HER2 amplification status in breast cancer: a comparison between immunohistochemical staining and fluorescence in situ hybridisation using manual and automated quantitative image analysis scoring techniques

Evaluation of HER2 Positivity Based on Clinicopathological Findings in HER2 Borderline Tumors in Iranian Patients with Breast Cancer

Background & Objective

Human epidermal growth receptor-2 (HER2) gene amplification is an important predictive and prognostic factor in breast cancer treatment. However, the expression of HER2 determined by immunohistochemistry (IHC) is considered as borderline in some cases, and confirmation of the HER2 status by either fluorescent in situ hybridization (FISH) or chromogenic in situ hybridization (CISH) is necessary for correct treatment decision-making. Considering the high cost of FISH and CISH, we aimed to investigate whether clinicopathological findings of the tumor could predict the HER2 status.

Methods

A retrospective study was performed using the data from 584 patients with breast cancer with HER2-borderline disease, confirmed by IHC. Final HER2 status, pathologic tumor size and type, nodal involvement, Ki67 index, presence of estrogen and progesterone receptors (ER, PR), lymphovascular invasion (LVI), and stage were retrieved from the clinical records.

Results

One hundred twenty-one (20.7%) patients were HER2-positive according to the FISH or CISH results. Logistic regression analysis showed that the pathologic size was positively associated with HER2 positivity with an odds ratio (OR) of 1.02 (95% CI: 1.01-1.04). In addition, the adjusted OR illustrated a statistically significant association between HER2 positivity and PR negativity (OR= 2.22, 95% CI: 1.29-3.83).

Conclusion

In HER2 borderline breast cancer, HER2 positivity significantly increases with tumor size and PR negativity. Further studies are recommended that may find an applicable model to predict the actual status of HER2 in borderline cases.

Deep learning to automatically evaluate HER2 gene amplification status from fluorescence in situ hybridization images

Human epidermal growth factor receptor 2 (HER2) gene amplification helps identify breast cancer patients who may respond to targeted anti-HER2 therapy. This study aims to develop an automated method for quantifying HER2 fluorescence in situ hybridization (FISH) signals and improve the working efficiency of pathologists. An Aitrox artificial intelligence (AI) model based on deep learning was constructed, and a comparison between the AI model and traditional manual counting was performed. In total, 918 FISH images from 320 consecutive invasive breast cancers were analysed and automatically classified into 5 groups according to the 2018 ASCO/CAP guidelines. The overall classification accuracy was 85.33% (157/184) with a mean average precision of 0.735. In Group 5, the most common group, the consistency was as high as 95.90% (117/122), while the consistency was low in the other groups due to the limited number of cases. The causes of this inconsistency, including clustered HER2 signals, coarse CEP17 signals and some section quality problems, were analysed. The developed AI model is a reliable tool for evaluating HER2 amplification statuses, especially for breast cancer in Group 5; additional cases from multiple centres could further improve the accuracy achieved for other groups.

Digital image analysis and assisted reading of the HER2 score display reduced concordance: pitfalls in the categorisation of HER2-low breast cancer

AIMS

Digital image analysis (DIA) is used increasingly as an assisting tool to evaluate biomarkers, including human epidermal growth factor receptor 2 (HER2) in invasive breast cancer (BC). DIA can assist pathologists in HER2 evaluation by presenting quantitative information about the HER2 staining in APP assisted reading (AR). Concurrently, the HER2-low category (HER2-1+/2+ without HER2 gene amplification) has gained prominence due to newly developed antibody-drug conjugates. However, major inter- and intraobserver variability have been observed for the entity. The present quality assurance study investigated the concordance between DIA and AR in clinical use, especially concerning the HER2-low category.

METHODS AND RESULTS

HER2 immunohistochemistry (IHC) in 761 tumours from 727 patients was evaluated in tissue microarray (TMA) cores by DIA (Visiopharm HER2-CONNECT) and AR. Overall concordance between HER2-scores were 73% (n = 552, weighted-κ: 0.66), and 88% (n = 669, weighted-κ: 0.70), when combining HER2-0/1+. A total of 205 scores were discordant by one category, while four were discordant by two categories. A heterogeneous HER2 pattern was relatively common in the discordant cases and a pitfall in the categorisation of HER2-low BC. AR more commonly reassigned a lower HER2 score (from HER2-1+ to HER2-0) within the HER2-low subgroup (n = 624) compared with DIA.

CONCLUSION

DIA and AR display moderate agreement with heterogeneous and aberrant staining, representing a source of discordance and a pitfall in the evaluation of HER2.

Determining HER2 Status by Artificial Intelligence: An Investigation of Primary, Metastatic, and HER2 Low Breast Tumors

The expression of human epidermal growth factor receptor 2 (HER2) protein or gene transcripts is critical for therapeutic decision making in breast cancer. We examined the performance of a digitalized and artificial intelligence (AI)-assisted workflow for HER2 status determination in accordance with the American Society of Clinical Oncology (ASCO)/College of Pathologists (CAP) guidelines. Our preliminary cohort consisted of 495 primary breast carcinomas, and our study cohort included 67 primary breast carcinomas and 30 metastatic deposits, which were evaluated for HER2 status by immunohistochemistry (IHC) and in situ hybridization (ISH). Three practicing breast pathologists independently assessed and scored slides, building the ground truth. Following a washout period, pathologists were provided with the results of the AI digital image analysis (DIA) and asked to reassess the slides. Both rounds of assessment from the pathologists were compared to the AI results and ground truth for each slide. We observed an overall HER2 positivity rate of 15% in our study cohort. Moderate agreement (Cohen's κ 0.59) was observed between the ground truth and AI on IHC, with most discrepancies occurring between 0 and 1+ scores. Inter-observer agreement amongst pathologists was substantial (Fleiss´ κ 0.77) and pathologists' agreement with AI scores was 80.6%. Substantial agreement of the AI with the ground truth (Cohen´s κ 0.80) was detected on ISH-stained slides, and the accuracy of AI was similar for the primary and metastatic tumors. We demonstrated the feasibility of a combined HER2 IHC and ISH AI workflow, with a Cohen's κ of 0.94 when assessed in accordance with the ASCO/CAP recommendations.

HER2 overexpression/amplification status in colorectal cancer: a comparison between immunohistochemistry and fluorescence in situ hybridization using five different immunohistochemical scoring criteria

OBJECTIVE

Although HER2 has gradually become an important therapeutic target for colorectal cancer (CRC), a unified and standard HER2 scoring system was still not established in CRC, and the debatable results of immunohistochemistry and fluorescence in situ hybridization (FISH) in CRC requires further exploration.

METHODS

In this study, we use five immunohistochemical (IHC) scoring criteria (i.e., IRS-p, IRS-m, GEA-s, GEA-b and HERACLES) and two FISH criteria to evaluate HER2 status, and further evaluate the correlation between HER2 status and clinicopathological features, survival in a large, unselected Chinese cohort of 664 CRCs.

RESULTS

Finally, we set HER2/CEP17 ratio ≥ 2.0, or an average HER2 copy number ≥ 6.0 as FISH-positive threshold and the amplification rate of HER2 gene was 7.08% (47/664).The HER2 positivity (IHC 3+) was 2.71%, 3.16%, 2.56%, 2.71% and 3.16%, according to the IHC scoring criteria of IRS-p, IRS-m, GEA-s, GEA-b and HERACLES, respectively. Set FISH results as the golden standard; receiver-operating characteristic analysis showed that IRS-p had both high sensitivity and specificity than other IHC scoring systems to evaluate HER2 status. Based on IRS-p criterion, There were significant differences in tumor differentiation (p = 0.038), lymphatic vascular invasion (p = 0.001), pN stage (p value = 0.043), and overall survival (p < 0.001) among IHC score 0-3 + groups. Meanwhile, there were significant differences in pT stage (p = 0.031), pN stage (p = 0.009) and overall survival (p < 0.001) among FISH subgroups.

CONCLUSION

The IRS-p criterion was more suitable for assessing the HER2 status in CRC patients than other IHC criteria. Whereas for FISH scoring system, only HER2/CEP17 < 2.0, meanwhile HER2cn < 4.0 and HER2cn ≥ 6.0 were subgroups with unique clinicopathological characteristics.

