Study of interlaboratory reliability and reproducibility of estrogen and progesterone receptor assays in Europe. Documentation of poor reliability and identification of insufficient microwave antigen retrieval time as a major contributory element of unreliable assays

Reporting Hormone Receptor Expression in Breast Carcinomas: Which Method has the Highest Prognostic Power and What Should be the Optimal Cut-off Value?

Background.Hormone receptor (HR) expression is a critical marker that plays a role in the treatment and management of breast cancer. Even if patients receive hormone treatment with a hormone positivity rate of over 1%, it is controversial at what level of positivity they benefit from treatment and contribute positively to their prognosis.Methods.We retrospectively examined the estrogen receptor (ER) / progesterone receptor (PR) expression status, clinicopathological findings, and survival data of 386 patients who underwent surgery for breast cancer. ER/PR expressions of the patients were evaluated according to Allred, H-score and were also grouped according to staining percentages. Separate cut-off values were determined for each of these evaluation methods, and the prognostic power of these methods was investigated using receiver operating characteristic analysis.Results.The prognostic power of all methods was found to be similar in terms of predicting survival. According to the staining percentage of the patients, survival was excellent if the ER value was >80% and the PR value was >1%.Conclusions.All recommended methods for reporting HRs have similar prognostic power. However, in patients with high percentage staining for ER using these methods, the prognosis is excellent. As a result, we predict that if the percentage of ER staining is low, changing the treatment management of patients may be considered clinically.

Low-positive controls for monitoring progesterone receptor immunohistochemical staining

AIMS

Progesterone receptor (PR) is a crucial prognostic marker in breast cancer. However, achieving consistent results in PR immunohistochemistry (IHC) remains challenging due to the lack of well-defined low-positive controls. This study aimed to identify benign tissues with consistent low-level PR expression to serve as ideal controls for IHC.

METHODS

We evaluated PR expression in the squamous epithelium of the uterine cervix, nipple smooth muscle and pancreatic islets. QuPath digital image analysis was employed to compare the intensity and quantity of PR staining in target cells within a 2×2 mm area.

RESULTS

The squamous epithelium of the secretory phase cervix, nipple smooth muscle and pancreatic islets displayed appreciable weak PR expression, with mean values of 73, 55 and 60 cells, respectively. Notably, 62% (8/13) of the 2×2 mm areas in the atrophic cervix were completely negative for PR expression. The coefficients of variation for weak PR-expressing cells in pancreatic islets (57.4%) and nipple smooth muscle (65.0%) were lower than those observed in the cervix (96.2%-222.0%). The squamous epithelium of the cervix, especially during the secretory phase, exhibited weak positivity confined to the basal layers, providing another viable control option. However, variations in PR expression may be influenced by physiological factors, such as hormonal fluctuations.

CONCLUSIONS

Pancreatic islets and nipple smooth muscle, with their consistent low-level PR expression, offer a promising solution to the challenges associated with PR IHC. This approach may help minimise variations resulting from differing staining methods across laboratories.

External Quality Assurance Helps Improve Infrastructure for Testing Breast Biomarkers Across a Lower- and Middle-Income Country: Our Experience With Breast Biomarker Testing in the National Cancer Grid External Quality Assurance System in India

CONTEXT.—

Biomarkers in breast cancer need strict monitoring given their role in patient management.

OBJECTIVE.—

To study the impact that regular participation in the National Cancer Grid (NCG) external quality assurance (EQA) system has on concordance rates for biomarkers in breast carcinoma.

DESIGN.—

Tissue microarrays (TMAs) containing breast carcinomas were circulated to participating laboratories that performed immunohistochemistry for breast biomarkers. The returned TMAs were then assessed for test concordance.

RESULTS.—

A total of 105 laboratories participated in the estrogen receptor (ER) and progesterone receptor (PR) EQA system cycles, and 99 centers participated in the human epidermal growth factor 2 (HER2) EQA system. In the ER EQA in the first cycle only 1 laboratory had a 100% concordance rate, which improved to 59 of 77 (76.6%) and 85 of 97 (87.6%) in the fourth and fifth cycles, respectively. In the PR EQA the 100% pass rate jumped from zero to 52 of 76 (68.4%) in the fourth cycle and 86 of 97 (88.6%) in the last cycle. For HER2 EQA, the 100% pass rates were seen in 7 of 23 laboratories (30.4%) in the first cycle, 49 of 78 laboratories (62.8%) in the fourth cycle, and 48 of 94 laboratories (51.1%) in fifth cycle of EQA. Centers that participated in the NCG EQA system for a longer period often changed testing methodology, with consequent improvement in their laboratory concordance rates. An increasing trend for the use of automated platforms and of the US Food and Drug Administration-approved antibody for HER2 testing was observed.

CONCLUSIONS.—

Our experience demonstrates that laboratory performance improves with participation in an EQA system even in less perfect settings, and this drives the placement of more proficient practices across the country.

Pathological Diagnosis, Work-Up and Reporting of Breast Cancer 1st Central-Eastern European Professional Consensus Statement on Breast Cancer

This text is based on the recommendations accepted by the 4th Hungarian Consensus Conference on Breast Cancer, modified on the basis of the international consultation and conference within the frames of the Central-Eastern European Academy of Oncology. The recommendations cover non-operative, intraoperative and postoperative diagnostics, determination of prognostic and predictive markers and the content of cytology and histology reports. Furthermore, they address some specific issues such as the current status of multigene molecular markers, the role of pathologists in clinical trials and prerequisites for their involvement, and some remarks about the future.

Percentage of Hormone Receptor Positivity in Breast Cancer Provides Prognostic Value: A Single-Institute Study

Background

A majority of breast cancer tumors express estrogen receptor (ER) and/or progesterone receptor (PR); however, the percentage of cancer cells expressing these receptors can range from 0-100%. The prognostic and therapeutic impact of the percentage of cells expressing hormone receptors in breast cancer is not fully understood.

Methods

A retrospective analysis of 411 breast cancer patients who were treated at the University of Nebraska Medical Center between 2010 and 2017 was performed. Patient tumors were evaluated for percentage of cells expressing ER and PR in conjunction with clinical outcomes.

