HER2Testing by Local, Central, and Reference Laboratories in Specimens From the North Central Cancer Treatment Group N9831 Intergroup Adjuvant Trial

A Root Cause Analysis Into the High Error Rate in Clinical Immunohistochemistry

The field of Clinical Immunohistochemistry (IHC) is beset with a high error rate, an order of magnitude higher than in other types of clinical laboratory testing. Despite the many improvements in the field, these errors have persisted over the last 2 decades. The improvements over the years include an extensive literature describing the potential causes of errors and how to avoid them. More stringent regulatory guidelines have also been implemented. These measures reflect the standard view is that fixing the broad confluence of causes of error will address the problem. This review takes a different tack. To understand the high error rates, this review compares Clinical IHC laboratory practice to practices of other clinical laboratory disciplines. What aspects of laboratory testing that minimize errors in other clinical laboratory disciplines are not found in Clinical IHC? In this review, we seek to identify causal factors and underlying root causes that are unique to the field of Clinical IHC in comparison to other laboratory testing disciplines. The most important underlying root cause is the absence of traceable units of measure, international standards, calibrators that are traceable to standards, and quantitative monitoring of controls. These tools and practices (in other clinical laboratory disciplines) provide regular accurate feedback to laboratory personnel on analytic test performance.

HER2 immunohistochemical scores provide prognostic information for patients with HER2-type invasive breast cancer

AIMS

Invasive breast cancer patients with human epidermal growth factor receptor 2 (HER2) immunohistochemical (IHC) scores of 3+ or 2+ with reflex in-situ hybridisation (ISH) positivity are suitable for anti-HER2 therapies. The aim of this study is to investigate whether the prognoses between IHC 3+ patients and IHC 2+/ISH+ patients are different.

METHODS AND RESULTS

We analysed the clinicopathological information of 886 consecutive cases of HER2-positive early breast cancer. The influences of the patients' age, cancer stage, hormone receptor status and anti-HER2 treatment were adjusted using a multivariate Cox regression model. Both HER2 copy numbers and HER2 ISH ratios of the IHC 3+ group were significantly higher than those of the IHC 2+/ISH+ group. The outcomes of IHC 3+ patients were significantly better than those of IHC 2+/ISH+ patients in the univariate and multivariate analyses. HER2 copy numbers of ≥8 represented the best prognostic value, and it was chosen to be the cut-off value. The reflex ISH for IHC 2+ patients with high HER2 copy numbers (≥8) predicted a better overall survival than that for those with low HER2 copy numbers.

CONCLUSION

HER2 IHC scores and HER2 copy numbers can provide prognostic information for patients with HER2-positive invasive breast cancer. Both IHC 3+ and IHC 2+ patients with high HER2 copy numbers had a better prognosis.

Hormone Receptors and Human Epidermal Growth Factor (HER2) Expression in Fine-Needle Aspirates from Metastatic Breast Carcinoma - Role in Patient Management

Introduction:

Estrogen receptors (ER), progesterone receptors (PR), and epidermal growth factor (HER2) are prognostic and predictive factors for breast carcinoma. We determined them by immunohistochemistry (IHC) on cell blocks from fine-needle aspirates (FNA) of metastatic breast carcinoma to axillary lymphnodes and compared them with that reported in the primary breast carcinoma (PBC) to document any change in their expression for future management.

Materials and Methods:

ER, PR, and HER2 by IHC and HER2 oncogene by fluorescent in-situ hybridization (FISH) were studied on cell blocks of FNA of axillary lymphnodes in 53 of 94 PBC cases from 2012 to 2016.

Results:

In 25 of 38 (65.8%) ER, PR negative PBC the metastasis on FNA was ER, PR+, whereas the 15 (28.3%) ER, PRPBC remained negative. In 10 of 11 (91%) of HER2-IHC+, PBC the metastatic tumor was HER2-IHC+. 7 of 32 (21.9%) HER2-IHC negative PBC were HER2-IHC+ in metastatic tumor. HER2-FISH was performed in 37 cases on FNA. Six of 37 were HER2 amplified/positive, whereas 9 and 19 remained equivocal and negative for HER2 copy number, and 3 were not interpretable. All the 6 HER2-FISH+ cases were positive by IHC. In our study, 34.2% of ER, PR+ cases of PBC became ER, PR– in the metastatic tumor and 21.9% of HER2-IHC negative PBC became HER2-IHC+ in the metastatic aspirate.

Conclusion:

ER, PR, and HER2 by IHC in cell blocks of metastatic lymphnodes are reliable. Change in receptor (34.2%) and HER2 status (21.9%) was documented, which is of clinical significance as these patients warrant a change of management.

The evolving role of receptors as predictive biomarkers for metastatic breast cancer

INTRODUCTION

In breast cancer, estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) are essential biomarkers to predict response to endocrine and anti-HER2 therapies, respectively. In metastatic breast cancer, the use of these receptors and targeted therapies present additional challenges: temporal heterogeneity, together with limited sampling methodologies, hinders receptor status assessment, and the constant evolution of the disease invariably leads to resistance to treatment. Areas covered: This review summarizes the genomic abnormalities in ER and HER2, such as mutations, amplifications, translocations, and alternative splicing, emerging as novel biomarkers that provide an insight into underlying mechanisms of resistance and hold potential predictive value to inform treatment selection. We also describe how liquid biopsies for sampling of circulating markers and ultrasensitive detection technologies have emerged which complement ongoing efforts for biomarker discovery and analysis. Expert commentary: While evidence suggests that genomic aberrations in ER and HER2 could contribute to meeting the pressing need for better predictive biomarkers, efforts need to be made to standardize assessment methods and better understand the resistance mechanisms these markers denote. Taking advantage of emerging technologies, research in upcoming years should include prospective trials incorporating these predictors into the study design to validate their potential clinical value.

Incorporating Biology Into Breast Cancer Staging: American Joint Committee on Cancer, Eighth Edition, Revisions and Beyond

Higher-quality imaging, refined surgical procedures, enhanced pathologic evaluation, and improved understanding of the impact of tumor biology on treatment and prognosis have necessitated revisions of the AJCC breast cancer staging system. The eighth edition includes clinical and pathologic prognostic stages that incorporate biologic variables-grade, estrogen and progesterone receptor status, HER2 status, and multigene panels-with the anatomic extent of disease defined by tumor, node, and metastasis categories. The prognostic staging systems facilitate more refined stratification with respect to survival than anatomic stage alone. Because the prognostic staging systems are dependent on biologic factors, accuracy is dependent on rigorous pathologic evaluation of tumors and on administration of treatment dictated by tumor biology. It is anticipated that technological advances will facilitate even more refined determination of underlying biology within tumors and in the peripheral blood, which increasingly is being evaluated as a compartment that reflects the primary tumor and sites of distant metastases. Diseases should be staged according to the eighth edition staging system to accurately reflect prognosis and to allow standardized data collection. Such standardization will facilitate assessment of the impact of advances in diagnosis and treatment of patients with breast cancer.

Interobserver variation in CD30 immunohistochemistry interpretation; consequences for patient selection for targeted treatment

AIMS

CD30 immunohistochemistry (IHC) in malignant lymphoma is used for selection of patients in clinical trials using brentuximab vedotin, an antibody drug-conjugate targeting the CD30 molecule. For reliable implementation in daily practice and meaningful selection of patients for clinical trials, information on technical variation and interobserver reproducibility of CD30 immunohistochemistry (IHC) staining is required.

