Comparison of HER2/neu status assessed by quantitative polymerase chain reaction and immunohistochemistry

Her2 assessment using quantitative reverse transcriptase polymerase chain reaction reliably identifies Her2 overexpression without amplification in breast cancer cases

BACKGROUND

Immunohistochemistry (IHC) and fluorescent-in situ hybridization (FISH) are standard methods to assess human epidermal growth factor receptor 2 (HER2) status in breast cancer (BC) patients. Real-time quantitative polymerase-chain-reaction (qRT-PCR) is able to detect HER2 overexpression. Here we compared FISH, IHC, quantitative PCR (qPCR), and qRT-PCR to determine the concordance rates and evaluate their relative roles in HER2 determination.

PATIENTS AND METHODS

We determined HER2 status in 153 BC patients, using IHC, FISH, Q-PCR and qRT-PCR. In discordant cases, we directly measured HER2 protein levels using Western blotting.

RESULTS

The overall agreement (OA) between FISH and Q-PCR was 94.1, with a k value of 0.87. Assuming FISH as the standard reference, Q-PCR showed an 86.1% sensitivity and a 99.0% specificity with a global accuracy of 91.6%. OA between FISH and qRT-PCR was 90.8% with a k value of 0.81. Of interest, the disagreement between FISH and qRT-PCR was mostly restricted to equivocal cases. HER2 protein analysis suggested that qRT-PCR correlates better than FISH with HER2 protein levels, particularly where FISH fails to provide conclusive results.

SIGNIFICANCE

qRT-PCR may outperform FISH in identifying patients overexpressing HER2 protein. Q-PCR cannot be used for HER2 status assessment, due to its suboptimal level of agreement with FISH. Both FISH and Q-PCR may be less accurate than qRT-PCR as surrogates of HER2 protein determination.

Determination of True ERBB2 Gene Amplification in Breast Cancer by Quantitative PCR Using a Reference and a Novel Control Gene

Human epidermal growth factor receptor 2 (ERBB2/HER2) is amplified and overexpressed in 20% to 25% of breast carcinomas, correlates with poor outcome, and is an indication for treatment with trastuzumab. Accurate assessment of ERBB2 status is crucial for proper prognosis and to offer appropriate treatment for patients. ERBB2 status is generally determined by immunohistochemistry or fluorescence in situ hybridization (FISH), and sporadically by quantitative real-time polymerase chain reaction (PCR). We developed a new algorithm, termed quantitative PCR algorithm (QPA) score, and compared its performance with the gold standard FISH assay. The QPA is a computation of the relative number of copies of the ERBB2 gene with respect to a nonstandard, short-arm centromeric sequence on chromosome 17, and referenced to a single-copy gene, RPP30. This provides a more reliable determination of ERBB2 amplification, reducing the false polysomy 17 error. A total of 69 breast carcinoma samples were tested for quantitative real-time PCR and FISH, and the degree of concordance was analyzed. Sixty-two cases were in agreement between the 2 methods, and the contingency study assigned a κ value of 0.729 for their correlation. A receiver operating characteristic analysis was used to determine the optimal cut-off point for ERBB2 amplification, which was estimated at a QPA=1.53 (sensitivity=0.863; specificity=0.944). Our data conclude that the QPA is able to determine ERBB2 gene status with high accuracy, while also overcoming the limitations of conventional techniques and providing better cost-effectiveness.

Validation of Intratumoral T-bet+ Lymphoid Cells as Predictors of Disease-Free Survival in Breast Cancer

We previously observed T-bet(+) lymphocytes to be associated with a good prognosis in a cohort of women with familial breast cancer. To validate this finding, we evaluated lymphocyte T-bet expression in an independent unselected prospectively accrued series of women with lymph node-negative breast carcinoma. T-bet and clinicopathologic data were available for 614 women. Hormone receptors, HER2, Ki-67, CK5, EGFR, p53, and T-bet status were determined using IHC and/or biochemical methods. Tumors were assigned to luminal A, luminal B, HER2, and basal subtypes based on the expression of IHC markers. Multiple cutpoints were examined in a univariate penalized Cox model to stratify tumors into T-bet(+/high) and T-bet(-/low). Fisher exact test was used to analyze T-bet associations with clinicopathologic variables, IHC markers, and molecular subtype. Survival analyses were by the Cox proportional hazards model. All tests were two sided. A test with a P value < 0.05 was considered statistically significant. T-bet(+/high) tumor status was significantly associated with large tumor size, high grade, hormone receptor negativity, CK5, EGFR and p53 positivity, high Ki-67, and basal subtype. With a median follow-up of 96.5 months, T-bet(-/low) tumor status was associated with a reduced disease-free survival compared with T-bet(+/high) tumor status in multivariate analysis (P = 0.0027; relative risk = 5.62; 95% confidence intervals, 1.48-50.19). Despite being associated with adverse clinicopathologic characteristics, T-bet(+) tumor-infiltrating lymphoid cells are associated with a favorable outcome. This supports their role in Th1-mediated antitumor activity and may provide insight for the development of new therapeutic strategies.

Distinguishing luminal breast cancer subtypes by Ki67, progesterone receptor or TP53 status provides prognostic information

The objectives of this study were to determine the prognostic significance of subgrouping estrogen receptor (ER)-positive breast tumors into low- and high-risk luminal categories using Ki67 index, TP53, or progesterone receptor (PR) status. The study group comprised 540 patients with lymph node negative, invasive breast carcinoma. Luminal A subtype was defined as being ER positive, HER2 negative, and Ki67 low (<14% cells positive) and luminal B subtype as being ER positive, HER2 negative, and Ki67 high (≥ 14% cells positive). Luminal tumors were also subgrouped into risk categories based on the PR and TP53 status. Survival analysis was performed. Patients with luminal B tumors (n=173) had significantly worse disease-free survival compared to those with luminal A tumors (n=186) (log rank P-value=0.0164; univariate Cox regression relative risk 2.00; 95% CI, 1.12-3.58; P=0.0187). Luminal subtype remained an independent prognostic indicator on multivariate analysis including traditional prognostic factors (relative risk 2.12; 95% CI, 1.16-3.88; P=0.0151). Using TP53 status or PR negativity rather than Ki67 to classify ER-positive luminal tumors gave similar outcome results to those obtained using the proliferation index. However, it was a combination of the three markers, which proved the most powerful prognostically. Ki67 index, TP53 status, or PR negativity can be used to segregate ER-positive, HER2-negative tumors into prognostically meaningful subgroups with significantly different clinical outcomes. These biomarkers particularly in combination may potentially be used clinically to guide patient management.

Assessment of HER-2 gene overexpression in Isfahan province breast cancer patients using Real Time RT-PCR and immunohistochemistry

PURPOSE

Overexpression of proto-oncogene HER-2 is one of the main molecular markers of breast cancer involved in prognosis and diagnosis and also in trastuzumab therapy. Thus, a request for the evaluation of HER-2 status in breast cancer has been increasing. The aim of our study was assessment of HER-2 overexpression in malignant and benign breast cancer specimens by Real Time RT-PCR technique and comparison of its results with IHC outcomes.

METHODS

Twenty benign and sixty malignant breast cancers in addition to fifteen normal breast tissue specimens were analyzed by Real Time RT-PCR method. Fresh tissue samples were disrupted by mortar and pestle. A syringe and a needle were used for complete homogenization of the tissues. The RNA was then isolated from the samples and converted to cDNA. A standard curve was initially plotted using BioEasy SYBR Green I and then all 95 specimens were studied by Real Time RT-PCR using 2(-ΔΔCt) method.