Results

Patient tumors demonstrated a highly bimodal pattern of ER and PR staining with a majority of tumors demonstrating either a high percentage (> 80% of cells) or lack of cells (0%) staining for ER or PR. An increase in the percentage of ER positivity correlated with decreased local recurrence and improved overall survival. An increase in the percentage of PR positivity demonstrated a trend towards decreased local recurrence and improved overall survival, but was not statistically significant.

Conclusions

Results based on both continuous and categorical evaluation of ER expression revealed that increasing expression correlated with improved patient outcomes. Similar evaluation of PR expression demonstrated a trend towards improved patient outcomes though not statistically significant. These findings suggest that the degree of hormone receptor positivity and not a Boolean representation of positivity could provide additional prognostic value in the treatment and management of breast cancer.

Validation of an Automated Quantitative Digital Pathology Approach for Scoring TMEM, a Prognostic Biomarker for Metastasis

Metastasis causes ~90% of breast cancer mortality. However, standard prognostic tests based mostly on proliferation genes do not measure metastatic potential. Tumor MicroEnvironment of Metastasis (TMEM), an immunohistochemical biomarker for doorways on blood vessels that support tumor cell dissemination is prognostic for metastatic outcome in breast cancer patients. Studies quantifying TMEM doorways have involved manual scoring by pathologists utilizing static digital microscopy: a labor-intensive process unsuitable for use in clinical practice. We report here a validation study evaluating a new quantitative digital pathology (QDP) tool (TMEM-DP) for identification and quantification of TMEM doorways that closely mimics pathologists’ workflow and reduces pathologists’ variability to levels suitable for use in a clinical setting. Blinded to outcome, QDP was applied to a nested case-control study consisting of 259 matched case-control pairs. Sixty subjects of these were manually scored by five pathologists, digitally recorded using whole slide imaging (WSI), and then used for algorithm development and optimization. Validation was performed on the remainder of the cohort. TMEM-DP shows excellent reproducibility and concordance and reduces pathologist time from ~60 min to ~5 min per case. Concordance between manual scoring and TMEM-DP was found to be >0.79. These results show that TMEM-DP is capable of accurately identifying and scoring TMEM doorways (also known as MetaSite score) equivalent to pathologists.

Association between low estrogen receptor positive breast cancer and staining performance

Estrogen receptor (ER) expression in breast carcinomas, determined by immunohistochemistry, indicates statistically significant benefit to endocrine therapy in patients with tumors expressing ER in ≥1% of tumor cells. Rare cases with low ER expression (1-10%) lead to the dilemma of treating these tumors as ER positive or negative. We hypothesize that low ER positive result from poor staining performance and that we may detect this artefact by assessing the average dynamic range of normal ducts adjacent to low ER positive tumors. Using quantitative tools, we compare the dynamic range of normal background ER expression in patients with low (1-10%) ER tumors to dynamic range of ER expression in normal epithelium from control patient populations, to determine if low ER cases are accompanied by decreased dynamic range. Low ER cases were infrequent (1% of invasive breast carcinomas). Twenty-one cases with low ER staining and two control cohorts, including a tissue microarray (TMA) of 10 benign breast sections and a group of 34 control breast carcinomas (reported as ER negative or >10% ER positive) with normal background epithelium, were digitally scanned. QuPath was utilized to quantify ER staining for each cell as the mean optical density of nuclear DAB staining. The dynamic range of ER expression in normal epithelium surrounding low ER tumors was significantly lower (range 2-240, median 16.5) than that of the benign epithelium in the control tumors (range 3-475, median 30.8; p < 0.001) and benign TMA sections (range 38-212, median 114; p < 0.001) suggesting inconsistent stainer performance.

External quality assessment (EQA) program for the immunohistochemical detection of ER, PR and Ki-67 in breast cancer: results of an interlaboratory reproducibility ring study in China

Background

An External Quality Assessment (EQA) program was developed to investigate the status of estrogen receptor (ER), progesterone receptor (PR), and Ki-67 immunohistochemical (IHC) detection in breast cancer and to evaluate the reproducibility of staining and interpretation in 44 pathology laboratories in China.

Methods

This program was implemented through three specific steps. In study I, three revising centres defined the reference value for 11 sections. In study II, 41 participating centres (PC) stained and interpreted 11 sections by their own daily practice IHC protocols. In study III, all cases received second interpretation opinions.

Results

The stained slides of 44 laboratories were up to the interpretation standard. The overall interpretation concordance rate of this study was over 90%. A perfect agreement was reached among the PCs for the cases with ER+ and PR+ > 50% and Ki-67 > 30%, whereas a moderate agreement was observed for intermediate categories. After second interpretations, the misclassification rates for ER were reduced by 12.20%, for PR were reduced by 17.07%, and for Ki-67 were reduced by 4.88%. Up to 31 PCs observed a benefit from the second opinion strategy.

Conclusions

This project is the first EQA study performed on a national scale for assessment of ER, PR and Ki-67 status by IHC in China. In the whole IHC evaluation process, the intermediate categories were less reproducible than those with high expression rates. Second opinions can significantly improve the diagnostic agreement of pathologists’ interpretations.

Rabbit monoclonal E-cadherin antibody: A cost-effective alternative to mouse monoclonal antibody in distinguishing ductal carcinoma in situ from lobular carcinoma in situ

Rabbit monoclonal antibody (RabMAb) demonstrates higher sensitivity without sacrificing specificity than mouse monoclonal antibody (MMAb). MMAb against E-cadherin stain is heavily utilized in distinguishing ductal carcinoma in situ (DCIS) from lobular carcinoma in situ (LCIS). We aimed to compare the E-cadherin stain using RabMAb vs MMAb in distinguishing DCIS from LCIS. One hundred and seventeen in situ breast carcinomas (55 DCIS, 58 LCIS, and 4 DCIS and LCIS) were studied. Sections from a representative block of each were stained with RabMAb [EP700Y] and MMAb [36B5]. Scanned images of stained slides were compared in tandem. All DCIS cases (59/59) showed comparable staining by RabMAb and MMAb. Comparable staining was also observed in all but one case of LCIS (61/62; 98%). One case of pleomorphic LCIS showed mostly complete, weak to moderately intense membranous staining with RabMAb and fragmented, weak membranous staining with MMAb. Consistently better staining quality was observed in slides stained by RabMAb vs MMAb. RabMAb and MMAb against E-cadherin were diagnostically equivalent with the exception of one case where RabMAb may have led to diagnostic misinterpretation. However, the not insignificant cost savings and easier interpretation using RabMAb may justify the risk of misinterpretation of increased staining in rare cases, largely avertable with proper training.