METHODS AND RESULTS

We conducted a three-round reproducibility assessment of CD30 scoring for categorised frequency and intensity, including a technical validation, a 'live polling' pre- and post-instruction scoring round and a web-based round including individual scoring with additional IHC information to mimic daily diagnostic practice. Agreement in all three scoring rounds was poor to fair (κ = 0.12-0.35 for CD30-positive tumour cell percentage and κ = 0.16-0.41 for staining intensity), even when allowing for one category of freedom in percentage of tumour cell positivity (κ = 0.30-0.61). The first round with CD30 staining performed in five independent laboratories showed objective differences in staining intensity. In the second round, approximately half the pathologists changed their opinion on CD30 frequency after a discussion on potential pitfalls, highlighting hesitancy in decision-making. Using fictional cut-off points for percentage of tumour cell positivity, agreement was still suboptimal (κ = 0.35-0.60).

CONCLUSIONS

Lack of agreement in cases with heterogeneous expression is shown to influence patient eligibility for treatment with brentuximab vedotin, both in clinical practice and within the context of clinical trials, and limits the potential predictive value of the relative frequency of CD30-positive neoplastic cells for clinical response.

3D Imaging Detection of HER2 Based in the Use of Novel Affibody-Quantum Dots Probes and Ratiometric Analysis

Patients with breast cancer (BC) overexpressing HER2 (HER2+) are selected for Trastuzumab treatment, which blocks HER2 and improves cancer prognosis. However, HER2+ diagnosis, by the gold standard, immunohistochemistry, could lead to errors, associated to: a) variability in sample manipulation (thin 2D sections), b) use of subjective algorithms, and c) heterogeneity of HER2 expression within the tissue. Therefore, we explored HER2 3D detection by multiplexed imaging of Affibody-Quantum Dots conjugates (Aff-QD), ratiometric analysis (RMAFI) and thresholding, using BC multicellular tumor spheroids (BC-MTS) (~120 μm of diameter) as 3D model of BC. HER2+, HER2- and hybrid HER2+/- BC-MTS (mimicking heterogeneous tissue) were incubated simultaneously with two Aff-QD probes (anti-HER2 and negative control (NC), respectively, (1:1)). Confocal XY sections were recorded along the Z distance, and processed by automatized RMAFI (anti-HER2 Aff-QD/ NC). Quantifying the NC fluorescence allowed to predict the fraction of non-specific accumulation of the anti-HER2 probe within the thick sample, and resolve the specific HER2 level. HER2 was detected up to 30μm within intact BC-MTS, however, permeabilization improved detection up to 70μm. Specific HER2 signal was objectively quantified, and HER2 3D-density of 9.2, 48.3 and 30.8% were obtained in HER2-, HER2+ and hybrid HER2+/- permeabilized BC-MTS, respectively. Therefore, by combining the multiplexing capacity of Aff-QD probes and RMAFI, we overcame the challenge of non-specific probe accumulation in 3D samples with minimal processing, yielding a fast, specific spatial HER2 detection and objective quantification.

The extracellular domain of Her2 in serum as a biomarker of breast cancer

Breast cancer is a major health problem worldwide. In ~15% of breast cancers, the epidermal growth factor receptor HER2, a transmembrane protein, is overexpressed. This HER2 overexpression is associated with an aggressive form of the disease and a poor clinical prognosis. The extracellular domain (ECD) of HER2 is released into the blood by a proteolytic mechanism known as "ECD shedding". This proteolytic shedding leaves a constitutively active truncated receptor in the membrane that is 10-100-fold more oncogenic than the full-length receptor and promotes the growth and survival of cancer cells. Shedding of the HER2 ECD is increased during metastasis: whereas 15% of primary breast cancer patients have elevated levels of serum HER2 ECD (sHER2 ECD), the levels reach 45% in patients with metastatic disease. Thus, sHER2 ECD has been proposed as a promising biomarker for cancer recurrence and for monitoring the disease status of patients overexpressing HER2. Nevertheless, in 2016, the American Society of Clinical Oncology advises clinicians not to use soluble HER2 levels to guide their choice of adjuvant therapy for patients with HER2-positive breast cancer, because the evidence was considered not strong enough. Currently, biomarkers such as carcinoembryonic antigen and cancer antigen 15-3 are widely used to monitor metastatic breast cancer disease even if the level of evidence of clinical impact of this monitoring is poor. In this article, we review the evidence that sHER2 ECD might be used in some situations as a biomarker for breast cancer. Although this serum biomarker will not replace the direct measurement of tumor HER2 status for diagnosis of early-stage tumors; it might be especially useful in metastatic disease for prognosis, as an indicator of cancer progression and of therapy response, particularly to anti-HER2 therapies. Owing to these data, sHER2 ECD should be considered as a promising biomarker to detect cancer recurrence and metastasis.

Concordance between Immunohistochemistry and Microarray Gene Expression Profiling for Estrogen Receptor, Progesterone Receptor, and HER2 Receptor Statuses in Breast Cancer Patients in Lebanon

Introduction

Accurate evaluation of estrogen and progesterone receptors and HER2 is critical when diagnosing invasive breast cancer for optimal treatment. The current evaluation method is via immunohistochemistry (IHC). In this paper, we compared results of ER, PR, and HER2 from microarray gene expression to IHC in 81 fresh breast cancer specimens.

Methods

Gene expression profiling was performed using the GeneChip Human Genome U133 Plus 2.0 arrays (Affymetrix Inc). Immunohistochemical staining for estrogen receptor, progesterone receptor, and HER2 status was performed using standard methods at a CAP-accredited pathology laboratory. Concordance rates, agreement measures, and kappa scores were calculated for both methods.

Results

For ER, Kappa score was 0.918 (95% CI, 0.77.3-1.000) and concordance rate was 97.5% (95% CI, 91.4%-99.7%). For PR, Kappa score was 0.652 (95% CI, 0.405-0.849) and concordance rate was 86.4% (95% CI, 77%-93%). For HER2, Kappa score was 0.709 (95% CI, 0.428-0.916) and concordance rate was 97.5% (95% CI, 91.4%-99.7%).

Conclusion

Our results are in line with the available evidence with the concordance rate being the lowest for the progesterone receptor. In general, microarray gene expression and IHC proved to have high concordance rates. Several factors can increase the discordance rate such as differences in sample processing.

Human Epidermal Growth Factor Receptor 2-Targeted PET/Single- Photon Emission Computed Tomography Imaging of Breast Cancer: Noninvasive Measurement of a Biomarker Integral to Tumor Treatment and Prognosis

Increased human epidermal growth factor receptor 2 (HER2) expression is a hallmark of aggressive breast cancer. Imaging modalities have the potential to diagnose HER2-positive breast cancer and detect distant metastases. The heterogeneity of HER2 expression between primary and metastatic disease sites limits the value of tumor biopsies. Molecular imaging is a noninvasive tool to assess HER2-positive primary lesions and metastases. Radiolabeled antibodies, antibody fragments, and affibody molecules devise a reliable and quantitative method for detecting HER2-positive cancer using PET. HER2-targeted PET imaging is a valuable clinical tool with respect to both the care and maintenance of patients with breast cancer.

Digital image analysis in breast pathology-from image processing techniques to artificial intelligence

Breast cancer is the most common malignant disease in women worldwide. In recent decades, earlier diagnosis and better adjuvant therapy have substantially improved patient outcome. Diagnosis by histopathology has proven to be instrumental to guide breast cancer treatment, but new challenges have emerged as our increasing understanding of cancer over the years has revealed its complex nature. As patient demand for personalized breast cancer therapy grows, we face an urgent need for more precise biomarker assessment and more accurate histopathologic breast cancer diagnosis to make better therapy decisions. The digitization of pathology data has opened the door to faster, more reproducible, and more precise diagnoses through computerized image analysis. Software to assist diagnostic breast pathology through image processing techniques have been around for years. But recent breakthroughs in artificial intelligence (AI) promise to fundamentally change the way we detect and treat breast cancer in the near future. Machine learning, a subfield of AI that applies statistical methods to learn from data, has seen an explosion of interest in recent years because of its ability to recognize patterns in data with less need for human instruction. One technique in particular, known as deep learning, has produced groundbreaking results in many important problems including image classification and speech recognition. In this review, we will cover the use of AI and deep learning in diagnostic breast pathology, and other recent developments in digital image analysis.

