HER2 status in gastro-oesophageal adenocarcinomas assessed by two rabbit monoclonal antibodies (SP3 and 4B5) and two in situ hybridization methods (FISH and SISH)

Principles of Analytic Validation of Immunohistochemical Assays: Guideline Update

CONTEXT.—

In 2014, the College of American Pathologists developed an evidence-based guideline to address analytic validation of immunohistochemical assays. Fourteen recommendations were offered. Per the National Academy of Medicine standards for developing trustworthy guidelines, guidelines should be updated when new evidence suggests modifications.

OBJECTIVE.—

To assess evidence published since the release of the original guideline and develop updated evidence-based recommendations.

DESIGN.—

The College of American Pathologists convened an expert panel to perform a systematic review of the literature and update the original guideline recommendations using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS.—

Two strong recommendations, 1 conditional recommendation, and 12 good practice statements are offered in this updated guideline. They address analytic validation or verification of predictive and nonpredictive assays, and recommended revalidation procedures following changes in assay conditions.

CONCLUSIONS.—

While many of the original guideline statements remain similar, new recommendations address analytic validation of assays with distinct scoring systems, such as programmed death receptor-1 and analytic verification of US Food and Drug Administration approved/cleared assays; more specific guidance is offered for validating immunohistochemistry performed on cytology specimens.

What Therapeutic Biomarkers in Gastro-Esophageal Junction and Gastric Cancer Should a Pathologist Know About?

Malignancies of upper gastrointestinal tract are aggressive, and most locally advanced unresectable and metastatic cancers are managed by a combination of surgery and neoadjuvant/adjuvant chemotherapy and radiotherapy. Current therapeutic recommendations include targeted therapies based on biomarker expression of an individual tumor. All G/gastro-esophageal junction (GEJ) cancers should be tested for HER2 status as a reflex test at the time of diagnosis. Currently, testing for PDL 1 and mismatch repair protein status is optional. HER2 testing is restricted to adenocarcinomas only and endoscopic biopsies, resections, or cellblocks. Facilities should be available for performing validated immunohistochemical stains and in-situ hybridization techniques, and importantly, pathologists should be experienced with preanalytical and analytical issues and scoring criteria. Genomic profiling via next-generation sequencing (NGS) is another strategy that assess numerous mutations and other molecular events simultaneously, including HER2 amplification, MSS status, tumor mutation burden, and neurotrophic tropomyosin-receptor kinases gene fusions.

Deviating HER2 test results in gastric cancer: analysis from the prospective multicenter VARIANZ study

PURPOSE

The prospective multicenter VARIANZ study aimed to identify resistance biomarkers for HER2-targeted treatment in advanced gastric and esophago-gastric junction cancer (GC, EGJC). HER2 test deviations were found in 90 (22.3%) of 404 cases (central versus local testing) and were associated with negative impact on survival for trastuzumab-treated patients. Here, we investigated methodological and biological variables that may promote deviating HER2 test results.

METHODS

We analyzed HER2 testing procedures and participation in quality assurance programs of 105 participating local pathology laboratories. Furthermore, tumor localization and histological subtypes were compared between patients with centrally confirmed (central HER2 + /local HER2 + , n = 68) and unconfirmed HER2 status (central HER2 -/local HER2 + , n = 68).

RESULTS

For central HER2 testing, concordance between in situ hybridization (ISH) and immunohistochemistry (IHC) was 98.3%, with IHC sensitivity of 93.3% (84 IHC + of 90 ISH +), specificity of 99.5% (389 IHC- of 391 ISH-), and a positive diagnosis rate of 97.7%. Central confirmation of the local HER2 IHC scores were seen for the majority of locally HER2- IHC 0/1 (172/178; 96.6%), but less frequently for locally IHC3 + (57/124; 46.0%) cases. Deviation rate was not associated with IHC antibody platform used in the local pathology institute neither with participation in quality-assuring tests. Regarding tumor characteristics, deviating test results were more frequently found in GC vs. EGJC (69.1% vs. 39.7%; p = 0.001) and in Laurén diffuse vs. intestinal subtype (23.5% vs. 5.9%, p = 0.004).

CONCLUSION

Tumor localization and histological subtype have an impact on HER2 test deviation rates. Assessment of HER2 remains challenging for GC and EGJC.

Human epidermal growth factor receptor-2 gene expression positivity determined by silver in situ hybridization/immunohistochemistry methods and associated factors in a cohort of Sri Lankan patients with gastric adenocarcinoma: a prospective study

OBJECTIVE

Positive human epidermal growth factor 2 (HER2) expression and its predictive clinicopathological features remain unclear in Sri Lankan gastric cancer (GC) patients. Here, we aimed to determine GC HER2 status predictors by analyzing associations between clinicopathological features and HER2 expression using immunohistochemistry (IHC) and silver in situ hybridization (SISH).

METHODS

During this 4-year prospective study, clinicopathological data were collected from participants in the National Hospital of Sri Lanka. HER2 IHC and SISH were performed using commercial reagents. Using chi-square tests, associations of HER2-IHC/SISH with clinicopathological features were analyzed.

RESULTS

Overall, 145 GC patients were included, 69 had gastrectomies and 76 had biopsies. Positive HER2 expression by IHC was associated with age <60 years, high T stage (assessed pathologically in resections and radiologically in biopsies), high nuclear grade, tumor necrosis, mitosis >5/high-power field, with additional perineural invasion and lymphovascular invasion in resections. These features, excluding lymphovascular invasion but including male sex, were associated with HER2 expression by SISH.

CONCLUSIONS

Age <60 years, high nuclear grade, tumor necrosis, and perineural invasion are associated factors of HER2 status. These could be used to triage GC patients for HER2 status testing in limited resource settings where IHC/SISH analysis is costly.

HER2 Heterogeneity in Gastric Cancer: A Comparative Study, Using Two Commercial Antibodies

BACKGROUND

Although amplification of the gene encoding human epidermal growth factor receptor 2 (HER2) is used as an indicator for response to trastuzumab, the reported response rate is low, and few patients with gastric cancer (GC) benefit from this individualized therapy. The aim of this study was to examine the expression of c-erbB-2 oncoprotein (HER2), in GC samples, using two commercial immunohistochemical (IHC) antibodies, and to validate the results by checking HER2 gene amplification by fluorescence in situ hybridization (FISH).

METHODS

We assessed the IHC expression of HER2 using the polyclonal antibody from Dako and CB11 clone from Leica, in 93 consecutive cases of GC samples. In all of the cases, FISH analysis was also performed using the BOND-MAX platform.

RESULTS

No significant difference was observed between the two HER2 antibodies. Of the 93 cases, 22.58% demonstrated at least focal and 1+ HER2 positivity. Seven cases (7.53%) exhibited 3+ expression, and another 7 carcinomas (7.53%) were equivocal (2+). HER2 amplification was seen in 11 cases (11.83%), 10 of which were differentiated adenocarcinomas. In 5 of the cases, 2-5 sections were examined, which proved the extremely high intratumorally/intraglandular heterogeneity. FISH heterogeneity was higher in cases with only 2+ positivity on IHC assessment, compared with those showing at least one small focus of 3+ overexpression. HER2 amplification proved to be an independent negative prognostic factor.

CONCLUSIONS

Due to the highly heterogeneous aspect of GC, at least 3-4 slides should be assessed by IHC, before considering a tumor to be HER2-negative. In cases with small 3+ foci representing less than 5% of tumor and in equivocal (2+) cases, FISH analysis remains the gold standard method.

