HER2 Status In Breast Cancer Research Articles

Assessment of HER-2 gene overexpression in Isfahan province breast cancer patients using Real Time RT-PCR and immunohistochemistry

PurposeOverexpression of proto-oncogene HER-2 is one of the main molecular markers of breast cancer involved in prognosis and diagnosis and also in trastuzumab therapy. Thus, a request for the evaluation of HER-2 status in breast cancer has been increasing. The aim of our study was assessment of HER-2 overexpression in malignant and benign breast cancer specimens by Real Time RT-PCR technique and comparison of its results with IHC outcomes. MethodsTwenty benign and sixty malignant breast cancers in addition to fifteen normal breast tissue specimens were analyzed by Real Time RT-PCR method. Fresh tissue samples were disrupted by mortar and pestle. A syringe and a needle were used for complete homogenization of the tissues. The RNA was then isolated from the samples and converted to cDNA. A standard curve was initially plotted using BioEasy SYBR Green I and then all 95 specimens were studied by Real Time RT-PCR using 2−ΔΔCt method. Results23.3% of 60 malignant specimens showed HER-2 overexpression, while all of the benign samples represented the normal expression level of HER-2 gene. The concordance rate between the results of Real Time RT-PCR and IHC was 86.6%. ConclusionReal Time RT-PCR method is an almost reliable technique and at least can be used as a complementary method for confirming IHC results. This is emanated from relatively high rate of concordance between outcomes of IHC test, as a routine method of detecting the HER-2 gene expression status, and Real Time RT-PCR technique.

Methods for evaluating HER2 status in breast cancer: comparison of IHC, FISH, and real-time PCR analysis of formalin-fixed paraffin-embedded tissue

Methods for evaluating HER2 status in breast cancer: comparison of IHC, FISH, and real-time PCR analysis of formalin-fixed paraffin-embedded tissue Hans Olsson,1,2 Agneta Jansson,3 Birgitta Holmlund,3 Cecilia Gunnarsson2,4 1Molecular and Immunological Pathology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden; 2Department of Clinical Pathology and Clinical Genetics, Östergötland County Council, Linköping, Sweden; 3Division of Oncology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden; 4Division of Genetics, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden Abstract: The human epidermal growth factor receptor 2 gene (HER2) is amplified in approximately 15%–20% of all breast cancers. This results in overexpression of the HER2 protein, which is associated with worse clinical outcomes in breast cancer patients. Several studies have shown that trastuzumab, a monoclonal antibody that interferes with the HER2/neu receptor, can improve overall survival in patients with HER2-positive breast cancer. Immunohistochemistry (IHC), combined with different methods for in situ hybridization, is currently used for routine assessment of HER2 status. The aim of the present study was to determine whether real-time polymerase chain reaction (PCR) can serve as a supplementary method for evaluation of HER2 status in primary breast cancer. For this purpose, 145 formalin-fixed paraffin-embedded primary breast cancer samples were tested by real-time PCR amplification of HER2, using amyloid precursor protein as a reference. The results were compared with HER2 status determined by fluorescence in situ hybridization (FISH) and IHC. The specificity, sensitivity, and reproducibility of real-time PCR were evaluated, and a comparison of formalin-fixed and fresh-frozen samples was performed. This showed concordance of 93% between real-time PCR and FISH, and 86% between real-time PCR and IHC. Therefore, we suggest that real-time PCR can be a useful supplementary method for assessment of HER2 status. Keywords: 17q, breast cancer, HER2, real-time PCR

Reliability of core needle biopsy for determining ER and HER2 status in breast cancer

BackgroundSeveral studies have assessed the concordance of estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) status between core needle biopsy (CNB) and resection specimens, usually in small patient series and with discordant results. Patients and methodsER and HER2 status determined on CNB and tissue micro-arrays of resected tumors were compared for patients treated at the Leiden University Medical Center (LUMC). When results were discordant, whole-sized slides were analyzed. Additionally, literature was searched for published patient series and combined with our data to assess the concordance of ER and HER2 determination between CNB and resection specimens. ResultsIn the LUMC series, concordance for ER status was 99.1%. Combined concordance from 20 studies and the LUMC patient series was 93.7%. For HER2 testing, concordance was 96.2% for patients in the LUMC series. Our study and three others have investigated the concordance when HER2 was determined according to the American Society of Clinical Oncology and College of Pathology guidelines and overall concordance was 97.8%. ConclusionsConcordance between CNB and surgical specimens was high for both ER and HER2 testing. However, we recommend retesting ER-negative CNB results on the surgical specimen and performing in situ hybridization assays on HER2 immunohistochemistry 3+ CNBs to confirm HER2 status.