A Deep Learning Quantification Algorithm for HER2 Scoring of Gastric Cancer

Gastric cancer is the third most common cause of cancer-related death in the world. Human epidermal growth factor receptor 2 (HER2) positive is an important subtype of gastric cancer, which can provide significant diagnostic information for gastric cancer pathologists. However, pathologists usually use a semi-quantitative assessment method to assign HER2 scores for gastric cancer by repeatedly comparing hematoxylin and eosin (H&E) whole slide images (WSIs) with their HER2 immunohistochemical WSIs one by one under the microscope. It is a repetitive, tedious, and highly subjective process. Additionally, WSIs have billions of pixels in an image, which poses computational challenges to Computer-Aided Diagnosis (CAD) systems. This study proposed a deep learning algorithm for HER2 quantification evaluation of gastric cancer. Different from other studies that use convolutional neural networks for extracting feature maps or pre-processing on WSIs, we proposed a novel automatic HER2 scoring framework in this study. In order to accelerate the computational process, we proposed to use the re-parameterization scheme to separate the training model from the deployment model, which significantly speedup the inference process. To the best of our knowledge, this is the first study to provide a deep learning quantification algorithm for HER2 scoring of gastric cancer to assist the pathologist's diagnosis. Experiment results have demonstrated the effectiveness of our proposed method with an accuracy of 0.94 for the HER2 scoring prediction.

Predicting HER2 Status in Breast Cancer on Ultrasound Images Using Deep Learning Method

Purpose

The expression of human epidermal growth factor receptor 2 (HER2) in breast cancer is critical in the treatment with targeted therapy. A 3-block-DenseNet-based deep learning model was developed to predict the expression of HER2 in breast cancer by ultrasound images.

Methods

The data from 144 breast cancer patients with preoperative ultrasound images and clinical information were retrospectively collected from the Shandong Province Tumor Hospital. An end-to-end 3-block-DenseNet deep learning classifier was built to predict the expression of human epidermal growth factor receptor 2 by ultrasound images. The patients were randomly divided into a training (n = 108) and a validation set (n = 36).

Results

Our proposed deep learning model achieved an encouraging predictive performance in the training set (accuracy = 85.79%, AUC = 0.87) and the validation set (accuracy = 80.56%, AUC = 0.84). The effectiveness of our model significantly exceeded the clinical model and the radiomics model. The score of the proposed model showed significant differences between HER2-positive and -negative expression (p < 0.001).

Conclusions

These results demonstrate that ultrasound images are predictive of HER2 expression through a deep learning classifier. Our method provides a non-invasive, simple, and feasible method for the prediction of HER2 expression without the manual delineation of the regions of interest (ROI). The performance of our deep learning model significantly exceeded the traditional texture analysis based on the radiomics model.

Single HER2-positive tumor cells are detected in initially HER2-negative breast carcinomas using the DEPArray™-HER2-FISH workflow

Background

In breast cancer (BC), overexpression of HER2 on the primary tumor (PT) is determined by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) to stratify samples as negative, equivocal and positive to identify patients (pts) for anti-HER2 therapy. CAP/ASCO guidelines recommend FISH for analyzing HER2/neu (ERBB2) gene amplification and for resolving equivocal HER2 IHC results. However, pre-analytical and analytical aspects are often confounded by sample related limitations and tumor heterogeneity and HER2 expression may differ between the PT and circulating tumor cells (CTCs), the precursors of metastasis. We used a validation cohort of BC patients to establish a new DEPArray™-PT-HER2-FISH workflow for further application in a development cohort, characterized as PT-HER2-negative but CTC-HER2/neu-positive, to identify patients with PT-HER2 amplified cells not detected by routine pathology.

Methods

50 µm FFPE tumor curls from the validation cohort (n = 49) and the development cohort (n = 25) underwent cutting, deparaffinization and antigen retrieval followed by dissociation into a single-cell suspension. After staining for cytokeratin, vimentin, DAPI and separation via DEPArray™, single cells were processed for HER2-FISH analysis to assess the number of chromosome 17 and HER2 loci signals for comparison, either with available IHC or conventional tissue section FISH. CTC-HER2/neu status was determined using the AdnaTest BreastCancer (QIAGEN, Hilden, Germany).

Results

Applying CAP/ASCO guidelines for HER2 evaluation of single PT cells, the comparison of routine pathology and DEPArray™-HER2-FISH analysis resulted in a concordance rate of 81.6% (40/49 pts) in the validation cohort and 84% (21/25 pts) in the development cohort, respectively. In the latter one, 4/25 patients had single HER2-positive tumor cells with 2/25 BC patients proven to be HER2-positive, despite being HER2-negative in routine pathology. The two other patients showed an equivocal HER2 status in the DEPArray™-HER2-FISH workflow but a negative result in routine pathology. Whereas all four patients with discordant HER2 results had already died, 17/21 patients with concordant HER2 results are still alive.

Conclusions

The DEPArray™ system allows pure tumor cell recovery for subsequent HER2/neu FISH analysis and is highly concordant with conventional pathology. For PT-HER2-negative patients, harboring HER2/neu-positive CTCs, this approach might allow caregivers to more effectively offer anti-HER2 treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12282-022-01330-8.

Discordance Between Immunohistochemistry and In Situ Hybridization to Detect HER2 Overexpression/Gene Amplification in Breast Cancer in the Modern Age: A Single Institution Experience and Pooled Literature Review Study

BACKGROUND

Human epidermal growth factor 2 (HER2) amplification and/or overexpression occurs in 12% to 25% of breast cancers. Accurate detection of HER2 is critical in predicting response to HER2-targeted therapy. Both immunohistochemistry (IHC) and in situ hybridization (ISH) are FDA-approved methods for detecting HER2 status because its protein overexpression is largely attributable to gene amplification. However, variable discordant results between IHC and ISH have been reported.

METHODS

We determined the frequency of HER2 IHC/ISH discordance in these patients and also performed a pooled literature review analysis.

RESULTS

Of the 1125 consecutive primary or metastatic breast cancers with HER2 IHC and ISH performed simultaneously between 2015 and 2020, 84.6% had an unequivocal HER2 status. Discordance was found in 30 cases from 26 patients, including 13 IHC^-/ISH⁺ and 17 IHC⁺/ISH^-, representing 1.6% and 11.9% of IHC^- and IHC⁺ cases, respectively. Review of the literature between 2001 and 2020 identified 46 relevant studies, with a total of 43,468 cases with IHC and ISH performed. The IHC^-/ISH+ and IHC⁺/ISH^- discordances were seen in all antibody clones and ISH methods used. The IHC⁺/ISH^- discordance was significantly higher than IHC^-/ISH⁺ (13.8% vs. 3%, P < .0001). The overall discordance constituted 4% of all cases and 5.4% of those with an unequivocal IHC status. Significantly lower incongruities for both IHC^-/ISH⁺ and IHC⁺/ISH^- were found in those published after 2018. The discordances probably reflect altered biology of HER2 oncogene/oncoprotein. Routinely performing both IHC and ISH may uncover such cases to prevent denial of potentially beneficial targeted therapy.

Correlation between HER2 Expression and Clinicopathological Features of Breast Cancer: A Cross- Sectional Study in Vietnam

BACKGROUND

HER2 is the target of the therapeutic agents which are used to treat HER2-positive breast cancer. Reports have shown that the HER2 oncogene expression and its association with clinicopathological factors remain unclear in breast cancer (BC) patients.  This study aimed to determine the correlation between HER2 expression and clinicalpathological characteristics of breast cancer in Vietnamese women.

METHODS

Between June 2016 and August 2018, paraffin-embedded specimens from 237 patients with primary invasive breast carcinoma in Hue University Hospital and Hue Center Hospital, Hue city, Vietnam were examined for pathological features. The gene expression of HER2, ER, PR and Ki-67 were determined by immunohistochemistry (IHC). The gene amplification of Her2 was assessed by using Dual color in situ hybridization (DISH).

RESULTS

The most frequent histological type was invasive carcinoma of no special type (NST) with 77.35%, the highest percentage of patients with Grade II was detected (59.36%), tumor size > 2 cm accounted for 71.31% of cases, Lymph node metastases were available in 57.86% cases. Most patients were diagnosed at stage II (59.18%). The majority of patients were classified as moderate Nottingham prognostic index (54.9%). Estrogen receptor and Progesterone receptor were positive in 53.16% and 50.63%, respectively. 76.37% of cases were in high expression group of Ki-67 (≥14%). HER2 IHC 2+, 3+ were accounted for 28.69% and HER2 gene amplification was detected in 31% cases. HER2 gene amplification and/or overexpression was significantly associated with cell proliferation index Ki67. Furthermore, HER2 gene expression tended to be more frequently found in tumors with large tumor size, high grade, high stage and high Nottingham prognostic index and confirmed their prognostic independent role.

CONCLUSIONS

Our data indicated that HER2 gene expression was significantly correlated with cell proliferation index Ki67, but not significantly associated with another clinicopathological factors in breast cancer of Vietnamese women.
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Molecular subtypes of screen-detected breast cancer

BACKGROUND

Detection of breast cancers by mammographic screening confers a survival advantage of 20-50% compared to symptomatic presentations. The improved prognosis is only partly explained by stage migration. The distribution of the molecular subtypes of screen-detected breast cancer (SDBC) or their HER2 status has not been studied extensively. We wished to address these issues through the study of a large series of SDBC, with other presentations serving as controls.

