Reliability of immunohistochemical demonstration of oestrogen receptors in routine practice: interlaboratory variance in the sensitivity of detection and evaluation of scoring systems

Correlation between NDRG1 and PTEN expression in endometrial carcinoma

N-myc Downstream-Regulated Gene 1 (NDRG1) is known as a differentiation-related gene that plays important roles in cell differentiation, organ formation, and embryonic development. NDRG1 has recently been shown to be associated with carcinogenesis and tumor progression in a wide variety of tumors. Phosphatase and tensin homolog deleted from chromosome (PTEN), a phosphatase and tensin homolog located on chromosome 10, is shown to be a tumor suppressor and is often mutated or deleted in various tumor cells, particularly in endometrial carcinoma. Using an immunohistochemical approach, we investigated the expression of NDRG1 and PTEN in normal endometrium, atypical hyperplasia, and endometrial carcinoma. All tumor tissues harvested in this study were derived from endometrioid carcinoma Type I, that were estrogen-related. Our results demonstrate that the expression of NDRG1 was up-regulated in 5/40 (12.5%), 18/34 (52.94%), and 86/103 (83.5%) normal endometrium, atypical hyperplasia, and endometrial carcinoma cases, respectively (P < 0.01), while in 6/40 (15%), 20/34 (58.82%), and 89/103 (86.41%) normal endometrium, atypical hyperplasia, and endometrial carcinoma cases, respectively. PTEN expression was significantly decreased (P < 0.01). Statistical analyzes demonstrated a positive correlation between NDRG1 up-regulation and PTEN down-regulation (P < 0.01). The expression of NDRG1 had no correlation with the differentiation degree of the tumor cells, lymph-node metastasis, and/or abdominal cavity implantation (P > 0.05). Our results indicated that development of endometrial carcinoma is associated with an overexpression of NDRG1 and the loss of PTEN expression. Identification of changes in the NDRG1 and PTEN expression may be a significant diagnostic tool for the early detection of endometrial carcinoma.

Evaluation of oestrogen receptor expression in breast cancer by quantification of mRNA

AIMS

cDNA microarrays have subclassified breast carcinomas into molecular subtypes with oestrogen receptor-alpha (ER) gene expression as a main marker. The aim was to compare ER expression in 97 patients with operable breast cancer estimated by real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) and by routine immunohistochemistry, and to determine which method was reliable for molecular subtyping in relation to basal-type keratins and HER2 gene expression.

METHODS AND RESULTS

Frozen tumour samples were analysed by real-time RT-PCR for the expression of ER, HER2, keratin 5 and keratin 17 genes. In a group of 27 tumours with a low level of ER mRNA (<1.00), there were eight ER+ cases as assessed by immunohistochemistry, and of 70 cases with a high level of ER mRNA (>or=1.00), 26 were ER- by immunohistochemistry (P = 0.003). Lack of prognostic relevance of ER mRNA level was demonstrated, whereas assessment by immunohistochemistry was related to clinical outcome. Expression of basal keratins and HER2 genes differed significantly between ER+ and ER- tumours based on immunohistochemistry, but not on mRNA level.

CONCLUSIONS

These results throw doubt on the assessment of ER mRNA as a key factor in the molecular distinction between breast tumours.

Is metalloproteinase-7 specific for idiopathic pulmonary fibrosis?

BACKGROUND

Matrix metalloproteinase (MMP)-7 was reported to be a key molecule in the pathogenesis of idiopathic pulmonary fibrosis (IPF) based on the result of microarray analysis and knockout mice. However, the role of MMP-7 has not been determined in other types of idiopathic interstitial pneumonia (IIP). The aim of this study was to investigate the role of MMP-7 in IIP by comparing its expression in usual interstitial pneumonia (UIP) and cryptogenic organizing pneumonia (COP).

METHODS

Levels of MMP and tissue inhibitors of metalloproteinase in BAL fluid and their expression on lung tissues were compared between normal control subjects (n = 5) and the patients with IPF (n = 6) and COP (n = 11).

RESULTS

There was no significant difference in BAL fluid MMP-7 levels between UIP and COP, although it was higher in both diseases compared to normal control subjects. Furthermore, the pattern and the degree of MMP-7 expression in lung tissues were also similar in both IPF and COP, whereas MMP-2 level was higher in COP and MMP-9 level was higher in IPF.

CONCLUSION

MMP-7 seems to play an important role in the pathogenesis of not only IPF but also COP; therefore, it may not be the key factor determining the prognosis or reversibility of IIPs.

Development of standard estrogen and progesterone receptor immunohistochemical assays for selection of patients for antihormonal therapy

Estrogen receptor (ER) and progesterone receptor (PR) status in breast carcinomas are considered validated predictive factors for selecting patients for antihormonal therapy. Published surveys have shown a significant rate of disagreement and lack of reproducibility of immunohistochemistry (IHC) results from laboratories around the world. To address these limitations IHC assays for ER and PR were developed using characterized reagents, after careful calibration of the sensitivity and specificity to match established assays previously validated in large clinical studies. The ER assay uses a cocktail of 2 mouse monoclonal antibodies (1D5 and ER-2-123) and the PR assay uses 1 mouse monoclonal antibody (PgR 1294); both are followed by a polymer-peroxidase-based detection system. All antibodies were tested for specificity by epitope mapping. The sensitivity of the new assays was calibrated to be equivalent to previously validated IHC assays followed by a comparison with the validated assays in a concordance study involving over 200 specimens. All slides were scored with the "Allred Score," also used for scoring of the original validated assays. The overall concordance between the new and the established IHC assays was nearly perfect (99%). The concordance study demonstrated greater than 98% positive agreement and 100% negative agreement of the new IHC assays with the previously validated IHC assays. This equivalence establishes the clinical validation of the assays and, as they are based on newer generation reagents and are produced and tested under stringent quality control conditions to ensure their consistency, they add additional advantages to the user and patients.

Human epidermal growth factor receptor 2 status correlates with lymph node involvement in patients with estrogen receptor (ER) negative, but with grade in those with ER-positive early-stage breast cancer suitable for cytotoxic chemotherapy

PURPOSE

Human epidermal growth factor receptor 2 (HER-2) expression is associated with increased risk of high-grade disease, nodal metastasis, and absence of estrogen receptors (ERs) in early breast cancer. We tested interactions between ER and HER-2 to determine if they may modulate breast cancer nodal metastasis and proliferation.