RESULTS

23.3% of 60 malignant specimens showed HER-2 overexpression, while all of the benign samples represented the normal expression level of HER-2 gene. The concordance rate between the results of Real Time RT-PCR and IHC was 86.6%.

CONCLUSION

Real Time RT-PCR method is an almost reliable technique and at least can be used as a complementary method for confirming IHC results. This is emanated from relatively high rate of concordance between outcomes of IHC test, as a routine method of detecting the HER-2 gene expression status, and Real Time RT-PCR technique.

Feline HER2 protein expression levels and gene status in feline mammary carcinoma: optimization of immunohistochemistry (IHC) and in situ hybridization (ISH) techniques

Human epidermal growth factor receptor (HER2) is a tumor biomarker that when overexpressed and/or amplified is associated with a poor prognosis for women with breast cancer. This specific tumor subtype is eligible for a specific immunotherapy that increases survival period. However, in feline oncology, only a few studies have been performed on molecular characterization of feline (fHER2) in feline mammary carcinoma (FMC), and the available data are inconsistent. In this study, fHER2 protein levels and gene status in FMC were evaluated by immunohistochemistry and in situ hybridization. After being optimized, these techniques revealed that fHER2 is overexpressed in 33% of FMC cases, although fHER2 and fTOP2A gene amplification could not be observed. Our results support the possibility of using FMC as a natural model for comparative oncology. Additional data obtained may also improve the diagnostics, and consequently the treatment, of this type of tumor in veterinary medicine.

Elevated expression of podocalyxin is associated with lymphatic invasion, basal-like phenotype, and clinical outcome in axillary lymph node-negative breast cancer

Lymphatic invasion (LVI) is associated with disease recurrence in axillary node-negative (ANN) breast cancer. Using gene expression profiling of 105 ANN tumors, we found that podocalyxin (PODXL) was more highly expressed in tumors with LVI (LVI+) than in those without LVI (LVI-). Differences in PODXL expression were validated using real-time polymerase chain reaction as well as by immunohistochemistry in an independent set of 652 tumors on tissue microarrays. Disease-free survival (DFS) analyses were conducted for association of high PODXL protein expression with risk of distant recurrence overall and within breast cancer subtypes using both Cox and cure-rate models. High PODXL expression was associated with poor prognosis features including large tumor size, high histological grade, estrogen and progesterone receptor negativity, and with clinical alterations characteristic of the basal-like breast cancer phenotype. Surprisingly, despite having other poor prognosis characteristics, women with high PODXL expressing tumors had better long-term DFS in multivariate analysis with traditional clinicopathologic factors including LVI and HER2 status (P = 0.001). PODXL has the potential to be a useful biomarker for identifying good prognosis patients in characteristically poor prognosis breast cancer groups and may impact treatment of women with this disease.

Tumoral lymphocytic infiltration and expression of the chemokine CXCL10 in breast cancers from the Ontario Familial Breast Cancer Registry

PURPOSE

Breast carcinomas, including basal and hereditary cases, often present with a prominent tumoral lymphocytic infiltrate. Chemokines could play a role in attracting these cells and contribute to tumor progression. We explored tumoral expression of CXCL10 and determined the relationship between CXCL10 and lymphocytic infiltrate in a cohort of breast cancers.

EXPERIMENTAL DESIGN

Using tissue microarrays of 364 breast tumors, we evaluated expression of CXCL10 and its receptor, CXCR3, in relation to histopathologic features, biomarkers, and lymphocyte markers. In addition, we overexpressed CXCL10 and CXCR3 in MCF7 breast cancer cells and monitored T-lymphocyte migration and invasion.

RESULTS

Forty-five percent of tumors expressed CXCL10, and a significant association was found with CXCR3 and lymphocytic infiltrate. Further characterization of the lymphocytic infiltrate revealed an association with CXCL10 expression for peritumoral CD4+ and CD8+ lymphocytes. CD8+ intratumoral lymphocytes, FOXP3+ regulatory T cells (Tregs), and T-BET+ T(H)1 cells were associated with BRCA1 and basal tumors. Conditioned media from MCF7 cells overexpressing both CXCL10 and CXCR3 increased T-lymphocyte migration and invasion.

CONCLUSIONS

Our findings suggest that CXCL10 may act in a paracrine manner, affecting the tumor microenvironment, and in an autocrine manner, acting on the tumor cells themselves and may play a role in tumor invasiveness and progression. The CXCL10-CXCR3 axis can serve as a potential target in BRCA1 and basal breast cancers, which present with a prominent lymphocytic infiltrate and a poor prognosis. Clin Cancer Res; 19(2); 336-46. ©2012 AACR.

Hematopoietic progenitor cells (HPCs) in node-negative invasive breast carcinomas: Immunohistochemical analysis and clinico-pathological correlations

Using immunohistochemistry, we investigated 603 negative lymph nodes from 51 patients affected by invasive breast cancer (BC) to recognize bone marrow-derived hematopoietic progenitor cells (HPCs). HPC aggregates, revealed by CD34, CD133, VEGFR1, and CD117 antisera, were determined by an intensity-distribution score (ID). Cases with an ID-score >3 at least for one marker were considered to strongly express HPCs. Twenty-five of 51 (49%) high expressor patients were identified by CD34 antiserum, while 24/51 (47.1%), 17/51 (33.3%), and 15/51 (29.4%) were identified by CD117, CD133, and VEGFR1, respectively. No significant relationships were found between HPCs status and histotype, tumor grade, stage, and hormone receptors, as determined at the moment of the first diagnosis. A significant correlation was recorded for Ki-67 values, as well as for death from invasive BC. No statistical significance was achieved regarding HER2 status, although a tendency toward a statistically significant P value was obtained. A significant relationship (P<0.001) was found between high expressors of HPC and progression of disease, documented by the development of distant metastases. An equivalent P value was ascertained for osseous localizations, with a lesser value in other metastatic sites. Regarding the appearance of distant metastases, the greatest efficiency value was obtained by CD133 (85.7%). Overall survival (OS) and distant metastases-free survival (DMFS) revealed a high statistical significance for HPC expression, Ki-67 values, and HER2 status. By multivariate analysis, HPC expression and Ki-67 values emerged as the higher independent prognostic variables in the analysis of DMFS and OS, respectively.

CK8/18 expression, the basal phenotype, and family history in identifying BRCA1-associated breast cancer in the Ontario site of the breast cancer family registry

BACKGROUND

BRCA1-associated breast cancer had been shown to be morphologically and genetically distinct from sporadic cancers. The aim of this study was to determine the association of CK8/18 with BRCA1-associated tumors and if, by using CK8/18 and basal biomarkers in conjunction with morphologic features and family history characteristics, the specificity of the BRCA1-associated tumor profile in a pathologically well-characterized cohort would be improved.

METHODS

Fifty-eight patients with known BRCA1 germline mutations and 221 control (familial non-BRCA) patients were selected from the Ontario Familial Breast Cancer Registry. From this database, information on family history and morphologic features was abstracted. Tissue microarrays were constructed and immunohistochemistry to determine expression of several biomarkers was performed. After a logistic regression fit, a best-subsets variable-selection procedure using model performance and predictive ability measures was applied to find a best predictor to distinguish BRCA1-associated tumors from non-BRCA associated tumors.

RESULTS

BRCA1-associated tumors differed significantly from control tumors in terms of morphology, family history, and biomarker profile. CK8/18 was highly significantly associated with BRCA1 tumors. Consistently, BRCA1 cancers showed low levels of CK8/18 compared to non-BRCA tumors, whether they were basal-like or not. A combination of 7 factors, including CK8/18 and family history, best predicted the BRCA1-associated cancers.