DESIGN

Deidentified cases of female invasive cancer, diagnosed in Australia and New Zealand during 2005-2015, were retrieved from the BreastSurgANZ Quality Audit (BQA). Method of detection and selected patient, tumour and treatment data were assessed. Immunohistochemical surrogates for molecular subtypes were defined as Luminal A (ER+ and/or PR+, HER2-), Luminal B (ER+ and/or PR+, HER2+), HER2-enriched (ER-, PR- and HER2+) and basal-like (triple negative). Results were compared with the findings of controls and previous studies.

RESULT

100983 invasive cancers were diagnosed, including 32493 (32.7%) SDBC and 66907 (67.3%) with other presentations. The biomarker profile for SDBC versus other presentations in the same population was ER 89.3 versus 80.3%, PR 78.8 versus 69.8% and for HER2 11 versus 15.6%. The distribution of molecular subtypes was Luminal A 81.9 versus 70.74%, Luminal B 7.39 versus 9.52%, HER2-enriched 3.63 versus 6.06% and Basal-like 7.08 versus 13.68%. These differences were significant (p < 0.0001).

CONCLUSION

Molecular profiles of SDBC are significantly different from those of symptomatic cancers, with over-representation of the Luminal A and proportionately lower rates of all other subtypes. We have shown, for the first time, significantly lower rates of HER2 positivity in SDBC. These differences may contribute to the better survival of SDBC and have implications for prognostication, targeted therapy decisions and for laboratory quality assurance programs in setting target ranges for proportions of ER-positive and HER2 results in heavily screened populations.

Her2Net: A Deep Framework for Semantic Segmentation and Classification of Cell Membranes and Nuclei in Breast Cancer Evaluation

We present an efficient deep learning framework for identifying, segmenting, and classifying cell membranes and nuclei from human epidermal growth factor receptor-2 (HER2)-stained breast cancer images with minimal user intervention. This is a long-standing issue for pathologists because the manual quantification of HER2 is error-prone, costly, and time-consuming. Hence, we propose a deep learning-based HER2 deep neural network (Her2Net) to solve this issue. The convolutional and deconvolutional parts of the proposed Her2Net framework consisted mainly of multiple convolution layers, max-pooling layers, spatial pyramid pooling layers, deconvolution layers, up-sampling layers, and trapezoidal long short-term memory (TLSTM). A fully connected layer and a softmax layer were also used for classification and error estimation. Finally, HER2 scores were calculated based on the classification results. The main contribution of our proposed Her2Net framework includes the implementation of TLSTM and a deep learning framework for cell membrane and nucleus detection, segmentation, and classification and HER2 scoring. Our proposed Her2Net achieved 96.64% precision, 96.79% recall, 96.71% F-score, 93.08% negative predictive value, 98.33% accuracy, and a 6.84% false-positive rate. Our results demonstrate the high accuracy and wide applicability of the proposed Her2Net in the context of HER2 scoring for breast cancer evaluation.

Correlation of Immunohistochemistry and Fluorescence in Situ Hybridization for HER-2 Assessment in Breast Cancer Patients: Single Centre Experience

BACKGROUND:

Accurate assessment of HER-2 is imperative in selecting patients for targeted therapy. Most commonly used test methods for HER-2 are immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH). We evaluated the concordance between FISH and IHC for HER-2 in breast cancer samples using Food and Drug Administration approved tests.

MATERIAL AND METHODS:

Archived paraffin tissue blocks from 73 breast cancer patients were used. HER-2 immunostaining was performed using Ventana anti–HER-2 monoclonal antibody. The FISH assay was performed using PathVysion™ HER-2 DNA Probe Kit.

RESULTS:

Of the 73 cases 68.5% were IHC 0/1+, 15.07% were IHC 2+ and 16.44% were IHC 3+. Successful hybridisation was achieved in 72 cases. HER-2 FISH amplification was determined in 16.67% cases. Ten IHC 3+ and two IHC 2+ cases were FISH positive. Two of the IHC 3+ cases were FISH negative. Concordance rate was 100%, 18.18% and 83.33% for IHC 0/1+, 2+ and 3+ group, respectively. Total concordance was 84.72%, kappa 0.598 (p < 0.0001). The sensitivity of IHC in detecting IHC 2+ and IHC 3+ cases was 16.7% and 83.3%, and the specificity was 85% and 96.67%, respectively.

CONCLUSION:

The consistency between the methods was highest for IHC negative and lowest for IHC equivocal cases. The immunohistochemistry showed high sensitivity for IHC 2+/3+ cases and high specificity for IHC 3+ cases. Our results support the view that false-positive rather than false-negative IHC results are a problem with HER-2/IHC testing, and that IHC should be used as an initial screening test, but IHC 2+/ 3+ results should be confirmed by FISH.

A nomogram to predict HER2 status in breast cancer patients with HER2-borderline disease as determined via immunohistochemistry

This study aimed to develop a nomogram to predict fluorescence in situ hybridization (FISH) assay results for HER2-borderline breast cancer as determined via immunohistochemistry (IHC) among patients in China. We reviewed a database of breast cancer patients diagnosed between January 2007 and April 2013 at our institutions. We used logistic regression to develop a nomogram and we used receiver operating characteristic curve analysis and calibration plots to validate our nomogram. In total, 1138, 301 and 344 patients had IHC-determined HER2-negative, HER2-borderline and HER2-positive disease, respectively. Within the training cohort, univariate and multivariate analyses suggested that estrogen receptor (ER) status, progesterone receptor (PR) status and tumor grade were significantly associated with HER2 status (P<0.01). A nomogram was developed and the AUCs for the training and validation cohorts were 0.795 and 0.749, respectively. The calibration plots suggested that the model was well calibrated. This new nomogram can be used to predict HER2 status in HER2-borderline breast cancer patients and will be particularly helpful to resource-limited countries.

PIK3CA amplification and PTEN loss in diffused large B-cell lymphoma

Although it has been known that PIK3CA was amplified and PTEN was deficient on protein level in DLBCL, the clinicopathological significance of PIK3CA and PTEN genetic change on DNA level hasn't been established. Here, in our present study, to understand the clinical significance of genetic status of PIK3CA and PTEN in DLBCL, fluorescent in-situ hybridization (FISH) was employed to evaluate the genetic change of PIK3CA and PTEN in clinical sample tissues consist of 205 cases. Incidentally, to understand the clinicopathological significance of genetic change of PIK3CA and PTEN, Cross-table analysis was used to analyze the association between genetic change of PIK3CA and PTEN versus clinicopathological variables available to us, including age, gender, size, location, international prognosis index, performance state, B-symptom, clinical stage, Extra nodal site, concentration of lactate dehydrogenase, therapeutic effects, treatment and overall prognosis. It was found that PIK3CA was amplified and PTEN was deficient on DNA level, the percentage of amplification and loss was 12.7% (26/205) and 12.2% (25/205), respectively. Additionally, no significant association was observed between genetic change of PIK3CA and PTEN versus clinicopathological variables available. Nor was the significant correlation found between loss of PTEN versus PIK3CA amplification. Our results suggest that PTEN deficiency and amplification of PIK3CA on DNA level was an event in the pathogenesis of DLBCL.

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.

Validation of immunoexpression of tenascin-C in oral precancerous and cancerous tissues using ImageJ analysis with novel immunohistochemistry profiler plugin: An immunohistochemical quantitative analysis

BACKGROUND

Immunohistochemistry (IHC) is a molecular technique that has grown tremendously over the years. However, the assessment is only qualitative which is subjective and causes errors. Due to this limitation, several excellent markers have not gained importance and reached clinical trials. Hence, we aimed to quantify IHC by ImageJ analysis with a novel IHC profiler plugin. ImageJ has not been tried in oral precancerous tissues with minimal attempt for matrix markers.

AIM

This study aimed to validate the quantification of immunoexpression of tenascin-C (TN-C) in oral precancerous tissues and oral squamous cell carcinoma (OSCC) using ImageJ software with IHC profiler plugin.

MATERIALS AND METHODS

After IHC staining for TN-C and image acquisition, ImageJ analysis was performed as per the standard recommended algorithm. Assessment was done by two observers by blinding the histopathological diagnosis. The immunoscore was assessed for interobserver variability using Kohen's kappa statistics.

RESULTS

All our cases were in agreement and found to be statistically significant with P < 0.005. Moderate agreement was for mild dysplasia, moderate dysplasia and oral lichen planus. Substantial agreement was for oral submucous fibrosis and OSCC and almost perfect agreement noted for cases of severe dysplasia.

