Immunohistochemical determination of HER-2/neu expression in invasive breast carcinoma

Establishment and characterization of a cell line (BTIC) including HER-2-positive cells derived from pleural effusion of recurrent breast invasive ductal carcinoma, scirrhous type

Human epidermal growth factor receptor-2 (HER-2) overexpression in breast cancer occurs in 20% to 30% of patients with breast cancer. Trastuzumab (Herceptin) targets HER-2 tyrosine kinase receptors expressed on tumor cells and mediates anti-proliferative effects against HER-2-positive tumor cells. Adjuvant chemotherapy with trastuzumab has improved the prognosis of patients with HER-2 positive high-grade breast cancer. However, patients often experience appearance and proliferation of recurrent tumor cells after trastuzumab treatment. In this study, we report the successful establishment and characterization of a cell line (BTIC) derived from a patient with recurrent breast cancer after adjuvant chemotherapy with trastuzumab. Characteristics of the BTIC cell line were investigated by phase contrast or electron microscopic observations, chromosome analysis, xenotransplantation, immunohistochemistry and radioimmunoassay for tumor markers. We confirmed that the BTIC cell line grown as multilayered culture in culture dishes, has a poorly developed endoplasmic reticulum in the cytoplasm and some desmosomes. The population doubling time was approximately 44 hr. A graft in nude mouse after xenotransplantation was diagnosed as scirrhous carcinoma. Immunohistochemistry on cultured BTIC cells revealed that the BTIC cells were negative for estrogen receptor and progesterone receptor, and 30% positive for HER-2. Radioimmunoassay indicated secretion of HER-2 protein, NCC-ST-439 and CA15-3.

Cost-effectiveness analysis of strategies for HER2 testing of breast cancer patients in France

OBJECTIVES

A cost-effectiveness analysis was conducted comparing diagnostic strategies for determining the HER2 status of invasive breast carcinomas, as an indication for trastuzumab at metastatic relapse.

METHODS

A decision tree compared five strategies distinguished by (i) the use of immunohistochemical (IHC) and/or fluorescent in situ hybridization (FISH) techniques, and (ii) the test schedule (at initial diagnosis or metastatic relapse). Most cost and effectiveness data came from a French multicentric study of 2,045 patients from eight hospitals. We were not able to select final criteria for trastuzumab effectiveness, because published data rely on IHC techniques not used in France (i.e., HercepTest). We, therefore, selected two intermediate criteria for inappropriate treatment at relapse, that is, patients with HER2-amplified tumors not receiving trastuzumab (Criterion 1) and HER2-nonamplified tumors improperly treated with trastuzumab (Criterion 2). Sensitivity analyses were then performed to assess the robustness of the results to (i) discount rate, (ii) cost of FISH, and (iii) tissue fixation technique.

RESULTS

The strategy using IHC at diagnosis was dominated by the four other strategies. Among these approaches, the only efficient strategy for both criteria was IHC used alone at metastatic relapse; strategies using FISH, or IHC followed by FISH on IHC2+ cases were efficient for Criterion 1, whereas IHC followed by FISH on IHC2+ and 3+ cases was efficient for Criterion 2.

CONCLUSIONS

Determining HER2 status at diagnosis, as an indication for trastuzumab at metastatic relapse, incurs substantial incremental costs, which do not appear to be justified. No other strategy can be excluded at first.

Assessment of HER-2/neu overexpression and/or gene amplification in breast carcinomas: should in situ hybridization be the method of choice?

AIMS

Since the release of Herceptin, pathology laboratories have been requested to test breast carcinomas for HER-2/neu overexpression and/or gene amplification. Standardized IHC and FISH are mandatory in order to get reliable results, but there are problems even with standardized procedures. We decided to evaluate the two methods to determine which, or possibly if both, should be the primary investigation method(s).

METHODS AND RESULTS

The material consisted of 215 primary invasive breast carcinomas with complete clinical follow-up of 15 years. HER-2/neu protein expression was determined for all specimens, whereas FISH for assessing HER-2/neu gene signal number was done in 165 cases. IHC was double-checked with two or three different antibodies in 35 tumours, including all cases with discrepancies between IHC and FISH. Among these, there were discrepancies in a third. IHC overexpression of HER-2/neu was found in 13% and gene amplification in 18%. Discordance between IHC and FISH was found in 11 cases (8%). Five tumours were IHC+/FISH- and six were IHC-/FISH+. IHC and FISH positive cases as well as FISH only positive tumours had the same prognosis respecting survival. Tumours with >2 but <or=4 HER-2 gene signals per nucleus had the same survival as cases with >4 gene signals per nucleus. In contrast, cases with IHC overexpression without gene amplification had a prognosis similar to that of IHC-/FISH- tumours.