Clinical relevance and concordance of HER2 status in local and central testing-an analysis of 1581 HER2-positive breast carcinomas over 12 years

Human epidermal growth factor receptor 2 (HER2) is a central predictive biomarker in breast cancer. Inaccurate HER2 results in different laboratories could be as high as 20%. However, this statement is based on data generated more than 13 years ago and may not reflect the standards of modern diagnostic pathology. We compared central and local HER2 testing in a total of 1581 HER2-positive tumors from five clinical trials. We evaluated the clinical relevance for pathological complete response (pCR) and disease-free survival in a subgroup of 677 tumors, which received an anti-HER2 therapy. Over the period of 12 years, the discordance rate for HER2 decreased from 52.4 (GeparTrio) to 8.4% (GeparSepto). Discordance rates were significantly higher in hormone receptor (HR)-positive tumors (26.6%), compared to HR-negative tumors (16.3%, P<0.0001), which could be explained by a different distribution of HER2 mRNA levels in HR-positive and HR-negative tumors. pCR rates were significantly lower in discordant tumors (13.7%) compared to concordant tumors (32.2%, GeparQuattro and GeparQuinto, P<0.001). In survival analysis, tumors with discordant HER2 testing had a reduced overall survival (OS) in the HR-negative group (P=0.019) and a trend for improved OS in the HR-positive group (P=0.125). The performance of local HER2 testing was considerably improved over time and has reached a 92% concordance, which shows that quality initiatives in diagnostic pathology are working. Tumors with discordant HER2 testing had a reduced therapy response and different survival rates.

Clinical Value of RNA Sequencing-Based Classifiers for Prediction of the Five Conventional Breast Cancer Biomarkers: A Report From the Population-Based Multicenter Sweden Cancerome Analysis Network-Breast Initiative

Purpose

In early breast cancer (BC), five conventional biomarkers-estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2), Ki67, and Nottingham histologic grade (NHG)-are used to determine prognosis and treatment. We aimed to develop classifiers for these biomarkers that were based on tumor mRNA sequencing (RNA-seq), compare classification performance, and test whether such predictors could add value for risk stratification.

Methods

In total, 3,678 patients with BC were studied. For 405 tumors, a comprehensive multi-rater histopathologic evaluation was performed. Using RNA-seq data, single-gene classifiers and multigene classifiers (MGCs) were trained on consensus histopathology labels. Trained classifiers were tested on a prospective population-based series of 3,273 BCs that included a median follow-up of 52 months (Sweden Cancerome Analysis Network-Breast [SCAN-B], ClinicalTrials.gov identifier: NCT02306096), and results were evaluated by agreement statistics and Kaplan-Meier and Cox survival analyses.

Results

Pathologist concordance was high for ER, PgR, and HER2 (average κ, 0.920, 0.891, and 0.899, respectively) but moderate for Ki67 and NHG (average κ, 0.734 and 0.581). Concordance between RNA-seq classifiers and histopathology for the independent cohort of 3,273 was similar to interpathologist concordance. Patients with discordant classifications, predicted as hormone responsive by histopathology but non-hormone responsive by MGC, had significantly inferior overall survival compared with patients who had concordant results. This extended to patients who received no adjuvant therapy (hazard ratio [HR], 3.19; 95% CI, 1.19 to 8.57), or endocrine therapy alone (HR, 2.64; 95% CI, 1.55 to 4.51). For cases identified as hormone responsive by histopathology and who received endocrine therapy alone, the MGC hormone-responsive classifier remained significant after multivariable adjustment (HR, 2.45; 95% CI, 1.39 to 4.34).

Conclusion

Classification error rates for RNA-seq-based classifiers for the five key BC biomarkers generally were equivalent to conventional histopathology. However, RNA-seq classifiers provided added clinical value in particular for tumors determined by histopathology to be hormone responsive but by RNA-seq to be hormone insensitive.

Prognostic value of O-6-methylguanine-DNA methyltransferase (MGMT) protein expression in glioblastoma excluding nontumour cells from the analysis

AIMS

It is important to predict response to treatment with temozolomide (TMZ) in glioblastoma (GBM) patients. Both MGMT protein expression and MGMT promoter methylation status have been reported to predict the response to TMZ. We investigated the prognostic value of quantified MGMT protein levels in tumour cells and the prognostic importance of combining information of MGMT protein level and MGMT promoter methylation status.

METHODS

MGMT protein expression was quantified in tumour cells in 171 GBMs from the population-based Region of Southern Denmark (RSD)-cohort using a double immunofluorescence approach. Pyrosequencing was performed in 157 patients. For validation we used GBM-patients from a Nordic Study (NS) investigating the effect of radiotherapy and different TMZ schedules.

RESULTS

When divided at the median, patients with low expression of MGMT protein (AF-low) had the best prognosis (HR = 1.5, P = 0.01). Similar results were observed in the subgroup of patients receiving the Stupp regimen (HR = 2.0, P = 0.001). In the NS-cohort a trend towards superior survival (HR = 1.6, P = 0.08) was seen in patients with AF-low. Including MGMT promoter methylation status, we found for both cohorts that patients with methylated MGMT promoter and AF-low had the best outcome; median OS 23.1 and 20.0 months, respectively.

CONCLUSION

Our data indicate that MGMT protein expression in tumour cells has an independent prognostic significance. Exclusion of nontumour cells contributed to a more exact analysis of tumour-specific MGMT protein expression. This should be incorporated in future studies evaluating MGMT status before potential integration into clinical practice.

Deep Convolutional Neural Networks Enable Discrimination of Heterogeneous Digital Pathology Images

Pathological evaluation of tumor tissue is pivotal for diagnosis in cancer patients and automated image analysis approaches have great potential to increase precision of diagnosis and help reduce human error. In this study, we utilize several computational methods based on convolutional neural networks (CNN) and build a stand-alone pipeline to effectively classify different histopathology images across different types of cancer. In particular, we demonstrate the utility of our pipeline to discriminate between two subtypes of lung cancer, four biomarkers of bladder cancer, and five biomarkers of breast cancer. In addition, we apply our pipeline to discriminate among four immunohistochemistry (IHC) staining scores of bladder and breast cancers. Our classification pipeline includes a basic CNN architecture, Google's Inceptions with three training strategies, and an ensemble of two state-of-the-art algorithms, Inception and ResNet. Training strategies include training the last layer of Google's Inceptions, training the network from scratch, and fine-tunning the parameters for our data using two pre-trained version of Google's Inception architectures, Inception-V1 and Inception-V3. We demonstrate the power of deep learning approaches for identifying cancer subtypes, and the robustness of Google's Inceptions even in presence of extensive tumor heterogeneity. On average, our pipeline achieved accuracies of 100%, 92%, 95%, and 69% for discrimination of various cancer tissues, subtypes, biomarkers, and scores, respectively. Our pipeline and related documentation is freely available at https://github.com/ih-_lab/CNN_Smoothie.

Ioncopy: a novel method for calling copy number alterations in amplicon sequencing data including significance assessment

Recently, it has been demonstrated that calling of copy number alterations (CNAs) from amplicon sequencing (AS) data is feasible. Most approaches, however, require non-tumor (germline) DNA for data normalization. Here, we present the method Ioncopy for CNA detection which requires no normal controls and includes a significance assessment for each detected alteration.