PATIENTS AND METHODS

Tumors from the Cancer Research UK Taxotere as Adjuvant Chemotherapy phase III trial were tested for HER-2 using current diagnostic procedures. ER status, progesterone status, clinicopathologic characteristics, and patient age were included in a logistic regression analysis to identify associations with HER-2 status (positive v negative).

RESULTS

A total of 841 (23.6%) of 3,565 samples were HER-2 positive (3+ by immunohistochemistry or positive by fluorescent in situ hybridization). ER-negative tumors were more likely to be HER-2 positive than were ER-positive tumors (odds ratio [OR] = 1.87, ER negative v ER positive; P < .001). For ER-positive tumors, risk of HER-2 positivity increased by grade (OR = 7.6, grade 3 v grade 1; P < .001) but not nodal status (OR = 1.3, four or more positive nodes v node negative; P = .08). Conversely, ER negative node-positive tumors were markedly more frequently HER-2 positive than node-negative cases (OR = 3.05, four or more positive nodes v node negative; P < .001) but independent of grade (OR = 0.82, grade 3 v grade 1; P = .76).

CONCLUSION

In early breast cancer patients selected for cytotoxic chemotherapy, we identified significant interactions between HER-2 and ER expression that correlate with tumor pathology. In ER-positive breast cancers, HER-2 expression correlates with grade, not nodal metastasis. In ER-negative breast cancers, HER-2 expression correlates with increased nodal positivity, not grade. ER and HER-2 expression may modify tumor pathology via ER/HER-2-mediated cross talk.

A comparison of immunohistochemical staining for oestrogen receptor, progesterone receptor and HER-2 in breast core biopsies and subsequent excisions

AIMS

To compare immunohistochemical staining for oestrogen receptor, progesterone receptor and HER-2 between core biopsy and matched subsequent excisional specimens.

METHODS

One hundred consecutive core biopsy cases and subsequent excisional specimens were retrieved and immunohistochemical staining performed. Proportion and intensity of staining for hormone receptors and HercepTest score were recorded for each case in a blinded fashion by the authors.

RESULTS

Overall hormone receptor status was concordant between cores and excisions in 96.9% of cases. ER status was concordant between the core and excision in 95.8% of cases. The intensity of staining for ER was similar in both core and excision specimens. PR status was concordant in cores and excisions in 90.3% of cases. There was weaker PR staining in the excisional specimens when compared with the cores. HER-2 status was concordant in cores and excisions in 86.6% of cases.

CONCLUSIONS

Hormone receptor staining produced similar results on core and excisional specimens, although a small number of additional hormone receptor positive cases could be detected by performing staining on a previously received core in the case of a negative result on the excisional specimen. HER-2 staining is less reproducible between cores and excisions, but the clinical significance of this observation remains to be tested.

The breast cancer continuum in hormone-receptor-positive breast cancer in postmenopausal women: evolving management options focusing on aromatase inhibitors

There are now a number of highly effective options for the treatment of hormone-receptor-positive breast cancer. Although tamoxifen was the standard hormonal treatment for many years, we now have another option for postmenopausal women: the third-generation aromatase inhibitors (AIs) anastrozole, exemestane and letrozole. A number of trials have investigated the use of third-generation AIs compared with tamoxifen throughout the continuum of treatment settings for postmenopausal women with breast cancer. In the neoadjuvant setting, letrozole, given for 4 months, resulted in better overall clinical response and breast-conserving surgery rates than tamoxifen. The Immediate Preoperative Anastrozole Tamoxifen or Combined with Tamoxifen trial gave anastrozole for 3 months with no difference in clinical response but significantly improved breast-conserving surgery rates. Compared with tamoxifen, anastrozole and letrozole significantly improved disease-free survival as early adjuvant treatment for hormone-receptor-positive disease. Switching to anastrozole or exemestane after 2 to 3 years of adjuvant tamoxifen for a total of 5 years of therapy was also more effective than continued tamoxifen. All three agents are approved in the early adjuvant or switching setting in the USA. Letrozole following 5 years of tamoxifen as extended adjuvant treatment improved disease-free survival and, in the node-positive subgroup, overall survival when compared with placebo. Anastrozole and letrozole are both approved for the first-line treatment of hormone-sensitive advanced breast cancer in postmenopausal women; letrozole showed an improved response rate compared with tamoxifen. Anastrozole, letrozole and exemestane are all indicated for the second-line treatment of advanced breast cancer. In summary, third-generation AIs have been shown to have superior efficacy over tamoxifen in the metastatic, neoadjuvant and adjuvant settings and to improve outcome as extended adjuvant therapy following 5 years of tamoxifen. Ongoing studies will further define the role of sequential adjuvant treatment. Appropriate duration of treatment is another important area of investigation. This review will cover hormonal therapy for postmenopausal women with breast cancer and will not address the treatment of premenopausal women.

An overview of assessment of prognostic and predictive factors in breast cancer needle core biopsy specimens

Needle core biopsy (NCB), as part of triple assessment for preoperative evaluation and diagnosis of breast cancer, is now considered as an established, highly accurate method for diagnosing breast cancer that has replaced either fine needle aspiration cytology or excisional biopsy as the initial diagnostic biopsy procedures in many institutions. In addition to its primary role in establishing an accurate histological diagnosis, NCB can potentially provide important additional pathological prognostic information which may be of direct clinical value in certain situations, such as patients being considered for preoperative (neoadjuvant) therapy. With this background in mind we briefly review the current role of NCB in breast cancer diagnosis and then concentrate this review on the usefulness and issues relating to use of this technique in providing accurate, reliable and clinically relevant preoperative prognostic and predictive information in patients with breast cancer.

Recommendations for improved standardization of immunohistochemistry

Immunohistochemistry (IHC) continues to suffer from variable consistency, poor reproducibility, quality assurance disparities, and the lack of standardization resulting in poor concordance, validation, and verification. This document lists the recommendations made by the Ad-Hoc Committee on Immunohistochemistry Standardization to address these deficiencies. Contributing factors were established to be underfixation and irregular fixation, use of nonformalin fixatives and ancillary fixation procedures divested from a deep and full understanding of the IHC assay parameters, minimal or absent IHC assay optimization and validation procedures, and lack of a standard system of interpretation and reporting. Definitions and detailed guidelines pertaining to these areas are provided.

