0% (88/734) of the GC and GJC cases. There were significantly higher rates of HER2 positivity in patients with GJC (GJC: 18.1%, GC: 9.7%, P=0.002), and intestinal-type cancers using the Lauren classification (intestinal: 23.6%, diffuse/mixed: 4.3%, P<0.0001). No significant difference in HER2 positivity was identified between resection and biopsy samples, or between early and advanced disease stages. The agreement between local laboratories and the central laboratory on HER2 status scoring was good (kappa=0.86). The main reason of HER2 status discordance between local and the central laboratories was IHC result mis-interpretation in local laboratories. These results suggest that IHC followed by DSISH testing is an accurate and cost-effective procedure in China.     

Reverse-phase protein microarray highlights HER2 signaling activation in immunohistochemistry/FISH/HER2-negative breast cancers

Evaluation of: Wulfkuhle JD, Berg D, Wolff C et al. Molecular analysis of HER2 signaling in human breast cancer by functional protein pathway activation mapping. Clin. Cancer Res. 18(23), 6426–6435 (2012).

Exhaustive characterization and mapping of pivotal molecules and downstream effectors deregulated in breast cancer is of fundamental clinical value to define the most effective therapy. Wulfkuhle et al. applied reverse-phase protein microarray, a highly sensitive immunoassay able to perform quantitative and multiplexed analysis of total and/or modified cellular proteins, to assess protein levels and activation/phosphorylation status of the HER family (EGFR, HER2, HER3) and downstream signaling molecules in HER2⁺ and HER2^- breast cancers. The research was performed using laser capture microdissected tumor epithelial cells from frozen samples and formalin-fixed paraffin embedded specimens, which were also analyzed by immunohistochemistry (IHC) and FISH. This study identified a subgroup of IHC/FISH/HER2^- patients with HER2 activation/phosphorylation levels comparable with those obtained from IHC/FISH/HER2⁺ tumors. HER2 signaling activation was independent from total HER2 expression and involved HER3 and EGFR activation. These findings indicate that molecular characterization by reverse-phase protein microarray of HER2 and its partners/effectors in the signaling cascade enables the identification of a subgroup of IHC/FISH/HER2^- patients showing HER2 signaling activation. These patients, currently excluded from targeted therapy administration, could potentially benefit from this and it could improve prognosis and survival.     

胃癌HER2蛋白表达及基因拷贝分析

目的：探讨胃癌组织HER2蛋白表达和基因拷贝数增加频率,以及蛋白表达与基因拷贝数之间的相关性。方法：分别采用免疫组织化学（1HC）和显色原位杂交（ClSH）方法,检测80例青岛人胃癌组织中HER2蛋白表达和基因扩增情况。结果：HER2免疫组织化学0者51例、1＋者12例、2＋者12例、3＋者5例。通过CISH分析：这组患者中HER2基因拷贝数扩增者共7例（8．8％）,其中包括基因临界扩增3例（3．8％）。HER2的蛋白表达与基因拷贝数增加相关（P〈0．05）,这两个指标与肿瘤分化程度相关。HER2免疫组织化学3＋和基因扩增结果一致,与乳腺癌相似。结论：这组患者中,具有较高的HER2蛋白表达和基因拷贝数增加的比率,基因扩增可能是其蛋白过表达的主要分子机制。     

Overexpression of HER2/neu oncoprotein in cytologic specimens

OBJECTIVE: To assess the rate of HER2/neu overexpression in cytologic specimens by immunocytochemistry (ICC) and compare these results in matched surgical specimens by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), when available. STUDY DESIGN: All cytologic specimens processed for HER2/neu evaluation by ICC (72 cases) and available corresponding histologic specimens (16 cases) were retrieved from our files. ICC was applied to previously Papanicolaou stained, routine fine needle aspirations specimens (64 cases) and cytocentrifuged, alcohol-fixed, fluid specimens (8 cases). FISH was performed on 6 histologic specimens. RESULTS: Overexpression of HER2/neu was seen in 7/22 breast cancers (31.8%), 3/18 pulmonary adenocarcinomas (16.6%), 2/5 colorectal adenocarcinomas (40%), 1/2 adenocarcinomas of the biliary system (50%), 1/3 thyroid papillary carcinomas (33.3%) and 1/3 prostate adenocarcinomas (33.3%). Sixteen cases had IHC in matched histologic specimens: 14 (87.5%) cases were concordant (11 negative and 3 positive in both specimens), 1 case was negative in the cytologic specimen and positive in the histologic specimen (with no amplification by FISH), and 1 case was positive in the cytologic specimen and negative in the histologic specimen (not informative by FISH). CONCLUSION: Our data suggest that overexpression of HER2/neu oncoprotein can be successfully detected in routine cytologic specimens, providing a simple, fast and cost-effective method of selecting patients for specific treatment.     