CONCLUSIONS

CK8/18 expression was independently associated with BRCA1-associated breast cancers. Reduced CK8/18 expression in conjunction with the basal-like phenotype and family history may have improved the ability to identify which tumors were likely to be associated with a BRCA1 germline mutation and thereby help streamline genetic testing.

Genetic and expression analysis of HER-2 and EGFR genes in salivary duct carcinoma: empirical and therapeutic significance

PURPOSE

Salivary duct carcinoma overexpresses epidermal growth factor receptor (EGFR) and HER-2, although the underlying mechanisms remain undefined. Because of the potential utilization of these markers as treatment targets, we evaluated protein and gene status by several techniques to determine complementary value.

EXPERIMENTAL DESIGN

A tissue microarray of 66 salivary duct carcinomas was used for immunohistochemical analysis of HER-2 and EGFR expression (semiquantitatively evaluated into a three-tiered system), and fluorescence in situ hybridization for gene copy number, and chromosomes 7 and 17 ploidy status. Sequencing of exons 18, 19, and 21 of the EGFR gene for mutations was carried out.

RESULT

For EGFR, 46 (69.7%) of the 66 tumors showed some form of EGFR expression (17 at 3+, 17 at 2+, 12 at 1+) but none gene amplification. Five (9.4%) of 53 tumors showed mutations in exon 18 (n = 3) and exon 19 (n = 2). Polysomy of chromosome 7 (average >2.5 copies/cell) was detected in 15 (25.0%) of 60 tumors (6 at 3+, 5 at 2+, 2 at 1+, 2 at 0+ expression) and correlated with poor 3-year survival (P = 0.015). For HER-2, 17 (25.8%) of 66 tumors expressed HER-2 (10 at 3+, 3 at 2+, 4 at 1+). Eight tumors showed HER-2 gene amplification (6 at 3+, 1 at 1+, 1 at 0+ protein expression). Chromosome 17 polysomy was found in 8 (15.7%) of 51 tumors; two had HER-2 expression (3+, 1+).

CONCLUSION

Our study shows that salivary duct carcinomas (a) harbor EGFR gene mutations in a subset of tumors that may guide therapy, (b) pursue an aggressive clinical course in cases with chromosome 7 polysomy and high EGFR expression, and (c) with HER-2 gene amplification and protein high expression, may be selected for targeted therapy.

Borderline HER‐2 breast cancer cases: Histochemical versus real‐time PCR analysis and impact of different cut‐off values

Seventy-one cases that had resulted borderline for HER-2 protein expression at conventional immunohistochemical assay (2+) were assessed for HER-2 gene amplification by real-time PCR and by FISH in accordance with the manufacturer's recommendations (gene amplification with ratio >or=2 in both methods). Thirty-three out of 71 cases (47%) resulted amplified at real-time PCR analysis, whereas 15 cases resulted positive at FISH (21%). Apparently, PCR was more sensitive than FISH in HER-2 determination, only 10 cases resulting amplified in both tests. When the mean ratio value obtained in all PCR experiments was adopted as threshold in determining HER-2 gene amplification, the apparent sensitivity of PCR was reduced but correlation between PCR and FISH results was dramatically increased. Furthermore, when the mean PCR ratio value observed in the FISH-positive group was chosen as threshold, the best agreement between PCR and FISH results was achieved. Therefore, we found that the proposed threshold ratio value of >or=2 is not accurate in separating HER-2 amplified and non-amplified cases. We suggest that the threshold ratio value in PCR tests should be determined in each laboratory using FISH controlled cases. Finally, above certain in-lab generated threshold values, PCR might be proposed as a highly predictive positive test in HER-2 assessment.

The epidermal growth factor receptor family in breast cancer

THE HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR (HER) FAMILY COMPRISES FOUR HOMOLOGOUS MEMBERS: EGFR, HER-2, HER-3, and HER-4. The activation of these receptors triggers a complex series of signal transduction pathways which affect pivotal tumorigenic processes. The deregulation of HER signaling is seen in several human malignancies. HER-2 is now recognized as a key oncogene in breast cancer pathogenesis. Assessment of HER-2 status is of central importance in the prognosis of breast cancer patients. In the light of clinical data suggesting that HER-2 can also be useful as a predictive marker both for trastuzumab and chemotherapy, standardized determination of the HER-2 status in tumors has become more important. Moreover, current data provide evidence for the significance of HER-3 and HER-4 alterations in breast carcinogenesis. Because of the complex interactions among the HER receptors, it is likely that the effect on cell proliferation and tumor growth depends on receptor trans-signaling and thus, the evaluation of the combined expression pattern of all family members is of particular interest. This review presents the current evidence highlighting the role of the family as a whole panel and an update on the role of HER-3 and HER-4 receptors in breast cancer. Moreover, we provide updated data regarding the prognostic value of HER family members giving emphasis to novel methods for the determination of their status, such as real-time polymerase chain reaction. In addition, we review recent therapeutic approaches aimed at targeting the HER family in breast cancer patients.

Prognostic effect of basal-like breast cancers is time dependent: evidence from tissue microarray studies on a lymph node-negative cohort

PURPOSE

To determine whether data obtained from tissue microarrays (TMA) of a prospectively accrued node-negative breast cancer cohort are prognostically informative, we compared data derived from TMA with previously determined molecular markers. Subsequent to this validation, we examined outcome in specific subgroups defined using TMA data.

EXPERIMENTAL DESIGN

A consecutive series of 1,561 patients were followed for recurrence (median follow-up of 107 months). Estrogen receptor, progesterone receptor, p53, and HER2 expression, examined using TMA constructed from 887 tumors, was compared with status evaluated previously by biochemical and molecular methods. The associations with risk of recurrence were examined for biomarkers as well as for HER2, luminal, and basal subgroups defined by immunohistochemical expression.

RESULTS

In line with earlier molecular studies, a significant risk of recurrence was found in patients with HER2 overexpression (relative risk = 2.30; P = 0.002) and p53-positive tumors (relative risk = 1.81; P = 0.005) in univariate Cox model analysis. Although complete concordance between methodologies was not observed for estrogen receptor and progesterone receptor, their associations with disease-free survival were consistent with established prognostic findings. Patients with basal-type tumors fared worse within 36 months of diagnosis but not thereafter.

CONCLUSIONS

This study shows the clinical validity of TMA in evaluating the importance of prognostic markers in this cohort. Furthermore, it shows a marked time-dependent effect in tumor subgroups, most notable within the basal subgroup. Our data suggest that patients with basal-like tumors may be broadly separable into two clinically distinctive groups: those likely to experience disease recurrence in the short term and those that will experience long-term survival.

HER2 testing in a population-based study of patients with metastatic breast cancer treated with trastuzumab

CONTEXT

The development of trastuzumab has led to new therapeutic strategies for patients with breast cancer. Trastuzumab has been shown to only be effective in those patients whose cancers are HER2 positive by either immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH).

OBJECTIVE

To determine the accuracy of HER2 testing in 2 provinces in Canada.

DESIGN

Patients with metastatic breast cancer diagnosed between 1999 and 2002 who were HER2 positive in the local laboratories were included in this study. All cases were retested centrally, by IHC (using 4 methods) and FISH. In addition, 205 locally reported HER2-negative metastatic breast cancer cases were retested centrally.

RESULTS

Concordance between the 505 local IHC-positive cases with central IHC testing varied between 79.3% and 89.6% depending on the IHC method and scoring method used. HER2 gene amplification by FISH was present in 86.1% of local IHC-positive cases. Concordance between the 205 local IHC-negative tumors with central testing ranged between 94.8% and 100% for IHC and was 98.5% for FISH.