HER2, NF-κB, and SATB1 Expression Patterns in Gastric Cancer and Their Correlation with Clinical and Pathological Parameters

Gastric cancer (GC) is currently recognized as one of the most common and fatal tumor worldwide. The identification of novel biomarkers in relation to clinical information as well as extending the knowledge on a multiple crosstalk between various oncogenic pathways implicated in GC carcinogenesis seems pivotal to limit the disease-associated mortality. Therefore, we assessed the expression of HER2, NF-κB, and SATB1 in a total of 104 gastric adenocarcinomas and 30 normal gastric samples and correlated the expression patterns with each other and with some clinicopathological variables. Protein expression was examined by immunohistochemistry (IHC) on tissue microarrays (TMAs), and fluorescence in situ hybridization (FISH) was employed to detect HER2 amplification. In the studied group, HER2 and SATB1 were found to be overexpressed in gastric cancer tissue in comparison to normal gastric mucosa. The expression status of the former protein was seen to differ according to some clinicopathological features, but without statistical significance, whereas the expression of the latter was not importantly associated with any of them. In turn, the NF-κB protein level was significantly related to the presence of lymph node metastasis. HER2 expression was not significantly correlated with that of other proteins, but a positive correlation was found between the expression of SATB1 and NF-κB. Further studies with a larger group of patients combined with in vitro mechanistic experiments are required to fully elucidate the role and relationship of HER2, NF-κB, and SATB1 expression in gastric cancer progression. However, to the best of our knowledge, this study is the first look at a simultaneous evaluation of these three markers in the samples of gastric cancer patients.

Molecular biomarkers in gastro-esophageal cancer: recent developments, current trends and future directions

Gastro-esophageal adenocarcinomas (GEA) represent a severe global health burden and despite improvements in the multimodality treatment of these malignancies the prognosis of patients remains poor. HER2 overexpression/amplification has been the first predictive biomarker approved in clinical practice to guide patient selection for targeted treatment with trastuzumab in advanced gastric and gastro-esophageal junction cancers. More recently, immunotherapy has been approved for the treatment of GEA and PD-L1 expression is now a biomarker required for the administration of pembrolizumab in these diseases. Significant progress has been made in recent years in dissecting the genomic makeup of GEA in order to identify distinct molecular subtypes linked to distinct patterns of molecular alterations. GEA have been found to be highly heterogeneous malignances, representing a challenge for biomarkers discovery and targeted treatment development. The current review focuses on an overview of established and novel promising biomarkers in GEA, covering recent molecular classifications from TCGA and ACRG. Main elements of molecular heterogeneity are discussed, as well as emerging mechanisms of primary and secondary resistance to HER2 targeted treatment and recent biomarker-driven trials. Future perspectives on the role of epigenetics, miRNA/lncRNA and liquid biopsy, and patient-derived xenograft models as a new platform for molecular-targeted drug discovery in GEA are presented. Our knowledge on the genomic landscape of GEA continues to evolve, uncovering the high heterogeneity and deep complexity of these tumors. The availability of new technologies and the identification of promising novel biomarker will be critical to optimize targeted treatment development in a setting where therapeutic options are currently lacking. Nevertheless, clinical validation of novel biomarkers and treatment strategies still represents an issue.

The dynamics of HER2 status in esophageal adenocarcinoma

Trastuzumab, a monoclonal antibody against HER2, has become standard of care for metastatic HER2-overexpressing esophagogastric adenocarcinoma and is currently investigated as (neo)adjuvant treatment option in HER2-positive esophagogastric adenocarcinoma. The HER2 status is commonly determined on archived material of the primary tumor. However, this status may change over the course of treatment or disease progression. The aim of this study was to assess the dynamics of HER2 status in esophageal adenocarcinoma (EAC) in patients with resectable and recurrent disease, and to determine the associations of these changes with clinical outcome. Discordance, defined as any change in HER2 status between matched biopsy and post-neoadjuvant chemoradiation therapy resection specimen (N = 170), or between matched resection specimen and recurrence of patients not eligible for curative treatment (N = 61), was determined using the standardized HER2 status scoring system. Clinically relevant positive discordance was defined as a change to HER2 positive status, as this would imply eligibility for HER2-targeted therapy. A difference in HER2 status between biopsy and resection specimen and resection specimen and metachronous recurrence was observed in 2.1% (n = 3) and 3.3% (n = 2) of the paired cases, respectively. Clinically relevant discordance was detected in 1.4% (n = 2) of the resectable patients and 1.6% (n = 1) of the patients with recurrent disease. Patients with HER2-positive status tumors before start of neoadjuvant treatment showed better overall survival, but not statistically significant. No association between HER2 status discordance and survival was found. Clinically relevant HER2 status discordance was observed and in order to prevent under-treatment of patients, the assessment of HER2 status in the metastatic setting should preferably be performed on the most recently developed lesions if the previous HER2 assessment on archival material of the primary tumor was negative.

Diagnostic, Predictive, Prognostic, and Therapeutic Molecular Biomarkers in Third Millennium: A Breakthrough in Gastric Cancer

Introduction

Gastric cancer is the fifth most common cancer and the third cause of cancer death. The clinical outcomes of the patients are still not encouraging with a low rate of 5 years' survival. Often the disease is diagnosed at advanced stages and this obviously negatively affects patients outcomes. A deep understanding of molecular basis of gastric cancer can lead to the identification of diagnostic, predictive, prognostic, and therapeutic biomarkers.

Main Body

This paper aims to give a global view on the molecular classification and mechanisms involved in the development of the tumour and on the biomarkers for gastric cancer. We discuss the role of E-cadherin, HER2, fibroblast growth factor receptor (FGFR), MET, human epidermal growth factor receptor (EGFR), hepatocyte growth factor receptor (HGFR), mammalian target of rapamycin (mTOR), microsatellite instability (MSI), PD-L1, and TP53. We have also considered in this manuscript new emerging biomarkers as matrix metalloproteases (MMPs), microRNAs, and long noncoding RNAs (lncRNAs).

Conclusions

Identifying and validating diagnostic, prognostic, predictive, and therapeutic biomarkers will have a huge impact on patients outcomes as they will allow early detection of tumours and also guide the choice of a targeted therapy based on specific molecular features of the cancer.

Human Epidermal Growth Factor Receptor-2 in Sri Lankan Gastric Carcinoma Patients with Clinicopathological Association and Survival

BACKGROUND

HER2 protein expression indicates adverse prognosis in gastric adenocarcinoma (GCa). GCa HER2 positivity ranges from 10 to 22.8%. Similar data are scarce in South Asia and unavailable in Sri Lanka.

AIM

To evaluate HER2 protein expression, its clinicopathological relationship and survival in a Sri Lankan GCa cohort.

METHODS

One hundred consecutive GCa patients were recruited prospectively for 2 years. Histological diagnosis was confirmed on endoscopic biopsies/gastrectomy specimens. Clinicopathological and overall survival data were collected. HER2 expression was assessed using immunohistochemistry. 2+ and 3+ scores were considered positive. HER2 expression and clinicopathological parameters were analyzed by Chi-squared test and multivariate analysis with logistic regression using SPSS-21. Kaplan-Meier method and log-rank test were used for survival analysis.

RESULTS

Study includes 56 biopsies and 44 resections. Male/female ratio was 1.9:1. Mean age of diagnosis was 61.1 years (range 32-82). Majority tumors were proximally located (58%). HER2 positivity was 9%. Even though intestinal subtype predominated HER2 positivity was mostly among diffuse variant (14.8%). In multivariate analysis, mitotic count >5/hpf, high nuclear grade and tumor necrosis were significantly associated with HER2 positivity, while poor differentiation, signet cells, extracellular mucin, perineural invasion and pathological nodal metastasis (all p < 0.05) showed a correlation in univariate analysis. Mean follow-up duration was 37.4 weeks (range 0-104). HER2 positivity was associated with a significantly lower median overall survival (p = 0.046).

CONCLUSION

GCa HER2 positivity was 9%, associated with a lower median overall survival. Adverse histological features had a positive correlation with HER2 positivity. These histological features could direct patients for confirmatory HER2 testing in limited resource settings.