CONCLUSION

IHC can now be quantified using freely downloadable software ImageJ analysis in oral precancerous tissues and OSCC. This software with good threshold control can quantify matrix marker such as TN-C. Hence, herewith, we propose that IHC markers should be quantified using ImageJ by our entire oral pathology fraternity so as to have a standard immunoscore for all markers.

Revisiting determinants of prognosis in cutaneous melanoma

The American Joint Committee on Cancer staging system for cutaneous melanoma is based on primary tumor thickness and the presence of ulceration, mitoses, lymph node spread, and distant metastases as determinants of prognosis. Although this cutaneous melanoma staging system has evolved over time to more accurately reflect patient prognosis, improvements are still needed, because current understanding of the particular factors (genetic mutation, expression alteration, host response, etc) that are critical for predicting patient outcomes is incomplete. Given the clinical and biologic heterogeneity of primary melanomas, new prognostic tools are needed to more precisely identify patients who are most likely to develop advanced disease. Such tools would affect clinical surveillance strategies and aid in patient selection for adjuvant therapy. The authors reviewed the literature on prognostic molecular and immunologic markers in primary cutaneous melanoma, their associations with clinicopathologic and survival outcomes, and their potential for incorporation into current staging models. Overall, the studies considered in this review did not define prognostic markers that could be readily incorporated into the current staging system. Therefore, efforts should be continued in these and other directions to maximize the likelihood of identifying clinically useful prognostic biomarkers for cutaneous melanoma.

A meta-analysis on concordance between immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) to detect HER2 gene overexpression in breast cancer

BACKGROUND

We performed this meta-analysis study to evaluate the concordance and discordance between immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in detecting HER2 alteration in human breast cancer.

METHODS

As a meta-analysis, the present study evaluated the available data from previous studies on the HER2 gene detected by IHC and FISH. To indicate the meta-analysis results, a forest plot was used.

RESULTS

We identified 172 citations, for which our inclusion criteria were met by 18 articles, representing 6629 cases. The overall concordance and discordance rate between IHC staining with score 0/1+ and FISH for detection failure of HER2 expression was 96 and 4 %, respectively. The present study showed that the overall proportion of FISH positive and negative rate for IHC score 2+ for detection of HER2 expression was 36 and 64 %, respectively; and 91 and 9 % for 3+ IHC scores.

CONCLUSION

The results of this study show that IHC score 0/1+ and 3+ cannot be completely considered as negative and positive breast cancer test, respectively. Therefore, we suggest a valid and complementary test, the same as FISH, to explore HER2 expression.

Evaluation of HER2/neu Status by Immunohistochemistry Using Computer-Based Image Analysis and Correlation With Gene Amplification by Fluorescence In Situ Hybridization Assay: A 10-Year Experience and Impact of Test Standardization on Concordance Rate

CONTEXT

The American Society of Clinical Oncology/College of American Pathologists proposed several recommendations for human epidermal growth factor receptor 2 (HER2) test standardization. One suggestion was that image analysis (IA) could be useful for scoring of HER2/neu immunohistochemistry. The utilization of IA in a real-world practice in a large cohort of cases has not been previously reported.

OBJECTIVES

To compare HER2/neu quantification by IA with gene amplification by fluorescence in situ hybridization (FISH); to determine sensitivity, specificity, and concordance rates with the FISH assay; and to determine association between HER2 status with estrogen receptor (ER), progesterone receptor (PR), and Ki-67 expression.

DESIGN

We evaluated HER2 results performed by immunohistochemistry and FISH in conjunction with ER, PR, and Ki-67 in 3093 invasive breast cancer cases from 2002 to 2011.

RESULTS

The overall concordance between immunohistochemistry and FISH was 87.3% (1768 of 2026). When analyzed by year, there was an improvement in the positive concordance rate from 49.4% (44 of 89) to 95.0% (57 of 60) (P < .001). The negative concordance rate was at least 95% with a median false-negative rate of 1.5%. In the FISH+ group, amplification ratio showed significant correlation with IA scores (P < .001). Positive versus negative HER2 status was associated with lower ER and PR levels (P < .001) and higher Ki-67 expression (P < .001).

CONCLUSION

Scoring of HER2/neu by IA was associated with high false-positive rates before 2008. Improvement in concordance rate after 2008 may be due to proper tissue handling, improved HER2/neu scoring by IA, and assay standardization.

Monocyte-Induced Prostate Cancer Cell Invasion is Mediated by Chemokine ligand 2 and Nuclear Factor-κB Activity

STUDY BACKGROUND

The tumor microenvironment contains inflammatory cells which can influence cancer growth and progression; however the mediators of these effects vary with different cancer types. The mechanisms by which prostate cancer cells communicate with monocytes to promote cancer progression are incompletely understood. This study tested prostate cancer cell and monocyte interactions that lead to increased prostate cancer cell invasion.

METHODS

We analyzed the prostate cancer cell invasion and NF-κB activity and cytokine expression during interaction with monocyte-lineage cells in co-cultures. The roles of monocyte chemotactic factor (MCP-1/CCL2) and NF-κB activity for co-culture induced prostate cancer invasion were tested. Clinical prostate cancer NF-κB expression was analyzed by immunohistochemistry.

RESULTS

In co-cultures of prostate cancer cell lines with monocyte-lineage cells, (C-C motif) ligand 2 (CCL2) levels were significantly increased when compared with monocytes or cancer cells cultured alone. Prostate cancer cell invasion was induced by recombinant CCL2 in a dose dependent manner, similar to co-cultures with monocytes. The monocyte-induced prostate cancer cell invasion was inhibited by CCL2 neutralizing antibodies and by the CCR2 inhibitor, RS102895. Prostate cancer cell invasion and CCL2 expression induced in the co-cultures was inhibited by Lactacystin and Bay11-7082 NF-κB inhibitors. Prostate cancer cell NF-κB DNA binding activity depended on CCL2 dose and was inhibited by CCL2 neutralizing antibodies. Clinical prostate cancer NF-κB expression correlated with tumor grade.

CONCLUSIONS

Co-cultures with monocyte-lineage cell lines stimulated increased prostate cancer cell invasion through increased CCL2 expression and increased prostate cancer cell NF-κB activity. CCL2 and NF-κB may be useful therapeutic targets to interfere with inflammation-induced prostate cancer invasion.

Overexpression and gene amplification of EGFR, HER2, and HER3 in biliary tract carcinomas, and the possibility for therapy with the HER2-targeting antibody pertuzumab

BACKGROUND

Pertuzumab is a humanized monoclonal antibody that binds to HER2 at an epitope that prevents HER2 from dimerizing with ligand-activated HER-family receptors. To assess the potential of pertuzumab as a new therapy, the expression status of HER family members was determined in biliary tract carcinoma (BTC), and the antitumor activity of pertuzumab was investigated by assessing the inhibition of BTC cell growth.

METHODS

The expression status of HER family members in 113 archival specimens of BTC was analyzed by using immunohistochemistry and fluorescence in situ hybridization. Using ten BTC cell lines, heregulin-alpha (HRG-α) stimulated cell proliferation and its inhibition by pertuzumab was tested in vitro. The phosphorylated HER family proteins and their respective downstream molecules were analyzed. In vivo antitumor activity of pertuzumab was evaluated in a xenograft model.

RESULTS

Protein overexpression of HER2 and/or HER3 was observed in 23-34 % of the specimens and gene amplification in 17-27 %. Seven of the ten cell lines showed HER2 and/or HER3 protein overexpression and gene amplification, and HRG-α stimulated cell proliferation was observed in four of the ten cell lines. In a BTC cell line co-overexpressing HER2 and HER3, pertuzumab potently inhibited the HRG-α stimulated cell proliferation in a dose-dependent manner, and completely blocked the phosphorylation of HER3. Suppression of downstream pathway molecules including p-AKT was also observed. Pertuzumab inhibited the in vivo growth of subcutaneous tumors, and increased the number of apoptotic cancer cells.

CONCLUSIONS

Pertuzumab exerts potent antitumor activity in BTC cells co-overexpressing HER2 and HER3. Pertuzumab provides a new therapeutic option against BTC.

BGX-Ki-67 index as a supplementary marker to MIB-1 index, enabling more precise distinction between luminal A and B subtypes of breast carcinoma and eliminating the problem of membranous/cytoplasmic MIB-1 staining

OBJECTIVES

We compared clinical utility of MIB-1 and BGX-Ki-67 clones of anti-Ki-67 antibody in a group of 156 patients with invasive ductal breast cancer.

METHODS

MIB-1 labeling index (MIB-1LI) and BGX labeling index (BGXLI) were evaluated immunohistochemically both in primary tumors (T) and synchronous lymph node metastasis (LNM).