CONCLUSIONS

This study demonstrated that locally reported HER2-negative results were highly accurate, but less accuracy was demonstrated with local HER2-positive results. These results emphasize the need for participation in a quality assurance program.

Metallographic in situ hybridization

Metallographic methods, in which a target is visualized using a probe or antibody that deposits metal selectively at its binding site, offers many advantages for bright-field in situ hybridization (ISH) detection as well as for other labeling and detection methods. Autometallographically enhanced gold labeling procedures have demonstrated higher sensitivity than conventional enzyme chromogens. Enzyme metallography, a novel procedure in which an enzymatic probe is used to deposit metal directly from solution, has been used to develop bright-field ISH methods for HER2 gene determination in breast cancer and other biopsy specimens. It provides the highest level of sensitivity and resolution, both for visualizing endogenous gene copies in nonamplified tissues and for resolving multiple gene copies to allow copy enumeration in amplified tissues without the need for oil immersion or fluorescence optics. An automated enzyme metallography procedure, silver ISH, has been developed for use in slide-staining instruments. Metallographic staining also provides excellent results for immunohistochemistry and may be combined with other staining procedures for the simultaneous detection of more than one gene or combinations of genes and proteins.

Gene copy numbers of HER family in breast cancer

AIM

The aim of the study was to analyze the occurrence of abnormal gene copy numbers of all HER oncogenes and to correlate these alterations to other clinicopathological variables in a consecutive series of 225 breast cancer patients.

METHODS

Gene copy number of HER oncogenes was analyzed with double differential polymerase chain reaction (ddPCR). Statistical analysis was performed with a set of nonparametric tests.

RESULTS

Sixty-five percent of the tumors contained abnormal gene copy number of at least one HER oncogene. Alterations of at least two oncogenes were found in 31% of cases. The correlations between average gene copy numbers (AGCNs) of particular HER oncogenes were much stronger in node positive compared to node-negative tumors. Deletions of EGFR were associated with the lack of steroid hormone receptors. The HER3 and HER4 amplifications were more common in well differentiated tumors.

CONCLUSIONS

Our results indicate a key role of HER heterodimers in tumor progression and confirm earlier data that HER2 is the preferred partner for other HER oncogenes in this process. Deletions of EGFR were associated with unfavorable characteristics, whereas HER3 and HER4 amplifications may be linked with less aggressive phenotypes.

BRCA2 mutation-associated breast cancers exhibit a distinguishing phenotype based on morphology and molecular profiles from tissue microarrays

A distinct morphologic and molecular phenotype has been reported for BRCA1-associated breast cancers; however, the phenotype of BRCA2-associated breast cancers is less certain. To comprehensively characterize BRCA2-associated breast cancers we performed a retrospective case control study using tumors accrued through the Breast Cancer Family Registry. We examined the tumor morphology and hormone receptor status in 157 hereditary breast cancers with germline mutations in BRCA2 and 314 control tumors negative for BRCA1 and BRCA2 mutations that were matched for age and ethnicity. Tissue microarrays were constructed from 64 BRCA2-associated and 185 control tumors. Tissue microarray sections were examined for HER2/neu protein overexpression, p53 status and the expression of basal markers, luminal markers, cyclin D1, bcl2, and MIB1 by immunohistochemistry. The majority of BRCA2-associated tumors and control tumors were invasive ductal, no special-type tumors. In contrast to control tumors, BRCA2-associated cancers were more likely to be high grade (P<0.0001) and to have pushing tumor margins (P=0.0005). Adjusting for grade, BRCA2-associated tumors were more often estrogen receptor positive (P=0.008) and exhibited a luminal phenotype (P=0.003). They were less likely than controls to express the basal cytokeratin CK5 (P=0.03) or to overexpress HER2/neu protein (P=0.06). There was no difference in p53, bcl2, MIB1, or cyclin D1 expression between BRCA2-associated and control tumors. We have demonstrated, in the largest series of BRCA2-associated breast cancers studied to date, that these tumors are predominantly high-grade invasive ductal carcinomas of no special type and they demonstrate a luminal phenotype despite their high histologic grade.

Insulin receptor is an independent predictor of a favorable outcome in early stage breast cancer

Fasting insulin is related to outcome in early breast cancer. We evaluated the expression of insulin receptor (IR) and its prognostic significance in patients with early stage breast cancer. Tumors from 191 patients with T1-3, N0-1, M0 breast cancer who were enrolled at a single center of a multicenter cohort study were used to construct microarrays with subsequent immunohistochemical evaluation of IR, IGF-IR, ER, PgR and HER2/neu. Correlation of biomarker expression with traditional prognostic factors, serum biochemistry (notably insulin) and clinical outcome was assessed. IR was strongly positive (Allred score = 8) in 54% of tumors. High IR expression significantly correlated with favorable prognostic markers (low tumor grade, lymph node negativity and progesterone receptor positivity) but not with fasting levels of circulating insulin. At a median follow-up of 9.1 years, high vs. low IR expression (an Allred score of 8 vs. 0-7) was associated with statistically significant improved distant disease-free survival (multivariate hazard ratio (HR) = 0.4; P = 0.027) and overall survival (multivariate HR = 0.26; P = 0.005). IR is highly expressed in the majority of early stage breast cancers but this expression is not clearly down-regulated in the presence of high insulin levels. Furthermore, high expression of IR is independently and significantly associated with more favorable clinical outcomes. Follow-up intervention research is recommended.

The effects of antibody clone and pretreatment method on the results of HER2 immunostaining in cytologic samples of metastatic breast cancer: A query and a review of the literature

The standardization and use of heat-induced epitope retrieval (HIER) is particularly important with immunohistochemical markers that direct the course of cancer treatment, such as Herceptin therapy. Increasingly, many laboratories are performing immunohistochemical analysis using various antibodies and methodologies for HER2/neu. We attempted to determine the effects of antibody clone and pretreatment methods on the interpretation of HER-2/neu staining in cytologic samples. Cell block sections from 54 cases of metastatic breast cancer (24 FNAs, 30 effusions) were analyzed for HER2 expression using antibodies to CB-11, TAB250, and A0485. Antibodies were analyzed with and without HIER. One pathologist using the FDA-approved scoring system for the HercepTest reviewed all slides in a blinded fashion. Five of fifty-four cases (9%) using CB-11 showed a significant increase in HER2 immunoreactivity using HIER (i.e. from 0/1+ to 2-3+). However, in twenty-nine of fifty-four cases (54%), the cytoplasmic background was significantly higher after HIER. With the A0485 antibody, two of fifty four cases (4%) showed a significant increase in immunoreactivity using HIER, while seventeen of fifty-four cases (31%) exhibited only more pronounced cytoplasmic staining. HIER pretreatment did not increase HER2 staining in any TAB250 stained sample, rather four of fifty-four cases (7%) showed a significant decrease in staining with HIER. We conclude that HIER may enhance membrane staining with the CB-11 and A0485 antibodies, but also increases cytoplasmic background. Loss of antigenicity is seen when HIER is used with TAB250.