Ioncopy was evaluated in a cohort of 184 clinically annotated breast carcinomas. A total number of 252 amplifications were detected, of which 183 (72.6%) could be validated by a call of an additional amplicon interrogating the same gene. Moreover, a total number of 33 deletions were found, whereof 27 (81.8%) could be validated. Analyzing the 16 most frequently amplified genes, validation rates of over 89% could be achieved for 11 of these genes. 11 of the top 16 genes showed significant overexpression in the amplified tumors. 89.5% of the HER2-amplified tumors were GRB7 and STARD3 co-amplified, whereas 68.4% of the HER2-amplified tumors had additional MED1 amplifications. Correlations between CNAs measured by amplicons in HER2 exons 19, 20 and 21 were strong (all R > 0.93). AS based detection of HER2 amplifications had a sensitivity of 90.0% and a specificity of 98.8% compared to the gold standard of HER2 immunohistochemistry combined with in situ hybridization.

In summary, we developed and validated a novel method for detection and significance assessment of CNAs in amplicon sequencing data. Using Ioncopy, AS offers a straightforward and efficient approach to simultaneously analyze gene amplifications and gene deletions together with simple somatic mutations in a single assay.

Monosomy 17 in potentially curable HER2-amplified breast cancer: prognostic and predictive impact

PURPOSE

HER2 copy number by fluorescence in situ hybridization (FISH) is typically reported relative to the centromere enumeration probe 17 (CEP17). HER2/CEP17 ratio could be impacted by alterations in the number of chromosome 17 copies. Monosomy of chromosome 17 (m17) is found in ~ 1900 cases of early-stage HER2-positive breast cancer annually in the United States; however, the efficacy of HER2-directed trastuzumab therapy in these patients is not well characterized. Here, we retrospectively identified HER2-amplified, stage I-III breast cancers with m17 and characterized the impact of trastuzumab treatment.

METHODS

From January 1, 2000 to June 1, 2011, we identified 99 women with HER2-amplified m17 breast cancers, as defined by a CEP17 signal of < 1.5 per nucleus and a HER2/CEP17 ratio of ≥ 2.0.

RESULTS

Most HER2-amplified m17 patients were treated with trastuzumab plus chemotherapy (51%, n = 50), whereas 31% (n = 31) received chemotherapy alone and 18% (n = 18) received no chemotherapy. The 4-year overall survival (OS) was superior with trastuzumab compared to chemotherapy alone or no chemotherapy (100 vs. 93 vs. 81%, respectively; p = 0.005). OS was not influenced by estrogen/progesterone-receptor (ER/PR) status, tumor stage, or degree of FISH positivity. A proportion of patients who would be considered HER2-negative by standard immunohistochemistry staging criteria (0-1+) were HER2 amplified by FISH.

CONCLUSIONS

In the largest series reported to date, patients with HER2-amplified m17 cancers treated with trastuzumab have outcomes comparable to patients from the large phase III adjuvant trastuzumab trials who were HER2-positive, supporting the critical role of HER2-directed therapy in this patient population.

Oncologists' influence on receipt of adjuvant chemotherapy: does it matter whom you see for treatment of curable breast cancer?

PURPOSE

We know little about whether it matters which oncologist a breast cancer patient sees with regard to receipt of chemotherapy. We examined oncologists' influence on use of recurrence score (RS) testing and chemotherapy in the community.

METHODS

We identified 7810 women with stages 0-II breast cancer treated in 2013-15 through the SEER registries of Georgia and Los Angeles County. Surveys were sent 2 months post-surgery, (70% response rate, n = 5080). Patients identified their oncologists (n = 504) of whom 304 responded to surveys (60%). We conducted multi-level analyses on patients with ER-positive HER2-negative invasive disease (N = 2973) to examine oncologists' influence on variation in RS testing and chemotherapy receipt, using patient and oncologist survey responses merged to SEER data.

RESULTS

Half of patients (52.8%) received RS testing and 27.7% chemotherapy. One-third (35.9%) of oncologists treated >50 new breast cancer patients annually; mean years in practice was 15.8. Oncologists explained 17% of the variation in RS testing but little of the variation in chemotherapy receipt (3%) controlling for clinical factors. Patients seeing an oncologist who was one standard deviation above the mean use of RS testing had over two-times higher odds of receiving RS (2.47, 95% CI 1.47-4.15), but a parallel estimate of the association of oncologist with the odds of receiving chemotherapy was much smaller (1.39, CI 1.03-1.88).

CONCLUSIONS

Clinical algorithms have markedly reduced variation in chemotherapy use across oncologists. Oncologists' large influence on variation in RS use suggests that they variably seek tumor profiling to inform treatment decisions.

Inter-observer agreement among pathologists in grading the pathological response to neoadjuvant chemotherapy in breast cancer

BACKGROUND

The degree of pathological response to neoadjuvant chemotherapy (NAC) was correlated with the prognosis in breast cancer. There are few studies published on inter-observer variability in the assessment of pathological responses among pathologists.

METHODS

We collected 64 surgically resected specimens from patients who had received NAC. Three pathologists assessed the pathological responses and classified them into 7 grades according to grading system of the Japanese Breast Cancer Society. The levels of concordance among pathologists were categorized into 3 classes: full concordance (all pathologists gave the same grade), partial concordance (two of them gave the same grade), and discordance (all three gave different grades). The inter-observer agreement among pathologists was estimated using the percentage concordance and Cohen's kappa statistics.

RESULTS

Full concordance, partial concordance, and discordance were seen in 28 (43%), 33 (52%), and 3 (5%) specimens, respectively. In most of partial concordance specimens (30 out of 33), the pathological response grades differed by only one level. The kappa value was 0.59. The concordance rate with regard to pCR was 97%.

CONCLUSIONS

Most of the judgments among pathologists differed within one level, but there is room for improving harmonization in the assessment of pathological responses.

Multiplexed ion beam imaging analysis for quantitation of protein expression in cancer tissue sections

Part of developing therapeutics is the need to identify patients who will respond to treatment. For HER2-targeted therapies, such as trastuzumab, the expression level of HER2 is used to identify patients likely to receive benefit from therapy. Currently, chromogenic immunohistochemistry on patient tumor tissue is one of the methodologies used to assess the expression level of HER2 to determine eligibility for trastuzumab. However, chromogenic staining is fraught with serious drawbacks that influence scoring, which is additionally flawed due to the subjective nature of human/pathologist bias. Thus, to advance drug development and precision medicine, there is a need to develop technologies that are more objective and quantitative through the collection and integration of larger data sets. In proof of concept experiments, we show multiplexed ion beam imaging (MIBI), a novel imaging technology, can quantitate HER2 expression on breast carcinoma tissue with known HER2 status and those values correlate with pathologist-determined IHC scores. The same type of quantitative analysis using the mean pixel value of five individual cells and total pixel count of the entire image was extended to a blinded study of breast carcinoma samples of unknown HER2 scores. Here, a strong correlation between quantitation of HER2 by MIBI analysis and pathologist-derived HER2 IHC score was identified. In addition, a comparison between MIBI analysis and immunofluorescence-based automated quantitative analysis (AQUA) technology, an industry-accepted quantitation system, showed strong correlation in the same blind study. Further comparison of the two systems determined MIBI was comparable to AQUA analysis when evaluated against pathologist-determined scores. Using HER2 as a model, these data show MIBI analysis can quantitate protein expression with greater sensitivity and objectivity compared to standard pathologist interpretation, demonstrating its potential as a technology capable of advancing cancer and patient diagnostics.

Abel E, Heinrich G, Schueller K, Schneeweiss A, Fasching P, Beckmann MW, Scholz C, Friedl TWP, Friese K, Pantel K, Fehm T, Janni W, Rack B. The HER2 phenotype of circulating tumor cells in HER2-positive early breast cancer: A translational research project of a prospective randomized phase III trial

BACKGROUND

HER2 is one of the predominant therapeutic targets in breast cancer. The metastatic selection process may lead to discrepancies between the HER2 status of the primary tumor and circulating tumor cells (CTCs). This study analyzed the HER2 status of CTCs in patients with HER2-positive primary breast cancer at the time of diagnosis. Aim of the study was to assess potential discordance of HER2 status between primary tumor and CTCs, as this may have important implications for the use of HER2-targeted therapy.