A pathologist's perspective on emerging genomic tests for breast cancer

Emerging molecular tests for breast cancer indicate how future progress in diagnostic pathology might guide patient care. However, the challenge will be to bring the best results from this exciting research into clinical use as accurate and reliable standardized tests that integrate into the diagnostic work-up.

Morphological detection of hormone and growth factor receptors in breast cancer

In the multidisciplinary effort of today's clinical oncology, histopathology has to deal increasingly with the genetic and proteomic profiles of neoplastic cells obtained in ever smaller samples via various diagnostic routes. None of the numerous molecular markers available has surpassed hormone and growth factor receptors in their relevance for the selection of targeted therapies. In the following, morphologic concepts and histopathologic methods pertinent to the clinically most important receptors are discussed with a focus on tumors of the breast.

New generation of molecular prognostic and predictive tests for breast cancer

Breast cancer is a clinically heterogeneous disease, and it is generally accepted that the different clinical courses of patients with histologically similar tumors are due to molecular differences among cancers. Therefore, detailed molecular analysis of the cancer could yield prognostic information. Recent advances in molecular analytical techniques have led to rapid expansion of novel diagnostics designed to personalize breast cancer care. Diagnostic companies are also increasingly adopting a clinical trial-based approach to develop their products. This article reviews some of the most important advances in this field in the past few years, including the emergence of several multigene and prognostic predictors, as well as methods allowing enumeration of circulating tumor cells that are currently offered as commercially available diagnostic assays.

Taking gene-expression profiling to the clinic: when will molecular signatures become relevant to patient care?

The advent of microarray technology has enabled scientists to simultaneously investigate the expression of thousands of genes. Gene-expression profiling studies have provided a molecular classification of breast cancer into clinically relevant subtypes, new tools to predict disease recurrence and response to different treatments, and new insights into various oncogenic pathways and the process of metastatic progression. Here we describe the state of the art of gene-expression studies in breast cancer, and consider both their current limitations and future promises. We also discuss the potential of molecular signatures to have an impact on individual breast cancer patient management, and ultimately to accelerate the transition between empirical and tailored medicine.

Standardizing Slide-Based Assays in Breast Cancer: Hormone Receptors, HER2, and Sentinel Lymph Nodes

Despite the rapid expansion of novel diagnostics designed to personalize breast cancer care, there remain several significant unmet needs for improving the accuracy and reliability of tests that are already in common daily clinical practice. For example, although immunohistochemistry has been the predominant method for measuring estrogen receptor and progesterone receptor status for over 15 years, this assay remains unstandardized and there is a widespread concern that inaccuracy in immunohistochemistry technique and interpretation is leading to an unacceptably high error rate in determining the true hormone receptor status. Similarly, there is considerable concern that both false-negative and false-positive result rates for testing for HER2 status are unacceptably high in current clinical practice. This commentary considers a variety of factors, including preanalytic conditions and slide-scoring procedures, and other variables that may be contributing to current testing error rates and why there is a great need for the standardization of these biomarker assay procedures to further enable the highest possible quality of care for newly diagnosed breast cancer patients.

Use of adjuvant systemic therapy for early breast cancer among women 65 years of age and older

BACKGROUND

The National Institutes of Health (NIH) consensus statement recommends adjuvant therapy for early breast cancer irrespective of age. However, the actual use of such therapy is not well documented among women over 65 years of age.

METHODS

We studied the frequency of use of adjuvant therapy and report the receipt of this therapy among 200 women aged > or = 65 years diagnosed with early breast cancer who were identified from the New Jersey State Cancer Registry.

RESULTS

In this population, 28% of patients received chemotherapy alone or in combination with hormonal therapy, whereas 42% received hormonal therapy alone. Less than half of the women with estrogen receptor-negative tumors received chemotherapy alone or in combination with hormonal treatment. Adjuvant therapy was not prescribed in 30% of patients.

CONCLUSIONS

Despite NIH recommendations, the frequency of use of adjuvant therapy in New Jersey is low among women over 65 years of age, regardless of their receptor status.

Determination of oestrogen-receptor status and ERBB2 status of breast carcinoma: a gene-expression profiling study

BACKGROUND

Gene expression microarrays are being used to develop new prognostic and predictive tests for breast cancer, and might be used at the same time to confirm oestrogen-receptor status and ERBB2 status. Our goal was to establish a new method to assign oestrogen receptor and ERBB2-receptor status to breast carcinoma based on mRNA expression measured using Affymetrix U133A gene-expression profiling.

METHODS

We used gene expression data of 495 breast cancer samples to assess the correlation between oestrogen receptor (ESR1) and ERBB2 mRNA and clinical status of these genes (as established by immunohistochemical [IHC] or fluorescence in-situ hybridisation [FISH], or both). Data from 195 fine-needle aspiration (FNA) samples were used to define mRNA cutoff values that assign receptor status. We assessed the accuracy of these cutoffs in two independent datasets: 123 FNA samples and 177 tissue samples (ie, resected or core-needle biopsied tissues). Profiling was done at two institutions by use of the same platform (Affymetrix U133A GeneChip). All data were uniformly normalised with dCHIP software.

FINDINGS

ESR1 and ERBB2 mRNA levels correlated closely with routine measurements for receptor status in all three datasets. Spearman's correlation coefficients ranged from 0.62 to 0.77. An ESR1 mRNA cutoff value of 500 identified oestrogen-receptor-positive status with an overall accuracy of 90% (training set), 88% (first validation set), and 96% (second validation set). An ERBB2 mRNA threshold of 1150 identified ERBB2-positive status with the overall accuracy of 93% (training set), 89% (first validation set), and 90% (second validation set). Reproducibility of mRNA measurements in 34 replicate experiments was high (correlation coefficient 0.975 for ESR1, 0.984 for ERBB2).

INTERPRETATION

Amounts of ESR1 and ERBB2 mRNA as measured by the Affymetrix GeneChip reliably and reproducibly establish oestrogen-receptor status and ERBB2 status, respectively.