Detection of HER-2/neu gene amplification in breast carcinomas using quantitative real-time PCR - a comparison with immunohistochemical and FISH results

The aim of our study was to evaluate the value of quantitative real-time-PCR (qPCR) in the determination of HER-2/neu amplification status of human breast carcinomas by comparing qPCR, FISH and immunohistochemistry results from the same samples. A total of 210 breast carcinomas were examined. Ready-to-use CB11 antibody was applied to detect HER-2/neu oncoprotein expression. In 76 out of 210 cases FISH was performed, and 162 cases were investigated with qPCR. Seventy-five tumors were 2+ or 3+ positive with immunohistochemistry, while 135 samples were either completely negative or 1+. In 45 cases results from all three methods were available. Out of these, in twenty negative and sixteen positive cases both FISH and qPCR led to similar results. The mean qPCR amplification ratio in the concordant positive cases was 5.424 while in the qPCR+/FISH- group the mean ratio was 2.765. Out of 121 samples with scores of 0 or 1+ immunohistochemical result, analyzed also with qPCR, 26 showed HER-2/neu gene amplification. In these cases the mean amplification ratio was 2.53. Comparison of FISH and qPCR together with immunohistochemistry shows that qPCR is more sensitive to detect HER-2/neu gene amplification in tumors scored as 2+ with immunohistochemistry, but the diagnostic cut-off ratio should be defined above 2.7 to avoid high number of false positive cases. Amongst the immunohistochemistry score 2+ cases, 10 of 18 showed gene amplification by qPCR while 10 of 26 by FISH. In conclusion, a well calibrated HER-2/neu qPCR assay may serve as useful alternative to FISH in breast cancer patients.

HER2 and responsiveness of breast cancer to adjuvant chemotherapy

BACKGROUND

Amplification of the human epidermal growth factor receptor type 2 (HER2, also called HER2/neu) gene and overexpression of its product in breast-cancer cells may be associated with responsiveness to anthracycline-containing chemotherapy regimens.

METHODS

In the randomized, controlled Mammary.5 trial, we studied 639 formalin-fixed paraffin-embedded specimens obtained from 710 premenopausal women with node-positive breast cancer who had received either cyclophosphamide, epirubicin, and fluorouracil (CEF) or cyclophosphamide, methotrexate, and fluorouracil (CMF) as adjuvant chemotherapy. HER2 amplification or overexpression was evaluated with the use of fluorescence in situ hybridization, immunohistochemical analysis, and polymerase-chain-reaction analysis.

RESULTS

Amplification of HER2 was associated with a poor prognosis regardless of the type of treatment. In patients whose tumors showed amplification of HER2, CEF was superior to CMF when assessed on the basis of relapse-free survival (hazard ratio, 0.52; 95 percent confidence interval, 0.34 to 0.80; P=0.003) and overall survival (hazard ratio, 0.65; 95 percent confidence interval, 0.42 to 1.02; P=0.06). For women whose tumors lacked amplification of HER2, CEF did not improve relapse-free survival (hazard ratio for relapse, 0.91; 95 percent confidence interval, 0.71 to 1.18; P=0.49) or overall survival (hazard ratio for death, 1.06; 95 percent confidence interval, 0.83 to 1.44; P=0.68). The adjusted hazard ratio for the interaction between treatment and HER2 amplification was 1.96 for relapse-free survival (95 percent confidence interval, 1.15 to 3.36; P=0.01) and 2.04 for overall survival (95 percent confidence interval, 1.14 to 3.65; P=0.02).

CONCLUSIONS

Amplification of HER2 in breast-cancer cells is associated with clinical responsiveness to anthracycline-containing chemotherapy. (cancer.gov number, NCI-V90-0027.).

Selecting Antibodies to Detect HER2 Overexpression by Immunohistochemistry in Invasive Mammary Carcinomas

There is an increasing clinical demand for HER2 analysis in breast cancer, especially since the release of trastuzumab. The authors assessed the ability of immunohistochemistry to detect HER2 overexpression in invasive mammary carcinomas (IMC) using five antibodies. Paraffin-embedded samples of 86 IMCs (T2N0) were used to compare the immunohistochemical overexpression of HER2 using two polyclonal antibodies (HercepTest [DAKO] and A0485 [DAKO]) and three monoclonal antibodies (CB11 from two different laboratories, Biogenex and Novocastra, and 4D5 [Genentech]). All immunostainings were scored according to the FDA-approved HercepTest recommendations. The HercepTest-positive cases were compared with gene amplification by FISH (Oncor Inform, Ventana). The HercepTest was positive in 31 of the 86 cases (36.1%). The DAKO antibody A0485 was positive in 25 of the 66 (37.8%). Monoclonal antibody 4D5 was positive in only 15 of the 86 cases (17.4%). There was almost total agreement in results between the two CB11 antibodies: 25 of the 86 positive cases (29.1%). All cases positive for CB11 or 4D5 were HercepTest positive. Most of the HercepTest 2+ cases were negative when using either monoclonal antibody. FISH was positive in 19 of the 20 HercepTest 3+ cases and negative in 5 HercepTest 2+ cases. Three CB11-2+ cases showed no amplification by FISH. In three FISH-positive cases the immunohistochemistry showed no overexpression by all antibodies used. These findings suggest that immunohistochemistry may be used reliably as a primary methodology for evaluating HER2; however, the use of polyclonal antibodies may not be adequate to assess HER2 overexpression. CB11, regardless of the manufacturer (Biogenex or Novocastra), showed better concordance with FISH (kappa=0.83) than did the polyclonal antibodies.

Expression of HER2 and the coamplified genes GRB7 and MLN64 in human breast cancer: quantitative real-time reverse transcription-PCR as a diagnostic alternative to immunohistochemistry and fluorescence in situ hybridization

PURPOSE

Accurate testing of HER2 is centrally important for breast cancer therapy and prognosis. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are current standard testing methods. As a potential alternative for assessment of HER2, we explored quantitative real-time reverse transcription-PCR (RT-PCR), a fast and inexpensive method yielding quantitative results insensitive to interobserver variability and amenable to standardized scoring.

EXPERIMENTAL DESIGN

We assessed HER2 status at the DNA, mRNA, and protein levels with FISH, quantitative RT-PCR, and IHC in 136 tumor samples from 85 breast cancer patients. Expression of GRB7, MLN64, and p21, genes coregulated with HER2, was also quantified with quantitative RT-PCR and correlated with the overall survival (OS) and disease-free survival (DFS) individually and in combination with HER2.

RESULTS

Twenty-nine percent and 19% of the patients scored HER2 positive with IHC and quantitative RT-PCR, respectively. In 18 of 19 cases, HER2 statuses in tumors and lymph node metastases were identical. HER2 status significantly correlated with DFS when determined by IHC (P < 0.01), quantitative RT-PCR (P < 0.003), but not with FISH (P = 0.09). The combination of HER2 with MLN64, but not with GRB7 or p21, enhanced the prognostic power for the DFS (P < 0.00005) and OS (P < 0.0008).

CONCLUSIONS

Quantitative RT-PCR seems to be clinically as useful in the assessment of HER2 status as IHC and FISH, yielding comparable correlations of HER2 status with the OS and DFS. Thus, quantitative RT-PCR analysis of HER2 or HER2 plus MLN64 is a promising complement or alternative to current methods for HER2 testing, particularly in laboratories lacking FISH or IHC technology.

Evaluation of the quantitative analytical methods real-time PCR for HER-2 gene quantification and ELISA of serum HER-2 protein and comparison with fluorescence in situ hybridization and immunohistochemistry for determining HER-2 status in breast cancer patients

BACKGROUND

HER-2 status is generally determined by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH). Both methods are only semiquantitative, require a tumor sample, and can be difficult to reproduce. We compared these methods with 2 quantitative approaches, one measuring HER-2 gene copy number in tissue by real-time quantitative PCR (qPCR), and the other measuring shed HER-2 protein in serum by ELISA in patients with metastatic disease.

METHODS

We analyzed 52 cases of metastatic breast cancer for which both serum collected at the diagnosis of metastasis and stored primary breast tumor specimens were available. The within- and between-run imprecision of real-time qPCR and ELISA were evaluated according to Clinical and Laboratory Standards Institute (formerly known as NCCLS) recommendations. Concordance among the 4 methods was assessed by calculating the kappa statistic and its 95% confidence interval (95% CI).

