Bright-field HER2 dual in situ hybridization (DISH) assay on breast cancer cell blocks: a comparative study with histological sections

Evaluation of HER2-Low breast carcinoma in metastatic settings: a cytological approach to proliferation and survival

INTRODUCTION

Human epidermal growth factor receptor 2 (HER2)-low breast cancer, defined by HER2 immunohistochemistry scores of 1+ or 2+ without gene amplification, represents a unique subgroup with emerging therapeutic implications. Limited data describe the behavior of HER2-low tumors, particularly in metastatic settings. This study evaluated the frequency of HER2-low expression, Ki-67 proliferation index, and survival outcomes across HER2 subtypes in metastatic breast carcinoma using cytology specimens.

MATERIALS AND METHODS

A 3-year retrospective analysis identified 43 patients with metastatic breast carcinoma diagnosed via fine-needle aspiration or exfoliative cytology. HER2, ER, PR, and Ki-67 status were determined by immunohistochemistry, with equivocal HER2 cases assessed by in situ hybridization. Survival outcomes were estimated using the Kaplan-Meier method, with Cox regression identifying predictors of survival.

RESULTS

Among 43 cases, 31 (70.5%) were HER2-low, 6 (13.6%) HER2-positive, and 6 (13.6%) HER2-zero. HER2 discordance between primary and metastatic lesions occurred in 19%, mainly involving transitions to HER2-low status. Hormone receptor positivity was more frequent in HER2-low tumors (71%) than HER2-zero tumors (33%) (P < 0.001). Mean Ki-67 was highest in HER2-low (45%) versus HER2-negative (34%) and HER2-positive (33%) cases (P = 0.549). Median survival was 13 months for HER2-low and 5 months for HER2-negative patients; survival differences were not significant (P = 0.225). Younger age (HR = 0.240, P = 0.048) and hormone receptor positivity (HR = 0.273, P = 0.011) were significant predictors of survival.

CONCLUSION

HER2-low expression is prevalent in metastatic breast carcinoma with a unique hormone receptor profile. Findings highlight the need for reassessment of HER2 status in metastatic settings, with potential therapeutic implications.

Diagnostic Accuracy of Immunohistochemistry for HER2-Positive Breast Cancer

OBJECTIVE

Currently, human epidermal growth factor receptor 2 (HER2)-positive breast cancer cells are diagnosed under the American Society of Clinical Oncology (ASCO) and College of American Pathologists (CAP) 2018 guidelines. The guideline combined the results of in situ hybridization (DISH) and immunohistochemistry (IHC) techniques. The IHC technique is easy, cheap, and suitable for developing country. Therefore, in this study, we validated the use of IHC alone compared to the results of HER2 amplification under ASCO/CAP 2018 guidelines in diagnosed HER2 positive breast cancer cells.

METHODS

A total of 510 breast cancer tissue samples from Rajavithi Hospital in Bangkok, Thailand, from January 1st, 2022, to May 31st, 2023, were analyzed by IHC, followed by dual ISH (DISH). We selected 58 samples of IHC equivocal (score 2+) and 98 samples of IHC positive (score 3+) to analyze the diagnostic values by comparing them to the results of HER2 amplification.

RESULTS

The HER2 IHC score was found to agree with HER2 amplification with a sensitivity of 87.96%, a specificity of 93.75%, a positive predictive value of 96.94%, a negative predictive value of 77.59%, a positive likelihood ratio of 14.07, a negative likelihood ratio of 0.13, and an accuracy of 89.74%.

CONCLUSION

The promising outcomes suggest that a positive IHC test result (score 3+) could potentially stand alone for patients with breast cancer undergoing anti-HER2 treatment, even without DISH confirmation.

Detection of ERBB2 and CEN17 signals in fluorescent in situ hybridization and dual in situ hybridization for guiding breast cancer HER2 target therapy