CONCLUSIONS

From our data, it seems to be more important to assess HER-2/neu gene amplification than IHC overexpression. Failure to detect FISH-amplified (IHC-negative) cases would have an adverse effect on the survival of these patients. On the other hand, IHC overexpression tumours without gene amplification appear to belong to a better prognostic group, and failure to detect them would probably not have a negative effect on the survival of these women. Even though FISH is a more complex and expensive procedure, it should be considered the method of choice for primary assessment of HER-2/neu status in breast cancer patients.

Effect of fixation period on HER2/neu gene amplification detected by fluorescence in situ hybridization in invasive breast carcinoma

This study investigated if formalin fixation duration affects HER2/neu gene amplification detection by fluorescence in situ hybridization (FISH) in breast cancer. Tumor tissues from 35 cases were divided into three groups and subjected to two formalin fixation protocols per group (12 hr, 27 hr in the first; 2 hr, 17.5 hr in the second; 28.5 hr, 541 hr in the third) before FISH analysis. There was no significant difference in FISH signal detection between the two different fixation protocols in the first two groups. In the third, no signal was detected in 4/6 cases fixed for an extended duration.

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.

Evaluation of HER-2/NEU protein expression in breast cancer by immunohistochemistry: an interlaboratory study assessing the reproducibility of HER-2/NEU testing

This study investigated the degree of interlaboratory agreement when HER-2/neu was evaluated by immunohistochemistry (IHC) on archival primary breast cancer samples. IHC for HER-2/neu was performed on the same archival tissue sections from 394 invasive primary breast cancers in two different laboratories. Both laboratories used the primary antibody NCL-CB11; however, different methods of immunostaining (antigen retrieval procedure and manual processing or no antigen retrieval and autostainer processing) as well as different scoring systems were used. Fluorescence in situ hybridization (FISH), considered as the correlation method for HER-2/neu status determination, was performed using the PathVysion kit and compared to the IHC results. Forty-eight of 394 analyzed tumors (12.2%) were scored as HER-2/neu positive in one laboratory, and 109 (27.7%) in the other laboratory where antigen retrieval was performed. Complete concordance in categorization of HER-2/neu status between the two laboratories was achieved in 333 of 394 cases (84.5%). FISH performed in 248 formalin-fixed samples revealed HER-2/neu gene amplification in 55/248 (22.2%). Concordance of FISH and IHC was found in 211/248 cases (85.1%) and 220/248 cases (88.7%) when the CB11 antibody was used without and with antigen retrieval, respectively. Both IHC methods generated similar rates of false results, but with different positive predictive values. Our data demonstrate that HER-2/neu evaluation by IHC is not a reproducible technique if there is no standardization of the procedure.

Overexpression of extracellular-signal regulated kinases on oral squamous cell carcinoma

Mitogen-activated protein kinases (MAPKs) consist of major three subfamilies, extracellular-signal regulated kinases (ERK MAPKs), the c-Jun N-terminal kinases/stress activated protein kinases (JNK MAPKs/SAP MAPKs), and p38 MAPKs. ERK MAPKs pathway is one of the most important pathways for cell proliferation. ERK MAPKs are located at downstream of a lot of growth factors (epidermal growth factor (EGF), nerve growth factor (NGF), platelet-derived growth factor (PDGF), etc.), the overexpressions and activation of which are frequently detected on a number of cancers including oral squamous cell carcinoma (OSCC). These data indicate that overexpression and activation of ERK MAPKs play an important role in cancer progression. On the contrary, JNK MAPKs are possible regulators of cell death induced by chemotherapeutic agents. p38 MAPKs are activated by pro-inflammatory cytokines and inflammatory drugs (non-steroidal anti-inflammatory drug), which are known to suppress cancer growth. These findings imply that each MAPKs can be molecular targets for cancer therapy in OSCC and its investigation is very important things in OSCC.