Frequency and reliability of oestrogen receptor, progesterone receptor and HER2 in breast carcinoma determined by immunohistochemistry in Australasia: results of the RCPA Quality Assurance Program

BACKGROUND AND AIMS

Immunohistochemistry (IHC) has replaced radioligand binding assay for the determination of oestrogen receptor (ER) status in breast carcinoma. IHC is also used for assessment of progesterone receptor (PR) and HER2. The Royal College of Pathologists of Australasia (RCPA) Quality Assurance Program (QAP) introduced a breast markers module in 2003 to evaluate the performance of laboratories with IHC for ER, PR and HER2.

METHODS

An audit of laboratories reporting breast carcinomas was performed in 2005 and 2006 to evaluate in-house results. Laboratories were asked to submit the hormone receptor and HER2 status on each invasive breast carcinoma for the previous 6 month period up to a maximum of 100 cases. The time periods were 1 July 2004 to 31 December 2004, and 1 July 2005 to 31 December 2005. A total of 55 laboratories returned information for 2004 and 67 for 2005.

RESULTS

Complete data on 8128 patients was returned for both surveys, 3353 cases for 2004 and 4775 for 2005. The results were similar for both surveys. Of the 8128 cases, 59.0% were ER+/PR+, 15.9% ER+/PR-, 2.4% ER-/PR+ and 22.7% ER-/PR-. HER2 data were submitted for a total of 6512 patients (excludes 52 patients with incomplete data sets); 17.1% were reported as 3+ positive on IHC, 12.5% as 2+ and 70.4% as negative.

CONCLUSIONS

A laboratory audit was introduced into the RCPA QAP for breast markers due to concerns raised by participating laboratories about technical differences in supplied tissues for testing. This audit indicates that overall the results for ER, PR and HER2 fall inside established parameters. However, a number of individual laboratories do not meet the target values and variation in results would impact on patient treatment decisions.

Identification and meta-analysis of a small gene expression signature for the diagnosis of estrogen receptor status in invasive ductal breast cancer

In breast cancer, the determination of estrogen receptor (ER) expression is crucial for the decision on therapeutic strategies. Current ER expression analysis is based on immunohistochemical (IHC) staining of ER on formalin fixed tissue sections. However, low levels of ER expression frequently escape detection because of varying sensitivities of routine histopathological laboratories. Moreover, in estimating ER by IHC the receptor protein only is tested instead of the complex underlying ER pathway, which reflects its biological activity. To overcome this limitation, we have used the microarray technology to study 56 samples of invasive ductal carcinoma. We infer a robust and reliable signature of 10 genes, which is associated with ER expression and presumably therapeutically relevant biological processes. In a meta-analysis, the signature was tested on 3 further independent microarray gene expression data sets, covering different laboratories, array platforms, and clinics. The classification based on the signature showed a very low misclassification rate. In summary, the expression of few genes is sufficient to determine ER status. Future decisions on antiestrogen based therapy in breast cancer could be based on this signature rather than on immunostaining alone.

Molecular classification of breast cancer: implications for selection of adjuvant chemotherapy

Adjuvant chemotherapy improves survival of patients with stage I-III breast cancer but it is being increasingly recognized that the benefit is not equal for all patients. Molecular characteristics of the cancer affect sensitivity to chemotherapy. In general, estrogen-receptor-negative disease is more sensitive to chemotherapy than estrogren-receptor-positive disease. Large-scale genomic analyses of breast cancer suggest that further molecular subsets may exist within the categories defined by hormone receptor status. It is hoped that the new molecular classification schemes might improve patient selection for therapy. Before any new molecular classification (or predictive test) is adopted for routine clinical use, however, several criteria need to be met. There must be an agreed and reproducible method by which to assign molecular class to a new case. Cancers that belong to different molecular classes must show differences in disease outcome and treatment efficacy that affect management and treatment selection. Also desirable are results from prospective clinical trials that demonstrate improved patient outcome when the new test is used in decision-making, compared with the current standard of care. This Review describes the current limitations and future promises of gene-expression-based molecular classification of breast cancer and how it might impact on selection of adjuvant therapy for individual patients.

Molecular classification of breast cancer: limitations and potential

Reverse transcription polymerase chain reaction and DNA microarrays are increasingly used in the clinic and in clinical research as prognostic or predictive tests. Results from these tests led to novel risk stratification methods and to new molecular classification of breast cancer. Some of these tools already complement existing diagnostic tests and can aid medical decision making in some situations. Better understanding of the molecular classes of breast cancer, independent of their prognostic and predictive values, may also lead to new biological insights and eventually to better therapies that are directed toward particular molecular subsets. However, there is substantially less experience with these emerging technologies than with the more established methods, the accuracy of which is often overestimated. This review discusses some of the limitations and strengths of current gene expression-based molecular classification of breast cancer. To provide context for this discussion, we also briefly examine the performance of estrogen receptor immunohistochemistry, which represents an essential part of the routine diagnostic workup for all breast cancer patients.

External quality assurance of HER2 fluorescence in situ hybridisation testing: results of a UK NEQAS pilot scheme

BACKGROUND AND AIMS

Trastuzumab provides clinical benefit for advanced and early breast cancer patients whose tumours over-express or have gene amplification of the HER2 oncogene. The UK National External Quality Assessment Scheme (NEQAS) for immunohistochemical testing was established to assess and improve the quality of HER2 immunohistochemical testing. However, until recently, no provision was available for HER2 fluorescence in situ hybridisation (FISH) testing. A pilot scheme was set up to review the performance of FISH testing in clinical diagnostic laboratories.

METHODS

FISH was performed in 6 reference and 31 participating laboratories using a cell line panel with known HER2 status.

RESULTS

Using results from reference laboratories as a criterion for acceptable performance, 60% of all results returned by participants were appropriate and 78% either appropriate or acceptable. However, 22.4% of results returned were deemed inappropriate, including 13 cases (4.2%) where a misdiagnosis would have been made had these been clinical specimens.

CONCLUSIONS

The results of three consecutive runs show that both reference laboratories and a proportion of routine clinical diagnostic (about 25%) centres can consistently achieve acceptable quality control of HER2 testing. Data from a significant proportion of participating laboratories show that further steps are required, including those taken via review of performance under schemes such as NEQAS, to improve quality of HER2 testing by FISH in the "real world".

Observer variation in immunohistochemical analysis of protein expression, time for a change?