The overexpression of the human epidermal growth factor receptor 2 (HER2) is a predictive biomarker in therapeutic effects for metastatic breast cancer. Accurate HER2 testing is critical for determining the most suitable treatment for patients. Fluorescent in situ hybridization (FISH) and dual in situ hybridization (DISH) have been recognized as FDA-approved methods to determine HER2 overexpression. However, analysis of HER2 overexpression is challenging. Firstly, the boundaries of cells are often unclear and blurry, with large variations in cell shapes and signals, making it challenging to identify the precise areas of HER2-related cells. Secondly, the use of sparsely labeled data, where some unlabeled HER2-related cells are classified as background, can significantly confuse fully supervised AI learning and result in unsatisfactory model outcomes. In this study, we present a weakly supervised Cascade R-CNN (W-CRCNN) model to automatically detect HER2 overexpression in HER2 DISH and FISH images acquired from clinical breast cancer samples. The experimental results demonstrate that the proposed W-CRCNN achieves excellent results in identification of HER2 amplification in three datasets, including two DISH datasets and a FISH dataset. For the FISH dataset, the proposed W-CRCNN achieves an accuracy of 0.970±0.022, precision of 0.974±0.028, recall of 0.917±0.065, F1-score of 0.943±0.042 and Jaccard Index of 0.899±0.073. For DISH datasets, the proposed W-CRCNN achieves an accuracy of 0.971±0.024, precision of 0.969±0.015, recall of 0.925±0.020, F1-score of 0.947±0.036 and Jaccard Index of 0.884±0.103 for dataset 1, and an accuracy of 0.978±0.011, precision of 0.975±0.011, recall of 0.918±0.038, F1-score of 0.946±0.030 and Jaccard Index of 0.884±0.052 for dataset 2, respectively. In comparison with the benchmark methods, the proposed W-CRCNN significantly outperforms all the benchmark approaches in identification of HER2 overexpression in FISH and DISH datasets (p<0.05). With the high degree of accuracy, precision and recall , the results show that the proposed method in DISH analysis for assessment of HER2 overexpression in breast cancer patients has significant potential to assist precision medicine.

A Soft Label Deep Learning to Assist Breast Cancer Target Therapy and Thyroid Cancer Diagnosis

According to the World Health Organization Report 2022, cancer is the most common cause of death contributing to nearly one out of six deaths worldwide. Early cancer diagnosis and prognosis have become essential in reducing the mortality rate. On the other hand, cancer detection is a challenging task in cancer pathology. Trained pathologists can detect cancer, but their decisions are subjective to high intra- and inter-observer variability, which can lead to poor patient care owing to false-positive and false-negative results. In this study, we present a soft label fully convolutional network (SL-FCN) to assist in breast cancer target therapy and thyroid cancer diagnosis, using four datasets. To aid in breast cancer target therapy, the proposed method automatically segments human epidermal growth factor receptor 2 (HER2) amplification in fluorescence in situ hybridization (FISH) and dual in situ hybridization (DISH) images. To help in thyroid cancer diagnosis, the proposed method automatically segments papillary thyroid carcinoma (PTC) on Papanicolaou-stained fine needle aspiration and thin prep whole slide images (WSIs). In the evaluation of segmentation of HER2 amplification in FISH and DISH images, we compare the proposed method with thirteen deep learning approaches, including U-Net, U-Net with InceptionV5, Ensemble of U-Net with Inception-v4, Inception-Resnet-v2 encoder, and ResNet-34 encoder, SegNet, FCN, modified FCN, YOLOv5, CPN, SOLOv2, BCNet, and DeepLabv3+ with three different backbones, including MobileNet, ResNet, and Xception, on three clinical datasets, including two DISH datasets on two different magnification levels and a FISH dataset. The result on DISH breast dataset 1 shows that the proposed method achieves high accuracy of 87.77 ± 14.97%, recall of 91.20 ± 7.72%, and F1-score of 81.67 ± 17.76%, while, on DISH breast dataset 2, the proposed method achieves high accuracy of 94.64 ± 2.23%, recall of 83.78 ± 6.42%, and F1-score of 85.14 ± 6.61% and, on the FISH breast dataset, the proposed method achieves high accuracy of 93.54 ± 5.24%, recall of 83.52 ± 13.15%, and F1-score of 86.98 ± 9.85%, respectively. Furthermore, the proposed method outperforms most of the benchmark approaches by a significant margin (p <0.001). In evaluation of segmentation of PTC on Papanicolaou-stained WSIs, the proposed method is compared with three deep learning methods, including Modified FCN, U-Net, and SegNet. The experimental result demonstrates that the proposed method achieves high accuracy of 99.99 ± 0.01%, precision of 92.02 ± 16.6%, recall of 90.90 ± 14.25%, and F1-score of 89.82 ± 14.92% and significantly outperforms the baseline methods, including U-Net and FCN (p <0.001). With the high degree of accuracy, precision, and recall, the results show that the proposed method could be used in assisting breast cancer target therapy and thyroid cancer diagnosis with faster evaluation and minimizing human judgment errors.

Dual-color dual-hapten in situ hybridization (D-DISH) - Comparison with fluorescence in situ hybridization (FISH) for HER2/neu testing in breast cancer

Context

HER2/neu testing in breast cancer is a mandate due to availability of trastuzumab, a monoclonal antibody targeted against this biomarker. Dual-color dual-hapten in situ hybridization (D-DISH) is a new test for assessment of HER2/neu gene overexpression on light microscopy.

Aims

This was a validation study for D-DISH in our laboratory and was conducted to study the concordance between fluorescence in situ hybridization (FISH) and D-DISH for HER2/neu testing in breast cancer.