Common protein biomarkers assessed by reverse phase protein arrays show considerable intratumoral heterogeneity in breast cancer tissues

Proteins are used as prognostic and predictive biomarkers in breast cancer. However, the variability of protein expression within the same tumor is not well studied. The aim of this study was to assess intratumoral heterogeneity in protein expression levels by reverse-phase-protein-arrays (RPPA) (i) within primary breast cancers and (ii) between axillary lymph node metastases from the same patient. Protein was extracted from 106 paraffin-embedded samples from 15 large (≥3 cm) primary invasive breast cancers, including different zones within the primary tumor (peripheral, intermediate, central) as well as 2-5 axillary lymph node metastases in 8 cases. Expression of 35 proteins including 15 phosphorylated proteins representing the HER2, EGFR, and uPA/PAI-1 signaling pathways was assessed using reverse-phase-protein-arrays. All 35 proteins showed considerable intratumoral heterogeneity within primary breast cancers with a mean coefficient of variation (CV) of 31% (range 22-43%). There were no significant differences between phosphorylated (CV 32%) and non-phosphorylated proteins (CV 31%) and in the extent of intratumoral heterogeneity within a defined tumor zone (CV 28%, range 18-38%) or between different tumor zones (CV 24%, range 17-38%). Lymph node metastases from the same patient showed a similar heterogeneity in protein expression (CV 27%, range 18-34%). In comparison, the variation amongst different patients was higher in primary tumors (CV 51%, range 29-98%) and lymph node metastases (CV 65%, range 40-146%). Several proteins showed significant differential expression between different tumor stages, grades, histological subtypes and hormone receptor status. Commonly used protein biomarkers of breast cancer, including proteins from HER2, uPA/PAI-1 and EGFR signaling pathways showed higher than previously reported intratumoral heterogeneity of expression levels both within primary breast cancers and between lymph node metastases from the same patient. Assessment of proteins as diagnostic or prognostic markers may require tumor sampling in several distinct locations to avoid sampling bias.     

Tissue microarray-based immunohistochemical study can significantly underestimate the expression of HER2 and progesterone receptor in ductal carcinoma in situ of the breast

Abstract

The accuracy of immunohistochemical (IHC) analysis on tissue microarray (TMA)-based studies largely depends on the uniformity of the staining pattern for a given antibody and minimal intratumor heterogeneity of a given tumor. Our study was designed to investigate the concordance of expression in TMA and whole sections of estrogen receptor (ER), progesterone receptor (PR) and HER2 using IHC analysis for ductal carcinoma in situ (DCIS) of the breast. Seventy-five consecutive cases of DCIS were retrieved, reviewed and used to construct the TMA. IHC analysis of the expression of ER, PR, and HER2 were performed on TMA and whole sections of the corresponding cases, and the results were compared. The specificity and sensitivity for TMA-based assays were 87.0, 75.9, 90.6 and 90.4%, and 76.1, 27.3 for ER, PR and HER2, respectively. The concordance and discordance were 89.3, 76.0 and 72.0%, and 6.7, 13.3 and 16.0% for ER, PR, HER2, respectively. The kappa values were 0.83, 0.89 and 0.42 for ER, PR and HER2, respectively. The non-concordance rates were inversely related to core number, with 46.67, 22.67 and 11.56% for one core, two cores, and three cores, respectively, per marker per case (p < 0.001), but not associated with tumor size. Our results showed that the intratumor heterogeneity and the number of cores have a great impact on the results of TMA-based studies. Increasing the number of tissue cores per case may help improve the accuracy and concordance with whole section results. Although TMA remains an effective tool for translational research, we should be cautious in our interpretation of these results.     

The use of TMA for interlaboratory validation of FISH testing for detection of HER2 gene amplification in breast cancer.

HER2 fluorescence in situ hybridization (FISH) testing for breast cancer is largely limited to academic centers and commercial laboratories. As testing demands increase, methods for rapid and cost-effective technical validation and quality assessment will be required. Tissue microarray (TMA), a technique for high-throughput biomarker evaluation, could help facilitate these needs. Our objective was to assess the usefulness of TMA technology for validation of HER2 FISH testing. Two TMA blocks containing paired cores from 41 breast cancers were constructed. HER2 FISH was performed in parallel at two institutions and the results compared. One institution, with considerable HER2 FISH experience, served as the reference laboratory. HER2 chromogenic in situ hybridization (CISH) and immunohistochemistry (IHC) were compared to the FISH results. For positive and negative results, the concordance rate between laboratories was 100%. Using kappa statistical analysis to determine interobserver agreement, HER2 to chromosome 17 gene copy ratios showed strong agreement between laboratories with kappa = 0.85 (perfect agreement = 1.0). Four cases displaying low-level amplification by CISH contained chromosome 17 polysomy and gene copy ratios of <2.0 by FISH. Good concordance was observed between HER2 IHC and in situ hybridization testing. TMA is a robust and effective method for the technical validation of HER2 FISH testing and should be considered for use by quality assessment programs.     