Validation of a new classifier for the automated analysis of the human epidermal growth factor receptor 2 (HER2) gene amplification in breast cancer specimens

Amplification of the human epidermal growth factor receptor 2 (HER2) is a prognostic marker for poor clinical outcome and a predictive marker for therapeutic response to targeted therapies in breast cancer patients. With the introduction of anti-HER2 therapies, accurate assessment of HER2 status has become essential. Fluorescence in situ hybridization (FISH) is a widely used technique for the determination of HER2 status in breast cancer. However, the manual signal enumeration is time-consuming. Therefore, several companies like MetaSystem have developed automated image analysis software. Some of these signal enumeration software employ the so called “tile-sampling classifier”, a programming algorithm through which the software quantifies fluorescent signals in images on the basis of square tiles of fixed dimensions. Considering that the size of tile does not always correspond to the size of a single tumor cell nucleus, some users argue that this analysis method might not completely reflect the biology of cells. For that reason, MetaSystems has developed a new classifier which is able to recognize nuclei within tissue sections in order to determine the HER2 amplification status on nuclei basis. We call this new programming algorithm “nuclei-sampling classifier”. In this study, we evaluated the accuracy of the “nuclei-sampling classifier” in determining HER2 gene amplification by FISH in nuclei of breast cancer cells. To this aim, we randomly selected from our cohort 64 breast cancer specimens (32 nonamplified and 32 amplified) and we compared results obtained through manual scoring and through this new classifier. The new classifier automatically recognized individual nuclei. The automated analysis was followed by an optional human correction, during which the user interacted with the software in order to improve the selection of cell nuclei automatically selected. Overall concordance between manual scoring and automated nuclei-sampling analysis was 98.4% (100% for nonamplified cases and 96.9% for amplified cases). However, after human correction, concordance between the two methods was 100%. We conclude that the nuclei-based classifier is a new available tool for automated quantitative HER2 FISH signals analysis in nuclei in breast cancer specimen and it can be used for clinical purposes.

Bright-Field Microscopy for HER2 Gene Assessment

The human epidermal growth factor receptor gene ERBB2 (HER2) is located on chromosome 17 and amplified in approximately 20% of invasive breast carcinomas.1,2 Due to the availability of effective anti-HER2 therapies, the prognostic significance of HER2 gene amplification, and the predictive value of HER2 status with regard to response to chemotherapy, laboratory testing for protein overexpression and/or amplification is critical for clinical decision making in individual patients. Testing of HER2 on all newly diagnosed invasive breast carcinoma is standard of care. Although there is no gold standard for assessing HER2 status in breast cancer, immunohistochemistry (IHC) for protein expression and fluorescence in situ hybridization (FISH) for HER2 gene copy number are the preferred assays.3 Although no test is perfect, clinical utilization depends on a number of factors, including test accuracy but also consistency of results, as well as ease of performance and interpretation. Due to early standardization, consistency in reporting, and only a small number of equivocal results, the FISH assay became the preferred method for assessing HER2 gene status.4,5 FISH is also used as the reflex test in IHC equivocal (2+ score) cases. FISH on IHC equivocal cases can identify a small percentage of amplified cases but also aneuploidy and other difficult to assess abnormalities of chromosome 17. Despite its widespread use, the FISH assay does have some drawbacks. FISH is considered a morphology-based assay, but the fluorescent nature of the assay results in less than optimal histologic details (compared with bright-field microscopy), so the area of invasive tumor generally needs to be marked on a parallel H&E-stained section. The procedure …