RESULTS

In addition to nuclear MIB-1 staining, in 23 of 145 and 19 of 144 T and LNM, respectively, membranous/cytoplasmic labeling was found. In these cases, BGX-Ki-67 showed exclusively nuclear labeling and presented significantly higher labeling index. High BGXLI(T) was a significant independent negative prognostic factor for disease-free survival. Moreover, based on BGXLI(T)/BGXLI(LNM), patients with high MIB-1LI(T) were stratified into low- and high-risk carriers.

CONCLUSIONS

In carcinomas with membranous/cytoplasmic MIB-1 staining, additional assessment of BGXLI is recommended. It may help in defining breast cancer subtype and in selection of individuals at risk who, despite appropriate therapy, would benefit from more frequent controls aimed at earlier implementation of second-line treatment.

Monocyte-Induced Prostate Cancer Cell Invasion is Mediated by Chemokine ligand 2 and Nuclear Factor-κB Activity

Study Background

The tumor microenvironment contains inflammatory cells which can influence cancer growth and progression; however the mediators of these effects vary with different cancer types. The mechanisms by which prostate cancer cells communicate with monocytes to promote cancer progression are incompletely understood. This study tested prostate cancer cell and monocyte interactions that lead to increased prostate cancer cell invasion.

Methods

We analyzed the prostate cancer cell invasion and NF-κB activity and cytokine expression during interaction with monocyte-lineage cells in co-cultures. The roles of monocyte chemotactic factor (MCP-1/CCL2) and NF-κB activity for co-culture induced prostate cancer invasion were tested. Clinical prostate cancer NF-κB expression was analyzed by immunohistochemistry.

Results

In co-cultures of prostate cancer cell lines with monocyte-lineage cells, (C-C motif) ligand 2 (CCL2) levels were significantly increased when compared with monocytes or cancer cells cultured alone. Prostate cancer cell invasion was induced by recombinant CCL2 in a dose dependent manner, similar to co-cultures with monocytes. The monocyte-induced prostate cancer cell invasion was inhibited by CCL2 neutralizing antibodies and by the CCR2 inhibitor, RS102895. Prostate cancer cell invasion and CCL2 expression induced in the co-cultures was inhibited by Lactacystin and Bay11-7082 NF-κB inhibitors. Prostate cancer cell NF-κB DNA binding activity depended on CCL2 dose and was inhibited by CCL2 neutralizing antibodies. Clinical prostate cancer NF-κB expression correlated with tumor grade.

Conclusions

Co-cultures with monocyte-lineage cell lines stimulated increased prostate cancer cell invasion through increased CCL2 expression and increased prostate cancer cell NF-κB activity. CCL2 and NF-κB may be useful therapeutic targets to interfere with inflammation-induced prostate cancer invasion.

Synthesis, physicochemical and biological evaluation of technetium-99m labeled lapatinib as a novel potential tumor imaging agent of Her-2 positive breast cancer

Tumors that are Her-2-positive tend to grow and spread more quickly than other types of breast cancer. Overexpression of Her-2 can be a predictive biomarker for stratification of patients for therapy with Herceptin (containing humanized IgG1 monoclonal antibody trastuzumab) or Tykerb (containing lapatinib di-p-toluenesulfonate) drug. Usually, Her-2 status is determined by immunohistochemical (IHC) as well as fluorescent or chromogenic in situ hybridisation (FISH or CISH) analysis of biopsy material. The objective of the present work was to standardize the conjugation of anti-cancer drug lapatinib (which recognizes selectively the Her-2 extracellular domain) with technetium-99m complex, of type '4+1', to obtain (99m)Tc(NS3)(CN-lapatinib) conjugate for use as in vivo tracer of the Her-2 expression in breast cancer. The conjugate (99m)Tc(NS3)(CN-lapatinib) was formed with high yield, high radiochemical purity and specific activity within the range 25-30 GBq/μmol. The biological in vitro and in vivo studies of the conjugate showed its high affinity to Her-2 receptor (Kd = 3.5 ± 0.4 nM, Ki = 2.9 ± 0.5 nM, Bmax = 2.4 ± 0.3 nM, approximate number of 2.4 × 10(6) binding sites per cell, IC50 = 41.2 ± 0.4 nM) and also pointed out to the clearance through the hepatic and renal route in comparable degree. Basing on these results one can conclude that (99m)Tc(NS3)(CN-lapatinib) conjugate could be a promising radiopharmaceutical for in vivo diagnosis of the Her-2 status in breast with impact on treatment planning.

Quantitative RT-PCR assay of HER2 mRNA expression in formalin-fixed and paraffin-embedded breast cancer tissues

Detection of human epidermal growth factor receptor 2 gene (HER2, also known as erbB2) expression is a preparatory process to decide a treatment strategy for breast cancer patients. 20-30% of breast cancer patients have HER2 overexpression, and they usually show poor recovery rate. For detection of HER2 expression, immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) methods are conventionally used. Although these methods are accurate and reliable, their time-consuming process and high cost need a concise method with high sensitivity and accuracy. As a complementary method to the current IHC/FISH standard techniques, PCR-based methods have been developed. Here we employed a quantitative PCR method to detect HER2 expression in one hundred ninety nine formalin-fixed and paraffin-embedded (FFPE) breast cancer tissue samples from the patients treated over two years at the Yonsei University Severance Hospital, Republic of Korea. Relative expression of HER2 mRNA in the FFPE samples was analyzed using a quantitative RT-PCR (RT-qPCR) method and the obtained HER2 expression levels were compared with those from IHC/FISH methods. Our results show that the RT-qPCR method was highly concordant with IHC/FISH methods for detecting HER2 expression. Overall sensitivity and specificity of the BrightGen HER2 RT-qDx assay kit (Syantra, Calgary, Canada), which is a kit we used for RT-qPCR analyses, were 93.0% and 89.8% (P < 0.0001), respectively. The diagnostic cut-off value of HER2 RT-qDx for the clinical samples was determined by likelihood ratio, among which the highest likelihood ratio of relative HER2 mRNA levels was over 105.5 (AUC = 0.9466) with the highest sensitivity and specificity. Our study indicates that quantification of HER2 mRNA expression with the RT-qPCR could be an alternative method of conventional IHC/FISH methods.

Correlation of HER2 overexpression with gene amplification and its relation to chromosome 17 aneuploidy: a 5-year experience with invasive ductal and lobular carcinomas

The HER2 oncogene shows expression or amplification, or both, in approximately 15% to 20% of breast cancers and has been associated with poor prognosis and a response to trastuzumab therapy. HER2 gene status determines the eligibility of breast cancer patients for trastuzumab therapy and a large fraction (41-56%) of these patients respond to targeted therapy. Several studies have related the increased expression of HER2 to an increased copy number of chromosome 17, rather than amplification of the HER2 gene. We compared the results of immunohistochemistry and fluorescence in situ hybridization in both invasive ductal and invasive lobular carcinomas, to determine the frequency of chromosome 17 aneuploidy associated with discordant results. In total, 390 invasive ductal carcinomas and 180 invasive lobular carcinomas diagnosed from January 2000 to December 2005 were included in the study only if results were available for immunohistochemistry (HercepTest; DAKO, Carpinteria, California) and fluorescence in situ hybridization (PathVysion HER2 DNA Probe Kit; Abbott Laboratories, Des Plaines, Illinois). Tumors classified as invasive ductal carcinomas were graded according to the Bloom-Richardson grading system. Correlation between the results of immunohistochemistry and fluorescence in situ hybridization was performed for all categories. Among invasive ductal carcinomas, 29% (115/390) showed chromosome 17 aneuploidy, mostly associated with grade 3/HER2 2+ (45%) or grade 2/HER2 3+ (55%) that were not amplified. Also, 34% (12/35) of invasive lobular carcinomas showed chromosome 17 aneuploidy; approximately one-third of these cases were HER2 2+ (33%) and HER2 3+ (37%) that were not amplified. Discordance between the results of immunohistochemistry and fluorescence in situ hybridization in both ductal and lobular carcinomas is largely associated with chromosome 17 aneuploidy.