Hormone- and HER2-receptor assessment in 33,046 breast cancer patients: a nationwide comparison of positivity rates between pathology laboratories in the Netherlands

Purpose

Patient management of invasive breast cancer (IBC) is to a large extent based on hormone- and HER2-receptor assessment. High-quality, reliable receptor assessment is of key importance as false results may lead to under- or overtreatment of patients. Surveillance of case-mix adjusted positivity rates has been suggested as a tool to identify laboratories with insufficient testing assays, as this covers the whole process of receptor assessment and enables laboratories to benchmark their positivity rates against other laboratories. We studied laboratory-specific variation in hormone- and HER2 positivity rates of 33,046 breast cancer patients using real-life nationwide data.

Methods

All synoptic pathology reports of IBC resection-specimens, obtained between 2013 and 2016, were retrieved from the nationwide Dutch pathology registry (PALGA). Absolute and case-mix adjusted receptor positivity rates were compared to the mean national proportion and presented in funnel plots in separate analyses for estrogen (ER), progesterone (PR) and HER2. Case-mix adjustment was performed by multivariable logistic regression.

Results

33,794 IBC lesions from 33,046 patients of 39 pathology laboratories were included. After case-mix adjustment, mean positivity rates were 87.2% for ER (range 80.4–94.3), 71.3% for PR (62.5–77.5%), and 9.9% for HER2 (5.5–12.7%). Overall, 14 (35.9%), 17 (43.6%) and 11 (28.2%) laboratories showed positivity rates outside the 95% confidence interval for ER, PR and HER2, respectively.

Conclusion

This nationwide study shows that absolute variation in hormone- and HER2-receptor positivity rates between Dutch pathology laboratories is limited. Yet, the considerable number of outlying laboratories shows that there is still need for improvement. Continuous monitoring and benchmarking of positivity rates may help to realize this.

Expression Patterns of Biomarkers in Primary Tumors and Corresponding Metastases in Breast Cancer

Tumor heterogeneity has been shown for several cancers including breast cancer (BC). Despite the fact that expression of tumor markers may change throughout the metastatic process, rebiopsies at the time of recurrence are still not performed routinely at all institutions. The aims of the study were to evaluate changes in biomarker profiles during the metastatic process and to investigate whether previous anthracycline or endocrine therapy given in the adjuvant setting could affect the biomarker profile in metastatic lesions. We investigated the expression pattern of ER, HER2, TOP2a, TOP1, p53, Bcl-2, and Ki-67 in 110 paired samples of primary BC and corresponding asynchronous metastases. We found discordant expressions in primary tumor and metastasis for all biomarkers, although only significant for Ki-67. Changes in the expression profile of the metastatic lesions would have altered treatment decisions in 14% of patients. We found no effect of previous anthracycline or endocrine therapy on the expression profiles. Our data confirm that discordant expressions of biomarkers are common in BC and often carry therapeutic consequences. This emphasizes the need for biopsies from metastatic lesions, even in cases where the localization of the metastatic process is not easily accessible.

Improving accuracy of breast cancer biomarker testing in India

There is a global mandate even in countries with low resources to improve the accuracy of testing biomarkers in breast cancer viz. oestrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2neu) given their critical impact in the management of patients. The steps taken include compulsory participation in an external quality assurance (EQA) programme, centralized testing, and regular performance audits for laboratories. This review addresses the status of ER/PR and HER2neu testing in India and possible reasons for the delay in development of guidelines and mandate for testing in the country. The chief cause of erroneous ER and PR testing in India continues to be easily correctable issues such as fixation and antigen retrieval, while for HER2neu testing, it is the use of low-cost non-validated antibodies and interpretative errors. These deficiencies can however, be rectified by (i) distributing the accountability and responsibility to surgeons and oncologist, (ii) certification of centres for testing in oncology, and (iii) initiation of a national EQA system (EQAS) programme that will help with economical solutions and identifying the centres of excellence and instill a system for reprimand of poorly performing laboratories.

Immunohistochemical Performance of Estrogen and Progesterone Receptor Antibodies on the Dako Omnis Staining Platform: Evaluation in Multicenter Studies

The analysis of estrogen receptor (ER) and progesterone receptor (PR) expression levels by immunohistochemistry is an important part of the initial evaluation of breast cancer and critically important in treatment planning. Anti-ERα (clone EP1) and anti-PR (clone PgR 1294) antibodies are in development for the Dako Omnis automated staining platform. These antibodies are not yet commercially available and are in performance evaluation, including the 4 international, multicenter studies reported here. For each antibody, a reproducibility study and a method comparison study was done in a randomized manner in order to test the antibodies under conditions closest to real-world user conditions. The reproducibility studies included 5 staining runs on the Dako Omnis with 20 formalin-fixed and paraffin-embedded human breast carcinoma specimens in 3 independent laboratories, and the method comparison studies included several hundred specimens stained on the Dako Omnis and on the Autostainer Link 48 platforms. Stained slides were evaluated for nuclear ER or PR expression according to American Society of Clinical Oncology/College of American Pathologists guidelines (≥1% cut-off for positive) by pathologists who were blinded from the staining method and specimen ID. For both anti-ERα (clone EP1) and anti-PR (clone PgR 1294) on the Dako Omnis, high reproducibility agreement rates were obtained on the interrun, interlaboratory, and interobserver endpoints. High concordance rates were observed between the specimens stained on the Dako Omnis platform and the Autostainer Link 48 platform. Staining quality was excellent for both anti-ERα (clone EP1) and anti-PR (clone PgR 1294) on the Dako Omnis. These results suggest that these antibodies are reliable and reproducible tools for immunohistochemistry analysis of ER and PR expression levels in formalin-fixed and paraffin-embedded breast carcinoma tissues on the Dako Omnis platform.