Development of a highly specific HER2 monoclonal antibody for immunohistochemistry using protein microarray chips

HER2 is an orphan receptor tyrosine kinase of the EGFR families and is considered to be a key tumor driver gene [1]. Breast cancer and gastric cancer with HER2 amplification can be effectively treated by its neutralizing antibody, Herceptin. In clinic, Immunohistochemistry (IHC) was used as the primary screening method to diagnose HER2 amplification [2]. However, recent evidence suggested that the frequently used rabbit HER2 antibody 4B5 cross reacted with another family member HER4 [3]. IHC staining with 4B5 also indicated that there was strong non-specific cytoplasmic and nuclear signals in normal gastric mucosal cells and some gastric cancer samples. Using a protein lysate array which covers 85% of the human proteome, we have confirmed that the 4B5 bound to HER4 and a nuclear protein ZSCAN18 besides HER2. The non-specific binding accounts for the unexpected cytoplasmic and nuclear staining of 4B5 of normal gastric epithelium. Finally, we have developed a novel mouse HER2 monoclonal antibody UMAB36 with similar sensitivity to 4B5 but only reacted to HER2 across the 17,000 proteins on the protein chip. In 129 breast cancer and 158 gastric cancer samples, UMAB36 showed 100% sensitivity and specificity comparing to the HER2 FISH reference results with no unspecific staining in the gastric mucosa layer. Therefore, UMAB36 could provide as an alternative highly specific IHC reagent for testing HER2 amplification in gastric cancer populations.

HER2 Testing and Clinical Decision Making in Gastroesophageal Adenocarcinoma: Guideline From the College of American Pathologists, American Society for Clinical Pathology, and the American Society of Clinical Oncology

Context ERBB2 (erb-b2 receptor tyrosine kinase 2 or HER2) is currently the only biomarker established for selection of a specific therapy for patients with advanced gastroesophageal adenocarcinoma (GEA). However, there are no comprehensive guidelines for the assessment of HER2 in patients with GEA. Objectives To establish an evidence-based guideline for HER2 testing in patients with GEA, formalize the algorithms for methods to improve the accuracy of HER2 testing while addressing which patients and tumor specimens are appropriate, and to provide guidance on clinical decision making. Design The College of American Pathologists (CAP), American Society for Clinical Pathology (ASCP), and the American Society of Clinical Oncology (ASCO) convened an Expert Panel to conduct a systematic review of the literature to develop an evidence-based guideline with recommendations for optimal HER2 testing in patients with GEA. Results The Panel is proposing 11 recommendations with strong agreement from the open comment participants. Recommendations The Panel recommends that tumor specimen(s) from all patients with advanced GEA, who are candidates for HER2-targeted therapy, should be assessed for HER2 status before the initiation of HER2-targeted therapy. Clinicians should offer combination chemotherapy and an HER2-targeted agent as initial therapy for all patients with HER2-positive advanced GEA. For pathologists, guidance is provided for morphologic selection of neoplastic tissue, testing algorithms, scoring methods, interpretation and reporting of results, and laboratory quality assurance. Conclusion This guideline provides specific recommendations for assessment of HER2 in patients with advanced GEA while addressing pertinent technical issues and clinical implications of the results.

A potential pitfall in evaluating HER2 immunohistochemistry for gastric signet ring cell carcinomas

Signet ring cell carcinoma (SRC) more commonly presents as metastatic disease and renders patients to be considered for chemotherapy. While treatment options are limited overall, trastuzumab has been shown to be effective for HER2 positive SRC cases. The current algorithm for HER2 evaluation heavily relies on positive membrane-specific staining by immunohistochemistry (IHC), but several anecdotal reports have suggested that SRCs may be susceptible to misinterpretation due to non-specific staining in the marginated cytoplasm with/without nucleus. Results of two FDA-approved IHC methods of HER2 evaluation, Pathway and HercepTest, along with silver in situ hybridisation were interpreted retrospectively and compared in 155 primary SRC cases. IHC results were discrepant between the two assays in SRC even at the strongest IHC scores. Discordance indeed occurred due to dark, non-specific staining obscured by the unique SRC morphology. True HER2 positive SRC was identified in three cases (3/155, 1.9%). In this study, we demonstrate the importance of recognising potential discrepancy in interpreting HER2 status depending on the assay used. Understanding this possible pitfall may prevent unnecessary trastuzumab in SRC patients.

HER2 Testing and Clinical Decision Making in Gastroesophageal Adenocarcinoma: Guideline From the College of American Pathologists, American Society for Clinical Pathology, and American Society of Clinical Oncology

CONTEXT

- ERBB2 (erb-b2 receptor tyrosine kinase 2 or HER2) is currently the only biomarker established for selection of a specific therapy for patients with advanced gastroesophageal adenocarcinoma (GEA). However, there are no comprehensive guidelines for the assessment of HER2 in patients with GEA.

OBJECTIVES

- To establish an evidence-based guideline for HER2 testing in patients with GEA, to formalize the algorithms for methods to improve the accuracy of HER2 testing while addressing which patients and tumor specimens are appropriate, and to provide guidance on clinical decision making.

DESIGN

- The College of American Pathologists, American Society for Clinical Pathology, and American Society of Clinical Oncology convened an expert panel to conduct a systematic review of the literature to develop an evidence-based guideline with recommendations for optimal HER2 testing in patients with GEA.

RESULTS

- The panel is proposing 11 recommendations with strong agreement from the open-comment participants.

RECOMMENDATIONS

- The panel recommends that tumor specimen(s) from all patients with advanced GEA, who are candidates for HER2-targeted therapy, should be assessed for HER2 status before the initiation of HER2-targeted therapy. Clinicians should offer combination chemotherapy and a HER2-targeted agent as initial therapy for all patients with HER2-positive advanced GEA. For pathologists, guidance is provided for morphologic selection of neoplastic tissue, testing algorithms, scoring methods, interpretation and reporting of results, and laboratory quality assurance.

CONCLUSIONS

- This guideline provides specific recommendations for assessment of HER2 in patients with advanced GEA while addressing pertinent technical issues and clinical implications of the results.

HER2 Testing and Clinical Decision Making in Gastroesophageal Adenocarcinoma: Guideline From the College of American Pathologists, American Society for Clinical Pathology, and American Society of Clinical Oncology

CONTEXT

ERBB2 (erb-b2 receptor tyrosine kinase 2 or HER2) is currently the only biomarker established for selection of a specific therapy for patients with advanced gastroesophageal adenocarcinoma (GEA). However, there are no comprehensive guidelines for the assessment of HER2 in patients with GEA.

OBJECTIVES

To establish an evidence-based guideline for HER2 testing in patients with GEA, to formalize the algorithms for methods to improve the accuracy of HER2 testing while addressing which patients and tumor specimens are appropriate, and to provide guidance on clinical decision making.

DESIGN

The College of American Pathologists, American Society for Clinical Pathology, and American Society of Clinical Oncology convened an expert panel to conduct a systematic review of the literature to develop an evidence-based guideline with recommendations for optimal HER2 testing in patients with GEA.

RESULTS

The panel is proposing 11 recommendations with strong agreement from the open-comment participants.

RECOMMENDATIONS

The panel recommends that tumor specimen(s) from all patients with advanced GEA, who are candidates for HER2-targeted therapy, should be assessed for HER2 status before the initiation of HER2-targeted therapy. Clinicians should offer combination chemotherapy and a HER2-targeted agent as initial therapy for all patients with HER2-positive advanced GEA. For pathologists, guidance is provided for morphologic selection of neoplastic tissue, testing algorithms, scoring methods, interpretation and reporting of results, and laboratory quality assurance.

CONCLUSIONS

This guideline provides specific recommendations for assessment of HER2 in patients with advanced GEA while addressing pertinent technical issues and clinical implications of the results.

Gastric biomarkers: a global review

BACKGROUND

Gastric cancer is an aggressive disease with a poor 5-year survival and large global burden of disease. The disease is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Despite the many prognostic, predictive, and therapeutic biomarkers investigated to date, gastric cancer continues to be detected at an advanced stage with resultant poor clinical outcomes.