METHODS

The number and HER2 status of CTCs out of 30ml peripheral blood were assessed in 642 patients using the CellSearch System (Janssen Diagnostics, USA). The cutoff for CTC positivity was the presence of at least 1 CTC, and the cutoff for HER2 positivity of CTCs was the presence of at least 1 CTC with a strong HER2 staining.

RESULTS

258 (40.2%) of the 642 patients were positive for CTCs (median 2; range 1-1,689). 149 (57.8%) of these 258 patients had at least 1 CTC with strong HER2 staining. The presence of HER2-positive CTCs was not associated with tumor size (p = 0.335), histopathological grading (p = 0.976), hormone receptor status (ER: p = 0.626, PR: p = 0.263) or axillary lymph node involvement (p = 0.430). Overall, 83 (32.2%) of the CTC-positive patients exclusively had CTCs with strong HER2 staining, whereas 31 (12.0%) had only CTCs with negative HER2 staining. Within-sample variation in the HER2 status of CTCs was found in 86 (57.8%) of the 149 patients with more than 1 CTC.

CONCLUSION

This study demonstrated that discordance between the HER2 expression of CTCs and that of the primary tumor frequently occurs in early breast cancer. Future follow-up evaluation will assess whether this discrepancy may contribute to trastuzumab resistance.

Immune-Related Gene Expression Profiling After PD-1 Blockade in Non-Small Cell Lung Carcinoma, Head and Neck Squamous Cell Carcinoma, and Melanoma

Antibody targeting of the immune checkpoint receptor PD1 produces therapeutic activity in a variety of solid tumors, but most patients exhibit partial or complete resistance to treatment for reasons that are unclear. In this study, we evaluated tumor specimens from 65 patients with melanoma, lung nonsquamous, squamous cell lung or head and neck cancers who were treated with the approved PD1-targeting antibodies pembrolizumab or nivolumab. Tumor RNA before anti-PD1 therapy was analyzed on the nCounter system using the PanCancer 730-Immune Panel, and we identified 23 immune-related genes or signatures linked to response and progression-free survival (PFS). In addition, we evaluated intra- and interbiopsy variability of PD1, PD-L1, CD8A, and CD4 mRNAs and their relationship with tumor-infiltrating lymphocytes (TIL) and PD-L1 IHC expression. Among the biomarkers examined, PD1 gene expression along with 12 signatures tracking CD8 and CD4 T-cell activation, natural killer cells, and IFN activation associated significantly with nonprogressive disease and PFS. These associations were independent of sample timing, drug used, or cancer type. TIL correlated moderately (∼0.50) with PD1 and CD8A mRNA levels and weakly (∼0.35) with CD4 and PD-L1. IHC expression of PD-L1 correlated strongly with PD-L1 (0.90), moderately with CD4 and CD8A, and weakly with PD1. Reproducibility of gene expression in intra- and interbiopsy specimens was very high (total SD <3%). Overall, our results support the hypothesis that identification of a preexisting and stable adaptive immune response as defined by mRNA expression pattern is reproducible and sufficient to predict clinical outcome, regardless of the type of cancer or the PD1 therapeutic antibody administered to patients. Cancer Res; 77(13); 3540-50. ©2017 AACR.

Counting invasive breast cancer cells in the HER2 silver in-situ hybridization test: how many cells are enough?

AIM

To evaluate the intraobserver and interobserver reproducibility of the HER2 in-situ hybridization (ISH) test in breast cancer by measuring the impact of counting different numbers of invasive cancer cells.

METHODS AND RESULTS

A cohort of 101 primary invasive breast cancer cases were evaluated for HER2 gene amplification by silver ISH, and the concordance among four observers with different levels of experience, counting different numbers of invasive cancer cells, was determined. The evaluation of the samples included scoring 20 nuclei, in three different areas. The cases were scored twice, with a washout interval of at least 2 weeks. We observed an increase in the intraobserver concordance rate between the first and second evaluations with an increase in cell count. A count of 60 invasive cells was needed to obtain a concordance rate near 95% and an agreement rate greater than 0.80 by all observers. The interobserver concordance rate of the HER2 test also increased with the increase in cell count, reaching at least a 90% concordance rate with a count of 60 invasive cells. The median variability of both the HER2/CEP17 ratio and the average HER2 copy number between different evaluations decreased with the increase in cell count, being statistically higher in HER2-positive cases.

CONCLUSIONS

The minimal cell number recommended in current guidelines should be raised to at least 40, and preferably 60, invasive cells. Moreover, cases with amplification levels close to the threshold should be subjected to a dual count from an experienced observer.

Relevance of deep learning to facilitate the diagnosis of HER2 status in breast cancer

Tissue biomarker scoring by pathologists is central to defining the appropriate therapy for patients with cancer. Yet, inter-pathologist variability in the interpretation of ambiguous cases can affect diagnostic accuracy. Modern artificial intelligence methods such as deep learning have the potential to supplement pathologist expertise to ensure constant diagnostic accuracy. We developed a computational approach based on deep learning that automatically scores HER2, a biomarker that defines patient eligibility for anti-HER2 targeted therapies in breast cancer. In a cohort of 71 breast tumour resection samples, automated scoring showed a concordance of 83% with a pathologist. The twelve discordant cases were then independently reviewed, leading to a modification of diagnosis from initial pathologist assessment for eight cases. Diagnostic discordance was found to be largely caused by perceptual differences in assessing HER2 expression due to high HER2 staining heterogeneity. This study provides evidence that deep learning aided diagnosis can facilitate clinical decision making in breast cancer by identifying cases at high risk of misdiagnosis.

Spectrum of genetic variants of BRCA1 and BRCA2 in a German single center study

BACKGROUND

Determination of mutation status of BRCA1 and BRCA2 has become part of the clinical routine. However, the spectrum of genetic variants differs between populations. The aim of this study was to deliver a comprehensive description of all detected variants.

METHODS

In families fulfilling one of the German Consortium for Hereditary Breast and Ovarian Cancer (GC-HBOC) criteria for genetic testing, one affected was chosen for analysis. DNA of blood lymphocytes was amplified by PCR and prescreened by DHPLC. Aberrant fragments were sequenced. All coding exons and splice sites of BRCA1 and BRCA2 were analyzed. Screening for large rearrangements in both genes was performed by MLPA.

RESULTS

Of 523 index patients, 121 (23.1%) were found to carry a pathogenic or likely pathogenic (class 4/5) mutation. A variant of unknown significance (VUS) was detected in 73/523 patients (13.9%). Two mutations p.Gln1756Profs*74 and p.Cys61Gly comprised 42.3% (n = 33/78) of all detected pathogenic mutations in BRCA1. Most of the other mutations were unique mutations. The most frequently detected mutation in BRCA2 was p.Val1283Lys (13.9%; n = 6/43). Altogether, 101 different neutral genetic variants were counted in BRCA1 (n = 35) and in BRCA2 (n = 66).

CONCLUSION

The two most frequently detected mutations are founder mutations in Poland and Czech Republic. More similarities seem to be shared with our direct neighbor countries compared to other European countries. For comparison of the extended genotype, a shared database is needed.

Discrepancies in central review re-testing of patients with ER-positive and HER2-negative breast cancer in the OPTIMA prelim randomised clinical trial

Background:

There is limited data on results of central re-testing of samples from patients with invasive breast cancer categorised in their local hospital laboratories as oestrogen receptor (ER) positive and human epidermal growth factor receptor homologue 2 (HER2) negative.