Determination of HER2 gene amplification by chromogenic in situ hybridization (CISH) in archival breast carcinoma

PURPOSE

To compare the efficacy of chromogenic in situ hybridization (CISH(TM)) with fluorescence in situ (FISH) hybridization and immunohistochemistry (IHC) in determination of the HER2 status in human breast cancer.

MATERIALS AND METHODS

HER2 gene amplification was determined on formalin-fixed paraffin-embedded (FFPE) sections of 62 invasive breast cancers by FISH and followed by CISH using a digoxigenin (DIG)-labeled HER2 DNA probe generated by Subtraction Probe Technology (SPT(TM)), and a biotin-labeled chromosome 17 centromeric (chr.17cen) probe. The sections were heat treated and enzyme digested. After in situ hybridization, the HER2 probe was detected with fluorescein (FITC)-anti-DIG for FISH, followed by peroxidase-anti-FITC and diaminobenzidine (DAB) for CISH. The chr.17cen probe was detected with peroxidase-streptavidin and DAB. For CISH application, HER2 gene copies or chromosome 17 centromeres and morphology of cells were easily visualized simultaneously with a 40x objective under bright-field microscope in hematoxylin-counterstained sections. IHC study of HER2 overexpression was performed on adjacent sections using a panel of three HER2 antibodies (TAB 250, CB11, A0485), and staining was scored according to the criteria specified in the HercepTest.

RESULTS

HER2 gene amplification detected by CISH was visualized typically as large DAB-stained clusters or by many dots in the nucleus. FISH and CISH identified HER2 gene amplification in 19% of the tumors. Chromosome 17 polysomy was detected in 31% of the tumors. HER2 overexpression was demonstrated in 19% (TAB 250), 23% (CB11), and 36% (A0485) of the tumors. Complete concordance between the results of CISH with FISH, TAB 250, CB11, and A0485 was seen in 100%, 97%, 94%, and 84% of the cases, respectively.

CONCLUSION

By permitting observation of morphology using a bright-field microscope, CISH is an accurate, practical, and economical approach to screen HER2 status in breast cancers. It is a useful methodology for confirming ambiguous IHC results.

Overexpression of HER-2 in thick melanoma

In this study we evaluated the overexpression status of HER-2 and its prognostic significance on survival in patients with thick cutaneous malignant melanoma. The immuno-alkaline phosphatase antigen detection technique was applied to archival diagnostic material from 51 patients with primary lesions measuring >or= 10 mm in Breslow thickness. Eleven additional patients with primary lesions measuring <or= 1 mm were also studied. HER-2 overexpression was evaluated using conventional light microscopy and an automated cellular imaging system (Chromavision Medical System). Fifteen (29.4%) out of 51 patients with thick lesions showed HER-2 overexpression. In contrast, no overexpression was seen in any of the thin lesions. Overexpression of HER-2 in this group of patients was of no prognostic significance for freedom from recurrence or survival when studied using univariate and multivariate analyses. Whilst the incidence of HER-2 overexpression in patients with thick cutaneous primary melanoma is similar to that reported in breast cancer, it was of no prognostic significance for survival in this study. However, further evaluation in larger numbers of patients with the full spectrum of Breslow thickness is clearly indicated.

Phase II study of weekly docetaxel and trastuzumab for patients with HER-2-overexpressing metastatic breast cancer

PURPOSE

To evaluate the safety and efficacy of weekly docetaxel plus trastuzumab in women with HER-2-overexpressing metastatic breast cancer. Efficacy was correlated with serum HER-2 extracellular domain (ECD) levels.

PATIENTS AND METHODS

Thirty women with metastatic breast cancer were treated with weekly docetaxel and trastuzumab as first- or second-line therapy. Both docetaxel 35 mg/m(2)/wk and trastuzumab 2 mg/kg/wk were delivered in 4-week cycles consisting of three weekly treatments followed by 1 week of rest. A loading dose of trastuzumab 4 mg/kg was administered 1 day before the start of the first cycle.