Evaluation of BrightGen HR RT-qDx assay to detect nuclear receptors mRNA overexpression in FFPE breast cancer tissue samples for selection of tamoxifen therapy

Breast cancer is a significant cause of death in women. Estrogen receptor (ER) and progesterone receptor (PR) are important prognostic factors indicating higher recovery rate in the breast cancer patients. Currently, immunohistochemical (IHC) staining is a conventional method to identify expression of ER and PR. If a breast cancer patient expresses ER or PR, a chemotherapy with estrogen inhibitors such as tamoxifen is supposed to be effective. Although IHC staining is a reliable method, it may not a useful method for continuous monitoring of ER and PR expression changes in multiple breast cancer patients. In the present study, we evaluated an alternative method of IHC for detection of ER and PR expression. A quantitative RT-PCR method called 'the BrightGen HR RT-qDx assay' was employed to detect mRNA expression of the nuclear receptors in 199 formalin-fixed paraffin-embedded (FFPE) breast cancer tissue samples. Among the ER/PR positive samples by IHC, 83 were determined positive and 16 were determined negative for the nuclear receptor mRNA by the quantitative RT-PCR method. Among the ER/PR negative samples by IHC, 37 were determined negative and 2 were determined positive by the quantitative RT-PCR method. The overall sensitivity and specificity of the quantitative RT-PCR method were 83.8% and 94.8% (P = 0.0026), respectively. We also optimized the quantitative RT-PCR method by setting up the diagnostic cut-off value using the likelihood ratio. The highest likelihood ratio was when the expression levels of the relative nuclear receptor mRNA passed 103.3 at which sensitivity and specificity was highest. These data suggest that BrightGen HR RT-qDx assay could be an alternative method for detection of the prognostic factors of nuclear receptors expressed in breast cancer patients for providing essential information for therapeutic application of tamoxifen.

IHC Profiler: an open source plugin for the quantitative evaluation and automated scoring of immunohistochemistry images of human tissue samples

In anatomic pathology, immunohistochemistry (IHC) serves as a diagnostic and prognostic method for identification of disease markers in tissue samples that directly influences classification and grading the disease, influencing patient management. However, till today over most of the world, pathological analysis of tissue samples remained a time-consuming and subjective procedure, wherein the intensity of antibody staining is manually judged and thus scoring decision is directly influenced by visual bias. This instigated us to design a simple method of automated digital IHC image analysis algorithm for an unbiased, quantitative assessment of antibody staining intensity in tissue sections. As a first step, we adopted the spectral deconvolution method of DAB/hematoxylin color spectra by using optimized optical density vectors of the color deconvolution plugin for proper separation of the DAB color spectra. Then the DAB stained image is displayed in a new window wherein it undergoes pixel-by-pixel analysis, and displays the full profile along with its scoring decision. Based on the mathematical formula conceptualized, the algorithm is thoroughly tested by analyzing scores assigned to thousands (n = 1703) of DAB stained IHC images including sample images taken from human protein atlas web resource. The IHC Profiler plugin developed is compatible with the open resource digital image analysis software, ImageJ, which creates a pixel-by-pixel analysis profile of a digital IHC image and further assigns a score in a four tier system. A comparison study between manual pathological analysis and IHC Profiler resolved in a match of 88.6% (P<0.0001, CI = 95%). This new tool developed for clinical histopathological sample analysis can be adopted globally for scoring most protein targets where the marker protein expression is of cytoplasmic and/or nuclear type. We foresee that this method will minimize the problem of inter-observer variations across labs and further help in worldwide patient stratification potentially benefitting various multinational clinical trial initiatives.

Correlation of breast cancer subtypes, based on estrogen receptor, progesterone receptor, and HER2, with functional imaging parameters from ⁶⁸Ga-RGD PET/CT and ¹⁸F-FDG PET/CT

PURPOSE

Imaging biomarkers from functional imaging modalities were assessed as potential surrogate markers of disease status. Specifically, in this prospective study, we investigated the relationships between functional imaging parameters and histological prognostic factors and breast cancer subtypes.

METHODS

In total, 43 patients with large or locally advanced invasive ductal carcinoma (IDC) were analyzed (47.6 ± 7.5 years old). (68)Ga-Labeled arginine-glycine-aspartic acid (RGD) and (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) were performed. The maximum and average standardized uptake values (SUVmax and SUVavg) from RGD PET/CT and SUVmax and SUVavg from FDG PET/CT were the imaging parameters used. For histological prognostic factors, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression was identified using immunohistochemistry (IHC) or fluorescent in situ hybridization (FISH). Four breast cancer subtypes, based on ER/PR and HER2 expression (ER/PR+,Her2-, ER/PR+,Her2+, ER/PR-,Her2+, and ER/PR-,Her2-), were considered.

RESULTS

Quantitative FDG PET parameters were significantly higher in the ER-negative group (15.88 ± 8.73 vs 10.48 ± 6.01, p = 0.02 for SUVmax; 9.40 ± 5.19 vs 5.92 ± 4.09, p = 0.02 for SUVavg) and the PR-negative group (8.37 ± 4.94 vs 4.79 ± 3.93, p = 0.03 for SUVavg). Quantitative RGD PET parameters were significantly higher in the HER2-positive group (2.42 ± 0.59 vs 2.90 ± 0.75, p = 0.04 for SUVmax; 1.60 ± 0.38 vs 1.95 ± 0.53, p = 0.04 for SUVavg) and showed a significant positive correlation with the HER2/CEP17 ratio (r = 0.38, p = 0.03 for SUVmax and r = 0.46, p < 0.01 for SUVavg). FDG PET parameters showed significantly higher values in the ER/PR-,Her2- subgroup versus the ER/PR+,Her2- or ER/PR+,Her2+ subgroups, while RGD PET parameters showed significantly lower values in the ER/PR-,Her2- subgroup versus the other subgroups. There was no correlation between FDG and RGD PET parameters in the overall group. Only the ER/PR-,Her2- subgroup showed a significant positive correlation between FDG and RGD PET parameters (r = 0.59, p = 0.03 for SUVmax).

CONCLUSION

(68)Ga-RGD and (18)F-FDG PET/CT are promising functional imaging modalities for predicting biomarkers and molecular phenotypes in breast cancer patients.

Automated analysis of intracellular calcium fluorescence in rat organotypic hippocampal cultures: comparison to a manual, observer based method

The technical advances made in microscopy have been matched by an increase in the application of fluorescent microscopy to answer scientific questions. While analysis of fluorescent microscopy images represents a powerful tool, one must be aware of the potential pitfalls. Frequently, the analysis methods applied involve at least some manual steps which are dependent on an observers input. Typically these steps are laborious and time consuming, but more importantly they are also influenced by an individual observer's bias, drift or imprecision. This raises concerns about the repeatability and definitiveness of the reported observations. Using calcium fluorescence in organotypic hippocampal slices as an experimental platform, we demonstrate the influence that manual interventions can exert on an analysis. We show that there is a high degree of variability between observers, and that this can be sufficient to affect the outcome of an experiment. To counter this, and to eliminate the disagreement between observers, we describe an alternative fully automated method which was created using EBImage package for R. This method has the added advantage of being fully open source and customisable, allowing for this approach to be applied to other analyses.

Added value of HER-2 amplification testing by multiplex ligation-dependent probe amplification in invasive breast cancer

Background

HER-2 is a prognostic and predictive marker, but as yet no technique is perfectly able to identify patients likely to benefit from HER-2 targeted therapies. We aimed to prospectively assess the added value of first-line co-testing by IHC, and multiplex ligation-dependent probe amplification (MLPA) and chromogenic in situ hybridization (CISH).

Methods

As local validation, HER-2 MLPA and CISH were compared in 99 breast cancers. Next, we reviewed 937 invasive breast cancers, from 4 Dutch pathology laboratories, that were prospectively assessed for HER-2 by IHC and MLPA (and CISH in selected cases).

Results

The validation study demonstrated 100% concordance between CISH and MLPA, if both methods were assessable and conclusive (81.8% of cases). Significant variation regarding percentages IHC 0/1+ and 2+ cases was observed between the laboratories (p<0.0001). Overall concordance between IHC and MLPA/CISH was 98.1% (575/586) (Kappa = 0.94). Of the IHC 3+ cases, 6.7% failed to reveal gene amplification, whereas 0.8% of the IHC 0/1+ cases demonstrated gene amplification. Results remained discordant after retrospective review in 3/11 discordant cases. In the remaining 8 cases the original IHC score was incorrect or adapted after repeated IHC staining.

Conclusions

MLPA is a low-cost and quantitative high-throughput technique with near perfect concordance with CISH. The use of MLPA in routinely co-testing all breast cancers may reduce HER-2 testing variation between laboratories, may serve as quality control for IHC, will reveal IHC 0/1+ patients with gene amplification, likely responsive to trastuzumab, and identify IHC 3+ cases without gene amplification that may respond less well.

Software-automated counting of Ki-67 proliferation index correlates with pathologic grade and disease progression of follicular lymphomas

OBJECTIVES

To examine the accuracy of software-assisted measurement of the Ki-67 proliferation index (PI) and its correlation with the grade and clinical progression of follicular lymphoma (FL).

METHODS

High-power field equivalents were extracted from H&E- and Ki-67-immunostained slides of FL, and a nuclear quantitation algorithm was used to calculate a PI. Representative fields were manually counted for validation with close agreement.

RESULTS

The PI was significantly higher in World Health Organization grade 3 FL than grade 1 to 2 FL. Disease progression, as defined by subsequent treatment with radiation or cytotoxic chemotherapy, was also significantly associated with elevated PI but not pathologic grade.