MAIN BODY

This is a global review of gastric biomarkers with an emphasis on HER2, E-cadherin, fibroblast growth factor receptor, mammalian target of rapamycin, and hepatocyte growth factor receptor as well as sections on microRNAs, long noncoding RNAs, matrix metalloproteinases, PD-L1, TP53, and microsatellite instability.

CONCLUSION

A deeper understanding of the pathogenesis and biological features of gastric cancer, including the identification and characterization of diagnostic, prognostic, predictive, and therapeutic biomarkers, hopefully will provide improved clinical outcomes.

HER2 testing in gastric cancer: An update

Human epidermal growth factor receptor 2 (HER2) overexpression is increasingly recognized as a frequent molecular abnormality in gastric and gastroesophageal cancer. With the recent introduction of HER2 molecular targeted therapy for patients with advanced gastric cancer, determination of HER2 status is crucial in order to select patients who may benefit from this treatment. This paper provides an update on our knowledge of HER2 in gastric and gastroesophageal cancer, including the prognostic relevance of HER2, the key differences between HER2 protein expression interpretation in breast and gastric cancer, the detection methods and the immunohistochemistry scoring system.

Concordance rate between HER2 immunohistochemistry and in situ hybridization in gastric carcinoma: systematic review and meta-analysis

PURPOSE

The aim of this study was to investigate the diagnostic accuracy of HER2 immunohistochemistry (IHC) in gastric carcinoma (GC) through a systematic review, meta-analysis and diagnostic test accuracy review.

METHOD

The current study included 12,679 GC cases and 181 subsets in 45 eligible studies. We performed concordance analysis between HER2 IHC and in situ hybridization (ISH) in GC. Diagnostic test accuracy was analyzed and the area under the curve (AUC) on the summary receiver operating characteristic (SROC) curve was calculated.

RESULTS

HER2 amplification rates were 3.0%, 31.8%, and 93.0% in the IHC score 0/1+, 2+, and 3+ groups, respectively. The concordance rates between IHC and ISH were 0.969 (95% confidence interval [CI] 0.962-0.975), 0.393 (95% CI 0.331-0.458) and 0.915 (95% CI 0.882-0.939) in the HER2 IHC score 0/1+, 2+, and 3+ groups, respectively. For all the HER2 IHC score groups, the positive rates were higher in the silver ISH (SISH) subgroup than in the fluorescence ISH (FISH) and chromogenic ISH (CISH) subgroups. In diagnostic test accuracy review, the pooled sensitivity and specificity were 0.86 (95% CI 0.84-0.87) and 0.91 (95% CI 0.90-0.91). The AUC on SROC curve was 0.958. However, there was no significant difference in the values of AUC between the ISH methods.

CONCLUSIONS

Our results showed that HER2 IHC was well concordant with ISH in HER2 IHC score 0/1+ or 3+. Although this meta-analysis showed higher diagnostic accuracy of HER2 IHC, more detailed criteria for HER2 IHC score 2+ cases will be required to predict HER2 status.

Targeting HER 2 and angiogenesis in gastric cancer

Gastric cancer is one of the most commonly diagnosed and the second leading cause of cancer death worldwide. Surgery combined with multimodal therapy remains the only curative therapy. However, local relapse or distant metastases occur in more than 50% of radically resected patients. Due to molecular therapies, targeting HER2 and angiogenesis, major advances in the treatment of gastric cancer could be achieved. Nevertheless, development of resistance to monoclonal antibodies, such as trastuzumab, is arising. Currently a number of promising new therapeutic are under investigation, combining chemotherapy with newly developed agents to overcome cancer resistance. In this review we report current clinical applications of targeted therapies and overview ongoing trials, investigating the use of monoclonal antibodies in (HER2 positive) gastric cancer.

Association between HER2 status in gastric cancer and clinicopathological features: a retrospective study using whole-tissue sections

BACKGROUND

Gastric cancer is usually diagnosed in an advanced stage of disease and treatment options are sparse. Trastuzumab was recently approved for metastatic or locally advanced carcinomas arising in the stomach or in the gastroesophageal junction in patients with HER2-positive tumors. However, data on the frequency of HER2-positive cases among Brazilian patients are limited. Our aim was to characterize HER2 protein and gene status in a series of Brazilian patients with gastric cancer and to evaluate its association with clinicopathological data.

METHODS

Histological slides from 124 primary gastrectomies were reviewed and their pathological reports were retrieved from the files at a Brazilian university hospital. Automated immunohistochemistry for HER2 was performed on whole-tissue sections from each tumor. HER2-equivocal cases by immunohistochemistry were submitted to automated dual in situ hybridization for gene amplification evaluation. HER2 status was confronted with clinicopathological parameters in order to assess statistically significant associations.

RESULTS

Immunohistochemistry analysis revealed that 13/124 cases (10.5 %) were HER2 positive (3+), 10/124 cases (8.1 %) were equivocal (2+) and 101/124 cases (81.4 %) were negative, being 7 cases 1+. None of the equivocal cases showed gene amplification. The overall HER2 positivity rate was 10.5 %. There was an association between HER2 expression and Laurén's intestinal histological subtype (P = 0.048), well to moderately differentiated tumors (P = 0.004) and presence of lymphovascular invasion (P = 0.031). No association was found between HER2 status and tumor topography.

CONCLUSIONS

Confronted with data published by other authors, the lower percentage of HER2-positive cases found in our series might be partially explained by the lower frequency of tumors arising at the gastroesophageal junction in comparison with distal gastric carcinomas in Brazilian patients. This could also account for the lack of statistically significant association between HER2 status and tumor topography in our study.

Companion diagnostics for the targeted therapy of gastric cancer

Gastric cancer is the fourth most common type of cancer and represents a major cause of cancer-related deaths worldwide. With recent biomedical advances in our understanding of the molecular characteristics of gastric cancer, many genetic alterations have been identified as potential targets for its treatment. Multiple novel agents are currently under development as the demand for active agents that improve the survival of gastric cancer patients constantly increases. Based on lessons from previous trials of targeted agents, it is now widely accepted that the establishment of an optimal diagnostic test to select molecularly defined patients is of equal importance to the development of active agents against targetable genetic alterations. Herein, we highlight the current status and future perspectives of companion diagnostics in the treatment of gastric cancer.

Current and Future Therapies for Advanced Gastric Cancer

The treatment of patients with advanced gastric cancer remains a challenging area of oncology. Extensive trials of differing chemotherapy regimens have yielded no international consensus on the optimal combination, and overall survival with chemotherapy alone remains poor. Recently an improved understanding of the molecular drivers of the disease has opened up promising new avenues of treatment through the use of biological targeted agents. The anti-HER2 monoclonal antibody trastuzumab was the first targeted agent to significantly prolong survival in the first-line treatment of a molecularly-selected subgroup of patients. More recently the anti-vascular endothelial growth factor receptor 2 monoclonal antibody ramucirumab has demonstrated a modest survival benefit in previously treated patients as both a monotherapy and in combination with chemotherapy. Immunotherapy and the use of checkpoint inhibitors are a further exciting area of development with promising preliminary results for the activity of the anti-Programmed Death 1 Receptor antibody pembrolizumab and ongoing trials of a number of immune-modulating agents. Continuing research to identify novel targets and therapies aims to make further incremental gains in survival. In this review we outline the evidence base supporting current chemotherapy regimens and describe the latest advances in the development and use of molecularly targeted and immune-modulating agents.

HER2 testing in gastric and gastroesophageal adenocarcinomas

The human epidermal growth factor receptor 2 (HER2) is overexpressed in 10% to 35% of gastric and gastroesophageal junction (GEJ) adenocarcinomas. In 2010, the phase III Trastuzumab for Gastric Cancer (ToGA) trial showed that addition of the anti-HER2 monoclonal antibody trastuzumab to chemotherapy significantly improved survival of patients with advanced or metastatic tumors that were positive for HER2 overexpression. As a result, HER2 testing is now recommended for all patients with advanced or metastatic disease, although there is still some debate as to the optimal methods of assessment. HER2 expression in gastric and GEJ tumors shows several differences compared with breast tumors and, for this reason, the proposed criteria for scoring HER2 expression in biopsies and resections of gastric and GEJ carcinomas differ from those used in breast carcinomas. This review discusses what is currently known about the patterns of HER2 expression in gastric and GEJ adenocarcinomas, summarizes the findings of the ToGA trial and its clinical implications, and provides an overview of the recommended guidelines for the most accurate evaluation of HER2 status in gastric and GEJ cancer.