Estrogen and progesterone receptors in breast cancer

Breast cancer is the most common cancer in women worldwide. The majority of breast cancers show overexpression of estrogen receptors (ERs) and progesterone receptors (PRs). The development of drugs to target these hormone receptors, such as tamoxifen, has brought about significant improvement in survival for women with hormone receptor-positive breast cancers. Since information about ER and PR is vital for patient management, quality assurance is important to ensure accurate testing. In recent guidelines, the recommended definition of ER and PR positivity is 1% or more of cells that stain positive. Semiquantitative assessment of ER and PR is important for prognosis and, hence, management. Even with the development of genomic tests, hormone receptor status remains the most significant predictive and prognostic biomarker.

Quality assessment of estrogen receptor and progesterone receptor testing in breast cancer using a tissue microarray-based approach

Assessing hormone receptor status is an essential part of the breast cancer diagnosis, as this biomarker greatly predicts response to hormonal treatment strategies. As such, hormone receptor testing laboratories are strongly encouraged to participate in external quality control schemes to achieve optimization of their immunohistochemical assays. Nine Dutch pathology departments provided tissue blocks containing invasive breast cancers which were all previously tested for estrogen receptor and/or progesterone receptor expression during routine practice. From these tissue blocks, tissue microarrays were constructed and tested for hormone receptor expression. When a discordant result was found between the local and TMA result, the original testing slide was revised and staining was repeated on a whole-tissue block. Sensitivity and specificity of individual laboratories for testing estrogen receptor expression were high, with an overall sensitivity of 99.7 and 95.4 %, respectively. Overall sensitivity and specificity of progesterone receptor testing were 94.8 and 92.6 %, respectively. Out of 96 discordant cases, 36 cases would have been concordant if the recommended cut-off value of 1 % instead of 10 % was followed. Overall sensitivity and specificity of estrogen and progesterone receptor testing were high among participating laboratories. Continued enrollment of laboratories into quality control schemes is essential for achieving and maintaining the highest standard of care for breast cancer patients.

Evaluation of grading and hormone receptor immunostaining on fine needle aspirates in carcinoma breast

Background:

Grading and hormone receptor determination in breast carcinoma are predictive factors for response to hormonal therapy.

Aim:

This study was undertaken to grade breast carcinoma and to determine estrogen receptor (ER) and progesterone receptor (PR) expression on fine-needle aspiration cytology (FNAC). Furthermore, the objective was to compare the results with histological grading and immunohistochemistry on surgical material.

Materials and Methods:

Fifty cases of breast carcinoma diagnosed on FNAC were included. The cytological grading was done according to the Robinson's grading system. The corresponding histology sections were graded using the modified Bloom-Richardson system. Immunostaining for ER and PR was done on smears and tissue sections.

Results:

On both cytological and histological evaluation, 49 cases were infiltrating ductal carcinoma and one case was colloid carcinoma. On comparing cytological and histological grading, 78% were correctly graded on cytology. The sensitivity, specificity, positive predictive value and negative predictive value for ER detection on immunocytochemistry (ICC) were 55.6%, 95%, 93.8% and 61.3%, respectively. The sensitivity, specificity, positive and negative predictive value for PR detection on ICC were 57.7%, 95.2%, 93.8% and 64.5%, respectively. The correlation for ER and PR between cytology and histology was 72.3% and 74.5%.

Conclusion:

The grading along with ER and PR immunostaining of breast carcinoma on smears is advocated because of high concordance between cytology and histology. This allows the patient to be treated with hormonal therapy on the basis of FNAC alone.

The effect of freezing on the immunoprofile of breast carcinoma cells

BACKGROUND

Intraoperative frozen section procedure may be required in some operations performed for breast masses.

AIMS

We investigated the effect of frozen section procedure on the immunoprofile of breast carcinoma cells.

STUDY DESIGN

Cross-sectional study.

METHODS

A total of 53 breast carcinoma cases evaluated with intraoperative frozen sections were included in this study. Immunohistochemically, oestrogen (ER), progesterone (PR) and HER2 primary antibodies were evaluated in both frozen and non-frozen sections of each tumour sample.

RESULTS

No difference was found between the frozen and non-frozen sections in 33 cases in terms of staining rate and intensity of ER, PR and HER2. A decrease was found in the ER, PR and HER2 staining rate (in 10 cases, 9 cases and 6 cases, respectively). Likewise, a decrease was detected in ER, PR and HER2 staining intensity in 6 patients for each. Although there was no staining in frozen sections, immunopositivity was observed in 3 non-frozen sections for ER, in 2 for PR and in 5 for HER2. Statistically, a significant difference was found between the frozen and non-frozen sections in terms of staining rate and intensity for each of the three markers.

CONCLUSION

In this study, the frozen section procedure in breast carcinoma had a negative effect on the immunoprofile. However, considering the importance of hormone receptor status in the treatment, these results should be supported with larger series.

Dynamic classification using case-specific training cohorts outperforms static gene expression signatures in breast cancer

The molecular diversity of breast cancer makes it impossible to identify prognostic markers that are applicable to all breast cancers. To overcome limitations of previous multigene prognostic classifiers, we propose a new dynamic predictor: instead of using a single universal training cohort and an identical list of informative genes to predict the prognosis of new cases, a case-specific predictor is developed for each test case. Gene expression data from 3,534 breast cancers with clinical annotation including relapse-free survival is analyzed. For each test case, we select a case-specific training subset including only molecularly similar cases and a case-specific predictor is generated. This method yields different training sets and different predictors for each new patient. The model performance was assessed in leave-one-out validation and also in 325 independent cases. Prognostic discrimination was high for all cases (n = 3,534, HR = 3.68, p = 1.67 E-56). The dynamic predictor showed higher overall accuracy (0.68) than genomic surrogates for Oncotype DX (0.64), Genomic Grade Index (0.61) or MammaPrint (0.47). The dynamic predictor was also effective in triple-negative cancers (n = 427, HR = 3.08, p = 0.0093) where the above classifiers all failed. Validation in independent patients yielded similar classification power (HR = 3.57). The dynamic classifier is available online at http://www.recurrenceonline.com/?q=Re_training. In summary, we developed a new method to make personalized prognostic prediction using case-specific training cohorts. The dynamic predictors outperform static models developed from single historical training cohorts and they also predict well in triple-negative cancers.

Is the differentiation into molecular subtypes of breast cancer important for staging, local and systemic therapy, and follow up?