HER2 status in ovarian carcinomas: a multicenter GINECO study of 320 patients

Background

Despite a typically good response to first-line combination chemotherapy, the prognosis for patients with advanced ovarian cancer remains poor because of acquired chemoresistance. The use of targeted therapies such as trastuzumab may potentially improve outcomes for patients with ovarian cancer. HER2 overexpression/amplification has been reported in ovarian cancer, but the exact percentage of HER2-positive tumors varies widely in the literature. In this study, HER2 gene status was evaluated in a large, multicentric series of 320 patients with advanced ovarian cancer, including 243 patients enrolled in a multicenter prospective clinical trial of paclitaxel/carboplatin-based chemotherapy.

Methodology/Principal Findings

The HER2 status of primary tumors and metastases was evaluated by both immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) analysis of paraffin-embedded tissue on conventional slides. The prognostic impact of HER2 expression was analyzed. HER2 gene was overexpressed and amplified in 6.6% of analyzed tumors. Despite frequent intratumoral heterogeneity, no statistically significant difference was detected between primary tumors and corresponding metastases.

Conclusions/Significance

Our results show that the decision algorithm usually used in breast cancer (IHC as a screening test, with equivocal results confirmed by FISH) is appropriate in ovarian cancer. In contrast to previous series, HER2-positive status did not influence outcome in the present study, possibly due to the fact that patients in our study received paclitaxel/carboplatin-based chemotherapy. This raises the question of whether HER2 status and paclitaxel sensitively are linked.     

Comparison of chromogenic <Emphasis Type="Italic">in situ</Emphasis> hybridization with other methodologies for HER2 status assesment in breast cancer

The high incidence of human epidermal growth factor receptor (HER)2 overexpression on breast and various other cancer cells and the prognostic and potentially predictive value of HER2 render this growth receptor a novel and important therapeutic target. Out of a wide range of assays that have been used in research for the detection of HER2 status, only two techniques are now predominant and readily applicable in the routine clinical pathology laboratory: determination of HER2 overexpression by immunohistochemistry (IHC) and HER2 gene amplification by fluorescence in situ hybridisation (FISH). In a retrospective study on a cohort of 173 archival invasive breast carcinomas a chromogenic in situ hybridisation (CISH) assay for the detection of HER2 amplification was established. Results were compared to HercepTest, which is the most frequently used method for detecting HER2 alteration. Additionally, HER2 gene copy number was investigated using differential PCR (dPCR) as a testing system. Discrepant cases between CISH and HercepTest and all IHC positive cases (2+ and 3+), a total of 42 cases, were analysed with FISH Path Vysion (Vysis) assay. HER2 overexpression was found by IHC in 24.3%, HER2 amplification by CISH in 19.1% and by dPCR in 9.2% of the tumours. The overall concordance rate between CISH and IHC was 95.9%, between dPCR and IHC 85% and between CISH and FISH 100%, respectively. Among 25 HercepTest positive cases (score 3+) two showed no gene amplification and four out of 13 tumours with score 2+ were negative with CISH and FISH. The current study showed that CISH offers an ideal approach that allows detection of HER2 amplification in the context of morphology, whereas the major drawback of dPCR is the impracticability of tissue differentiation of invasive and non-invasive carcinoma.     

c-erbB-2 expression in breast cancer detected by immunoblotting and immunohistochemistry

Evidence that the c-erbB-2 proto-oncogene is important in prognosis and oncogenesis in a number of human malignancies is increasing. DNA (Southern) hybridization and immunoblotting (Western) techniques are most commonly utilized to determine the amplification and protein expression of this proto-oncogene, respectively. These extraction techniques are often time consuming, costly, and subject to variability depending on the histological characteristics of the tumor. Immunohistochemistry (IHC), on the other hand, is more often time and cost effective. In addition, IHC may offer enhanced sensitivity over extraction techniques because of the in situ nature of analysis. In data presented here, 71 cases of human mammary carcinoma were concomitantly assessed for c-erbB-2 gene copy number and oncoprotein expression by dilution DNA hybridization and IHC, respectively. In 65 (92%) of 71 cases, high-level expression was associated with gene amplification, whereas moderate or low-level expression was associated with a normal diploid gene copy number. In five of the six discrepant cases, IHC predicted amplification which was not corroborated by Southern analysis. In these cases, tumor mass was limited by the intraductal component of the lesion or by an abundance of stromal elements within the specimen. In 39 of the 71 total cases, Western immunoblotting was compared with IHC in the assessment of oncoprotein expression. Concordance was found in 33 (85%) of 39 cases. In four of the six discrepant cases, high levels of c-erbB-2 expression were demonstrated by IHC but not by immunoblotting. In these cases, intraductal disease and stroma-rich tumors again led to a relative paucity of neoplastic tissue within the specimens. We conclude that IHC offers a favorable alternative to either Southern analysis or Western immunoblotting in the assessment of c-erbB-2 gene copy number and expression levels of oncoprotein in human mammary carcinoma. Furthermore, IHC may prove advantageous to either extraction technique in specimens with limited tumor mass, such as biopsy materials, stroma-rich tumors, or early stage lesions such as intraductal carcinoma.