Correlations of Human Epithelial Growth Factor Receptor 2 Overexpression with MUC2, MUC5AC, MUC6, p53, and Clinicopathological Characteristics in Gastric Cancer Patients with Curative Resection

Background. The purpose of this study was to evaluate the relationships between HER2 overexpression in the tumor and MUC2, MUC5AC, MUC6, and p53 status and clinicopathological characteristics of gastric cancer patients. Methods. This retrospective study included 282 consecutive patients with gastric cancer who underwent surgery at the Kosin University Gospel Hospital between April 2011 and December 2012. All tumor samples were examined for HER2 expression by immunohistochemistry (IHC) and MUC2, MUC5AC, MUC6, and p53 expression by staining. A retrospective review of the medical records was conducted to determine the correlation between the presence of HER2 overexpression and clinicopathological factors. Results. The HER2-positive rate was 18.1%. Although no association was found between HER2 expression and MUC5AC, the expression of MUC2, MUC6, and p53 was significantly correlated with HER2 positivity, respectively (P = 0.004, 0.037, 0.002). Multivariate analysis revealed that HER2 overexpression and nodal status were independent prognostic factors. Conclusions. HER2 overexpression in gastric carcinoma is an independent poor prognostic factor.

HER2 assessment by silver in situ hybridization: where are we now?

HER2 testing in breast and gastric cancer is critical not only as a prognostic tool but also as a predictive marker for response to the humanized monoclonal antibody trastuzumab. Currently, HER2 status is assessed on histological and cytological specimens by conventional validated methods such as immunohistochemistry and FISH, while bright-field in situ hybridization techniques, such as silver in situ hybridization and chromogenic in situ hybridization, may offer performance benefits over FISH. The major points are first, technical issues, advantages and disadvantages relevant to each methods, and their clinical implications and second, the well-known genetic heterogeneity of HER2, and the occurrence of polysomy of chromosome 17. This review aims to summarize the growing body of literature on the accuracy of bright-field in situ techniques, notably silver in situ hybridization, in assessing HER2 status, and to discuss the role of such methods in pathology practice.

Brachmann-Cornelia de Lange syndrome with a papilloma of the choroid plexus: analyses of molecular genetic characteristics of the patient and the tumor. A single-case study

PURPOSE

A 10-month-old girl with a Brachmann-Cornelia de Lange syndrome and a choroid plexus papilloma of the brain was studied at the Hospital Infantil de México Federico Gómez (HIMFG) in Mexico City.

METHODS AND RESULTS

Presumptive papilloma of the third ventricle was evidenced on CT and MR images and removed. Pathological analysis confirmed its origin. A posterior radiosurgery was required due to a tumor relapse. Karyotypes (GTG bands) of the patient and her parents undertaken at HIMFG were normal. Array comparative genomic hybridization (array CGH) analyses of blood DNA of the patient and her parents carried out at BlueGnome's Laboratory in Cambridge, UK, set in evidence amplification of genes SPNS2, GGT6, SMTNL2, PELP1, MYBBP1A, and ALOX15 in chromosome 17p of the patient. Since MYBBP1A is a proto-oncogene and ALOX15 participates in the development of cancer and metastases of tumors, further fluorescent in situ hybridization (FISH) analyses of these two genes were implemented at HIMFG. Amplification of the two genes was found in the tumor of the case under study but not in an unrelated papilloma of the choroid plexus.

DISCUSSION

Further analyses of the association of choroid plexus papillomas with disorders of psycho-neural development and its relationship to molecular genetic modifications at chromosome 17p are now under way at HIMFG.

Principles of analytic validation of immunohistochemical assays: Guideline from the College of American Pathologists Pathology and Laboratory Quality Center

CONTEXT

Laboratories must validate all assays before they can be used to test patient specimens, but currently there are no evidence-based guidelines regarding validation of immunohistochemical assays.

OBJECTIVE

To develop recommendations for initial analytic validation and revalidation of immunohistochemical assays.

DESIGN

The College of American Pathologists Pathology and Laboratory Quality Center convened a panel of pathologists and histotechnologists with expertise in immunohistochemistry to develop validation recommendations. A systematic evidence review was conducted to address key questions. Electronic searches identified 1463 publications, of which 126 met inclusion criteria and were extracted. Individual publications were graded for quality, and the key question findings for strength of evidence. Recommendations were derived from strength of evidence, open comment feedback, and expert panel consensus.

RESULTS

Fourteen guideline statements were established to help pathology laboratories comply with validation and revalidation requirements for immunohistochemical assays.

CONCLUSIONS

Laboratories must document successful analytic validation of all immunohistochemical tests before applying to patient specimens. The parameters for cases included in validation sets, including number, expression levels, fixative and processing methods, should take into account intended use and should be sufficient to ensure that the test accurately measures the analyte of interest in specimens tested in that laboratory. Recommendations are also provided for confirming assay performance when there are changes in test methods, reagents, or equipment.

Correlation between HER2 Overexpression and Clinicopathological Characteristics in Gastric Cancer Patients Who Have Undergone Curative Resection

Purpose

At present, a human epidermal growth factor receptor 2 (HER2)-based concept of tumor biology has been established, and trastuzumab (Herceptin®; Genentech/Roche, San Francisco, CA, USA), a monoclonal humanized antibody directed against HER2, is a pivotal agent for the management of HER2 positive (HER2+) metastatic breast cancer. It is also known that HER2 has a predictive value in gastric cancer; however, its association with the prognosis of this disease remains uncertain. The purpose of this study was to evaluate both the relationship between HER2 overexpression in the tumors of gastric cancer patients, and the prognosis of these patients who have had curative resection.

Materials and Methods

A total of 139 consecutive patients with gastric cancer who underwent surgery at the Kosin University Gospel Hospital between October 2011 and March 2012 were included in this retrospective study. All tumor samples were examined for HER2 expression by immunohistochemistry. A retrospective review of the medical records was conducted to determine the correlation between the presence of HER2 overexpression and clinicopathological factors.

Results

The HER2+ rate was 15.1%. HER2 overexpression was associated with histological grade (P=0.044) and Lauren classification (P=0.036). There was no significant difference in the 2-year overall survival between HER2+ and HER2- patients (P=0.396). Multivariate analysis showed that HER2 was not an independent prognostic factor.

Conclusions

HER2 overexpression in tumors was associated with histological grade and Lauren classification in gastric cancer patients with curative resection. However, HER2 was not an independent prognostic factor for gastric cancer in our study.

The validation of a novel method combining both HER2 immunohistochemistry and HER2 dual-colour silver in situ hybridization on one slide for gastric carcinoma testing

Background

HER2 status assessment is a prerequisite for the establishment of an appropriate treatment strategy in gastric cancer. Gastric cancers are very heterogeneous and separate evaluations of gene amplification and protein expression lead to uncertainties in localizing distinct clones and are time consuming. This study evaluates the equivalence of the novel method combining both gene and protein platforms on one slide.

Methods

Immunohistochemistry (IHC) and HER2 dual-colour silver in situ hybridization (SISH) as single methods (IHC/SISH) and gene-protein platform combining both methods on one slide (gene/protein) were performed in randomly collected 100 cases of gastric adenocarcinoma. Results of IHC/SISH were compared with gene/protein staining.