Comparison of Fluorescence In Situ Hybridization (FISH) and Dual-ISH (DISH) in the Determination of HER2 Status in Breast Cancer

The determination of HER2 amplification is critical to selecting appropriate patients for HER2 targeted therapy in breast cancer. Dual in situ hybridization (DISH), an alternative to fluorescence in situ hybridization (FISH) and immunohistochemistry, is now available. To compare the FISH and DISH methods, we tested 251 samples enriched for common or difficult-to-assess HER2 anomalies. Seven samples failed DISH testing. There was a 64% (156/244) concordance between FISH and DISH by anomaly (κ = 0.58, 95% confidence interval, 0.51-0.65; P < .0001) and an 83% (203/244) concordance by amplification status (κ = 0.58; 95% confidence interval, 0.47-0.69; P < .0001). DISH resulted in lower estimates of HER2/ centromere 17 ratios than FISH, and many cases that were equivocal with FISH were normal with DISH. DISH did not detect any case with coamplification of HER2 and centromere 17. Using a cohort of difficult specimens, we observed less than 95% concordance between FISH and DISH. DISH may underestimate the HER2/chromosome 17 ratio, or FISH may overestimate this ratio.

The individualization of treatment based on molecular markers

Recent developments have revealed various decisive discoveries in individualized oncology for many different entities—the individualization of treatment based on molecular markers representing just one of those milestones. The implication of epidermal growth factor receptor (EGFR) mutations for EGFR-tyrosine kinase inhibitor (TKI) treatment, the definition of the HER2 status in breast cancer and the application of the KRAS mutation analysis in colorectal cancer are examples for this development. All these activities have also been the major focus at the Cancer Research Institute in St. Petersburg, where I worked for many years. Within the last years, a growing connection between basic research activities and clinical application can be observed.

The Bioinformatics Analysis of miRNAs Signatures Differentially Expressed in HER2(+) Versus HER2(−) Breast Cancers

To identify the signatures of miRNAs differentially expressed in HER2(+) versus HER2(-) breast cancers that accurately predict the HER2 status of breast cancer, and to provide further insight into breast cancer therapy. By the methods of literature search, aberrant expressed miRNAs were collected. By target prediction algorithm of TargetScan and PicTar and the data enrichment analysis, target gene sets of miRNAs differentially expressed in HER2(+) versus HER2(-) breast cancers were built. Then, using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) database, the function modules of Gene Ontology categories and Kyoto Encyclopedia of Genes and Genomes (KEGG) and BIOCARTA pathway, biological functions and signaling pathways that are probably regulated by miRNAs, were analyzed. We got five sets of miRNAs expressed in different HER2 status of breast cancers finally. The five sets of data contain 22; 32; 3; 38; and 62 miRNAs, respectively. After miRNAs target prediction and data enrichment, 5,734; 22,409; 1,142; 22,293; and 43,460 target genes of five miRNA sets were collected. Gene ontology analysis found these genes may be involved in transcription, protein transport, angiogenesis, and apoptosis. Moreover, certain KEGG and BIOCARTA signaling pathways related toHER2 status were found. Using TargetScan and PicTar for data enrichment, and DAVID database, Gene Ontology categories, KEGG and BIOCARTA pathway for analysis of miRNAs different expression, we conducted a new method for biological interpretation of miRNA profiling data in HER2(+) versus HER2(-) breast cancers. It may improve understanding the regulatory roles of miRNAs in different molecular subtypes of breast cancers. Therefore, it is beneficial to improve the accuracy of experimental efforts to breast cancer and potential therapeutic targets.

MRNA In Situ Hybridization (HistoSonda)