RESULTS

The CVs for within- and between-run imprecision were both <10% with qPCR and ELISA. There was good agreement of results between qPCR and IHC (kappa = 0.81; 95% CI, 0.64-0.99), qPCR and FISH (kappa = 0.77; 95% CI, 0.58-0.96), ELISA and IHC (kappa = 0.65; 95% CI, 0.41-0.89); and ELISA and FISH (kappa = 0.69; 95% CI, 0.46-0.92).

CONCLUSIONS

Measurements of HER-2 gene expression by qPCR and of serum HER-2 protein by ELISA are highly reproducible approaches for determining HER-2 status in metastatic breast cancer. In addition, ELISA eliminates the need for biopsy.

Invasive lobular carcinoma: to grade or not to grade

Grading of invasive ductal carcinoma of no special type using the Nottingham combined histologic grading system provides independent prognostic information. The prognostic utility of grading invasive lobular carcinomas, however, has not been fully elucidated. In addition, the relationship between grade in invasive lobular carcinomas and expression of predictive biomarkers is less certain. The purpose of this study was to correlate histologic grade in invasive lobular carcinoma with known prognostic and predictive markers. All primary resections for invasive mammary carcinomas diagnosed in Mount Sinai Hospital, Toronto, between the years 1996 and 2002 were reviewed (n=1053). Of these cases, 50 were pure invasive lobular carcinoma (incidence 4.7%). The median age at diagnosis was 64 years. These tumors were graded using the Nottingham combined histologic grading system and analyzed for estrogen receptor, progesterone receptor, HER2/neu and E-cadherin expression. Tumor grade was correlated with tumor size (P=0.03), and the American Joint Committee on Cancer nodal status (P=0.05). Assessment of the individual components of grade showed that the mitotic score was highly correlated with tumor size (P=0.02), lymph node positivity (P=0.02) and overall American Joint Committee on Cancer stage (P=0.01). Estrogen receptor and progesterone receptor were highly expressed irrespective of the grade of tumor. HER2/neu protein overexpression and E-cadherin protein expression was absent in all invasive lobular carcinomas studied. We conclude that pure invasive lobular carcinoma is uncommon and occurs predominantly in postmenopausal women. Increasing tumor grade is correlated with median tumor size and the American Joint Committee on Cancer nodal stage, but not correlated with the expression of estrogen receptor, progesterone receptor, E-cadherin or HER2/neu protein overexpression.

Interlaboratory comparison in HercepTest assessment of HER2 protein status in invasive breast carcinoma fixed with various formalin-based fixatives

Although formalin-based fixatives are used in pathologic laboratories, there is no strictly standardized fixation protocol in Japan. To examine interlaboratory variation caused by different conditions of fixation in the assessment of human epidermal growth factor receptor (HER) 2 status on pathologic tissues, 274 archival invasive breast carcinomas from 5 different laboratories were evaluated using the HercepTest. In 1 laboratory in which 10% neutral buffered formalin was used, as recommended by the manufacturer, the overexpression rate was 22.4% and fell within the statistical expected range (20%-30%) for HER2 overexpression in breast carcinomas. The overexpression rates in the other 4 laboratories, in which either 20% nonbuffered formalin or 15% neutral buffered formalin was used, were near the expected range for HER2 overexpression. To clarify the influence of prolonged formalin fixation on the HercepTest, we compared 1-day with 7-day fixations using 36 cases fixed with 20% nonbuffered formalin. Of the 36 cases, 7 showed 3+ staining with 1-day fixation and sustained the same scoring results with 7-day fixation, although the staining intensities in these cases were reduced with the prolonged fixation. These results indicated that the immunohistochemical assessment of HER2 status with the HercepTest was comparatively resistant to prolonged fixation conditions and provided stable staining results in positive cases, particularly 3+ patients.

Identification of HER2/neu-Derived Peptides Capable of Inducing both Cellular and Humoral Immune Responses in HLA-A24 Positive Breast Cancer Patients

HRE2/neu-specific cellular and humoral immune responses are often detected in breast cancer patients, but identification of more immunogenic CTL epitope peptides is necessary prior to development of a cancer vaccine. There is accumulating evidence of strong immunogenicity of peptides capable of inducing both cellular and humoral immune responses. To identify such peptides, this study intended to determine HER2/neu-derived peptides capable of inducing both cellular and humoral immunity in HLA-A24(+) breast cancer patients. IgGs reactive to the HER2(342-350), HER2(485-493), and HER2(553-561) peptides were detected in the sera of these patients with the frequency of 47, 24, and 24%, respectively. These peptides also induced peptide-specific and tumor-reactive CTL activity in the peripheral blood mononuclear cells of HLA-A24(+) breast cancer patients with the frequency of 50, 63, and 25%, respectively, but such activity was not induced from any HLA-A24(-) patients. Cellular and humoral responses to each of these three peptides were also observed in PBMCs and sera from the other epithelial cancer patients. These results may provide a scientific basis for new clinical trials of HER2/neu-peptide-based immunotherapy for breast cancer and also other epithelial cancer patients.

Amplification of the TOP2A gene does not predict high levels of topoisomerase II alpha protein in human breast tumor samples

Recent clinical trials have suggested that patients whose breast tumors overexpress HER2 may derive particular benefit from anthracycline-containing chemotherapy compared to that without anthracycline. It has been proposed that the HER2 gene amplification reported in these tumors might mask an underlying TOP2A gene amplification that occurs frequently and concurrently with HER2 amplification. Topoisomerase II alpha, encoded by TOP2A, is a direct molecular target of anthracycline drug action and is potentially useful as a predictive marker of response to anthracycline therapy for breast cancer. In this study, we examined whether TOP2A gene amplification is an appropriate marker for identifying breast tumors expressing high levels of topoisomerase II alpha. We determined topoisomerase II alpha protein expression by immunohistochemistry in 81 human breast tumors in relation to HER2 and TOP2A gene copy numbers analyzed by fluorescence in situ hybridization, histologic grade, cell proliferation fraction measured by MIB-1 expression, and HER2 protein expression determined by immunohistochemistry. The results showed no correlation between TOP2A gene copy number and topoisomerase II alpha protein expression levels in breast tumors, in contrast to the analogous situation for HER2 gene amplification and HER2 immunohistochemistry. Our results suggest that TOP2A gene amplification in breast tumors does not predict high expression of topoisomerase II alpha protein.

Molecular markers in breast cancer: can we use c-erbB-2, p53, bcl-2 and bax gene expression as prognostic factors?

We examined the prognostic value of c-erbB-2, p53, bcl-2 and bax overexpression in breast cancer. Immunostaining for c-erbB-2, p53, bcl-2 and bax gene expression was performed on 121 paraffin-embedded specimens of Stage I, II and III breast cancer patients diagnosed and treated in Hippokration Hospital, Athens Medical School, between 1986 and 1992. The primary tumor from 27 (24.1%), 69 (59%), 18 (15%) and 63 (53.4%) patients stained positively for c-erbB-2, p53, bcl-2 and bax gene expression, respectively. Significant correlations were found between bax overexpression and age (P=0.04), tumor size (P=0.02) and disease stage (P=0.001), while no other significant associations were found between other molecular markers and clinical or histological parameters. None of the individual molecular markers examined proved to be independent prognostic factor for patients with breast carcinoma. C-erbB-2, p53, bcl-2 and bax genes have limited prognostic value. An approach that combines several molecular markers with established clinicopathological criteria may help physicians make more accurate predictions of prognosis in patients with breast cancer.