Results

96 of 100 samples were assessable. In the gene/protein staining, pathologists were able to assess gene amplification and consequent protein expression at the single cell level. In comparison trials, gene amplification was observed in 14.6% by both, conventional SISH and gene/protein platform (agreement 100%; Kappa-coefficient κ = 1.0). Protein expression scores by IHC were 70.8% (0), 10.4% (1+), 9.4% (2+), and 9.4% (3+). Protein expression by gene/protein method were: 70.8% (0), 11.5% (1+), 7.3% (2+) and 10.4% (3+) of patients. There were complete concordances in IHC assessment of cases with score 0 (100.0%; κ = 1). High concordances are shown in score 1+ (98.96%; κ = 0.947) and 3+ (96.88%; κ = 0.825) cases and good concordances in 2+ cases (95.83%; κ = 0.728).

Conclusions

This novel combined platform has the advantage of being able to evaluate both gene and the protein status in the same cancer cell and may be of particular interest for research and patient’s care.

Article category

Disease Biomarker.

A critical review of HER2-positive gastric cancer evaluation and treatment: from trastuzumab, and beyond

Identification of the importance of human epidermal growth factor receptor-2 (HER2) status, biomarker testing and the development of anti-HER2 treatments have changed the prognosis of breast and gastric cancers. The addition of trastuzumab to chemotherapy has improved outcomes for patients with HER2-positive metastatic adenocarcinoma of the stomach and gastroesophageal junction, but some relevant issues remain to be elucidated or will emerge with new drugs. This article reviews the current state of HER2 in gastric cancer focusing on diagnostic and anti-HER2 targeted treatment issues and the role of trastuzumab in localized disease, and its combination or integration with new therapies.

HER2 status in colorectal cancer: its clinical significance and the relationship between HER2 gene amplification and expression

This study aimed at determining the incidence and clinical implications of HER2 status in primary colorectal cancer (CRC). HER2 status was investigated in two retrospective cohorts of 365 consecutive CRC patients (cohort 1) and 174 advanced CRC patients with synchronous or metachronous distant metastasis (cohort 2). HER2 status was determined by performing dual-color silver in-situ hybridization (SISH), mRNA in-situ hybridization (ISH), and immunohistochemistry (IHC). The incidence of HER2 protein overexpression (IHC 2+/3+) was approximately 6% (22 of 365 in cohort 1; 10 of 174 in cohort 2). HER2 gene amplification was observed in 5.8% of the patients from cohort 1 and 6.3% of the patients from cohort 2. HER2 gene amplification was more frequently observed in CRCs located in the rectum than in the right and left colon (P = 0.013 in cohort 1; P = 0.009 in cohort 2). HER2 status, determined by IHC, ISH, and dual-color SISH, was not significantly associated with aggressive CRC behaviour or patients' prognosis in both the cohorts. Of the combined cohort with a total of 539 cases, the concordance rate was 95.5% between dual-color SISH and IHC detection methods. On excluding equivocally immunostained cases (IHC 2+), the concordance rate was 97.7%. HER2 mRNA overtranscription, detected by ISH, significantly correlated with protein overexpression and gene amplification (P<0.001). HER2 gene amplification was identified in a minority of CRC patients with high concordance rates between dual-color SISH and IHC detection methods. Although HER2 status did not predict patients' prognosis, our findings may serve as a basis for future studies on patient selection for HER2 targeted therapy.

Human epidermal growth factor receptor 2 overexpression and amplification in endoscopic biopsies and resection specimens in esophageal and junctional adenocarcinoma

Human epidermal growth factor receptor 2 (HER2) is overexpressed in a subset of esophageal adenocarcinomas. Frequently, biopsy material is used for evaluation of HER2 status. The aim of the study was to determine if HER2 expression in preoperative endoscopic biopsies is representative for the entire tumor. Preoperative endoscopic biopsies and matched resection specimens were collected from 75 patients who underwent esophagectomy for esophageal adenocarcinoma. Immunohistochemical staining (IHC) on HER2 and dual-color in situ hybridization (ISH) were performed. HER2 status was determined by following a clinical algorithm, first determining HER2 overexpression on immunohistochemistry and, when equivocal (2+), determining HER2 amplification on ISH. Seventy-one of 75 (95%) biopsies and 69/75 (92%) resection specimens could be analyzed due to technical failure. HER2 positivity was seen in 18/71 (25%) biopsies and in 15/69 (22%) resection specimens. Overall, HER2 status in the biopsy was concordant with HER2 status in the resection specimen in 94% of cases. Interobserver agreement on IHC scoring for all three observers was 83% in biopsies and 85% in resection specimens. HER2 positivity was detected in 22% of esophageal adenocarcinomas. Although interobserver agreement was moderate, HER2 status of a primary tumor can be reliably determined based on the endoscopically obtained pretreatment biopsy.

Molecular targeted therapy of gastric cancer

Gastric cancer is one of the most frequent malignancies of the digestive system. Despite decreasing incidence and mortality rate, the incidence of gastric cancer still ranks second and the mortality rate ranks third in China. Surgical resection is the preferred treatment for gastric cancer. However, due to the lack of typical early symptoms, the majority of gastric cancer patients are diagnosed at advanced stages, and the prognosis remains poor. In the past decades, a large number of studies have found a series of genes driving the development of gastric cancer. Molecular targeted therapies based on these genes have been developed, greatly improving the efficiency of treatment of gastric cancer and playing an important role in guiding individualized treatment of this malignancy. This review summarizes the advances in the molecular targeted therapy of gastric cancer.

HER2 in gastric cancer: Comparative analysis of three different antibodies using whole-tissue sections and tissue microarrays

AIM: To compare the performance of three commercially available anti-human epidermalgrowth factor receptor 2 (HER2) antibodies in whole-tissue sections and tissue microarrays (TMAs) of a series of gastric tumors.

METHODS: We present a comparative analysis of three anti-HER2 antibodies (HercepTest, 4B5 and SP3) using TMA and whole-tissue sections prepared from the same paraffin blocks of 199 gastric adenocarcinomas operated upon between January 2004 and December 2008 at a Brazilian cancer hospital. The data on the patients’ age, sex, the anatomical location of the tumor and the Lauren’s histological classification were collected from clinical and pathological records. The immunohistochemical (IHC) results were examined by two pathologists and the cases were classified as positive (3+), equivocal (2+) and negative (0 or 1+), according to the criteria of the IHC scoring system of gastric cancer. TMAs and whole-tissue sections were evaluated separately and independently. All cases yielding discordant IHC results and/or scored as 2+ were subjected to dual-color in situ hybridization in order to determine the final HER2 status. Besides determining the sensitivity and predictive value for HER2-positive status, we measured the accuracy of each antibody by calculating the area under the receiver operating characteristic (ROC) curve. The agreement between the results obtained using the TMAs and those obtained using the whole-tissue sections was assessed by means of Kappa coefficient.

RESULTS: Intratumoral heterogeneity of HER2 expression was observed with all antibodies. HER2-positive expression (3+) in the whole-tissue sections was observed in 23 cases (11.6%) using the 4B5 antibody, in 18 cases (9.1%) using the SP3 antibody and in 10 cases (5.1%) using the HercepTest antibody. In the TMAs, 11 positive cases (5.6%) were identified using SP3 antibody, 9 (4.6%) using the 4B5 antibody and 6 (3%) using the HercepTest antibody. The sensitivity using whole-tissue sections and TMA, respectively, was 95.2% and 42.9% with 4B5, 90.5% and 66.7% with SP3 and 47.6% and 42.9% with HercepTest. The accuracy, calculated from the area under the ROC curve, using whole-tissue sections and TMA, respectively, was 0.91 and 0.79 by 4B5, 0.86 and 0.80 by SP3 and 0.73 and 0.71 by HercepTest. The concordance of the results obtained using whole-tissue sections and TMA was 97.4% (Kappa 0.75) using HercepTest, 85.6% (Kappa 0.56) using SP3 and 84.1% (Kappa 0.38) using 4B5.

CONCLUSION: The use of the 4B5 antibody on whole-tissue sections was the most accurate IHC method for evaluating HER2 expression in gastric adenocarcinoma.