Breast cancer complexity has long been known and investigated. After a first classification of the disease based on histology features, starting from the 1980s breast cancers have been distinguished on the basis of oestrogen receptor expression and later according to HER2. By 2000 the "microarray revolution" had shown that the phenotypic differences between breast cancers were a reflection of their mRNA expression profiles, while the more recent "genomic revolution" is revealing the genomic bases of breast cancer heterogeneity. However, how this huge amount of data and knowledge translate into clinically relevant practice is currently not clear. In the present review we discuss how the different breast cancer classification methods might translate into improved clinical guidelines with regard to staging, therapy, and follow up of patients with breast cancer.

Digital pathology and image analysis in tissue biomarker research

Digital pathology and the adoption of image analysis have grown rapidly in the last few years. This is largely due to the implementation of whole slide scanning, advances in software and computer processing capacity and the increasing importance of tissue-based research for biomarker discovery and stratified medicine. This review sets out the key application areas for digital pathology and image analysis, with a particular focus on research and biomarker discovery. A variety of image analysis applications are reviewed including nuclear morphometry and tissue architecture analysis, but with emphasis on immunohistochemistry and fluorescence analysis of tissue biomarkers. Digital pathology and image analysis have important roles across the drug/companion diagnostic development pipeline including biobanking, molecular pathology, tissue microarray analysis, molecular profiling of tissue and these important developments are reviewed. Underpinning all of these important developments is the need for high quality tissue samples and the impact of pre-analytical variables on tissue research is discussed. This requirement is combined with practical advice on setting up and running a digital pathology laboratory. Finally, we discuss the need to integrate digital image analysis data with epidemiological, clinical and genomic data in order to fully understand the relationship between genotype and phenotype and to drive discovery and the delivery of personalized medicine.

Discordance in hormone receptor status among primary, metastatic, and second primary breast cancers: biological difference or misclassification?

INTRODUCTION

Discordance in hormone receptor status has been observed between two breast tumors of the same patients; however, the degree of heterogeneity is debatable with regard to whether it reflects true biological difference or the limited accuracy of receptor assays.

METHODS

A Bayesian misclassification correction method was applied to data on hormone receptor status of two primary breast cancers from the Surveillance, Epidemiology, and End Results database between 1990 and 2010 and to data on primary breast cancer and paired recurrent/metastatic disease assembled from a meta-analysis of the literature published between 1979 and 2014.

RESULTS

The sensitivity and specificity of the estrogen receptor (ER) assay were estimated to be 0.971 and 0.920, respectively. After correcting for misclassification, the discordance in ER between two primary breast cancers was estimated to be 1.2% for synchronous ipsilateral pairs, 5.0% for synchronous contralateral pairs, 14.6% for metachronous ipsilateral pairs, and 25.0% for metachronous contralateral pairs. Technical misclassification accounted for 53%-83% of the ER discordance between synchronous primary cancers and 11%-25% of the ER discordance between metachronous cancers. The corrected discordance in ER between primary tumors and recurrent or metastatic lesions was 12.4%, and there were more positive-to-negative changes (10.1%) than negative-to-positive changes (2.3%). Similar patterns were observed for progesterone receptor (PR), although the overall discordance in PR was higher.

CONCLUSION

A considerable proportion of discordance in hormone receptor status can be attributed to misclassification in receptor assessment, although the accuracy of receptor assays was excellent. Biopsy of recurrent tumors for receptor retesting should be conducted after considering feasibility, cost, and previous ER/PR status.

Improving Pathological Assessment of Breast Cancer by Employing Array-Based Transcriptome Analysis

Breast cancer research has paved the way of personalized oncology with the introduction of hormonal therapy and the measurement of estrogen receptor as the first widely accepted clinical biomarker. The expression of another receptor—HER2/ERBB2/neu—was initially a sign of worse prognosis, but targeted therapy has granted improved outcome for these patients so that today HER2 positive patients have better prognosis than HER2 negative patients. Later, the introduction of multigene assays provided the pathologists with an unbiased assessment of the tumors’ molecular fingerprint. The recent FDA approval of complete microarray pipelines has opened new possibilities for the objective classification of breast cancer samples. Here we review the applications of microarrays for determining ER and HER2 status, molecular subtypes as well as predicting prognosis and grade for breast cancer patients. An open question remains the role of single genes within such signatures. Openly available microarray datasets enable the execution of an independent cross-validation of new marker and signature candidates. In summary, we review the current state regarding clinical applications of microarrays in breast cancer molecular pathology.

Clinical relevance of the reappraisal of negative hormone receptor expression in breast cancer

Background

Accurate assessment of estrogen (ER) and progesterone (PR) receptors is critical in predicting the response to endocrine therapies in breast cancer.

Material and methods

From a series of 360 patients with breast invasive carcinoma assessed for hormone receptors by immunohistochemistry (IHC) in the 90’s, we re-analysed, on the same tumour material, the cases considered negative (n = 164), i.e., ER-/PR- (n = 95), ER+/PR- (n = 63) and ER-/PR+ (n=6), and 16 of 196 ER+/PR+ tumours with unfavourable outcome. Concordance between the previous IHC (Streptavidin-Biotin-Peroxidase) method and the current one (Peroxidase-Indirect-Polymer) was determined by the McNemar’s test. Relapse-free (RFS) and overall survival (OS) were estimated by the Kaplan-Meier method.

Results

From 101 ER- and 158 PR- cases, 38 (37.6%) and 58 (36.7%) became positive, increasing ER and PR expression from 71.9% and 56.1% to 82.5% and 72.2%, respectively (P<0.001). All 16 ER+/PR+ cases maintained their co-positivity, while all ER-/PR+ tumours changed to ER positive. Kaplan-Meier survival curves showed significant differences related to RFS and OS for PR, either in the whole series or in the subset (n = 151) submitted to hormonal treatment. The patients’ subgroup with ER+/PR- tumours exhibited the worst prognosis.

Conclusion

The current IHC method improves the clinical usefulness of ER/PR assessment by decreasing the rate of false negative results.

Changes in the expression of MMP2, MMP9, and ColIV in stromal cells in oral squamous tongue cell carcinoma: relationships and prognostic implications

BACKGROUND

Type IV collagen (ColIV) is the most important scaffold for the basement membrane (BM) proteins, and plays an important role in regulating and limiting tumour invasion and metastasis.