AIM

Immunohistochemical analysis of protein expression is central to most clinical translational studies and defines patient treatment or selection criteria for novel drugs. Interobserver variation is rarely analysed despite recognition that this is a key area of potential inaccuracy. Therefore our aim was to examine observer variation and suggest the revision of current standards.

METHODS AND RESULTS

We analysed inter- and intra-observer variation, by interclass correlation coefficient (ICCC) and kappa statistics, in 8661 samples. Intra-observer assessment of nuclear, cytoplasmic and membrane staining for seven proteins in 1323 samples resulted in an ICCC of 0.94 and a kappa-value of 0.787. Interobserver reproducibility, assessed on 28 proteins by seven observer pairs in 8661 carcinomas, gave an ICCC of 0.90 and a kappa-value of 0.70. No significant effect of either antibody or cellular compartmentalization was observed.

CONCLUSION

We have demonstrated that ICCC is a consistent method to assess observer variation when a continuous scoring system is used, compared with kappa statistics, which depends on a categorical system. Given the importance of accurate assessment of protein expression in diagnostic and experimental medicine, we suggest raising thresholds for observer variation: ICCC of 0.7 should be regarded as the minimum acceptable standard, ICCC of 0.8 as good and ICCC of > or = 0.9 as excellent.

The reliability of assessment of oestrogen receptor expression on needle core biopsy specimens of invasive carcinomas of the breast

AIM

To assess the reliability of assessment of oestrogen receptor expression on needle core biopsy specimens of invasive carcinomas of the breast. Previous studies have mostly been small, with a range of agreement from 62% to 100%.

METHODS

Retrospective audit of 338 tumours surgically excised within 60 days of core biopsy, that had had oestrogen receptor assessed on both the core biopsy and tumour specimens. Surgical specimens were incised when fresh to ensure good fixation. External controls including a weakly positive tumour were included in each immunohistochemistry run.

RESULTS

Oestrogen receptor expression was bimodal, with H score in both specimens of either 0 or >50 in 96% of tumours. Using H score cut-off of 10 for positivity, there was an agreement between core and excision in 334 of 338 tumours (98.8%). All discrepancies were between weakly positive and negative tumours. Intratumoral heterogeneity could explain the one tumour that was negative on core and positive on excision. H score tended to be slightly higher on core than excision (means 146 and 136). Better fixation on the core is the most likely explanation for this and for the three tumours that were positive on core and negative on excision. Repeat staining on tumours with discrepant results gave similar results in all except one case. An internal control was present in 97% of excisions and 55% of cores of oestrogen receptor-negative tumours; the internal control stained positively in all except two sections.

CONCLUSION

Oestrogen receptor can be assessed reliably on needle core biopsies of invasive carcinomas of the breast.

Reproducibility of Gene Expression Signature–Based Predictions in Replicate Experiments

PURPOSE

The goals of this analysis were to (a) determine concordance of gene expression results from replicate experiments, (b) examine prediction agreement of multigene predictors on replicate data, and (c) assess the robustness of prediction results in the face of noise.

PATIENTS AND METHODS

Affymetrix U133A gene chips were used for gene expression profiling of 97 fine-needle aspiration biopsies from breast cancer. Thirty-five cases were profiled in replicates: 17 within the same laboratory, 11 in two different laboratories, and 15 to assess manual and robotic labeling. We used data from 62 cases to develop 111 distinct pharmacogenomic predictors of response to therapy. These were tested on cases profiled in duplicates to determine prediction agreement and accuracy. To evaluate the robustness of the pharmacogenomic predictors, we also introduced random noise into the informative genes in one half of the replicates.

RESULTS

The average concordance correlation coefficient was 0.978 (range, 0.96-0.99) for intralaboratory replicates, 0.962 (range, 0.94-0.98) for between-laboratory replicates, and 0.971 (range, 0.93-0.99) for manual versus robotic labeling. The mean % prediction agreement on replicate data was 97% (95% CI, 0.96-0.98; SD, 0.006), 92% (95% CI, 0.90-0.93; SD, 0.009), and 94% (95% CI, 0.92-0.95; SD, 0.008) for support vector machines, diagonal linear discriminant analysis, and k-nearest neighbor prediction methods, respectively. Mean accuracy in the test set was 77% (95% CI, 0.74-0.79; SD, 0.014), 66% (95% CI, 0.63-0.73; SD, 0.015), and 64% (95% CI, 0.60-0.67; SD, 0.016), respectively.

CONCLUSION

Gene expression results obtained with Affymetrix U133A chips are highly reproducible within and across two high-volume laboratories. Pharmacogenomic predictions yielded >90% agreement in replicate data.

Immunohistochemical evaluation of hormone receptor status for predicting response to endocrine therapy in metastatic breast cancer

BACKGROUND

The importance of establishing hormone receptor status of tumors for the treatment of women with hormone receptor-positive breast cancer has been emphasized, however, there is no general agreement as to how immunohistochemical assays should be evaluated. It is critical to evaluate hormone receptor status when considering response to endocrine therapy.

METHODS

Estrogen receptor (ER) and progesterone receptor (PgR) expression was examined by immunohistochemistry using Allred's score for primary breast tumors from 75 metastatic breast cancer patients who received first-line treatment with endocrine therapy (56 patients received tamoxifen, 11 patients received aromatase inhibitors, and 8 patients received LH-RH agonist or other endocrine reagents) on relapse. Correlation between hormone receptor status and response to endocrine therapy as well as post-relapse survival was analyzed.

RESULTS

The most significant correlation between positive ER expression and response to any endocrine therapy (p = 0.011) or tamoxifen only (p = 0.030) occurred when the cutoff score was set at 10%. When the evaluation was based on Allred's score (TS), a cutoff point of TS>or=4 showed a more significant association between positive ER expression and response to all kinds of endocrine therapy (p = 0.020) or tamoxifen only (p = 0.047). When evaluated at a cutoff point of 1% positive cells, there were fifteen patients with both ER- and PgR-negative tumors, and three patients (20.0%) responded to the therapy. Patients with 1% or more ER or PgR positive cells had better survival after relapse (p = 0.0005 and p = 0.0008, respectively).

CONCLUSIONS

The proportion score alone might be enough to predict hormone responsiveness and post-relapse survival in metastatic breast cancer. The cutoff might be set low, for example 1%, especially for metastatic disease.