Methods:

The Optimal Personalised Treatment of early breast cancer usIng Multiparameter Analysis preliminary study (OPTIMA prelim) was the feasibility phase of a randomised controlled trial to validate the use of multiparameter assay-directed chemotherapy decisions in the UK National Health Service (NHS). Eligibility criteria included ER positivity and HER2 negativity. Central re-testing of receptor status was mandatory.

Results:

Of the 431 patients tested centrally, discrepant results between central and local laboratory results were identified in only 19 (4.4% 95% confidence interval 2.5–6.3%) patients (with 21 tumours). On central review, seven patients had cancers that were ER-negative (1.6%) and 13 (3.0%) patients with 15 tumours had HER2-positive disease, including one tumour discrepant for both biomarkers.

Conclusions:

Central re-testing of receptor status of invasive breast cancers in the UK NHS setting shows a high level of reproducibility in categorising tumours as ER-positive and HER2-negative, and raises questions regarding the cost effectiveness and clinical value of central re-testing in this sub-group of breast cancers in this setting.

A novel quantitative immunohistochemistry method for precise protein measurements directly in formalin-fixed, paraffin-embedded specimens: analytical performance measuring HER2

In clinical routine pathology today, detection of protein in intact formalin-fixed, paraffin-embedded tissue is limited to immunohistochemistry, which is semi-quantitative. This study presents a new and reliable quantitative immunohistochemistry method, qIHC, based on a novel amplification system that enables quantification of protein directly in formalin-fixed, paraffin-embedded tissue by counting of dots. The qIHC technology can be combined with standard immunohistochemistry, and assessed using standard bright-field microscopy or image analysis. The objective was to study analytical performance of the qIHC method. qIHC was tested under requirements for an analytical quantitative test, and compared with ELISA and flow cytometry for quantitative protein measurements. Human epidermal growth factor receptor 2 (HER2) protein expression was measured in five different cell lines with HER2 expression from undetectable with immunohistochemistry to strong positive staining (IHC 3+). Repeatability, reproducibility, robustness, linearity, dynamic range, sensitivity, and quantification limits were evaluated. Reproducibility and robustness were assessed in a setup to resemble daily work in a laboratory using a commercial immunohistochemistry platform. In addition, qIHC was correlated to standard HER2 immunohistochemistry in 44 breast cancer specimens. For all evaluated parameters, qIHC performance was either comparable or better than the reference methods. Furthermore, qIHC has a lower limit of detection than both immunohistochemistry and the ELISA reference method, and demonstrated ability to measure HER2 accurately and precise within a large dynamic range. In conclusion, the results show that qIHC provides a sensitive, quantitative, accurate, and robust assay for measurement of protein expression in formalin-fixed, paraffin-embedded cell lines, and tissue.

Assessing HER2 testing quality in breast cancer: variables that influence HER2 positivity rate from a large, multicenter, observational study in Germany

Despite >10 years of routine human epidermal growth factor receptor 2 (HER2) testing in breast cancer, testing quality is still an issue. Guidelines recommend assessing HER2 positivity rates as a quality indicator; however, the extent to which patient- or tumor-related factors influence HER2 positivity is still unknown. The present study analyzed these influences to identify pathology centers with HER2 positivity rates unexplained by patient- or tumor-related factors. This observational, prospective study monitored routine HER2 testing at 57 institutes of pathology in Germany (January 2013-August 2014). Data collected included HER2 test result, patient- and tumor-related factors, sample source, and method of sample retrieval. Factors influencing HER2 positivity rates were identified by multiple logistic regression. Individual center effects were assessed in an extended multiple logistic regression model by their statistical significance after adjusting for the combined effect of patient- or tumor-related covariates and multiple testing. Analyses included 15 332 invasive breast cancer samples. Histologic grade showed the strongest influence on HER2 positivity, followed by hormone receptor status, histologic subtype, age, and nodal status (all P<0.0001). The overall HER2 positivity rate across centers was 14.4% (range 7.1-27.3%). A statistically significant center effect on the HER2 positivity rate was identified for three centers (P<0.05), with a trend toward a center effect for a further three (P<0.2). This study, the first of its kind, highlights that assessing HER2 testing quality with HER2 positivity rates should include standardized assessment of patient- or tumor-related characteristics to identify centers with HER2 testing quality issues more effectively. As treatment options for HER2-positive breast cancer continue to evolve, identifying the right patients is key.

Discordance between original and central laboratories in ER and HER2 results in a diverse, population-based sample

PURPOSE

To investigate the discordance between original and central laboratories in estrogen receptor (ER) status, in tumors originally deemed to be ER-negative, and in HER2 status in a diverse population-based sample.

METHODS

In a follow-up study of 1785 women with Stage I-III breast cancer diagnosed between 2005 and 2007 in the Detroit and Los Angeles County SEER registry catchment areas, participants were asked to consent to reassessment of ER (in tumors originally deemed to be ER-negative) and HER2 status on archival tumor samples approximately four years after diagnosis. Blocks were centrally prepared and analyzed for ER and HER2 using standardized methods and the guidelines of the American Society of Clinical Oncology and the College of American Pathologists. Analyses determined the discordance between original and central laboratories.

RESULTS

132 (31%) of those eligible for ER reassessment and 367 (21%) eligible for HER2 reassessment had archival blocks reassessed centrally. ER discordance was only 6%. HER2 discordance by immunohistochemistry (IHC) was 26%, but final HER2 results-employing FISH in tumors that were IHC 2+ at the central laboratory-were discordant in only 6%. Half of the original laboratories did not perform their own assays.

CONCLUSIONS

Discordance between original and central laboratories in two large metropolitan areas was low in this population-based sample compared to previously reported patient samples. Centralization of testing for key pathology variables appears to be occurring in many hospitals. In addition, quality improvement efforts may have preceded the publication and dissemination of specialty society guidelines.

Targeted next-generation sequencing enables reliable detection of HER2 (ERBB2) status in breast cancer and provides ancillary information of clinical relevance

HER2-positive breast cancers are a heterogeneous group of tumors, which share amplification and overexpression of HER2. In routine diagnostics, the HER2 (ERBB2) status is currently assessed by immunohistochemistry (IHC) and in situ hybridization (ISH). Data on targeted next-generation sequencing (NGS) approaches that could be used to determine the HER2 status are sparse. Employing two breast cancer-related gene panels, we performed targeted NGS of 41 FFPE breast cancers for which full pathological work-up including ISH and IHC results was available. Selected cases were analyzed by qPCR. Of the 41 cases, the HER2 status of the 4 HER2-positive and 6 HER2-negative tumors was independently detected by our NGS approach achieving a concordance rate of 100%. The remaining 31 cases were equivocal HER2 cases by IHC of which 5 showed amplification of HER2 by ISH. Our NGS approach classified all non-amplified cases correctly as HER2 negative and corroborated all but one of the 5 cases with amplified HER2 as detected by ISH. For the overall cohort, concordance between the gold standard and NGS was 97.6% (sensitivity 88.9% and specificity 100%). Additionally, we observed mutations in PIK3CA (44%), HER2 (8%), and CDH1 (6%) among others. Amplifications were found in CCND1 (12%), followed by MYC (10%) and EGFR (2%) and deletions in CDKN2A (10%), MAP2K4 and PIK3R1 (2% each). We here show that targeted NGS data can be used to interrogate the HER2 status with high specificity and high concordance with gold standard methods. Moreover, this approach identifies additional genetic events that may be clinically exploitable. © 2016 Wiley Periodicals, Inc.

How may targeted proteomics complement genomic data in breast cancer?