METHODS

Here, we observed the changes in morphology and distribution of type IV collagen (ColIV) in the basement membrane (BM) surrounding nests of carcinoma in 48 patients with oral tongue squamous cell (OTSCC). We examined the correlation between the expressions of ColIV, MMP-2 and MMP-9 and the prognosis of OTSCC patients. The intensity and patterns of expression were assessed immunohistochemically using anti-human mouse monoclonal MMP-2, MMP-9 and Col IV antibodies. Statistical analyses were performed to determine the prognostic correlations of ColIV, MMP-2, and MMP-9 levels.

RESULTS

MMP-2 and MMP-9 expressions in OTSCC were higher than those in normal oral mucosa and dysplastic oral mucosa group(MMP-2 iOD: 66.40 ± 24.20, 134.69 ± 37.08, and 357.79 ± 116.78; MMP-9 iOD: 88.05 ± 23.85, 307.13 ± 93.22, and 791.31 ± 260.52; in normal, dysplastic oral mucosa, and tumour tissues, respectively, P < 0.01); however, ColIV immunoreactivity was lower (ColIV iOD: 406.87 ± 62.95, 247.83 ± 42.30, and 151.92 ± 38.17 in normal, dysplastic oral mucosa, and tumour tissues, respectively, P < 0.01). High tumour and stromal MMP-2 and MMP-9 expression was significantly associated with positive lymph node status. Col IV expression was associated with positive lymph node status (P < 0.05), and have negatively correlated with the expression of MMP-2 and MMP-9. Overall survival was significantly shorter in patients with high tumour and stromal MMP-2 and MMP-9 expression, and tended to be shorter in patients with low ColIV expression.

CONCLUSIONS

Degradation of ColIV was closely related to increased MMP-2 and MMP-9 expression; MMP-9 have more important function than MMP-2 during the cancer development. Monitoring changes in the expression of ColIV, MMP-2, and MMP-9 may be a useful technique for assessing prognoses in OTSCC patients.

Tailoring therapy for locally advanced breast cancer using molecular profiles: are we there yet?

The term 'locally advanced breast cancer' covers a range of clinical scenarios, and has the implications that surgical clearance and local control will be difficult or impossible, and long-term survival rates will be poor. Treatment selection is particularly important in this group of patients to try to obtain maximum control of disease, and potentially improve surgical options and cure rates. Currently, assessment of estrogen receptor, progesterone receptor and human epidermal receptor 2 status in tumour samples remains the gold standard for prediction of response to endocrine therapy, chemotherapy or targeted agents such as trastuzumab. Progress has been made in identifying markers that can help select treatments likely to be associated with response and avoid those associated with resistance. These potential markers include Ki67 proliferation rate, cytochrome P450 (CYP) 2D6 expression, BRCA1/2 gene status and others.

Impact of low estrogen/progesterone receptor expression on survival outcomes in breast cancers previously classified as triple negative breast cancers

PURPOSE

To evaluate the impact of low estrogen/progesterone receptor (ER/PR) expression and effect of endocrine therapy on survival outcomes in human epidermal growth factor receptor 2 (HER2)-negative tumors with ER/PR <10%, previously labeled as triple negative.

METHODS

In a retrospective review, 1257 patients were categorized according their ER/PR percentages into 3 groups, ER/PR <1% (group A), ER/PR 1% to 5% (group B), and ER/PR 6% to 10% (group C). Kaplan-Meier product limit method was used to estimate survival outcomes. Cox proportional hazards models was used to adjust for patient and tumor characteristics.

RESULTS

Groups A, B, and C had 897 (71.4%), 241 (19.2%), and 119 (9.4%) patients, respectively. After a median follow-up of 40 months there was no significant difference in 3-year recurrence-free survival (RFS): 64%, 67%, and 77% (P = .34) or overall survival (OS): 79%, 81%, and 88% (P = .33) for groups A, B, and C, respectively. ER/PR expression was not an independent predictor for RFS (hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.86-1.39; P = .46 for group B, and HR, 0.96; 95% CI, 0.66-1.38; P = .81 for group C, compared with group A), or OS (HR, 1.11; 95% CI, 0.84-1.46; P = .46 for group B, and HR, 0.94; 95% CI, 0.63-1.42; P = .78 for group C, compared with group A). Endocrine therapy had no impact on survival outcomes (RFS: P = .10; OS: P = .45) among groups.

CONCLUSIONS

In this cohort, a low ER/PR level (1%-5%) does not appear to have any significant impact on survival outcomes. There was a tendency for survival advantages in the ER/PR 6% to 10% is seen. Benefit of endocrine therapy in these patients is unclear.

Standardization of epidermal growth factor receptor (EGFR) measurement by quantitative immunofluorescence and impact on antibody-based mutation detection in non-small cell lung cancer

Challenges in measurement of epidermal growth factor receptor (EGFR) protein expression have led to conflicting data on its prognostic value and discontinuation of its use for prediction of response. Herein is described a quantitative standardized assay for EGFR and its use in a series of retrospective cohorts of patients with non-small cell lung cancer (NSCLC). The AQUA technology of quantitative immunofluorescence was used in conjunction with Western blot analysis to calculate the absolute concentration of EGFR in two independent NSCLC cohorts (170 from Yale New Haven Hospital and 335 from Sotiria and Patras Hospitals in Greece). EGFR and mutated EGFR were measured using D38B1 antibody and two mutation-specific antibodies. All patients positive or borderline for mutation-specific antibody were genotyped. A threshold for reproducible detection of EGFR was defined as 0.85 ng/μg total protein. EGFR expression demonstrated no prognostic value in either cohort. The mutation rate was 1.79% in the Yale cohort, and 1.52% in the Sotiria/Patras cohort, with no antibody detection-based false-positive cases. No mutations were detected for EGFR concentrations <1.46 ng/μg total protein. In summary, accurate measurement of EGFR still shows no prognostic value in NSCLC. In these two population-based cohorts, the antibody-based EGFR mutation rate was lower than has been frequently reported.

Estrogen Receptor Negative Breast Cancer in India: Do We Really Have Higher Burden of this Subtype?