RESULTS

The median delivered dose-intensity of docetaxel was 24 mg/m(2)/wk (range, 18 to 27 mg/m(2)/wk). The intent-to-treat overall response rate (ORR) was 63% (95% confidence interval [CI], 44% to 80%). The ORR in patients whose tumors were HER-2-positive by fluorescence in situ hybridization was 67% (16 of 24 patients; 95% CI, 45% to 84%). In patients with elevated serum HER-2 ECD at baseline, the ORR was 76% (95% CI, 53% to 92%), compared with 33% (95% CI, 7% to 70%) in patients with low HER-2 ECD levels (P =.04). Variations in HER-2 ECD concentrations during treatment correlated with response to treatment. Median time to progression was 9 months. Acute toxicity, including myelosuppression, was mild. Fatigue, fluid retention, and excessive tearing became more common with repetitive dosing.

CONCLUSION

Weekly docetaxel and trastuzumab is an active combination for treating patients with HER-2-overexpressing metastatic breast cancer. Serum HER-2 ECD testing may be a promising method for monitoring patients on trastuzumab-based therapy.

Salivary duct carcinoma--a highly aggressive salivary gland tumor with HER-2/neu oncoprotein overexpression

Salivary duct carcinoma (SDC) is a highly malignant salivary gland tumor with aggressive clinical behavior, and is characterized by its histological resemblance to invasive ductal carcinoma of the breast. Overexpression and/or amplification of proto-oncogene Her2/neu has been shown to influence both prognosis and treatment of breast cancer. Since salivary duct carcinoma and ductal breast carcinoma share many common characteristics, HER2/neu overexpression might also be important in SDC. However, data on the expression of c-erbB2/HER2/neu in salivary gland tumors are still scarce. Therefore, we have evaluated 15 cases of salivary duct carcinomas (SDC) for HER2/neu overexpression using immunohistochemistry with the HercepTest. Overexpression, identified as strong or moderate membrane immunostaining, was observed in all but one case of SDC in most neoplastic cells. Thus, our study suggests that anti-HER2/neu therapy with Herceptin is beneficial for patients with aggressive salivary duct carcinoma.

Assessment of HER-2/neu status in breast cancer. Automated Cellular Imaging System (ACIS)-assisted quantitation of immunohistochemical assay achieves high accuracy in comparison with fluorescence in situ hybridization assay as the standard

This retrospective study of formalin-fixed infiltrating breast cancer specimens compared manual immunohistochemical assay with a new image analyzer-assisted immunohistochemical quantitation method, using fluorescence in situ hybridization assay (FISH) as the standard. Following the manual immunohistochemical assay, 189 cases, including most manual immunohistochemically positive and some random negative cases, were analyzed by FISH assay for Her-2/neu gene amplification and by the Automated Cellular Imaging System (ACIS) for immunohistochemical staining. Using the FISH standard, the ACIS immunohistochemical assay attained a higher concordance rate and sensitivity than the manual immunohistochemical assay (91.0% and 88% vs 85.7% and 71%, respectively), with only a slight decrease in specificity (93% vs 96%, respectively). In particular, the ACIS immunohistochemical assay resulted in a higher correlation with the FISH assay in the manual immunohistochemical assay 2+ cases. The ACIS immunohistochemical assay achieved higher accuracy than the manual method according to receiver operating characteristic curve analysis. The ACIS method represents a substantial improvement over the manual method for objective evaluation of the HER-2/neu status.

Discrepancies in Clinical Laboratory Testing of Eligibility for Trastuzumab Therapy: Apparent Immunohistochemical False-Positives Do Not Get the Message

BACKGROUND: Several studies have reported what seem to be false-positive results using the Food and Drug Administration (FDA)–approved HercepTest (Dako Corp, Carpinteria, CA) to profile Her-2/neu amplification and overproduction in breast carcinoma. False-positive status has been based on comparisons with gene copy enumeration by fluorescence in situ hybridization (FISH) and with comparisons to immunohistochemistry (IMH) results using a monoclonal antibody. However, simple overexpression by tumor cells that have normal gene copy has not been evaluated by profiling mRNA expression, ie, such cases could simply represent true-positive, transcriptionally upregulated overexpression.

MATERIALS AND METHODS: Four hundred infiltrating ductal carcinomas of breast were evaluated by IMH using monoclonal (CB11; Ventana Medical Systems, Inc, Tucson, AZ) and polyclonal (HercepTest; Dako) antibodies after antigen retrieval (AR). A polyclonal antibody sans AR (PCA/SAR) was also used. All IMH stains were evaluated and scored according to the guidelines for the FDA-approved HercepTest. A total of 145 of 400 carcinomas were subsequently evaluated by direct and digoxigenin-labeled (Dig) FISH, and 144 of 400 were evaluated by detection of mRNA overexpression via autoradiographic RNA:RNA in situ hybridization.