CONCLUSIONS

These data show that software-automated quantitation of Ki-67 can provide both a useful adjunct to pathologic grade in FL and improved prognostic information for patients.

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.

Quantitative immunohistochemical analysis reveals association between sodium iodide symporter and estrogen receptor expression in breast cancer

BACKGROUND

Human sodium iodide symporter (hNIS) gene over-expression is under active consideration worldwide as an alternative target molecule for breast cancer (BC) diagnosis and targeted radio-iodine treatment. However, the field demands better stratified analysis of endogenous hNIS expression across major BC subtypes. Therefore, we have analyzed subtype-specific variation of hNIS overexpression in breast tumor tissue samples by immunohistochemistry (IHC) and also report the development of a homogeneous, quantitative analysis method of digital IHC images.

METHODS

hNIS expression was analyzed from 108 BC tissue samples by IHC. Sub-cellular localization of hNIS protein was analyzed by dual immunofluorescence (IF) staining method using hNIS and HER2 antibodies. An ImageJ based two-step digital analysis method was developed and applied for the bias-free analysis of the images.

RESULTS

Staining of the tumor samples show 70% cases are hNIS positive indicating high incidence of hNIS positive cases in BC. More importantly, a subtype specific analysis done for the first time shows that hNIS expression is overly dominated in estrogen receptor (ER) positive cases than the receptor negative cases. Further, 56% of the ER+ve, PgR+ve, HER2-ve and 36% of ER+ve, PgR+ve, HER2+ve cases show highest intensity staining equivalent to the thyroid tissue. A significant positive correlation is also observed between hNIS and estrogen receptor expression (p = 0.0033, CI = 95%) suggesting hNIS mediated targeted radio-iodine therapy procedures may benefit both ER+ve, PgR+ve, HER2-ve as well as HER2+ve cases. Further, in a few cases, hNIS and HER2 protein localization is demonstrated by overlapping membrane co-expression. ImageJ based image analysis method shows over 70% match with manual pathological scoring method.

CONCLUSION

The study indicates a positive link between hNIS and ER expression in BC. The quantitative IHC image analysis method reported here will further help in patient stratification and potentially benefit global clinical assessment where hNIS mediated targeted ¹³¹I radio-ablative therapy is aimed.

Is it necessary to evaluate nuclei in HER2 FISH evaluation?

A new method that simplifies the evaluation of the traditional HER2 fluorescence in situ hybridization (FISH) evaluation in breast cancer was proposed. HER2 status was evaluated in digital images (DIs) captured from 423 invasive breast cancer stained sections. All centromeric/CEP17 and HER2 gene signals obtained from separated stacked DIs were manually counted on the screen. The global ratios were compared with the traditional FISH evaluation and the immunohistochemical status. The 2 FISH scores were convergent in 96.93% of cases, showing an "almost perfect" agreement with a weighted k of 0.956 (95% confidence interval, 0.928-0.985). The new method evaluates at least 3 times more nuclei than traditional methods and also has an almost perfect agreement with the immunohistochemical scores. The proposed enhanced method substantially improves HER2 FISH assessment in breast cancer biopsy specimens because the evaluation of HER2/CEP17 copy numbers is more representative, easier, and faster than the conventional method.

Differential pathological response to preoperative chemotherapy across breast cancer intrinsic subtypes

BACKGROUND

Breast cancer is a heterogeneous disease with a diversity of clinical behaviors. The purpose of this study was to evaluate the utility of breast cancer intrinsic subtypes in the prediction of pathological complete response (pCR) in a cohort of breast cancer patients receiving preoperative chemotherapy.

METHODS

Patients with stage II/III breast cancer received 4 cycles of XT (capecitabine and docetaxel) followed by 4 cycles of FEC (fluorouracil, epirubicin, and cyclophosphamide) as preoperative chemotherapy. Tumors were classified as luminal A, luminal B, luminal/HER2, HER2, basal-like, or non-basal-like triple negative by immunohistochemical analysis in core needle biopsy samples at baseline.

RESULTS

The overall pCR rate was 11.9% (12/101). Multivariate analysis showed that intrinsic subtype was an independent factor to predict pCR. With luminal A patients as the reference group, luminal B (OR = 16.39; 95% CI 1.44-185.88; p = 0.024), HER2 (OR = 14.73; 95% CI 1.19-180.84; p = 0.035), and basal-like (OR = 13.27; 95% CI 1.27-138.79; p = 0.031) patients had a significantly higher likelihood of pCR.

CONCLUSION

The present data indicate that intrinsic subtypes may be useful predictive biomarkers of pCR in breast cancer patients treated with preoperative chemotherapy.

State-of-the-art FISHing: automated analysis of cytogenetic aberrations in interphase nuclei

Interphase fluorescence in situ hybridization (i-FISH) is a powerful tool for visualizing various molecular targets in non-dividing cells. Manual scoring of i-FISH signals is a labor intensive, time-consuming, and error-prone process liable to subjective interpretation. Automated evaluation of signal patterns provides the opportunity to overcome these difficulties. The first report on automated i-FISH analysis has been published 20 years ago and since then several applications have been introduced in the fields of oncology, and prenatal and fertility screening. In this article, we provide an insight into the automated i-FISH analysis including its course, brief history, clinical applications, and advantages and challenges. The lack of guidelines for describing new automated i-FISH methods hampers the precise comparison of performance of various applications published, thus, we make a proposal for a panel of parameters essential to introduce and standardize new applications and reproduce previously described technologies.

Efficacy of primed in situ labelling in determination of HER-2 gene amplification and CEN-17 status in breast cancer tissue

Considerable attention has been given to the accuracy of HER-2 testing and the correlation between the results of different testing methods. This interest reflects the growing importance of HER-2 status in the management of patients with breast cancer. In this study the detection of HER-2 gene and centromere 17 status was evaluated using dual-colour primed in situ labelling (PRINS) in comparison with fluorescence in situ hybridization (FISH). These two methods were evaluated on a series of 27 formalin fixed paraffin embedded breast carcinoma tumours, previously tested for protein overexpression by HercepTest (grouped into Hercep 1+/0, 2+ and 3+). HER-2 gene amplification (ratio ≥ 2.2) by PRINS was found in 3:3, 6:21 and 0:3 in IHC 3+, 2+ and 1+/0 cases, respectively. Comparing FISH and IHC (immunohistochemistry), showed the same results as for PRINS and IHC. Chromosome 17 aneusomy was found in 10 of 21 IHC 2+ cases (47.6%), of which 1 (10%) showed hypodisomy (chromosome 17 copy number per cell ≤ 1.75), 7 (70%) showed low polysomy (chromosome 17 copy number per cell=2.26 - 3.75) and 2 (20%) showed high polysomy (chromosome 17 copy number per cell ≥ 3.76). The overall concordance of detection of HER-2 gene amplification by FISH and PRINS was 100% (27:27). Furthermore, both the level of HER-2 amplification and copy number of CEN17 analysis results correlated well between the two methods. In conclusion, PRINS is a reliable, reproducible technique and in our opinion can be used as an additional test to determine HER-2 status in breast tumours.

Serine protease PRSS23 is upregulated by estrogen receptor α and associated with proliferation of breast cancer cells

Serine protease PRSS23 is a newly discovered protein that has been associated with tumor progression in various types of cancers. Interestingly, PRSS23 is coexpressed with estrogen receptor α (ERα), which is a prominent biomarker and therapeutic target for human breast cancer. Estrogen signaling through ERα is also known to affect cell proliferation, apoptosis, and survival, which promotes tumorigenesis by regulating the production of numerous downstream effector proteins.In the present study, we aimed to clarify the correlation between and functional implication of ERα and PRSS23 in breast cancer. Analysis of published breast cancer microarray datasets revealed that the gene expression correlation between ERα and PRSS23 is highly significant among all ERα-associated proteases in breast cancer. We then assessed PRSS23 expression in 56 primary breast cancer biopsies and 8 cancer cell lines. The results further confirmed the coexpression of PRSS23 and ERα and provided clinicopathological significance. In vitro assays in MCF-7 breast cancer cells demonstrated that PRSS23 expression is induced by 17β-estradiol-activated ERα through an interaction with an upstream promoter region of PRSS23 gene. In addition, PRSS23 knockdown may suppress estrogen-driven cell proliferation of MCF-7 cells.Our findings imply that PRSS23 might be a critical component of estrogen-mediated cell proliferation of ERα-positive breast cancer cells. In conclusion, the present study highlights the potential for PRSS23 to be a novel therapeutic target in breast cancer research.