ER negative and Triple negative breast cancers carry a poorer prognosis and are not amenable to hormone therapy. It has been previously observed that Indian patients with breast cancer have a higher tendency to have these tumours. Whether this is due to inherent biological differences in the tumours of our patients is a matter of much debate. We have analysed 250 patients of breast cancer for hormone receptor status, compared them with western series, and attempted to support the hypothesis that the higher ER negativity and triple negativity is indeed due to different tumour biology.

The effect of delay in fixation, different fixatives, and duration of fixation in estrogen and progesterone receptor results in breast carcinoma

Accurate determination of estrogen receptor (ER) and progesterone receptor (PR) status in breast carcinoma is essential. Preanalytic variation may contribute to discordant results. Recently, American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) made recommendations to normalize fixation for breast biomarkers. To evaluate this, a 4-cm invasive lobular carcinoma was processed according to ASCO/CAP guidelines. The remainder was stored fresh at 4°C for 4 days and cut into biopsy-sized pieces. Each was fixed in 10% formalin, Pen-Fix (Richard-Allan Scientific, Kalamazoo, MI), Bouin solution, Sakura Molecular Fixative (Sakura Tissue-Tek Xpress, Torrance, CA), zinc formalin, or 15% formaldehyde for times ranging between 1 and 168 hours. Immunohistochemical studies for ER and PR were performed and interpreted. After 4 days at 4°C, all samples showed no degradation or ER/PR staining differences, except 2 Bouin-fixed samples, in comparison with the patient's sample processed according to ASCO/CAP guidelines. In our study, the preanalytic variables of fixative type, fixation time, and 4 days of ischemic time did not affect immunohistochemical accuracy for ER/PR.

EpCAM expression in primary tumour tissues and metastases: an immunohistochemical analysis

Aims

Epithelial cell adhesion molecule (EpCAM) is a cell surface protein with oncogenic features that is expressed on healthy human epithelia and corresponding malignant tumours. EpCAM expression frequently correlates with more aggressive tumour behaviour and new EpCAM-specific therapeutic agents have recently been approved for clinical use in patients with cancer. However, no consensus exists on how and when to evaluate EpCAM expression in patients with cancer.

Material and methods

EpCAM expression was assessed by a well-established immunohistochemical staining protocol in 2291 primary tumour tissues and in 108 metastases using the EpCAM-specific antibody clone VU1D9. A total immunostaining score was calculated as the product of a proportion score and an intensity score. Four expression subgroups (no, weak, moderate and intense) were defined. As described previously, the term ‘EpCAM overexpression’ was reserved for tissues showing a total immunostaining score >4.

Results

EpCAM was highly expressed in most tumours of gastrointestinal origin and in some carcinomas of the genitourinary tract. However, hepatocellular carcinomas, clear cell renal cell cancer, urothelial cancer and squamous cell cancers were frequently EpCAM negative. EpCAM expression in breast cancer depended on the histological subtype; lobular histology usually showed no or weak expression. Most metastases were EpCAM positive and they frequently reflected the expression phenotype of the primary tumour.

Conclusion

EpCAM expression was detected on adenocarcinomas of various primary sites. If EpCAM-specific antibodies are intended to be used in patients with cancer, we recommend prior immunohistochemical evaluation of EpCAM expression, particularly in patients with renal cell cancer, hepatocellular carcinoma, urothelial carcinoma, breast cancer and squamous cell carcinomas.

Standardization in immunohistology

The rapid acceptance of immunohistology as an invaluable adjunct to morphologic diagnosis has been possible because of the development of new and more sensitive antibodies and detection systems that allow its application to formalin-fixed, paraffin-embedded tissue (FFPT). More importantly, antigen-retrieval techniques have resulted in some degree of consistency allowing immunohistology to be used reliably as a diagnostic tool. The advent of prognostic and predictive biomarkers, and the desire for individualized therapy has resulted in mounting pressure to employ the immunohistological assay in a quantitative manner. While it was not a major issue when the technique was employed in a qualitative manner, the numerous variables in the preanalytical and analytical phases of the test procedure that influence the immunoexpression of proteins in FFPT become critical to standardization. Tissue fixation is pivotal to antigen preservation but exposure to fixative prior to accessioning by the laboratory is not controlled. Antigen retrieval, crucial in the analytical phase, continues to be employed in an empirical manner with the actual mechanism of action remaining elusive. There is great variation in reagents, methodology, and duration of tissue processing and immunostaining procedure, and the detection systems employed are not standardized between laboratories. While many of these variables are offset by the application of antigen retrieval, which enables the detection of a wide range of antigens in FFPT, the method itself is not standardized. This myriad of variables makes it inappropriate to provide meaningful comparisons of results obtained in different laboratories and even in the same laboratory, as in current practice, each specimen experiences different preanalytical variables. Furthermore, variables in interpretation exist and cutoff thresholds for positivity differ. Failure to recognize false-positive and false-negative stains leads to further errors of quantitative measurement. Many of the problems relating to the technology and interpretation of immunostaining originate from failure to recognize that this procedure is different from other histological stains and involves many more steps that cannot be monitored until the end result is attained. While several remedial measures can be suggested to address some of these problems, accurate and reproducible quantitative assessment of immunostains presently remains elusive as important variables that impact on antigen preservation in the paraffin-embedded biopsy -cannot be standardized.

Estrogen and progesterone receptor testing in breast carcinoma: concordance of results between local and reference laboratories in Brazil

CONTEXT AND OBJECTIVE

Breast cancer accounts for approximately one quarter of all cancers in females. Estrogen and progesterone receptor testing has become an essential part of the clinical evaluation of breast carcinoma patients, and accurate results are critical in identifying patients who may benefit from hormone therapy. The present study had the aim of investigating the concordance of the results from hormone receptor tests between a reference laboratory and local (or community) laboratories in Brazil.

DESIGN AND SETTING

Retrospective study at a reference pathology laboratory.

METHODS

The concordance in the results from hormone receptor tests between a reference laboratory and 146 local laboratories in Brazil was compared in relation to 500 invasive breast carcinoma cases, using immunohistochemistry.

RESULTS

There was concordance in 89.4% (447/500 cases) and 85.0% (425/500 cases) of the results from estrogen (κ = 0.744, P < 0.001) and progesterone (κ = 0.688, P < 0.001) receptor tests, respectively, between local and reference laboratories. This was similar to findings in other countries. The false negative rates from estrogen and progesterone receptor tests in local laboratories were 8.7% and 14.4%, respectively. The false positive rates from estrogen and progesterone receptor tests in local laboratories were 15.5% and 16.0%, respectively.