Comparative value of tumour grade, hormonal receptors, Ki-67, HER-2 and topoisomerase II alpha status as predictive markers in breast cancer patients treated with neoadjuvant anthracycline-based chemotherapy

The aim of this study was to evaluate the predictive value of five different biological factors in breast cancer patients treated with neoadjuvant anthracycline-based chemotherapy: (1) tumour grade scored according to the Elston-Ellis classification, (2) hormonal receptor (HR) status; (3) tumour cell proliferation evaluated by Ki-67 staining, (4) HER-2 and topoisomerase II alpha (TopoIIalpha) expression evaluated by immunohistochemistry (IHC), (5) HER-2 and TopoIIalpha amplification evaluated by real-time polymerase chain reaction (PCR). 119 patients with operable breast cancer were treated with six cycles of FEC (100 5-fluorouracil (5-FU) 500 mg/m2, Epirubicin 100 mg/m2, Cyclophosphamide 500 mg/m2). Tumour response was assessed clinically and by computed tomography (CT) scan, then by pathological assessment. The clinical overall response (OR) was 80%, with 19% of complete responders (CR). The radiological OR was 71%, with 16% of CR. A pathological CR was demonstrated in 13% of the patients according to the Sataloff classification. In the multivariate analysis, the absence of HR expression and Ki-67 > or = 20% were predictive for a clinical CR. A high tumour grade was predictive for a pathological CR. Overexpression or amplification of HER2 or Topollcalpha were not predictive of response.

Current Diagnostic Methods of HER-2/neu Detection in Breast Cancer With Special Regard to Real-Time PCR

In this study we compare different diagnostic methods to measure HER-2/neu gene amplification in breast cancer with special regard to real-time polymerase chain reaction. Fifty specimens of breast cancer were analyzed, and the use of laser-assisted microdissection prior to PCR was investigated. A total of 38 of 50 cases showed HER-2/neu overexpression in immunohistochemistry. In the 2+ scored group, 2 of 23 cases turned out to be amplified after FISH analysis and 14 of 15 cases in the 3+ group were amplified. Of the 16 amplified cases, 3 initially were measured as nonamplified by real-time PCR but showed amplification after laser capture microdissection. One case showed amplification by PCR but turned out to have only one copy of chromosome 17 by FISH. All 0 or 1+ scored cases were measured as nonamplified both by FISH and PCR. Initial concordance rate between FISH and PCR was 92% and could be increased to 98% using laser-assisted microdissection. FISH and PCR showed high diagnostic accuracy and concordance while immunohistochemistry overestimates amplification within the 2+ scored group. Therefore, either FISH or PCR should be applied in cases scored 2+ by immunohistochemistry. Diagnostic accuracy of PCR can be increased using laser-assisted microdissection.

HER-2/neu assessment in primary chemotherapy treated breast carcinoma: no evidence of gene profile changing

HER-2/neu protein expression and gene amplification were analyzed in a series of 85 consecutive breast carcinoma patients entered into an adriamicin/taxol primary chemotherapy trial followed by surgery, 45 of whom underwent pre-treatment fine needle aspirate (FNA). Dual color FISH (fluorescent in situ hybridization) assay revealed high-level HER-2/neu gene amplification in the immunocytochemistry (ICC) indicated 3+ cases and no, low or moderate amplification in the ICC 2+ group, consistent with previous findings in untreated patients series. Results obtained with the ICC assay CB 11 showed higher overall concordance with FISH than did the Herceptest ICC assay, but CB 11 was less accurate than Herceptest in terms of selecting patients suitable for Herceptin treatment, which is currently restricted to ICC 3+/FISH amplified patients. The only ICC 3+ low-level amplified case (non-amplified according the two more stringent criteria applied) was found with the CB 11 assay. Comparison between pre-treatment smears and post-treatment sections by FISH revealed no significant changes in the HER-2/neu gene profile. In the clinical setting these findings point to the usefulness of HER-2/neu assessment in chemotherapy-treated patients, when pre-treatment material is unavailable.

The clinical evaluation of HER-2 status: which test to use?

Accurate determination of the status of the type I receptor tyrosine kinase HER-2 in breast carcinomas provides significant insight into patient prognosis and may also inform selection of chemotherapeutic and hormonal treatments. At present, however, the single most important application of HER-2 testing is in the selection of patients for treatment with targeted therapies such as Herceptin. Although, based on current literature, fluorescence in situ hybridization (FISH) detection of HER-2 gene amplification may provide more accurate information in this context, this method is not yet widely available. Therefore, screening by immunohistochemistry (IHC) for HER-2 protein, backed by rigorous quality controls and FISH testing of equivocal cases with intermediate staining intensity, remains the current practice. In laboratories with highly standardized testing and quality assurance procedures, this protocol appears highly effective. Improvements in fixation procedures, standardization of antibodies, and use of automated image analysis may all increase the precision of IHC testing. However, on the basis of current data, there is a case to be made for the wider implementation of FISH testing to determine HER-2 status in breast cancer.

Current perspectives on HER2 testing: a review of national testing guidelines

Knowledge of HER2 status is a prerequisite when considering a patient's eligibility for Herceptin (trastuzumab) therapy. Accurate assessment of HER2 status is essential to ensure that all patients who may benefit from Herceptin are correctly identified. There are several assays available to determine HER2 status: the most common in routine clinical practice are immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Various factors can affect the results achieved with these assays, including the assay antibody/probe, the methodology and the experience of personnel. Many countries have implemented national testing guidelines in an attempt to standardize testing procedures and make results more accurate. These guidelines vary in the level of detail and the number of recommendations. This review looks at areas of consensus between the different national testing guidelines and highlights where errors may arise during the testing procedure. The key point underlined by this review is that whatever method is used to test for HER2 status, the technology must be validated first, and there must be regular internal and external quality control and quality assurance procedures.

HER2 overexpression in muscle-invasive urothelial carcinoma of the bladder: prognostic implications

The HER2 (c-erbB-2) receptor is overexpressed in a variety of human malignant tumors and, in breast carcinoma, has been identified as a target for anti-HER2-directed therapy with the monoclonal antibody (MAb) trastuzumab. The aim of this retrospective study was to evaluate immunohistochemic HER2 expression in a large cohort of muscle-invasive urothelial cell carcinomas of the urinary bladder and to compare the results to pathologic characteristics and survival. Paraffin-embedded tumor specimens from 138 patients undergoing radical cystectomy for muscle-invasive bladder carcinoma were studied immunohistochemically with the Food and Drug Administration (FDA)-approved HercepTest (Dako, Glostrup, Denmark). HER2 overexpression was observed in 57 of 138 tumors (41%) and occurred more frequently in high-grade carcinomas than in low-grade carcinomas (p = 0.036). No significant relationship with HER2 overexpression was registered for tumor staging and lymph node status. Kaplan-Meier curves showed a significantly worse disease-related survival (p = 0.034) in patients with HER2-overexpressing tumors compared to those without HER2 overexpression. In addition to lymph node status (p = 0.0001; relative risk [RR] = 2.93), HER2 status (p = 0.020; RR = 2.22) was identified as an independent predictor for disease-related survival in a multivariate analysis. These results suggest that HER2 expression might provide additional prognostic information in patients with muscle-invasive bladder carcinomas. Because many of these patients harbor HER2-overexpressing tumors, clinical trials evaluating the efficacy of trastuzumab in bladder carcinoma are warranted.

HER-2/neu status and tumor morphology of invasive breast carcinomas in Ashkenazi women with known BRCA1 mutation status in the Ontario Familial Breast Cancer Registry

BACKGROUND

The prevalence of BRCA1 germline mutations is greater in the Ashkenazi Jewish population than in the general North American population. The Ontario Familial Breast Cancer Registry collects clinical and family history data in familial breast carcinoma cases, and unselected Ashkenazi breast carcinomas, and acts as a tumor tissue repository.