Monoclonal therapies could represent baseline-personalized medicine for patients with neoplasia. One of the most successful examples is Trastuzumab, a humanized antibody against epidermal growth factor receptor 2. Human epidermal growth factor receptor 2 (HER2) is a trans-membrane tyrosine kinase coded by the gene HER2/neu and overexpressed in approximately 12% to 20% of infiltrating breast carcinomas. The overexpression of HER2 is an independent adverse prognostic factor in relation to survival and is also predictive of response to treatment. Therefore, the correct evaluation of HER2 status is essential for the management of infiltrating breast carcinoma to determine the response to Trastuzumab. The most common evaluation technique is immunohistochemistry, which is confirmed by fluorescent or chromogenic monochrome or dual-gene in situ hybridization in ambiguous cases (immunohistochemical 2+). Our objective was to evaluate the diagnostic value of a new technique on the basis of HER2 mRNA in situ hybridization (HistoSonda) and study its correlation with immunohistochemistry and dual-chromogenic in situ hybridization (DUO-CISH) in 403 cases of infiltrating breast carcinoma. The percentage of DUO-CISH amplification was 25.8%, HistoSonda positivity was 31.2%, and positivity for Hercep-Test was 48.1%, including (+2) and (+3). Comparisons were made of each of the techniques, HistoSonda to IHQ and HistoSonda to DUO-CISH. The overall concordance between DUO-CISH and HistoSonda was 89%. Our data support the consistency of HistoSonda as a useful tool to determine HER2 status in breast cancer.

121P Brain Metastasis and Her-2 Status in Metastatic Breast Cancer (Mbc) in Oman

ABSTRACT Background Brain metastasis (BM) is increasingly encountered in up to 30% of MBC. Her-2 is over expressed in 30% of breast cancer (BC) patients, and BM is diagnosed in up to 40% of Her-2 positive BC. The risk factors are younger age, premenopause, invasive ductal carcinoma, tumor size > 2 cms, positive lymph nodes, high tumor grade, estrogen receptor negativity, p53 mutation, Her-2 positivity, and BRCA1 mutation. This study was carried out to analyze the Her-2 status of BC in our population, assess the frequency of BM, and its correlation to Her-2 status. Patients and methods Breast cancer data from 2006-2010 at National Oncology Center - Royal Hospital Muscat Sultanate of Oman was retrospectively retrieved from electronic patient record system. The cases of BC were analyzed with respect to Brain metastasis and their Her-2 status, their respective hormone receptor status, survival, and time to BM. Results A total of 542 cases of BC were evaluable during the period 2006-2010. BM was seen in 58, out of which 6 has an undetermined Her-2 status. One case presented as BM, to be diagnosed later as BC. Two cases developed further distant metastasis after BM. Isolated Her-2 positive BC and triple negative BC (TNBC) seems to have a similar spectrum in terms of BM, though patho-biology might not be the same. Her-2 positive tumor appears to have BM earlier. Some rare late BM was observed especially in Her-2 negative tumors. One case with Her-2 positive tumor survived 5 years after diagnosis of BM. There were 7 male BC with 2/7 Her2 positive, but none had a BM. Conclusions As the treatment modalities and survival improves, BM is anticipated to be encountered frequently. The correlation of Her-2 positive BC and BM concerns clinical outcome and needs validation. There are many open questions of interest including prophylactic Intra thecal Trastuzumab, concurrent Trastuzumab with radiation therapy, and concurrent Capecitabine or Temozolamide with Trastuzumab. The justification of frequent MRI surveillance is also debatable. Dual Her-2 inhibition by Lapitinib and Trastuzumab is another arena of further controlled clinical studies. There is a need to develop strategies of early diagnosis and prevention in BM, or to identify the molecular guided higher risk groups. Disclosure All authors have declared no conflicts of interest.

Dual color chromogenic in situ hybridization for determination of HER2 status in breast cancer: a large comparative study to current state of the art fluorescence in situ hybridization

BackgroundChromogenic in situ hybridization (CISH) is fast becoming a well established technique for easy and sensitive determination of HER2 gene status in breast cancer. However, for the chromogenic method to achieve status as a safe and reliable technique, the method needs to be validated against already known and validated FISH techniques.MethodsHere it is reported from a comparative study where HER2 gene status obtained by HER2 CISH pharmDx™ Kit was compared to HER2 gene status obtained by the FDA approved HER2 FISH pharmDx™ Kit and the PathVysion HER-2 DNA probe Kit. The study included 365 formalin fixed and paraffin-embedded invasive breast cancer tissue specimens collected consecutively at a US reference laboratory.ResultsThe data obtained revealed an overall HER2 status concordance of approximately 98% for comparisons of HER2 CISH pharmDx™ Kit to both HER2 FISH pharmDx™ Kit and PathVysion HER-2 DNA Probe Kit.ConclusionsThe concordance between results obtained using the recently FDA approved HER2 CISH pharmDx™ Kit with previously FDA approved FISH techniques for HER2 gene status determination indicate that the HER2 CISH pharmDx™ Kit is a reliable chromogenic alternative to fluorescence-based methods.