Digital image analysis: a review of reproducibility, stability and basic requirements for optimal results

Digital image analysis (DIA) is increasingly implemented in histopathological research to facilitate truly quantitative measurements, decrease inter-observer variation and reduce hands-on time. Originally, efforts were made to enable DIA to reproduce manually obtained results on histological slides optimized for light microscopy and the human eye. With improved technical methods and the acknowledgement that computerized readings are different from analysis by human eye, recognition has been achieved that to really empower DIA, histological slides must be optimized for the digital 'eye', with reproducible results correlating with clinical findings. In this review, we focus on the basic expectations and requirements for DIA to gain wider use in histopathological research and diagnostics. With a reference to studies that specifically compare DIA with conventional methods, this review discusses reproducibility, application of stereology-based quantitative measurements, time consumption, optimization of histological slides, regions of interest selection and recent developments in staining and imaging techniques.

Clinical and health economic outcomes of alternative HER2 test strategies for guiding adjuvant trastuzumab therapy

AIM

To evaluate the clinical outcomes and cost-effectiveness of human epidermal growth factor receptor 2 (HER2) testing strategies to guide adjuvant trastuzumab (AT) therapy in women with HER2-positive breast cancer.

METHODS

A literature review produced 72 studies comparing HER2 test methods, and we computed concordance (assuming fluorescence in situ hybridization [FISH] as a reference assay) to assess performance relative to American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines. An economic analysis provided cost-effectiveness of alternative strategies, including a Monte Carlo simulation to vary key assumptions such as test price and performance.

RESULTS

Of 46 studies comparing immunohistochemistry (IHC) and FISH, only seven met the ASCO/CAP guideline of 95% or better concordance. A total of 14 out of 21 studies comparing chromogenic in situ hybridization and three out of five studies comparing silver-enhanced in situ hybridization met the guideline. Confirmation of IHC 2+ and 3+ and primary FISH strategies are likely to reduce costs and improve quality of life relative to confirmation of IHC 2+ only. Initial testing with a gene amplification-based assay is probably a cost-effective alternative to confirmation of IHC 2+ and 3+. The results are not sensitive to varying test price but are sensitive to test accuracy below 98%.

CONCLUSION

Using a primary gene amplification-based assay to guide AT therapy for HER2-positive breast cancer probably results in lower US medical costs, increased life-years and increased quality of life compared with confirmation of IHC 2+ with a gene amplification-based assay. We recommend the ASCO/CAP guidelines reflect 98% or greater concordance relative to a reference assay. Additional research regarding therapy response is required to further differentiate between gene amplification-based assays.

Modular strategy for the construction of radiometalated antibodies for positron emission tomography based on inverse electron demand Diels-Alder click chemistry

A modular system for the construction of radiometalated antibodies was developed based on the bioorthogonal cycloaddition reaction between 3-(4-benzylamino)-1,2,4,5-tetrazine and the strained dienophile norbornene. The well-characterized, HER2-specific antibody trastuzumab and the positron emitting radioisotopes ⁶⁴Cu and ⁸⁹Zr were employed as a model system. The antibody was first covalently coupled to norbornene, and this stock of norbornene-modified antibody was then reacted with tetrazines bearing the chelators 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid (DOTA) or desferrioxamine (DFO) and subsequently radiometalated with ⁶⁴Cu and ⁸⁹Zr, respectively. The modification strategy is simple and robust, and the resultant radiometalated constructs were obtained in high specific activity (2.7–5.3 mCi/mg). For a given initial stoichiometric ratio of norbornene to antibody, the ⁶⁴Cu-DOTA- and ⁸⁹Zr-DFO-based probes were shown to be nearly identical in terms of stability, the number of chelates per antibody, and immunoreactivity (>93% in all cases). In vivo PET imaging and acute biodistribution experiments revealed significant, specific uptake of the ⁶⁴Cu- and ⁸⁹Zr-trastuzumab bioconjugates in HER2-positive BT-474 xenografts, with little background uptake in HER2-negative MDA-MB-468 xenografts or other tissues. This modular system—one in which the divergent point is a single covalently modified antibody stock that can be reacted selectively with various chelators—will allow for both greater versatility and more facile cross-comparisons in the development of antibody-based radiopharmaceuticals.

Trainable immunohistochemical HER2/neu image analysis: a multisite performance study using 260 breast tissue specimens

CONTEXT

Aperio Technologies, Inc (Vista, California) provides a new immunohistochemistry (IHC) HER2 Image Analysis (IA) system that allows tuning of the intensity thresholds of the HER2/ neu scoring scheme to adapt to the staining characteristics of different reagents.

OBJECTIVE

To compare the trainable IHC HER2 IA system for different reagents to conventional manual microscopy (MM) in a multisite study.

DESIGN

Two hundred sixty formalin-fixed, paraffin-embedded breast cancer specimens from 3 clinical sites were assayed: 180 specimens stained with Dako's HercepTest (Carpinteria, California), and 80 specimens stained with Ventana's PATHWAY HER-2/neu (Tucson, California). At each site, 3 pathologists performed a blinded reading of the glass slides with the use of a light microscope. The glass slides were then scanned and after a wash-out period and randomization, the same pathologists outlined a representative set of tumor regions to be analyzed by IHC HER2 IA. Each of the methods, MM and IA, was evaluated separately and comparatively by using κ statistics of negative HER2/neu scores (0, 1+) versus equivocal HER2/neu scores (2+) versus positive HER2/neu scores (3+) among the different pathologists.

RESULTS

κ Values for IA and MM were obtained across all sites. MM: 0.565-0.864; IA: 0.895-0.947; MM versus IA: 0.683-0.892 for site 1; MM: 0.771-0.837; IA: 0.726-0.917; MM versus IA: 0.687-0.877 for site 2; MM: 0.463-0.674; IA: 0.864-0.918; MM versus IA: 0.497-0.626 for site 3.

CONCLUSION

Aperio's trainable IHC HER2 IA system shows substantial equivalence to MM for Dako's HercepTest and Ventana's PATHWAY HER-2/neu at 3 clinical sites. Image analysis improved interpathologist agreement in the different clinical sites.

Implementation of whole slide imaging in surgical pathology: A value added approach

Background:

Whole slide imaging (WSI) makes it possible to capture images of an entire histological slide. WSI has established roles in surgical pathology, including support of off-site frozen section interpretation, primary diagnosis, educational activities, and laboratory quality assurance (QA) activities. Analyses of the cost of WSI have traditionally been based solely on direct costs and diagnostic accuracy; however, these types of analyses largely ignore workflow and cost issues that arise as a result of redundancy, the need for additional staffing, and customized software development when WSI is integrated into routine diagnostic surgical pathology. The pre-scan, scan, and post-scan costs; quality control and QA costs; and IT process costs can be significant, and consequently, pathology groups can find it difficult to perform a realistic cost–benefit analysis of adding WSI to their practice.

Materials and Methods:

In this paper, we report a “value added” approach developed to guide our decisions regarding integration of WSI into surgical pathology practice. The approach focuses on specific operational measures (cost, time, and enhanced patient care) and practice settings (clinical, education, and research) to identify routine activities in which the addition of WSI can provide improvements.

Results:

When applied to our academic pathology group practice, the value added approach resulted in expanded and improved operations, as demonstrated by outcome based measures.

Conclusion:

A value added can be used to perform a realistic cost-benefit analysis of integrating WSI into routine surgical pathology practice.

Expression of osteopontin coregulators in primary colorectal cancer and associated liver metastases

BACKGROUND

A transcription regulatory complex (TRC) that includes Ets1, Ets2, PEA3 and β-catenin/T-cell factors regulates osteopontin (OPN) that is implicated in colorectal cancer (CRC) dissemination. The consistency of OPN transcriptional control between primary CRC and metastases is unclear. This study investigates expression and prognostic significance of the OPN-TRC in primary human CRC and associated colorectal liver metastases (CRLM).

METHODS

Osteopontin-TRC factors were assayed by digital microscopy in 38 primary CRCs and matched CRLM specimens and assessed against clinical prognosis.

RESULTS

In primary CRC, OPN expression intensity correlated with that of its co-activators, PEA3 (r=0.600; P<0.01), Ets1 (r=0.552; P<0.01), Ets2 (r=0.521; P<0.01) and had prognostic significance. Osteopontin intensity in primary CRC inversely correlated with the interval between diagnosis and resection of CRLM. Overall OPN intensity was lower in CRLM than primary CRC and correlations with co-activators were weaker, for example, Ets1 (P=0.047), PEA3 (P=0.022) or nonsignificant (Ets2). The ratio of OPN expression in CRLM vs primary CRC had prognostic significance.

CONCLUSION

This study supports transcriptional control of OPN by known coregulators in both primary and secondary CRC. Weaker associations in CRLM suggest involvement of other unknown factors possibly from the liver microenvironment or resulting from additional genetic or epigenetic changes that drive tumour metastatic capability in OPN transcriptional control.