METHODS

Using this resource, we examined the tumor morphology, hormone receptor status, and HER-2/neu protein overexpression in Canadian Ashkenazi breast carcinoma patients whose germline BRCA1 mutation status is known.

RESULTS

Thirty-eight tumors from 32 BRCA1 carriers and 354 tumors from 334 noncarriers were analyzed. The tumors in BRCA1 mutation carriers were more likely to be high grade (P < 0.0001) and estrogen receptor negative (P < 0.004). There was an increased frequency of typical medullary carcinomas in mutation carriers when all tumors were analyzed. However, this difference did not remain statistically significant when only the first tumor diagnosed in each patient was included in the analysis. There was no difference in HER-2/neu protein overexpression between the two groups overall (P = 0.07). However, when the analysis was restricted to Grade III tumors, there were significantly fewer HER-2/neu-positive tumors in the mutation carriers versus noncarriers (3.1% vs. 21.5%, P = 0.012). No significant differences were found in the incidence of lymph node status, progesterone receptor status, lymphatic vessel invasion, degree of lymphocytic infiltration, or in the presence of ductal carcinoma in situ associated with the invasive tumors.

CONCLUSIONS

Increasing awareness of the morphologic and immunophenotypic features more commonly found in BRCA1-associated breast carcinomas may lead to a wider use of these characteristics in genetic screening programs and provide further clues to their pathogenesis.

Evaluation of HER-2/neu immunohistochemical assay sensitivity and scoring on formalin-fixed and paraffin-processed cell lines and breast tumors: a comparative study involving results from laboratories in 21 countries

Variation in assay sensitivity was studied in more than 90 laboratories that assayed 4formalin-fixed, paraffin-processed breast and ovarian carcinoma cell lines with graded levels of HER-2/neu protein overexpression and known levels of HER-2/neu gene amplification, in addition to breast carcinomas fixed and processed in the laboratories. Main methods were the HercepTest (DAKO, Ely, England) and individualized protocols using a polyclonal antibody and the CB11 clone. While the proportion of laboratories achieving appropriate results with the HercepTest was significantly higher than for participants using other assays, laboratories using other assays showed significant improvement in the second assessment run. The level of agreement in evaluations by 26 laboratories using the HercepTest was excellent on cell lines and tumors and was significantly greater than that achieved by the remaining 41 laboratories using other immunohistochemical methods. While laboratories using the DAKO HercepTest had the highest level of reproducibility in assay sensitivity and evaluation, the significant improvement in results by laboratories using other antibodies in the second assessment run suggests that stringent quality control and an ongoing quality assurance program using a standard reference material have the potential to improve the reliability of immunohistochemical assays for HER-2/neu, regardless of the antibody used.

Clinical laboratory assays for HER-2/neu amplification and overexpression: quality assurance, standardization, and proficiency testing

OBJECTIVE

To present and contrast the results of immunohistochemistry and fluorescence in situ hybridization (FISH) proficiency testing surveys for HER-2/neu, as conducted by the Cell Markers and Cytogenetics Committees of the College of American Pathologists.

DESIGN

During the past 2 years, unstained sections from invasive breast carcinomas have been used for both immunohistochemistry and interphase FISH proficiency surveys. In most instances, the same cases were used for both the Cell Markers and Cytogenetics surveys. Additional data regarding interpretative variability for immunohistochemistry surveys have also been captured.

RESULTS

The number of laboratories performing FISH for HER-2/neu testing doubled during the 2-year period. The results of FISH testing have been remarkably concordant for laboratories submitting results. In contrast, the results of immunohistochemistry testing continue to highlight substantial variability among laboratories evaluating the same cases. The data show that this variability is at least in part due to variability in interpretation among observers, as well as inherent differences between immunohistochemistry and FISH techniques.

CONCLUSIONS

College of American Pathologists proficiency survey programs provide useful information about clinical testing for HER-2/neu amplification/overexpression.

Interobserver interpretative reproducibility of GOLDFISH, a first generation gold-facilitated autometallographic bright field in situ hybridization assay for HER-2/neu amplification in invasive mammary carcinoma

Clinical laboratory testing for HER-2/neu gene amplification by fluorescence in situ hybridization is not widely used in diagnostic pathology laboratories. A bright field alternative permitting direct visualization of gene amplification using conventional microscopy may be more readily incorporated into routine diagnostic pathology practice. Interobserver reproducibility represents an important component of the validation of such an assay. We tested the hypothesis that a first-generation bright field alternative to fluorescence in situ hybridization, a Nanogold (Nanoprobes, Inc, Yaphank, NY, USA) (or gold-label)/autometallographic assay for HER-2/neu gene amplification in breast carcinoma, can be reproducibly interpreted by pathologists. Reference standard was direct fluorescence in situ hybridization supplemented by RNA/RNA in situ hybridization. Reproducibility of selected conventional histologic parameters was captured based on a hematoxylin and eosin slide accompanying the GOLDFISH preparation (gold-facilitated autometallographic in situ hybridization) as an indication of comparative reproducibility. The average kappa among GOLDFISH observers was 0.84, which was at least or concordant of observers scoring nuclear grade (kappa = 0.50) and the presence of in situ carcinoma (kappa = 0.57) by conventional histopathology. The GOLDFISH assay was specifically designed for qualitative interpretation, thus obviating the need for oil immersion microscopy and signal enumeration, and its interpretation was highly reproducible among five pathologists.

Gold-facilitated in situ hybridization: a bright-field autometallographic alternative to fluorescence in situ hybridization for detection of Her-2/neu gene amplification

Fluorescence in situ hybridization (FISH) represents an excellent method for profiling gene amplification in situ, but correlation with tissue morphology is difficult because of dark-field visualization. Validation of a bright-field assay for assessment of HER-2/neu gene amplification was investigated. Streptavidin-Nanogold was used to generate bright-field gene copy signals using GoldEnhance gold-based autometallography, catalyzed reported deposition, and a biotin-labeled probe. One hundred cases of invasive breast carcinoma were evaluated for which FISH gene copy results, and mRNA and oncoprotein gene expression, were known. Autometallographic signals were qualitatively evaluable without the use of oil immersion microscopy. Results correlated well with indirect and direct label FISH. Autometallographic gold-based in situ hybridization represents a promising bright-field assay for the assessment of HER-2/neu gene amplification.

Polymerase chain reaction in the staging of solid tumors

Polymerasechain reaction (PCR) is a molecular biology technique that holds great promise as a way to perform molecular staging of cancer by detecting very early metastatic disease. Significant data suggest that PCR analysis may play an important role in the management of colorectal cancer in the future. However, for PCR staging of breast cancer, progress awaits identification of gene markers that have sufficient sensitivity and specificity. Within the next few years, the results of the Sunbelt Melanoma Trial and other ongoing studies will determine whether PCR evaluation of sentinel lymph nodes and peripheral blood cells has prognostic relevance in melanoma. The future of cancer management will likely revolve around the molecular staging of tumors, and PCR is but one method that may better define subgroups of patients that are appropriate candidates forvarious anticancer therapies.

Exploiting molecular targets in pancreatic cancer

Oncology has entered an era of molecular therapy. Given the multitude of molecular defects involved with pancreatic carcinogenesis, invasion, and metastasis, it is unlikely that single-agent targeted therapy will alter the course of this disease. Given the emergence of molecular targets and a growing number of agents available for clinical development, however, meaningful improvements in patient outcomes are expected, particularly if treatments are designed and delivered rationally.