P1-07-12: Assessment of Real World HER2 Status by Immunohistochemistry (IHC) and Fluorescence In Situ Hybridization (FISH) in Breast Cancers: Comparison with HERmark®, a Validated Quantitative Measure of HER2 Protein Expression.

Abstract Background: Accurate assessment of the HER2 status is critical in determining appropriate therapy for patients with invasive breast cancer. ASCO/CAP HER2 testing guidelines caution that up to 20% of routine HER2 testing by IHC/FISH may be unreliable (Wolff et al. JCO 2007;25:118). The HERmark assay is a novel quantitative HER2 protein measurement for determining HER2 status in breast cancer. Central HER2 testing showed high concordance (96-98%) with HERmark for positive and negative categories when equivocal subsets were excluded (Huang et al. Am J Clin Pathol 2010;134:303; Joensuu et al, 2008 SABCS, abstract 2071). In this study, we examined concordance between HERmark and routine HER2 testing by IHC and FISH from “real world” formalin-fixed, paraffin-embedded (FFPE) breast cancers submitted commercially for HERmark testing. Methods: 717 HERmark results on FFPE breast cancers tested from 2008 to 2010 and corresponding HER2 IHC/FISH results were reviewed. The IHC and FISH results, per pathology reports submitted at the time of HERmark testing, were compared to HERmark categorical (negative, equivocal, positive) results. Results: 590 (419) samples had IHC (FISH) and HERmark results available. Of these cases, 92% (94%) were either negative or equivocal by IHC (FISH). The HERmark testing reported 33% HERmark negative, 33% HERmark equivocal and 34% HERmark positive. Comparisons of HER2 status by IHC and FISH vs. HERmark are detailed in Table 1. 19% of cases classified as IHC 0 or 1+ were positive by HERmark; 35% classified as FISH negative were HERmark positive. Of the 158 triple negative cases by IHC/FISH (ER, PR and HER2 negative, data not shown), 38 (24%) were reclassified as HER2 positive by HERmark. Conclusions: Higher than expected discordance between HER2 IHC/FISH and the HERmark assay was observed in this study compared with central HER2 testing of prior study cohorts. Selection bias may have impacted these results as ≥ 92% of cases submitted for HERmark testing were either equivocal or negative by routine HER2 IHC/FISH. Central HER2 FISH retesting of these samples will be performed and compared with HERmark results to further evaluate the discordance observed in this analysis. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-07-12.

Abstract PL07-01: Rational cancer drug development for targeted drugs: Views from academia and the European Medicines Agency (EMA).

Abstract PL07-01: Rational cancer drug development for targeted drugs: Views from academia and the European Medicines Agency (EMA).

Standardized Assessment of the HER2 Status in Breast Cancer by Immunohistochemistry

Immunohistochemistry (IHC) is widely used in surgical pathology, but it has been plagued by problems with reproducibility and lack of standardization resulting in poor concordance between laboratories. In particular, inaccuracy of routine human epidermal growth factor receptor 2 (HER2) testing in breast cancer patients has been a major issue. In 2006 this led the American Society of Clinical Oncologists (ASCO) and College of American Pathologists (CAP) to charge an expert panel with developing recommendations for HER2 testing. After subsequent publication and adoption of these guideline recommendations through dissemination of best practices, variation in clinical practice is expected to diminish and result in improved accuracy. In this article, we review the role of genomic HER2 alterations in the development and treatment of breast cancer, highlight the importance of accurate and reproducible HER2 testing, and discuss practical approaches to standardize HER2 testing by IHC. Pre-analytic and analytic variables are addressed, and a practical algorithm for test interpretation is introduced. * IHC : immunohistochemistry HER2 : human epidermal growth factor receptor 2 ASCO : American Society of Clinical Oncologists CAP : College of American Pathologists ER : estrogen receptor FISH : fluorescence in situ hybridization PR : progesterone receptor H&E : hematoxylin and eosin staining