Reliance on hormone receptor assays of surgical specimens may compromise outcome in patients with breast cancer

PURPOSE

To assess the concordance of breast cancer immunohistochemical receptor assays on core biopsy and surgical specimens.

PATIENTS AND METHODS

We identified 100 patients whose core biopsy and definitive surgical specimens were processed in our hospital. New sections, with core and surgical specimens on the same slides, were stained for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) immunohistochemistry (IHC). Two pathologists assessed the sections independently. Raw scores and clinically significant groupings were compared.

RESULTS

Concordance for ER, PR, overall hormone receptor (HR), and HER-2 status was seen in 86%, 83%, 90%, and 80% of patients, respectively. The core was positive, while the surgical specimen was negative in 13%, 11%, 9%, and 1% of patients, respectively. Using a log-linear model, differences in ER, PR, and HER-2 staining were all in the direction of stronger staining in the cores, and were statistically significant. Nine percent (95% CI, 4.2% to 16.4%) of women in this group would have had endocrine therapy inappropriately withheld if management decisions were based on surgical specimen results alone.

CONCLUSION

ER and PR assays on core biopsy specimens are more reliable than assays on surgical specimens. Receptor IHC should be performed on core biopsy specimens to avoid patients with HR positive cancers not receiving appropriate hormonal therapy and being overtreated with systemic chemotherapy. Biopsy should be considered in patients with "receptor negative" cancer and recurrent disease.

Development of pharmacogenomic markers to select preoperative chemotherapy for breast cancer

Individualized selection of the most effective adjuvant (or neoadjuvant) chemotherapy for breast cancer based on the molecular characteristics of the tumor could improve the risk:benefit ratio of current therapies. It could also streamline the development of new regimens for those who are unlikely to benefit from existing drugs. It is expected that combinations of markers will be more informative to predict response than any single gene and may yield regimen-specific predictors. Novel molecular analytical tools, particularly transcriptional profiling, provide a method to test this hypothesis. Several small exploratory studies have shown encouraging results. This article reviews recent progress in this field including experience from the breast cancer pharmacogenomic marker discovery program at the Nellie B. Connally Breast Center of the University of Texas M. D. Anderson Cancer Center. This manuscript is based on a presentation that was given during the Presidential Symposium of the annual meeting of the Japanese Breast Cancer Society in 2004.

Determination of threshold values for determining the size of the fraction of steroid hormone receptor-positive tumor cells in paraffin-embedded breast carcinomas

BACKGROUND

For 4 years we used a multiparameter DNA flow cytometric (MP-FCM) technique to assess steroid hormone receptor expression in the diagnostic workup of routinely processed formalin-fixed, paraffin-embedded breast carcinomas as an alternative to immunohistochemistry (IHC) for the quantification of hormone receptor-positive cells. In all cases a positive fraction of hormone receptor-expressing epithelial cells was detected. This observation raised the question of what the cutoff value might be to distinguish receptor-negative from receptor-positive tumors.

METHODS

In our search for a possible threshold value of positivity for estrogen receptor (ER) and progesterone receptor (PR) in MP-FCM, we developed four steps. First, we compared IHC results in our own laboratory with the results obtained by MP-FCM on a small series of breast tumors (n = 42). Second, after collecting our first 843 tumors, we made a comparison with the literature of the distribution of receptor positivity according to age classes. Third, using the most likely threshold that resulted from this comparison, we compared a subset of 340 node-negative tumors for their combined ER/PR profiles with the data from a similar group of node-negative tumor cases from the National Cancer Institute's Surveillance, Epidemiology and End-Result (SEER) study. Fourth, with the results of these comparisons, we prospectively collected IHC data and MP-FCM results of the same tumor samples for a period of 1 year. In this way, we collected data for an additional 180 tumors.

RESULTS

The first step in this process resulted in an previous publication where 20% of steroid hormone receptor-positive cells seemed to be an acceptable cutoff point for positivity. However, the second step provided the best correlation at approximately 35% of ER reactive cells in the cytokeratin-positive cell population. With this cutoff, the distribution of combined ER/PR profiles in our patient population of node-negative breast cancers also showed a distribution similar to the data from the SEER study. The fourth step, using the 35% threshold value, resulted in a good correlation (r = 0.85, P < 0.0001) for ER and PR between IHC and MP-FCM in the 180 tumors investigated.

CONCLUSION

By comparing in-house data with those from large external data collections in the literature, a threshold percentage can be defined that distinguishes steroid hormone receptor-negative from hormone receptor-positive tumors. As a result, information about DNA content and cell cycle distribution can be obtained. This observational study provides additional support to our opinion that MP-FCM is an alternative for IHC determination of ER and PR positivity. It is more objective and quantification can be done more appropriately. The additional value of this approach is that we generate continuous variables of ER/PR content instead of categorical classes, which can be used at different threshold levels for evaluation of clinical relevance.

Standardized assessment of cell proliferation: the approach of the RITA-CEPA working group

Since 1985, quantitative data on cell proliferation increasingly form an integral part in the risk assessment of many pharmaceutical, chemical, and agrochemical compounds. Technical guides for the conduct of cell proliferation studies are not readily available. The detection of cell proliferation relies almost exclusively on immunohistochemistry, which is rarely standardized between laboratories. Against this background pathologists formed the RITA-CEPA working group with the aim of elaborating standard guides for the conduct of cell proliferation studies. We present here, as examples, the general BrdU guide as well as the organ-specific guides for hepatocytes, thyroid gland follicular cells, and renal tubular epithelial cells in the rat. Today, RITA-CEPA has available guides for BrdU cell proliferation studies in 20 organs as well as for studies with PCNA as proliferation marker and for apoptosis studies with the TUNEL technique. The relevant information from more than 500 selected publications is organized in a database structure to make it easily traceable. New hardware and software used for image analysis are being assessed and are included in the information exchange practiced in the CEPA working group. Further fields of major relevance for cell proliferation studies, such as statistics and the validation of image analysis equipment in a GLP environment are investigated. A guide on the use of statistics in cell proliferation studies is in preparation. CEPA-group members meet regularly to exchange information. They use the electronic database for planning and interpretation of cell proliferation studies. CEPA will continue with the preparation of organ guides and expand the series for other proliferation markers, e.g. Ki-67. It promotes standardization of techniques applied in proliferation studies, especially immunohistochemistry and image analysis. Members of the CEPA-group have access to a comprehensive and steadily increasing knowledge base on all aspects of cell proliferation. Membership of the CEPA group is open for all industrial organizations who develop chemical, agrochemical, or pharmaceutical products.