Materials and Methods

In all, 150 cases of invasive breast carcinoma requested for FISH analysis were selected. Immunohistochemistry by Ventana PATHWAY anti-HER2/neu (4B5) antibody, FISH by ZytoLight SPEC ERBB2/CEN17 Dual Color Probe, and D-DISH using the Ventana INFORM HER2 Dual ISH DNA Probe Cocktail Assay was carried out.

Statistical Analysis

Cohen's kappa coefficient was used to calculate concordance between FISH and D-DISH assays. The ratios and average number of signals were compared with Lin's concordance correlation coefficient.

Results

About 93.1% of the cases showed concordance between FISH and D-DISH results. Cohen's kappa correlation coefficient was 0.836, indicating almost perfect level of agreement. Lin's concordance correlation coefficient (ρc) showed moderate strength of agreement for HER2/chromosome 17 ratios between FISH and D-DISH assays (ρc 0.9452). As per the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) 2018 updated guidelines, four of the cases that were nonamplified on FISH showed low-level amplification on D-DISH due to counting errors caused by faint signals or background dust. Genomic heterogeneity and larger red chromosome 17 signals on D-DISH led to discordance of the six cases amplified by FISH. D-DISH failure rate was 3.33%.

Conclusion

Overall, D-DISH showed good concordance with FISH but needs expertise for reporting.

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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Clinical significance of evaluating hormone receptor and HER2 protein using cell block against metastatic breast cancer: a multi-institutional study

Hormone receptor and human epidermal growth factor receptor 2 (HER2) protein tests in metastatic breast cancer tissue are recommended in the guidelines of the American Society of Clinical Oncology/American Pathology Association. As part of a multi-institutional study by the National Hospital Organization, we conducted an investigation to examine these molecular markers, using cytological specimens as a substitute for tissue specimens from breast cancer metastasis. To confirm the usefulness of receptors tested in metastatic lesions, the treatment course of registered metastatic breast cancer patients was analyzed. During the April 2015 to March 2016 registration period, there were 62 registrations. Types of metastatic lesions include pleural fluid (44 samples), ascites (14 samples), lymph nodes (2 samples), pericardial fluid (1 sample), and dorsal subcutaneous mass (1 sample). A stable test result was obtained by adopting the receptor examination method, using cell block for immunostaining cytological specimens. The discordance rates of estrogen receptor (ER), progesterone receptor (PR), and HER2 protein expression were 18.2% (95% confidence interval (CI): 7.9–28.8%), 36.4% (95% CI: 23.7–49.1%), and 8.2% (95% CI: 0.1–16.3%), respectively, between the primary tumor and metastatic lesion. Patients who changed from primary negative to metastatic positive ER status had taken a significantly longer time for metastatic foci to appear. Patients with positive ER status in metastatic lesions had significantly better prognosis than ER-negative cases (P = 0.030) by the Log-Rank test. The ER status of the metastatic lesion and the metastatic site were independent prognostic factors by Cox multivariate analysis. Receptor examination with cytological specimens in metastatic lesions has been useful as it provides guidance for the treatment of metastatic breast cancer.

HER2 assessment by bright-field dual in situ hybridization in cell blocks of recurrent and metastatic breast carcinoma

BACKGROUND

Breast cancer recurrences or metastases often are diagnosed using cytology material. Cell blocks (CBs) with adequate cellularity are crucial for the determination of accurate hormonal and human epidermal growth factor receptor 2 (HER2) status and to guide treatment. In the current study, the authors evaluated the concordance of HER2 status between bright-field dual in situ hybridization (DISH), fluorescence in situ hybridization (FISH), and HER2 immunohistochemistry (IHC) performed on formalin-fixed CBs of recurrent and metastatic breast cancers.

METHODS

The authors searched for patients who had breast carcinoma recurrences or metastases diagnosed between 2010 and 2018 by fine-needle aspiration or by the drainage of body cavity fluids with HER2 IHC and/or FISH performed on formalin-fixed CBs. Cases with adequate tumor cellularity (>50 cells) were selected. HER2 DISH was performed on all CBs. HER2 status of the primary breast carcinoma was recorded.

RESULTS

Formalin-fixed CBs were identified from 30 patients with breast cancer recurrences and metastases in axillary lymph nodes (LNs) (5 patients), mediastinal LNs (8 patients), internal mammary LNs (1 patient), supraclavicular LNs (2 patients), portocaval LNs (1 patient), chest wall (3 patients), pleural fluid (3 patients), bone (4 patients), liver (2 patients), and lung (1 patient). All cases had HER2 IHC performed at the study institution and were scored by breast pathologists according to the American Society of Clinical Oncology/College of American Pathologists guidelines. The HER2 DISH results demonstrated 100% concordance (30 of 30 cases) with the concurrent IHC and/or FISH.