CONCLUSION

Technical and result interpretation issues may explain most of the discordances in hormone receptor testing in local laboratories. Validation of estrogen and progesterone receptor tests at local laboratories, with rigorous quality control measures, is strongly recommended in order to avoid erroneous treatment of breast cancer patients.

Estrogen and HER-2 receptor discordance between primary breast cancer and metastasis

Discordance in estrogen receptor and human epidermal growth factor receptor 2 receptor status between the primary tumor and recurrence is frequently reported in the literature. This is frequently interpreted as evidence for a change in the biology of breast cancer during the course of the disease. This commentary discusses some of the caveats of this interpretation. Discordant receptor results can be caused by any of 3 factors: (a) a genuine switch in the biology of the disease, (b) sampling error in focally receptor-positive cancers, and (c) limited accuracy and reproducibility of receptor assays. The relative contribution of each of these factors to discordant results is unknown. A switch in molecular class between primary and recurrent cancer (or residual cancer after therapy) appears to be a rare event based on the available limited molecular profiling data. Small pockets of strongly focally receptor-positive tumor nests in a larger receptor-negative cancer are also relatively infrequently seen. Discordance resulting from inherent limitations in assay reproducibility is evident from the frequently discordant receptor results even when the same samples are assessed in different laboratories (e.g., central versus local laboratory). A repeat tumor biopsy is clearly justified when it is suspected, on clinical grounds, that the original receptor results may have been false negative or when the diagnosis of metastatic disease is in question. However, routine repeat biopsy for receptor re-evaluation does not necessarily improve diagnostic accuracy and have a potential to harm through a false-negative result. For patients with clinical courses consistent with hormone responsiveness, or with prior positive hormone receptor results, a course of endocrine therapy is reasonable regardless of the most recent hormone receptor assay result.

The reliability of rabbit monoclonal antibodies in the immunohistochemical assessment of estrogen receptors, progesterone receptors, and HER2 in human breast carcinomas

The reliability of the rabbit monoclonal antibodies SP1, SP2, SP3, and 4B5 was immunohistochemically assessed on a range of 96 invasive breast carcinomas and the results compared with those achieved with established antibody markers for estrogen receptors (6F11), progesterone receptors (PgR636), and HER2 (polyclonal A0485 and clone CB11), with HER2 status validated by fluorescence in situ hybridization (FISH) and silver in situ hybridization. Optimal results depended on the duration of microwave antigen-retrieval time and the use of a high pH buffer for rabbit and mouse estrogen receptor antibodies (SP1 and 6F11), although only on antigen-retrieval duration for the progesterone receptors SP2 and PgR636. The highest rate of concordance between HER2 overexpression and HER2 gene amplification was with the rabbit monoclonal antibodies (SP3 and 4B5) and FISH. Rabbit monoclonal antibodies are reliable alternatives to established antibody markers for the immunohistochemical testing of estrogen receptors, progesterone receptors, and HER2 in breast cancer.

Recommendations for validating estrogen and progesterone receptor immunohistochemistry assays

CONTEXT

Estrogen receptor and progesterone receptor status is assessed on all newly diagnosed, invasive breast carcinomas and in recurrences to determine patient eligibility for hormonal therapy, but 10% to 20% of estrogen receptor and progesterone receptor test results are discordant when tested in multiple laboratories.

OBJECTIVE

To define the analytic (technical) validation requirements for estrogen receptor and progesterone receptor immunohistochemistry assays used to select patients for hormonal therapy.

DATA SOURCES

Literature review and expert consensus.

CONCLUSIONS

A standardized process for initial test validation is described. We believe adoption of this process will improve the accuracy of hormone-receptor testing, reduce interlaboratory variation, and minimize false-positive and false-negative results. Required ongoing assay assessment procedures are also described.

Issues and updates: evaluating estrogen receptor-alpha, progesterone receptor, and HER2 in breast cancer

There are currently three prognostic/predictive biomarkers used in routine clinical management of patients with breast cancer, and their assessment is mandatory. They include estrogen receptor-alpha (ERalpha), progesterone receptor (PgR), and the HER2 oncogene/oncoprotein. This paper briefly reviews the assessment of ERalpha, PgR, and HER2 in breast cancer, emphasizing recent progress and persistent controversies.

Analytic variability in immunohistochemistry biomarker studies

BACKGROUND

Despite the widespread use of immunohistochemistry (IHC), there are no standardization guidelines that control for antibody probe variability. Here we describe the effect of variable antibody reagents in the assessment of cancer-related biomarkers by IHC.

METHODS

Estrogen receptor (ER), epidermal growth factor receptor (EGFR) 1, and human epidermal growth factor receptor 3 (HER3) were evaluated by quantitative immunofluorescence. Correlations between ER clones 1D5, SP1, F10, and ER60c, and EGFR monoclonal 31G7, 2-18C9, H11, and 15F8, and polyclonal 2232 antibodies were assessed in 642 breast cancer patients. HER3 was measured by RTJ1, RTJ2, SGP1, M7297, RB-9211, and C-17 antibodies in 42 lung cancer patients. Survival analysis was done with the use of multiple cutoff points to reveal any prognostic classification.

RESULTS

All ER antibodies were tightly correlated (Pearson's r(2) = 0.94-0.96; P < 0.0001) and western blotting confirmed their specificity in MCF-7 and BT474 cells. All EGFR antibodies but 2232 yielded specific results in western blotting; however, only 31G7 and 2-18C9 were strongly associated (Pearson's r(2) = 0.61; P < 0.0001). HER3 staining was nonspecific and nonreproducible. High EGFR-expressing patients had a worse prognosis when EGFR was measured with H11 or 31G7 (log rank P = 0.015 and P = 0.06). There was no statistically significant correlation between survival and EGFR detected by 2-18C9, 15F8, or polyclonal 2232 antibodies.

CONCLUSIONS

Antibody validation is a critical analytic factor that regulates IHC readings in biomarker studies. Evaluation of IHC proficiency and quality control are key components toward IHC standardization.

IMPACT

This work highlights the importance of IHC standardization and could result in the improvement of clinically relevant IHC protocols.