Personalizing therapies for gastric cancer: molecular mechanisms and novel targeted therapies

Globally, gastric cancer is the 4(th) most frequently diagnosed cancer and the 2(nd) leading cause of death from cancer, with an estimated 990000 new cases and 738000 deaths registered in 2008. In the advanced setting, standard chemotherapies protocols acquired an important role since last decades in prolong survival. Moreover, recent advances in molecular therapies provided a new interesting weapon to treat advanced gastric cancer through anti-human epidermal growth factor receptor 2 (HER2) therapies. Trastuzumab, an anti-HER2 monoclonal antibody, was the first target drug in the metastatic setting that showed benefit in overall survival when in association with platinum-5-fluorouracil based chemotherapy. Further, HER2 overexpression analysis acquired a main role in predict response for trastuzumab in this field. Thus, we conducted a review that will discuss the main points concerning trastuzumab and HER2 in gastric cancer, providing a comprehensive overview of molecular mechanisms and novel trials involved.

HER2 Assessment in Upper Gastrointestinal Tract Adenocarcinoma: A Practical, Algorithmic Approach

Gastric and gastroesophageal junction adenocarcinomas constitute a major health problem. For localized disease, adjuvant treatment is multidisciplinary and usually includes a combination of surgery, radiation and chemotherapy. Recently, trastuzumab (Herceptin) has been approved for the treatment of metastatic upper gastrointestinal (GI) tract (gastric, esophageal, and gastroesophageal) adenocarcinomas. The purpose of this review is to provide pathologists with practical guidance in HER2 assessment of upper GI tract adenocarcinomas in order to accurately identify patients eligible for trastuzumab therapy.

Expression of asialoglycoprotein receptor 1 in human hepatocellular carcinoma

Human hepatocellular carcinoma (HCC) is the fifth most common cancer in the world. Currently, surgical resection is the only effective treatment for HCC if the tumor is resectable. Small molecule, biologics and siRNA anti-cancer drugs have been explored for the treatment of HCC. Selective targeting to tumor tissue rather than normal liver in HCC patients is still a challenge. Galactosamine-mediated targeting delivery of anti-cancer drugs in the liver has been tested because its receptor, asialoglycoprotein receptor 1 (ASGPR1), is expressed in the liver and not in other human tissues. We examined ASGPR1 expression levels by immunohistochemistry in HCC with different grades. Guidance for a targeting delivery strategy for anti-cancer drugs to HCC is suggested in this report.

HER2 status in gastric cancer: a comparison of two novel in situ hybridization methods (IQ FISH and dual color SISH) and two immunohistochemistry methods (A0485 and HercepTest™)

In contrast to breast HER2 testing, the optimal ISH method and antibody for gastric HER2 testing are unclear. The aim of this study was to find out gastric HER2 positivity rates in our institutional data, and to compare the two novel ISH methods with A0485 antibody and HercepTest™. IHC and ISH were carried out on gastrectomy specimens of 88 patients up to the standardly advised procedure protocols, and interpretations were also carried out up to widely accepted international protocols., HER2 expression was (-) in 65, (+) in 5, (++) in 6, and (+++) in 12 cases by A0485 IHC. IHC (+) 4 cases and (++) 3 cases were (-) by HercepTest™. One IHC (-) amplified case was (++) by HercepTest™. All A0485 and HercepTest™ (+++) 12 cases were amplified by ISH. HER2 amplification was detected in 18 (20.4%) and in 15 (17.2%) cases by SISH and FISH, respectively. Of the 18 cases, 4 showed focal heterogeneous low level amplification by SISH. Focal amplification was noted in only 2 cases by FISH. The HER2 status of our gastric cancer file is 17.2% by FISH, 20.4% by SISH. The concordance between HercepTest™/A0485 IHC and ISH is perfect in (+++) cases. Equivocal results (++) with any IHC method should be clarified by one of the molecular methods (SISH and FISH). Probably up to the higher level of heterogeneity of gastric carcinomas, there is a 4.5% dilemma of cases that are negative or weakly positive by conventional IHC methods. Therefore, regarding HER2 status in gastric carcinoma, the reliability of IHC methods should be checked.

HER2 in gastric cancer: a digital image analysis in pre-neoplastic, primary and metastatic lesions

The assessment of human epidermal growth factor receptor 2 (HER2) status in gastric cancer is crucial in selecting patients who may benefit from targeted therapy, yet heterogeneous expression could represent an important drawback for HER2 testing. We aimed to analyze (i) HER2 heterogeneity in primary gastric cancers, pre-neoplastic and metastatic lesions and (ii) HER2 prognostic role. We studied 292 surgically resected primary gastric carcinomas and constructed 21 tissue microarrays including tumor tissue cores, invasive front, paired lymph node metastasis, low- and high-grade dysplasia. Microarrays were immunohistochemically stained with HER2 antibody and digitally scanned. Novel digital analysis algorithms were developed to score HER2 expression. Fluorescence in situ hybridization was performed on equivocal cases. HER2-positive cases were 13% and heterogeneous HER2 expression was observed in 71% of positive samples. Analysis of HER2 status in tumor and tumor invasive front demonstrate concordance in 177 cases (88%). Comparison of HER2 expression in primary cancer and synchronous lymph node metastasis exhibited discordant status in 14% of cases. Dysplastic epithelium surrounding the tumor showed immunohistochemical score 2 or 3 in 19% of high-grade and in 9% of low-grade dysplastic samples. HER2 status was significantly associated with intestinal-type carcinomas (P=0.018) and prognosis since patients with primary HER2-positive tumor showed decreased overall survival (P=0.006). Intratumoral HER2 expression heterogeneity and variable lymph node metastases status strongly suggest evaluating more than one sample and, if available, metastatic foci for routinely HER2 testing.

SP3, a reliable alternative to HercepTest in determining HER-2/neu status in breast cancer patients

Accurate assessment of HER-2/neu gene status in breast cancer patients has important prognostic and therapeutic implications. Overexpression/gene amplification of HER-2 is associated with a more aggressive clinical course and eligibility for targeted therapy with trastuzumab. A variety of immunohistochemical (IHC) antibodies and in situ hybridisation (ISH) methods have been employed to assess HER-2 status. SP3 is a rabbit monoclonal antibody that has been shown to have a high level of agreement with other anti-HER-2 antibodies and ISH methods. We assessed HER-2 status by SP3 and HercepTest IHC stains and by fluorescence in situ hybridisation (FISH) on invasive breast carcinomas from paired needle core biopsy and excisional biopsy specimens from 100 patients. We compared the two antibodies with respect to concordance rates with FISH, concordance rates between samples of the same tumour, and sensitivity and specificity using FISH as the reference test. Concordance between SP3 and FISH in needle core biopsy and excisional biopsy specimens was 96% (95% CI 91.9% to 99.7%) (κ=0.89 (95% CI 0.73 to 1.00)) and 97% (95% CI 90.3% to 99.3%) (κ=0.84 (95% CI 0.66 to 1.00)), respectively. Sensitivity and specificity of SP3 for detecting HER-2 overexpression/gene amplification were 78.3% and 100%, respectively, in needle core biopsy and excisional biopsy specimens. Concordance between SP3 results assessed on the needle core biopsy and excisional biopsy was 89% (95% CI 81.2% to 94.4%) (κ=0.62 (95% CI 0.42 to 0.82)). Concordance between SP3 and HercepTest antibodies, after excluding 2+ cases, was 97.6% (95% CI 94.0% to 99.3%) (κ=0.88 (95% CI 0.77 to 1.00)). SP3 is a reliable alternative to HercepTest in evaluating HER-2 status in breast cancer patients. Like other anti-HER-2 antibodies, SP3 may serve as a diagnostic tool in breast pathology and has potential utility as an IHC biomarker in non-mammary malignancies.

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.