Standardized on-slide control for quality assurance in the immunohistochemical assessment of therapeutic target molecules in breast cancer

Individualization and optimization of risk-adapted therapy in breast cancer requires molecular profiling of individual cancer specimens. In tissues of heterogeneous cellular composition, such as mammary tissue, cancer prognostic markers and potential therapeutic target molecules are preferentially detected by in situ techniques such as immunohistochemistry. The more therapy decisions are based on immunohistochemical findings, the more histopathologists are confronted with the demand to establish standardized procedures that enable reproducible evaluation independent from the investigating laboratory. Disappointing results of recent national and international immunohistochemistry trials for steroid receptor and HER-2 analysis in breast cancer underline the need to act now beyond recommendations and well-formulated guidelines for standardization. In order to ensure staining quality in every individual immunohistochemical analysis, we have developed an on-slide control with standardized samples which are placed on every slide of a therapy-decisive stain together with the tissue of interest. Novel mini tissue microarrays were constructed comprising cell lines as standardized controls, indicating the sensitivity and reliability of the staining procedure. Standardized control material on the same slide as the patient's specimen require neither additional reagents nor time and are automatically archived on the diagnostic slide to prove the quality of staining even after years.

The pathology of breast cancer and the role of the histopathology laboratory

Histopathology plays an important part in determining the treatment strategy for women with breast cancer, with the evaluation of breast specimens determining the surgical and the oncological therapeutic options used. The correct approach to specimens requires integration of clinical and imaging findings. This work is not trivial. It is time-consuming and skilled, and requires (and has in place) safeguards and checks in the form of national audit and quality-control schemes. The pathobiology of breast cancer is diverse, and the current taxonomy, rooted in morphological interpretation, has been underscored by molecular observations, such as the relationship of E-cadherin mutations to lobular carcinomas. Investigation of ductal carcinoma of no special type (NST) reveals covert tumour types, such as those with basal or myoepithelial features, whose distinctive features are only now being widely recognised. With the rise of modern molecular techniques, the demise of diagnostic histopathology has been predicted, but, for now and the intermediate future, the histopathologist remains a key element of the integrated breast-care team.

Relationship between hormone receptor status and tumour size, grade and comedo necrosis in ductal carcinoma in situ

BACKGROUND

Results of the National Surgical Adjuvant Breast Project B-24 trial indicate that adjuvant tamoxifen therapy is of benefit only in oestrogen receptor (ER)- positive ductal carcinoma in situ (DCIS). In the UK, ER status is not routinely determined in DCIS. The aim of this study was to assess the ER status in women with DCIS to determine whether any clinicopathological factors could predict positivity instead of immunohistochemical assessment.

METHODS

The ER and progesterone receptor (PR) status of consecutive women diagnosed with DCIS during 2001 and 2002 was determined by immunohistochemistry.

RESULTS

One hundred and nineteen tumours diagnosed between 2001 and 2002 were analysed; 73.0 per cent were ER positive and 61.1 per cent were PR positive. PR positivity was associated with ER positivity (P < 0.001). Increasing tumour grade correlated with a decrease in ER and PR positivity (both P = 0.002). Comedo necrosis was associated with ER negativity (P = 0.026), PR negativity (P = 0.033) and a lower percentage of ER expression in ER-positive tumours (mean(s.d.) 82(27) versus 93(10) per cent; P = 0.021).

CONCLUSION

Tumour grade and comedo necrosis were not strong enough predictors to be used as surrogates for immunohistochemical assessment. ER status should be determined before commencing endocrine therapy.

Clinical trial design for microarray predictive marker discovery and assessment

Transcriptional profiling technologies that simultaneously measure the expression of thousands of mRNA species represent a powerful new clinical research tool. Similar to previous laboratory analytical methods including immunohistochemistry, PCR and in situ hybridization, this new technology may also find its niche in routine diagnostics. Outcome predictors discovered by these methods may be quite different from previous single-gene markers. These novel tests will probably combine the information embedded in the expression of multiple genes with mathematical prediction algorithms to formulate classification rules and predict outcome. The performance of machine learning-algorithm-based diagnostic tests may improve as they are trained on larger and larger sets of samples, and several generations of tests with improving accuracy may be introduced sequentially. Several gene-expression profiling-technology platforms are mature enough for clinical testing. The most important next step that is needed for further progress is the development and validation of multigene predictors in prospectively designed clinical trials to determine the true accuracy and clinical value of this new technology. This manuscript reviews methodological and statistical issues relevant to clinical trial design to discover and validate multigene predictors of response to therapy.

Immunohistochemical assessment for estrogen receptor and progesterone receptor status in breast cancer: analysis for a cut-off point as the predictor for endocrine therapy

BACKGROUND

An immunohistochemical (IHC) method is commonly used for determining estrogen receptor (ER) and progesterone receptor (PR) status in breast cancer. However, the proper cut-off points of IHC have not been established. Cut-off points for ER and PR status as predictive factors for endocrine therapy are needed.

METHODS

A total of 249 cases of female breast cancer were enrolled. ER and PR status by IHC were analyzed using the proportion of stained cells and staining intensity by Allred's score.

RESULTS

Proportion score (PS) and intensity score (IS) were related to enzyme immunoassay (EIA) titers, for both in ER and PR (p < 0.0001, all). PS correlated with IS in both ER and PR (R = 0.47 and 0.41, respectively). ER status by IHC was related to tumor size and lymph node status, while PR was related to tumor size and menopausal status. In 152 patients who received endocrine therapy with a median follow-up term of 38 months, differences in disease-free survival were most significant using a cut-off point of PS 3 which indicated more than 10 % of cells stained positively for both ER and PR (p = 0.0007 and 0.0087, respectively). In addition, combination analysis of ER and PR using this cut-off point revealed a notable prognostic difference.

CONCLUSION

A 10 % staining proportion may be an acceptable cut-off point for both ER and PR status by IHC, in terms of predicting response to endocrine therapy in breast cancer.