Dual-color silver-enhanced in situ hybridization for assessing HER2 gene amplification in breast cancer

Amplification of the human epidermal growth factor receptor 2 (HER2) gene occurs in 20–25% of breast cancers, and is recognized as a prognostic and predictive marker. HER2 gene amplification, evaluated as a change in protein expression or gene copy number, can be identified by a number of methods. Fluorescence in situ hybridization (FISH) is considered the gold standard for HER2 gene copy number determination; however, a number of impediments prevent its wider use in a clinical setting. The aims of our study were to compare dual-color silver-enhanced in situ hybridization (SISH) with single-color SISH and FISH on formalin-fixed, paraffin-embedded sections, and to validate its use as a routine method for assessing HER2 status in breast cancers. A total of 146 invasive breast carcinoma cases were assessed for HER2 gene amplification by FISH and dual-color SISH. Dual-color SISH and FISH results exhibited a concordance rate of 97% (κ=0.912). A comparison of the single-color SISH method with dual-color SISH showed that 142 of 146 cases were in agreement (97%, κ=0.930). Our results showed that dual-color SISH is a viable alternative to FISH that offers a number of advantages in a clinical setting.

Does a change from IHC to FISH enhance patient selection for HER2 therapy?

e11015 Background: Breast cancer is the most commonly diagnosed malignancy among women in the United States. Among various subtypes of breast cancer, tumors that overexpress the human epidermal growth factor receptor 2 (HER2) have an aggressive biology. The frequency of HER2 gene amplification is about 20% among breast cancer patients. The diagnostic tests to determine HER2 status in breast cancer include Immunohistochemisty (IHC), and Fluorescence In-Situ Hybridization (FISH). The interpretation of IHC is subjective and may depend on the pathologist. It is unknown whether the use of FISH has led to higher detection of HER2 overexpression. Methods: We conducted a retrospective review of patients diagnosed with breast cancer from 2000 to 2008. A total of 865 breast cancer patients were reviewed. One hundred and sixty five (19%) were diagnosed with HER2+ subtype. Our institution utilized IHC (HER2-pY 1248 antibody, Dako Corporation) from 2000 to 2003 and FISH (Path Vysion, HER-2 DNA Probe Kit) from 2004 to 2008. Results: The frequency of HER2 detection in breast cancer by IHC from 2000-2003 was 17%. The detection by FISH from 2004-2008 was 20%, an increase of 3%. Conclusions: We observed an increase in the diagnosis of HER2+ breast cancer with the introduction of FISH. This modest difference when applied to a large group of patients could translate into more patients being eligible for anti-HER2 therapy and may enhance accrual to clinical trials.

Bright field in-situ hybridization for delineation of HER2 status in breast cancer

随着乳腺癌分子发病机制的快速发展,乳腺癌的治疗策略发生了极大变化.个体化治疗,尤其是分子靶向治疗的快速发展使得组织分子靶点的检测成为关键环节.分子检测需求量的增加使得多种原位杂交技术应用于临床实验室.亮视野原位杂交在这方面有很多优势,检测乳腺癌HER2基因状态已成为亮视野原位杂交技术发展的主要推动力。

Immunohistochemical and molecular analyses of HER2 status in breast cancers are highly concordant and complementary approaches