INTRODUCTION

Breast cancer (BC) is the most common female cancer in the world and was recently deconstructed in different molecular entities. Although most of the recent assays to characterize tumors at the molecular level are genomic-based, proteins are the actual executors of cellular functions and represent the vast majority of targets for anticancer drugs. Accumulated data has demonstrated an important level of quantitative and qualitative discrepancies between genomic/transcriptomic alterations and their protein counterparts, mostly related to the large number of post-translational modifications. Areas covered: This review will present novel proteomics technologies such as Reverse Phase Protein Array (RPPA) or mass-spectrometry (MS) based approaches that have emerged and that could progressively replace old-fashioned methods (e.g. immunohistochemistry, ELISA, etc.) to validate proteins as diagnostic, prognostic or predictive biomarkers, and eventually monitor them in the routine practice. Expert commentary: These different targeted proteomic approaches, able to complement genomic data in BC and characterize tumors more precisely, will permit to go through a more personalized treatment for each patient and tumor.

HER2 mRNA transcript quantitation in breast cancer

PURPOSE

The human epidermal growth factor receptor 2 (HER2) status in breast cancer is important for prognostic prediction and the determination of optimal treatment. Current methods rely on protein expression, as determined by immunohistochemistry (IHC), as well as gene amplification as determined by in situ hybridisation (ISH). We explored whether quantitative droplet digital PCR (ddPCR) can be used for the detection and absolute quantitation of HER2 mRNA.

METHODS

Digital droplet PCR (ddPCR) was performed for HER2 mRNA on 178 formalin-fixed paraffin-embedded (FFPE) breast cancer specimens. HER2 positive, equivocal and negative cases as defined by standard criteria were included and both core biopsies and tissue sections were assessed.

RESULTS

HER2 positive cases contained significantly higher levels of HER2 mRNA (169-1,000,000 copies/µl) by ddPCR compared with equivocal (112-139 copies/µl, p = 0.025) and negative cases (6.2-644 copies/µl. p < 0.001). A continuum of transcript quantity was observed but a cutoff of 490 copies/µl distinguished between HER2 positive and negative cases. Results were consistent between core biopsy and tissue sections.

CONCLUSIONS

ddPCR can be used to quantify HER2 mRNA transcripts in FFPE breast cancer specimens. Our results highlight the potential of ddPCR on FFPE tissue to be used to accurately quantify HER2 transcripts. Validation in large cohorts will be required to determine a clinically applicable cutoff.

Comparison of the types of candidate reference samples for quality control of human epidermal growth factor receptor 2 status detection

Background

Human epidermal growth factor receptor 2 (HER2) is as a target gene for trastuzumab in patients with breast cancer. Accurate determination of HER2 status and strict quality control are necessary to ensure reproducibility and accuracy of the techniques used for the determination of HER2 status.

Methods

We used three different types of samples: formalin-fixed and paraffin-embedded (FFPE) samples prepared from cell lines, agarose gel samples using cell lines, and xenograft tumor samples. One cell line for FFPE or xenografts did not overexpress HER2, while the others showed different levels of HER2 overexpression. We compared the morphology, HER2 gene amplification status, and HER2 protein expression status of these samples with those of clinical specimens.

Results

We successfully produced three kinds of samples for quality control. Cells from the cell line-sample sections were dispersed while those from the agarose gel-sample sections and xenograft tumor sample sections (prepared from the both cell lines) were concentrated in one area. The FISH results for all three kinds of samples were as expected. The IHC results of the cell line samples and xenograft tumor samples were as expected, but the staining level of the agarose gel samples, using HER2-overexpressed cell lines was weak which might be regarded as a false negative result.

Conclusions

Xenograft tumor samples might be used as an additional option for quality control in FISH and IHC. However, it might not replace the clinical specimen quality controls directly.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-016-0537-8) contains supplementary material, which is available to authorized users.

Intratumoral heterogeneity as a source of discordance in breast cancer biomarker classification

BACKGROUND

Spatial heterogeneity in biomarker expression may impact breast cancer classification. The aims of this study were to estimate the frequency of spatial heterogeneity in biomarker expression within tumors, to identify technical and biological factors contributing to spatial heterogeneity, and to examine the impact of discordant biomarker status within tumors on clinical record agreement.

METHODS

Tissue microarrays (TMAs) were constructed using two to four cores (1.0 mm) for each of 1085 invasive breast cancers from the Carolina Breast Cancer Study, which is part of the AMBER Consortium. Immunohistochemical staining for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was quantified using automated digital imaging analysis. The biomarker status for each core and for each case was assigned using clinical thresholds. Cases with core-to-core biomarker discordance were manually reviewed to distinguish intratumoral biomarker heterogeneity from misclassification of biomarker status by the automated algorithm. The impact of core-to-core biomarker discordance on case-level agreement between TMAs and the clinical record was evaluated.

RESULTS

On the basis of automated analysis, discordant biomarker status between TMA cores occurred in 9 %, 16 %, and 18 % of cases for ER, PR, and HER2, respectively. Misclassification of benign epithelium and/or ductal carcinoma in situ as invasive carcinoma by the automated algorithm was implicated in discordance among cores. However, manual review of discordant cases confirmed spatial heterogeneity as a source of discordant biomarker status between cores in 2 %, 7 %, and 8 % of cases for ER, PR, and HER2, respectively. Overall, agreement between TMA and clinical record was high for ER (94 %), PR (89 %), and HER2 (88 %), but it was reduced in cases with core-to-core discordance (agreement 70 % for ER, 61 % for PR, and 57 % for HER2).

CONCLUSIONS

Intratumoral biomarker heterogeneity may impact breast cancer classification accuracy, with implications for clinical management. Both manually confirmed biomarker heterogeneity and misclassification of biomarker status by automated image analysis contribute to discordant biomarker status between TMA cores. Given that manually confirmed heterogeneity is uncommon (<10 % of cases), large studies are needed to study the impact of heterogeneous biomarker expression on breast cancer classification and outcomes.

Meaningful interpretation of serum HER2 ECD levels requires clear patient clinical background, and serves several functions in the efficient management of breast cancer patients

BACKGROUND

This study was initiated to evaluate the clinical significant of HER2 extracellular domain (ECD) in the real-time management of breast cancer patients.

METHODS

Five-hundred forty-six eligible breast cancer patients were divided according to their clinical background. The correlation between ECD, tissue HER2, and clinical outcome of the patients were analyzed.

RESULTS

Receiver operating characteristic analysis revealed that ECD measured before receiving neoadjuvant therapy yielded the highest area under the curve (0.9185; P<0.0001), indicating that ECD and tissue HER2 levels are consistent in untreated tumor-bearing patients. At cut-off of 15.0ng/ml, the prognostic value of ECD was demonstrated using univariate (HR=1.664, P<0.0001) and multivariate (HR=1.547, P=0.011) Cox regression analysis. Kaplan-Meier survival curves revealed that patients with elevated ECD had shorter progression-free survival (PFS) (4.0 vs. 6.1months, P<0.0001). Elevated ECD was also an adverse predictor for PFS in response to anti-HER2 therapy (4.3 vs. 10.2months, P=0.0155). In contrast, ≥20%, decreased ECD was associated with longer PFS in patients who received anti-HER2 therapy (10.9 vs. 2.4months, P=0.0164) and overall (10.7 vs. 2.8months, P=0.0034).

CONCLUSIONS

A patient's clinical history can help determine whether ECD could provide added value for breast cancer management.