HER2 expression and its clinicopathological features in resectable gastric cancer

BACKGROUND

A recent randomized controlled trial (Trastuzumab for Gastric Cancer [ToGA] study) established standard scoring criteria of human epidermal growth factor receptor 2 (HER2) for gastric cancer and demonstrated the efficacy of trastuzumab for treating metastatic gastric cancer. The aim of the present study was to evaluate the frequency of HER2-positive cases by application of the standard criteria in patients with resectable gastric cancer and to examine the relationships between HER2 expression and prognosis, mucin phenotype, p53 status, and clinicopathological features.

METHODS

A total of 213 patients were included in this retrospective study. All tumor samples were examined for HER2 expression by immunohistochemistry (IHC), HER2 amplification by in situ hybridization, and mucin and p53 expression by staining for CD10, MUC2, MUC5AC, MUC6, and p53.

RESULTS

HER2-positive tumors were identified in 25 patients (11.7 %). HER2-positive cases were more frequently found in men, older patients, and in the intestinal histological type (P = 0.0048, 0.0309, and <0.0001, respectively). Although no association was found between HER2 overexpression and mucin phenotype, the expression of CD10 and p53 was significantly correlated with HER2 positivity (P = 0.0079 and 0.013). The overall survival of HER2-negative and -positive patients was not significantly different. However, in patients with stage III/IV, overall survival was worse in HER2-positive patients (P = 0.0149). In a comparison between dual-color in situ hybridization (DISH) and fluorescence in situ hybridization (FISH), four IHC2+/3+ cases that were DISH-positive were judged as negative by FISH.

CONCLUSIONS

Our study indicated that HER2 expression was less frequent in resectable gastric cancer than in metastatic gastric cancer. The impact of HER2 expression on survival was limited. DISH was superior to FISH for evaluating cases with limited HER2 expression.

HER2/neu gene amplification and protein overexpression in gastric and gastroesophageal junction adenocarcinoma: a review of histopathology, diagnostic testing, and clinical implications

Amplification of the human epidermal growth factor receptor 2/neu (HER2/neu) gene and overexpression of the HER2 protein (HER2) have been shown to occur in gastric and gastroesophageal junction adenocarcinoma in a number of studies. With a dismal survival rate, patients with these cancers stand to benefit from the identification of possible molecular targets such as HER2 for both prognostic and therapeutic purposes. Although these and other carcinomas that overexpress HER2 may have a poorer prognosis and exhibit resistance to conventional chemotherapy, they have also recently been shown to respond to targeted therapy with the anti-HER2 antibody trastuzumab. Here, we briefly review the molecular biology, histopathology, diagnostic techniques, and interpretation, as well as the clinical implications, of HER2 amplification/overexpression in gastric and gastroesophageal adenocarcinoma.

Trastuzumab: a novel standard option for patients with HER-2-positive advanced gastric or gastro-oesophageal junction cancer

The human epidermal receptor-2 (HER-2) is amplified in up to 25% of patients with gastroesophageal adenocarcinomas. Although the presence of this amplification does not appear to confer a poor prognosis, it provides a valuable novel therapeutic target for this group of patients. Trastuzumab is a fully humanized monoclonal antibody directed at HER-2 which binds the external domain of the receptor and exerts its action via a combination of antibody-dependent cytotoxicity, reduced shedding of the extracellular domain, inhibition of dimerization and possibly receptor downregulation. The ToGA trial was an international multicentre randomized phase III study which evaluated the addition of trastuzumab to a cisplatin plus fluoropyrimidine chemotherapy doublet in 594 patients with HER-2-positive advanced gastric or oesophagogastric junction adenocarcinoma. The combination of the antibody with chemotherapy significantly improved response rate, median progression-free survival and median overall survival without additional toxicity or adversely affecting quality of life. Accordingly, trastuzumab plus chemotherapy is now a standard first-line treatment option for patients with advanced HER-2-positive gastroesophageal cancer. Unfortunately, many patients with HER-2-positive cancer exhibit primary resistance to trastuzumab and the remainder will acquire resistance to the antibody; therefore, urgent investigation into novel agents which may circumvent resistance mechanisms is warranted. Small molecule inhibitors of HER-2, which commonly also target other members of the HER family of receptors, such as EGFR and HER-3, are currently undergoing evaluation in gastroesophageal cancer as first-line alternatives to trastuzumab and second-line salvage treatments for trastuzumab-resistant disease. Extrapolating the successful use of trastuzumab in the advanced disease setting, clinical trials are underway to assess the role of this antibody in the perioperative and adjuvant settings, where it is hoped that it will have a meaningful impact upon the currently poor survival rates.

Early HER2 dysregulation in gastric and oesophageal carcinogenesis

AIMS

To explore human epidermal growth factor receptor 2 (HER2) status in the histological phenotypes [metaplasia, intraepithelial neoplasia (IEN, i.e. dysplasia), and adenocarcinoma] involved in the morphogenesis of both intestinal-type gastric cancer (GC) and Barrett's adenocarcinoma (BAc).

METHODS AND RESULTS

A consecutive series of 275 samples of stomach and oesophagus tissue (representing the whole spectrum of the phenotypic changes involved in gastric and Barrett's carcinogenesis) was studied. HER2 status was assessed by applying two immunohistochemistry (IHC) protocols, using the antibodies 4B5 and CB11. Dual-colour silver chromogenic in-situ hybridization (SISH) was also performed on the same tissue samples. In both oesophageal and gastric samples, the rate of HER2 overexpression rose significantly from low-grade to high-grade IEN to adenocarcinoma (P < 0.001), with the two IHC protocols showing consistent staining (consistency 95%; k = 0.78; P < 0.001). Intratumour heterogeneity was documented in both GC and BAc (using both IHC protocols). The rate of HER2 amplification (using SISH) increased significantly along with IEN dedifferentiation (P < 0.001). Neither native nor metaplastic mucosa samples (obtained from either stomach or oesophagus) ever showed HER2 amplification. There was excellent agreement between HER2 amplification and protein overexpression (both IHC protocols: SISH/4B5--consistency 97.8%, k = 0.89, P < 0.001; SISH/CB11-consistency 97.8%, k = 0.91, P < 0.001).

CONCLUSIONS

There is early involvement of HER2 dysregulation (amplification and protein overexpression) in both gastric (intestinal-type) and Barrett's oncogenesis.

Comparison of four immunohistochemical tests and FISH for measuring HER2 expression in gastric carcinomas

AIM

: Accurate testing for HER2 is essential to identify patients who are likely to benefit from trastuzumab therapy. Although comparative studies on the performance of commercially available immunohistochemistry (IHC) antibodies for HER2 have been performed in breast cancer, similar studies have not been done in gastric carcinoma (GC) thus far.

METHODS

: Quadruplicate tissue microarrays (TMAs) of 289 advanced GCs were immunostained with HercepTest, A0485, 4B5 and CB11, and the results were compared to those of gene amplification by fluorescence in situ hybridisation (FISH).

RESULTS

: HER2 was amplified by FISH in 38 (13.2%) GCs. HER2 overexpression (2+ or 3+) was observed in 40 (13.8%) cases by HercepTest, 46 (15.9%) by A0485, 40 (13.8%) by 4B5 and 27 (9.3%) by CB11. The sensitivity and specificity of IHC compared to FISH was 78.9%/96% for HercepTest, 86.5%/94.4% for A0485, 76.3%/95.6% for 4B5 and 60.5%/98.4% for CB11. Focal HER2 gene amplification was more common in GCs with no (0 and 1+) or low (2+) HER2 expression. Discordant IHC results were seen in 23 cases (8.0%) with the four antibodies. All HER2 3+ cases (n = 22) by HercepTest were positive with A0485 and 4B5, while one was negative with CB11. CB11 was found to be negative in 10 HercepTest 2+ and FISH+ cases.

CONCLUSION

: Focal HER2 gene amplification is more common in GCs with no or low expression of HER2. Although the specificity and positive predictive value of CB11 for FISH is highest, it lacks sufficient sensitivity to be used as a first line screening test to assess HER2 status in GCs.