Background:Immunohistochemistry (IHC) and fluorescent in situ hybridisation (FISH) are currently the most commonly used methods to assess HER2 status. PCR-based assays allow quantitative determination of HER2 amplification (Q-PCR) or overexpression (Q-RT–PCR), but are not routinely used. We evaluated the relevance of Q-RT–PCR for HER2 status determination.Methods:We compared IHC and Q-RT–PCR in 466 breast tumours. In discordant or equivocal cases, five additional methods (IHC with two other antibodies, FISH, silver in situ hybridisation (SISH) and Q-PCR) were combined to determine HER2 status. Two cases with HER2 intra-tumour heterogeneity were further explored by allelic profiles analysis and HUMARA clonality determination after microdissection.Results:We observed 97.3% concordance between Q-RT–PCR and non-equivocal IHC. Twelve out of 466 cases (3%) revealed discordances between the two methods. The power of Q-RT–PCR to predict HER2 status (defined by seven methods) was similar to that of IHC. Although rare, some discordances between techniques might be due to HER2 intra-tumour heterogeneity and we report two examples, one tumour containing two distinct clones, another tumour consisting of HER2 amplified and non-amplified subclones.Conclusion:Q-RT–PCR and IHC are highly concordant methods for HER2 status assessment, and Q-RT–PCR allows a highly reliable quantitative assessment and could be a useful adjunct to IHC.

HER2 status in breast cancer: experience of a Spanish National Reference Centre

Accurate HER2 testing is of great clinical value for the identification of breast cancer patients who are eligible for trastuzumab therapy. The aim of this study is to review breast carcinomas diagnosed from 2001 to 2007 at a Spanish National Reference Centre for HER2 testing, evaluating the agreement between HER2 immunohistochemical (IHC) tests and fluorescence in situ hybridisation (FISH) tests. Demographic and clinical information was obtained from 2751 breast carcinoma patients. HER2 IHC and FISH tests were performed both in a local laboratory and in the reference centre. The HER2 IHC0/1+, IHC2+, IHC3+ and FISH-positive patients comprised 64%, 20%, 16% and 24% of the available population, respectively (results from the reference centre). Using statistical approaches, we evaluated the agreement between: (1) HER2 IHC and FISH tests, and (2) results provided by the local and the reference laboratories. The data confirmed a statistically significant relation between HER2 overexpression and amplification. We also found that instances of polysomy 17 and heterogeneous patterns of HER2 expression (heterogeneous staining distribution in different areas of the same tumour) are more frequently observed in HER2-positive tumours. Finally, since the diagnoses were made from 2001 to 2007, we could also observe a rising agreement rate between laboratories/pathologists with time. HER2 testing is most accurate when performed by experienced pathologists and at a high-volume reference laboratory. Polysomy 17 and HER2 heterogeneous staining patterns should also be considered for a better understanding of the variation in the anti-HER2 therapeutic response.

Prognostic Significance of Young Age (&lt;35 Years) by Subtype Based on ER, PR, and HER2 Status in Breast Cancer: A Nationwide Registry‐Based Study

Young age is regarded as an adverse prognostic factor in patients with breast cancer, especially in those with a hormone receptor (HR)-positive tumor. We investigated the prognostic significance of an age of <35 years stratified by molecular subtype based on HR and HER2. Two large databases of Korean breast cancer patients, which included nationwide registry data, were analyzed. In an analysis of 2,474 patients from the single institution, an age of <35 years was found to be an independent predictor of recurrence in patients with HR+/HER2- (hazard ratio 1.87; 95% confidence interval [CI]: 1.11-3.14; P=0.018), HR+/HER2+ (hazard ratio 3.09; 95% CI: 1.19-8.03; P=0.020), and HR-/HER2+ (hazard ratio 2.01; 95% CI: 1.03-3.92; P=0.040) subtypes, but not in those with the HR-/HER2- (triple-negative, TN) subtype (hazard ratio 1.08; 95% CI: 0.60-1.95; P=0.802). The results of an analysis of nationwide database data on 31,672 patients also showed that an age of <35 years significantly predicted poor cancer-specific survival in patients with HR+/HER2- (hazard ratio 3.40; 95% CI: 2.41-4.82; P<0.001), HR+/HER2+ (hazard ratio 1.96; 95% CI: 1.23-3.12; P=0.005), and HR-/HER2+ (hazard ratio 1.65; 95% CI: 1.07-2.52; P=0.022) subtypes, but again not in those with the TN subtype (hazard ratio 1.21; 95% CI: 0.88-1.67; P=0.240). The prognostic significance of young age was found to depend on molecular subtype. An age of <35 years was a poor prognosticator in patients with the HR+/HER2-, HR+/HER2+, and HR-/HER2+ subtypes, but not in those with the TN subtype.