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

Principles of Analytic Validation of Immunohistochemical Assays: Guideline Update

CONTEXT.—

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

OBJECTIVE.—

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

DESIGN.—

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

RESULTS.—

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

CONCLUSIONS.—

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

Immunocytochemical markers, molecular testing and digital cytopathology for aspiration cytology of metastatic breast carcinoma

Fine-needle aspiration cytology (FNAC) is a versatile diagnostic procedure uniquely suited for tissue biopsy of breast carcinomas and axillary metastases and/or recurrences. With the expanding treatment options and accompanying theragnostic tests, it is crucial to recognize the developments on ancillary testing and digital cytopathology techniques related to aspiration cytology of metastatic breast carcinoma. In this review, we aim to summarize and update the evidence of immunocytochemistry, for the detection of carcinoma cells (epithelial markers), confirmation of breast primary (breast-specific markers), assessment of surrogate immunostains (hormone receptors, ki-67 proliferative index and HER2) and theragnostic biomarkers, with discussion on potential diagnostic pitfalls, followed by the application of molecular tests, and digital cytopathologic techniques for assessing metastatic breast carcinoma in cytology.

Expression of EGFR, PD-L1, and the mismatch repair proteins before and following therapy in malignant serous effusions with metastatic high-grade serous tubo-ovarian carcinoma

AIM

To compare the immunochemical expression of EGFR, PD-L1, and the mismatch repair (MMR) proteins MLH1, PMS2, MSH2, and MSH6 between matched malignant effusions obtained before and following the administration of chemotherapy in patients with high-grade serous tubo-ovarian carcinoma (HGSC).

METHODS

In the enrolled HGSCs, matched formalin-fixed and paraffin-embedded cell blocks (CBs) from effusions sampled before (treatment-naïve patients) and during recurrence (following chemotherapy administration), in addition to their matched HGSC tissues obtained from the ovaries at initial diagnosis (treatment-naïve patients), were subjected to EGFR, PD-L1, and MMR immunochemical analysis.

RESULTS

EGFR was more often overexpressed in effusions obtained after chemotherapy administration compared to both effusions (100% vs. 57.1%) and their matched tubo-ovarian tumors (100% vs. 7.1%) from treatment-naïve patients, respectively. EGFR immunochemistry was concordant in just 9.1% of the effusions sampled during recurrence and their paired ovarian samples before recurrence. Whereas all HGSC treatment-naïve samples (ovarian lesions and effusions) were PD-L1 negative, 3/11 (27.3%) malignant effusions obtained during recurrence showed PD-L1 overexpression. Lastly, none of the tested HGSC samples exhibited MMR deficiency.

CONCLUSION

Measuring biomarkers using CBs from malignant effusions may provide clinicians with significant information related to HGSC prognosis and therapy selection, especially in patients with resistance to chemotherapy.

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.

Expression of tetraspanins NET-6 and CD151 in breast cancer as a potential tumor biomarker

Tetraspanins have been implicated in multiple biological functions including protein networking and cell signaling. NET-6 (TSPAN 13) has been demonstrated to be a tumor suppressor gene in breast cancer, while CD151 is more likely to act as an oncogene. However, the biological function of both proteins is still inconclusive. Immunohistochemistry was used to analyze the expression of NET-6 and CD151 proteins in breast tumors and benign epithelial cells. The cellular expression of both markers was correlated with HER2, ER, and PR status as well as tumor grade, Ki-67 scores, invasion, and metastasis. Expression of NET-6 and CD151 was variable both in tumors and in benign epithelial cells. Expression of NET-6 and CD151 was stronger in tumors than in benign epithelial cells. The expression of NET-6 was also stronger in HER2-negative, low-grade, lymphovascular invasion-negative, and non-metastatic breast tumors. There was no correlation between NET-6 expression and ER, or PR, or triple-negative status. There was no correlation between CD151 expression and HER2, ER, PR, or triple-negative status, tumor grade, or Ki-67 scores, invasion, and metastasis. The expression of tetraspanins NET-6 and CD151 may indicate an alteration of their biological function during neoplastic transformation. NET-6 expression in tumors might be a potential marker indicating the outcome of breast cancer.

Reliability of Estrogen Receptor and Human Epidermal Growth Factor Receptor 2 Expression on Breast Cancer Cells Stored in Cellprep® Vials

OBJECTIVE

The aim of this study was to evaluate the reliability of estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) expression levels in Cellprep® (CP).

STUDY DESIGN

We evaluated the stability of immunocytochemistry (ICC) of ER and HER2 for primary or recurrent breast cancer samples rinsed in CP vials. Samples were prepared from CP vials stored for 1-30 or 160-240 days. ER and HER2 statuses were determined after 1-30 days (26 and 25 tests, respectively) or 160-240 days (15 and 18 tests, respectively) with the same protocols as immunohistochemistry (IHC), and were compared with the corresponding surgically resected specimens.

RESULTS

ER statuses according to CP samples showed perfect agreement (1-30 days: kappa, κ = 1; 160-240 days: κ = 1). HER2 statuses also showed good agreement (1-30 days: κ = 0.79; 160-240 days: κ = 0.64), although there were more equivocal HER2 cases in CP than in the surgically resected specimens.

CONCLUSION

ER ICC in CP vials is reliable regardless of the preservation period. HER2 ICC in CP has more equivocal cases than HER2 IHC in surgically resected specimens. Both improvement of the immunostaining protocol and further validation study of in situ hybridization are indispensable for the practical application of ICC in CP.

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.