RESULTS: Overall HercepTest/CB11 IMH discordance was 12%. Expression of mRNA was highly concordant with FISH and DigFISH amplification and with CB11 and PCA/SAR immunohistology. IMH false-positive cases (no Her-2/neu gene amplification) occurred with both HercepTest (23%) and CB11 (17%), and the majority of false-positive results (34 of 44) were scored as 2+. All 2+ false-positive cases were mRNA-negative. Combined results of HercepTest and CB11 showed that 79% (38 of 48) of 3+ cases were Her-2/neu gene amplified, but only 17% (seven of 41) of 2+ cases had increased gene copy.

CONCLUSION: Discordant HercepTest/FISH results, and to a lesser extent discordance with CB11 IMH, are most commonly false-positive results with a score of 2+. The 2+ score as defined in the guidelines for the FDA-approved HercepTest should not be used as a criterion for trastuzumab therapy unless confirmed by FISH. Determination of Her-2 gene copy number by FISH may be a more accurate and reliable method for selecting patients eligible for trastuzumab therapy.

C-erbB-2 oncoprotein overexpression identifies a subgroup of estrogen receptor positive (ER+) breast cancer patients with poor prognosis

PURPOSE

To investigate the predictive value of c-erbB-2 oncoprotein expression as compared with established histopathological and cytometric indicators of disease evolution in breast carcinoma.

PATIENTS AND METHODS

A short-term retrospective study was conducted on a series of 306 breast cancer patients. Classic prognostic factors included tumour size, nodal involvement, histological grading, and hormone receptor status. Flow cytometric DNA ploidy and S-phase fraction (SPF) were also assessed. A Cox proportional hazards regression model was used for multivariate statistical analysis.

RESULTS

c-erbB-2 overexpression was present in 43 out of 295 (14.6%) tumours, and showed a statistically significant correlation with high histological grade, DNA aneuploidy, high SPF and lack of estrogen receptors (ER). Univariate analysis revealed its association with worse disease-free survival (DFS) and overall survival (OS). The combined evaluation of c-erbB-2 with ploidy and SPF defines a variable (P + S + c) that showed a significant correlation with disease outcome. By multivariate analysis, only nodal status (P < 0.001) and P + S + c subgrouping (group 2: P = 0.002; group 3: P = 0.001) in relation to DFS, and nodal status (P = 0.001) and DNA ploidy (P = 0.006) in relation to OS, retained independent prognostic significance. Subset analyses showed that cytometric parameters, P + S + c subgrouping and hormone receptors were significantly correlated with disease outcome in node-positive patients, whereas in node-negative subgroup no prognostic indicators were found. c-erbB-2 overexpression exhibited a trend in node-positive breast cancer (DFS: P = 0.068; OS: P = 0.086), and significant correlation with poor clinical evolution in ER positive patients (DFS: P = 0.015; OS: P = 0.004), mostly receiving tamoxifen.

CONCLUSIONS

c-erbB-2 is an independent prognostic indicator of DFS when evaluated in conjunction with ploidy and SPE. It also seems to predict response to tamoxifen therapy, by identifying a subgroup of ER positive (ER+) breast cancer patients with poor prognosis.

Laser capture microdissection: beyond functional genomics to proteomics

Proteomics will drive biology and medicine beyond genomics, and can have a profound impact on molecular diagnostics. The posttranslational modifications of cellular proteins that govern physiology and become deranged in disease cannot be accurately portrayed by gene expression alone. Consequently, new technology is being developed to discover, and quantitatively monitor, proteomic changes that are associated with disease etiology and progression. In the past, proteomic technologies were restricted to tumor cell lines or homogenized bulk tissue specimens. This source material may not accurately reflect molecular events taking place in the specific cells of the tissue itself. This article describes a completely new class of proteomic-based approaches aimed at the identification and investigation of protein markers in the actual histologically defined cell populations that are immersed in heterogeneous diseased tissue. It is envisioned that these investigations will eventually lead to novel diagnostic, prognostic, or therapeutic markers that can be applied to monitor therapeutic toxicity or efficacy.