CONCLUSIONS

All methods of HER2 evaluation were found to accurately identify the amplification status. DISH can be used in tandem with IHC as a reflex assay instead of FISH and is an efficient and reliable method with which to determine HER2 amplification in formalin-fixed CBs.

Evaluation of the HER2 and Hormone Receptor Status in Metastatic Breast Cancer Using Cell Blocks: A Multi-Institutional Study

OBJECTIVE

We explore the problems associated with the cell block (CB) method for receptor analysis in breast cancer metastases and propose a method for reporting the results.

STUDY DESIGN

Nine institutions used the CB method for the analysis of hormone receptors (HRs) and HER2 (human epidermal growth factor receptor 2) protein in cytological specimens of breast cancer metastases in routine practice. The stained slides were independently evaluated by 8 pathologists. Dual in situ hybridization assay was performed in cases of discordant results for HER2 protein. Based on the results, we propose a method for receptor scoring in the CB method.

RESULTS

Of 61 specimens, 57 contained tumor cells. Two or more pathologists disagreed on the results for the estrogen receptor, progesterone receptor, and HER2 protein in 3 (5.3%), 13 (22.8%), and 19 (33.3%) cases, respectively. The discrepant results for the HRs were attributed to the presence of a few positive cells or faintly stained cells. The high interobserver discordance rate for HER2 protein was explained by interobserver differences in the scoring criteria.

CONCLUSION

The use of categorical scoring into positive and negative is recommended for evaluating the HR expressions. Use of strict criteria for HER2 protein 2+ and 3+ cases is recommended, as HER2-positive cases should not be missed.

Identification of oestrogen, progesterone receptor and human epidermal growth factor receptor 2 expression in mediastinal metastases of breast cancer obtained by endobronchial ultrasound-guided transbronchial needle aspiration

BACKGROUND

In breast cancer patients, the expression statuses of oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) are crucial in the choice of treatment. Receptor expression in metastatic lesions can differ from the primary tumour. The aim of our study was to analyse the utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) to obtain samples allowing the identification of ER, PR and HER2 expression in patients with mediastinal metastases of breast cancer.

PATIENTS AND METHODS

The clinical files of all patients with a final diagnosis of breast cancer mediastinal metastases diagnosed by EBUS-TBNA in our institution were retrospectively analysed. The ability of EBUS-TBNA to obtain samples that allowed hormone receptor and HER2 expression analysis was calculated.

RESULTS

Twenty-four patients were included. ER, PR and HER2 assessments could be performed in 22, 20 and 22 patients, respectively. In 20 of the 24 patients it was possible to investigate all three types of receptor expression. In the remaining four cases, where ER, PR or HER2 expression tests could not be performed, it was due to a lack of tissue. In cases with adequate results for EBUS-TBNA and the primary tumour agreement was greater for ER (16/19) and HER2 (12/14) than PR (8/17). Based on receptor status, there was a change in the choice of treatment for five patients.

CONCLUSION

In patients with breast cancer mediastinal metastases, ER, PR and HER2 expression can be assessed in samples obtained by EBUS-TBNA whenever a sufficient tissue sample is collected.

HER 2 immunohistochemistry for breast cancer cell blocks can be used in the same way as that used for histological specimens

Background

Human epidermal growth factor receptor 2 (HER2) testing of samples from recurrent or metastatic breast cancer is recommended by the 2013 update of the American Society of Clinical Oncology/College of American Pathologists guidelines. Although cytological analysis can be applied to several types of metastatic lesions, the practical method for HER2 testing of cytological specimens is yet to be resolved. We conducted immunohistochemical (IHC) staining for HER2 in breast cancer cell blocks (CBs) and compared the results with those from the corresponding histological specimens. In cases of discrepancy between the two types of specimen, the bright‐field HER2 dual in situ hybridization (DISH) assay was performed.

Methods

CBs were prepared from 54 surgically excised breast cancers. The cells were fixed in 10% buffered formalin and embedded in paraffin. A Ventana BenchMark ULTRA (Roche Diagnostics) with anti‐HER‐2/neu (4B5) rabbit monoclonal primary antibody and INFORM HER2/neu Dual ISH DNA Probe Cocktail was used for the assays.

Results

Successful results were obtained in 52 of 54 CBs. Forty cases showed agreement between CBs and the histological specimens. No discrepancy was observed between the two types of specimens in cases where HER2 expression was positive. IHC results of CB in 12 discrepant cases were HER2 intermediate or negative. The DISH results of 11 of these cases were negative.

Conclusion

IHC staining of HER2 for breast cancer CBs can be used in the same way as that used for histological specimens, although the number of equivocal cases in CBs is greater than that in histological specimens. Diagn. Cytopathol. 2016;44:274–279. © 2016 The Authors Diagnostic Cytopathology Published by Wiley Periodicals, Inc.