HER2 FISH classification of equivocal HER2 IHC breast cancers with use of the 2013 ASCO/CAP practice guideline

The status of human epidermal growth factor receptor 2 (HER2, ERBB2) determines the eligibility of breast cancer patients to receive HER2-targeted therapy. The majority of HER2 testing in the U.S. is performed using a combination of immunohistochemistry (IHC) screening followed by fluorescence in situ hybridization (FISH) for IHC equivocal cases. In 2013, the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) updated the guideline for HER2 testing. This study evaluates the impact of the 2013 ASCO/CAP updated guideline on final HER2 FISH classification of breast cancers with an equivocal IHC result. For each case, we reported a FISH result according to the 2013 updated guideline and recorded a separated result using the 2007 guideline for investigational purpose. McNemar's test and Bowker's symmetry test were used to compare the classifications by the two guidelines. Among 172 HER2 IHC 2+ equivocal cases, use of the 2103 guideline changed classifications in 36 cases (21 %) when compared with the results expected by use of the 2007 guideline, and yielded a higher proportion of positive (28.5 vs. 23.3 %) and equivocal (16.3 vs. 4.1 %), and a lower proportion of negative (55.2 vs. 72.7 %) cases (p < 0.001). The major classification change with use of the updated guideline is from the HER2 FISH negative to equivocal in 26 cases (15 %). Our study has shown that implementation of the 2013 ASCO/CAP updated guideline has significant impact on HER2 classification for breast cancers with an equivocal HER2 IHC result and therefore increased the use of HER2-targeted therapy. Our data have also shown that reflex FISH is effective for final classification of the IHC equivocal cases and that polysomy 17 (CEP17 copy number ≥3/cell) is present in a significantly higher proportion of cases with an equivocal HER2 FISH classification.

TIRF high-content assay development for the evaluation of drug efficacy of chemotherapeutic agents against EGFR-/HER2-positive breast cancer cell lines

Elevated expression of epidermal growth factor receptor (EGFR) is reported to be associated with poor prognosis in breast cancer. EGFR subtype identification plays a crucial role in deciding the drug combination to treat the cancer patients. Conventional application of immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) produces more discordance results in EGFR subtype identification of cancer specimens. The present study is designed to develop an analytical method for simultaneous identification of cell surface biomarkers and quantitative estimation of drug efficacy in cancer specimens. For this study, we have utilized a total internal reflection fluorescence microscope (TIRFM), Qdot molecular probes and chemotherapeutic agent camptothecin (CPT)-treated breast cancer cell lines namely MCF-7, SK-BR-3 and JIMT-1. Highly sensitive detection signals with low background noise generated from the evanescent field excitation of TIRFM make it a highly suitable tool to detect the cell surface biomarkers in living cells. Moreover, single wavelength excitation of Qdot probes offers multicolour imaging with strong emission brightness. In the present study, TIRF high-content imaging system simultaneously showed the expression pattern of EGFRs and EC50 value for CPT-induced apoptosis and necrosis in MCF-7, SK-BR-3 and JIMT-1 cancer cell lines.

Estrogen-Receptor, Progesterone-Receptor and HER2 Status Determination in Invasive Breast Cancer. Concordance between Immuno-Histochemistry and MapQuant™ Microarray Based Assay

Background

Hormone receptor status and HER2 status are of critical interest in determining the prognosis of breast cancer patients. Their status is routinely assessed by immunohistochemistry (IHC). However, it is subject to intra-laboratory and inter-laboratory variability. The aim of our study was to compare the estrogen receptor, progesterone receptor and HER2 status as determined by the MapQuant™ test to the routine immuno-histochemical tests in early stage invasive breast cancer in a large comprehensive cancer center.

Patients and Methods

We retrospectively studied 163 invasive early-stage breast carcinoma with standard IHC status. The genomic status was determined using the MapQuant™ test providing the genomic grade index.

Results

We found only 4 tumours out of 161 (2.5%) with discrepant IHC and genomic results concerning ER status. The concordance rate between the two methods was 97.5% and the Cohen’s Kappa coefficient was 0.89.

Comparison between the MapQuant™ PR status and the PR IHC status gave more discrepancies. The concordance rate between the two methods was 91.4% and the Cohen’s Kappa coefficient was 0.74.

The HER2 MapQuant™ test was classified as « undetermined » in 2 out of 163 cases (1.2%). One HER2 IHC-negative tumour was found positive with a high HER2 MapQuant™ genomic score. The concordance rate between the two methods was 99.3% and the Cohen’s Kappa coefficient was 0.86.

Conclusion

Our results show that the MapQuant™ assay, based on mRNA expression assay, provides an objective and quantitative assessment of Estrogen receptor, Progesterone receptor and HER2 status in invasive breast cancer.

First application of the Automated QUantitative Analysis (AQUA) technique to quantify PTEN protein expression in ovarian cancer: A correlative study of NCIC CTG OV.16

BACKGROUND

Platinum resistance is a dominant cause of poor outcomes in advanced ovarian cancer (OC). A mechanism of platinum resistance is the inhibition of apoptosis through phosphatidylinositol 3 kinase (PI3K) pathway activation. The role of phosphatase and tensin homolog (PTEN), a negative regulator of this pathway, as a tumor biomarker is unclear. Quantitative analysis of PTEN expression as an alternative to immunohistochemistry has not been considered.

PATIENTS AND METHODS

In 238 patient tumors from the NCIC-CTG trial OV.16, PTEN protein expression was quantified by Automated QUantitative Analysis (AQUA). Cox model was used to study the association between PTEN expression and clinical outcomes using a minimum p-value approach in univariate analysis. Multivariate analysis was used to adjust for clinical and pathological parameters.

RESULTS

PTEN scores (range 13.9-192.3) of the 202 samples that passed quality control were analyzed. In univariate analysis, there was a trend suggesting an association between PTEN expression by AQUA as a binary variable (low ≤61 vs high >61) and progression free survival (HR=0.77, p=0.083), and in multivariate analysis, this association approached significance (HR=0.74, p=0.059). The relationship between quantitative PTEN expression and PFS differed (p=0.01 for interaction) by the extent of surgical debulking (residual disease (RD) <1cm or ≥1cm), with a numerically superior PFS in patients with high PTEN (23.5 vs 14.9m) only when RD<1cm (p=0.19). There was no association between PTEN levels and overall survival.

CONCLUSIONS

AQUA is a novel method to measure PTEN expression. Further study of PTEN as a biomarker in OC is warranted.

Serum HER2 as an adjunct to assess HER2 status for advanced gastric cancer: A prospective multicenter trial (SHERLOCK)

BACKGROUND

Intratumoral human epidermal growth factor receptor 2 (HER2) heterogeneity of gastric cancer can be an obstacle to accurate HER2 assessment. Serum HER2, concentrations of the HER2 extracellular domain shed into the bloodstream, has a potential to compensate HER2 immunohistochemistry (IHC) but has not been scrutinized in gastric cancer. This study sought to explore the clinical utility of serum HER2 in gastric cancer.

METHODS

We performed a prospective multicenter trial (SHERLOCK trial) involving patients with all-stage gastric or gastro-esophageal junction cancer. Serum HER2 was measured using direct chemiluminescence while tissue HER2 status was determined using IHC and fluorescent in situ hybridization. For stage IV cases, concordance between local and central laboratories in tissue HER2 assessment was also evaluated.

RESULTS

Of 224 patients enrolled, both tissue HER2 status and serum HER2 levels were successfully determined in 212 patients and 21% (45/212) were tissue HER2-positive. Serum HER2 levels, ranged from 4.5 to 148.0 ng/ml (median 10.3), correlated with tissue HER2 status (p = 0.003). At a cut-off level of 28.0 ng/ml determined by receiver operating characteristics analysis, sensitivity, specificity, positive and negative predictive values of serum HER2 were 22.6%, 100%, 100% and 82.3%, respectively. All nine cases with elevated serum HER2 were tissue HER2-positive stage IV cases. Among 61 stage IV cases, the agreement rate for IHC scoring between the local and the central laboratories was 82% and tissue HER2 judgment was conflicting in five (8.2%) cases. Of these five cases, four were confirmed as false-negative and two of these four patients demonstrated elevated serum HER2.

CONCLUSIONS

Serum HER2 levels correlated with tissue HER2 status in gastric cancer. Although the low sensitivity is a drawback, serum HER2 might be a useful adjunct tool to detect tissue HER2 false-negative gastric cancer.