Reduced PTEN expression predicts relapse in patients with breast carcinoma treated by tamoxifen

Tamoxifen treatment substantially improves the 10-year survival of women with estrogen-receptor (ER)-alpha-positive tumors. However, approximately one-third of all breast cancer patients with ER-alpha-positive tumors progress on antiestrogen therapy. The molecular mechanism(s) involved in antiestrogen-resistant phenotype of breast carcinoma is not completely understood. The PTEN (phosphatase and tensin homolog deleted on chromosome Ten) gene is a novel candidate tumor suppressor that plays an important role in cell cycle regulation and apoptosis by regulating Protein kinase-B/Akt activity. Previous studies have shown that PTEN downregulation in breast cancer is associated with high-grade tumor, distant metastases and poorer disease-free survival. Decreased PTEN and/or increased protein kinase B/Akt activity in breast cancer cells has recently been associated with resistance to tamoxifen-induced apoptosis. In this study, we have evaluated PTEN expression by immunohistochemistry in 100 tamoxifen-treated ER-alpha-positive breast cancer patients. Reduced PTEN protein expression was associated with shorter relapse-free survival. When stage I patients were analyzed separately, reduced PTEN expression was a strong predictor of both, shorter relapse-free survival and shorter disease-specific survival. An association of reduced PTEN expression with shorter relapse-free survival and disease-specific survival in stage I patients was still observed after stratification by stage, axillary lymph node status, tumor size, grade, and expression of ER-alpha, progesterone receptor, and Her-2/neu. In summary, our results showed a strong association between downregulation of PTEN expression in ER-alpha-positive tumors and failure to tamoxifen treatment.

Solving the dilemma of the immunohistochemical and other methods used for scoring estrogen receptor and progesterone receptor in patients with invasive breast carcinoma

BACKGROUND

The authors attempted to resolve the dilemma posed by the lack of unanimity concerning the optimal immunohistochemical (IHC) method for determining and scoring estrogen receptor (ER) and progesterone receptor (PR).

METHODS

Sections for IHC were prepared from paraffin embedded tumor samples from 402 patients with lymph node positive breast carcinoma who had biochemical receptor values (obtained with the dextran-coated charcoal [DCC] method) and who were enrolled in a prospective, randomized trial (National Surgical Adjuvant Breast and Bowel Project protocol B-09). IHC receptors were scored independently by two observers according to percent, intensity, and any-or-none algorithms. Results from these evaluations and from two computer-assisted evaluations, DCC, and common pathologic characteristics were analyzed for optimum splits for positive reactions in univariate and multivariate analyses using a tree-structured model. Concordance, sensitivity, and specificity were determined between the DCC method and all other methods.

RESULTS

Interobserver agreement and concordance between the DCC method and the other methods and among the methods were high. Univariate analyses revealed that a positive ER score obtained with all methods was related significantly to overall survival (OS) at 5 years and at 10 years. Results related to PR scores and disease-free survival and recurrence-free survival were less consistent. In multivariate analysis, it also was found that all methods for scoring ER predicted a better prognosis for OS in patients with an unfavorable lymph node status at 5 years and 10 years. Patients in a favorable lymph node status group were discriminated further by nuclear grade.

CONCLUSIONS

All IHC methods for scoring ER appeared valid as prognostic indicators of OS in patients with positive lymph nodes. The any-or-none IHC method, by virtue of its simplicity, represents an appropriate choice for practical use.

Testing for HER2 in breast cancer

HER2 is a paradigm of a molecular target whose appropriate assessment is pivotal in the targeting of novel therapies for breast cancer, notably including Herceptin/Trastuzumab. Determining the correct levels requires immunohistochemical and molecular biological skills that are reproducible and measurable, coupled with a knowledge of the appropriate morphological and pathobiological context. Attaining these goals is not easy and laboratories testing for HER2 should maintain a high level of throughput of tests and engage in a recognized external quality assurance scheme. Fluorescence in-situ hybridization testing remains a particular challenge and there is a range of testing strategies. This testing forms the model for the identification of other novel molecular targets. In the future rapid throughput techniques such as real-time quantitative polymerase chain reaction (rqPCR), tissue microarrays or both should bring significant economies of cost and scale.

Estrogen receptor analysis for breast cancer: current issues and keys to increasing testing accuracy

The estrogen receptor (ER) is a regulator of cellular growth, proliferation, and differentiation. In addition to having prognostic value, ER is the most important biologic marker of therapeutic response in breast cancer. Some level of measurable ER protein is expressed in 70-80% of human breast. Immunohistochemistry is the current method of choice for ER assessment, and its predictive value has been shown to be superior to that of biochemically based assays. Although accurate ER protein assessment is critical for optimal treatment of patients with breast cancer, studies have demonstrated inter-laboratory variability in ER detection. False-negative results for tumors with low ER protein levels have been a subject of recent concern. Lack of standardization for immunohistochemistry between laboratories is thought to be the major reason for testing errors, although variability in scoring methods and reporting practices, which can affect results, also plays a role. In this article, we review studies addressing interlaboratory variability and recommend optimal testing techniques and reporting procedures for ER testing, with the goal of increasing interlaboratory standardization for ER analysis by immunohistochemistry. We additionally highlight recent biologic, molecular, and gene expression profiling data related to ER in breast cancer.

Bimodal frequency distribution of estrogen receptor immunohistochemical staining results in breast cancer: an analysis of 825 cases

Immunohistochemical analysis is used routinely to determine the estrogen receptor (ER) status of breast cancers in paraffin sections. However, lack of standardization has raised concerns that weakly ER+ tumors often are classified erroneously as ER-. To determine the frequency of weakly ER+ tumors, we reviewed ER immunostains of 825 breast cancers. For each case, we estimated the proportion of ER+ tumor cells and also determined an Allred score (which results in scores of 0 or 2 through 8, based on staining intensity and proportion of positive cells). In 817 cases (99.0%), tumor cells showed complete absence of staining or staining in 70% or more of the cells. Similarly, 818 cases (99.2%) exhibited Allred scores of 0 or of 7 or 8. Thus, with the immunohistochemical method used in our laboratory, ER staining is essentially bimodal. The overwhelming majority of breast cancers are either completely ER- or unambiguously ER+, and cases with weak ER immunostaining are rare.