c-erbB-2 over-expression in amplified and non-amplified breast carcinoma samples

Correlation between ultrasonic features and expression levels of C-erbB-2, VEGF and nm23 in breast cancer

Breast cancer is one of the most common female malignancies in clinical practice, which ranks number one in terms of its high incidence. We investigated the relevance of ultrasonic features of breast cancer and expression levels of C-erbB-2, vascular endothelial growth factor (VEGF) and nm23 and its clinical significance. A total of 76 patients with breast cancer were recruited who were admitted to The Affiliated Hospital of Qingdao University from January, 2016 to August, 2017. All patients underwent color Doppler ultrasonic imaging, and expression levels of C-erbB-2, VEGF and nm23 in their tumor tissues were measured by immunohistochemistry. The ultrasonic features were evaluated and compared with the expression levels of C-erbB-2, VEGF and nm23 for each patient. Ultrasonography showed a tumor mass with spiculated margins, abnormal vasculature, and a diameter no less than 3 cm, as well as lymph node metastasis. The above signs were associated with high expression of C-erbB-2, VEGF and nm23 (p<0.05), but calcification was not associated with high expression of these biomarkers (p>0.05). For patients with highly expressed C-erbB-2 and VEGF, the time to peak (TTP) of the time-intensity curve obtained by contrast enhanced ultrasound was shorter, while the peak intensity (PI) was higher. On the contrary, for patients with highly expressed nm23, the TTP was apparently longer, while the PI was lower (p<0.05). The ultrasonic features of breast cancer were relevant to the expression levels of C-erbB-2, VEGF and nm23. Thus, the expression levels of C-erbB-2, VEGF and nm23 were predictable indirectly according to the ultrasonic features of the patient, which can be used as a reference for breast cancer treatment and prognosis prediction.

Fluorescence in situ hybridization of chromosome 17 polysomy in breast cancer using thin tissue sections causes the loss of CEP17 and HER2 signals

Human epidermal growth factor receptor 2 (HER2 gene) and chromosome 17 polysomy are associated with breast cancer prognosis, chemotherapy and hormone therapy. HER2 gene analysis using fluorescence in situ hybridization (FISH) with 4-µm sections assuming a nuclear diameter of 6 µm caused the loss of genetic DNA. Using intact whole nuclei FISH (WNFISH) and thin tissue section FISH (TTFISH), 109 cases of invasive breast cancer were examined to observe correlations among HER2 gene amplification, CEP17 polysomy and the HER2/CEP17 ratio. The results showed significant differences in the mean copy number of HER2 and the HER2/CEP17 ratios between the WNFISH and TTFISH groups. No significant differences were observed in HER2 amplified, equivocal and non-amplified HER2 samples. Thirty-seven cases of CEP17 polysomy and 72 cases of non‑polysomy were detected by WNFISH. Twenty-nine cases of CEP17 polysomy and 72 cases of non-polysomy were detected by TTFISH. Significant differences were observed between the two methods using the McNemar test (P=0.039). In conclusion, detection of chromosome 17 polysomy in breast cancer with fluorescence in situ hybridization using thin tissue sections may cause the loss of CEP17 and HER2 signals.

Evaluation of chromosome 17 polysomy in breast cancer by FISH analysis of whole nuclei, and its clinicopathological significance

Human epidermal growth factor receptor 2 (HER2) amplification and overexpression are associated with poor prognosis and resistance to cytotoxic drugs in patients with breast cancer. Increases in the number of HER2 gene copies have been shown to be associated with chromosome 17 polysomy. The use of whole, intact nuclei for fluorescence in situ hybridization (FISH) assay improves the accuracy of the results. FISH analysis of whole nuclei (WNFISH) and immunohistochemistry (IHC) were used to analyze HER2 gene amplification and HER2 protein expression in 109 breast cancer specimens. Chromosome 17 polysomy and its correlations with HER2 gene amplification, HER2 protein expression and the clinicopathological outcomes of the patients were also investigated. Among the 109 cases, WNFISH detected HER2 amplification in 30 cases, equivocal amplification in 19 cases and no amplification in 60 cases. WNFISH detected chromosome 17 centromere (CEP17) polysomy in 37 cases and no polysomy in 72 cases. Among the 109 cases assessed by tissue microarray and IHC, 31 cases were HER2-negative, 14 cases were scored 1+, 23 cases were scored 2+ and 41 cases were scored 3+. The results demonstrated that in the cases with chromosome 17 polysomy, the HER2 gene was amplified, HER2 protein expression was increased and the incidences of nuclear atypia and lymph node metastases were higher compared with those in the cases without chromosome 17 polysomy. Chromosome 17 polysomy may correlate with increased malignant potential and metastatic spread in breast cancer.

From bench to bedside: lessons learned in translating preclinical studies in cancer drug development

The development of targeted agents in oncology has rapidly expanded over the past 2 decades and has led to clinically significant improvements in the treatment of numerous cancers. Unfortunately, not all success at the bench in preclinical experiments has translated to success at the bedside. As preclinical studies shift toward defining proof of mechanism, patient selection, and rational drug combinations, it is critical to understand the lessons learned from prior translational studies to gain an understanding of prior drug development successes and failures. By learning from prior drug development, future translational studies will provide more clinically relevant data, and the underlying hope is that the clinical success rate will improve and the treatment of patients with ineffective targeted therapy will be limited.

Breast cancer and aneusomy 17: implications for carcinogenesis and therapeutic response

Abnormalities of chromosome 17, recognised over two decades ago to be important in tumorigenesis, often occur in breast cancer. Changes of specific loci on chromosome 17 including ERBB2 amplification, P53 loss, BRCA1 loss, and TOP2A amplification or deletion are known to have important roles in breast-cancer pathophysiology. Numerical aberrations of chromosome 17 are linked to breast-cancer initiation and progression, and possibly to treatment response. However, the clinical importance of chromosome 17 anomalies, in particular the effect on ERBB2 protein expression, is unknown. Reports are conflicting regarding the association of copy gain of chromosome 17 (polysomy 17) with strong ERBB2 protein expression in the absence of true ERBB2 gene amplification. Copy-number anomalies in chromosome 17 seem to be common in tumours that show discrepant ERBB2 expression and in tumours with discordant ERBB2-protein and ERBB2 gene copy number measurements. The mechanisms of ERBB2 dosage changes-gene amplification versus chromosome gain and loss-probably differ in primary and metastatic disease; however, a correction for chromosome 17 copy-number is necessary to completely distinguish between these mechanisms. A better understanding of how polysomy 17 affects gene-copy number and protein expression will help to select patients who will respond to therapies targeting ERBB2 and other protein products of chromosome 17 loci.

HER-2/neu in breast cancer: a comparative study between histology, immunohistochemistry, and molecular technique (FISH)

HER-2/neu is a protooncogene frequently overexpressed in breast cancer. Fluorescence in situ hybridization (FISH) is a technique targeting the gene amplification, while immunohisto-chemistry detects the protein expression. Usually both are applied to paraffin-embedded tissue. The authors studied HER-2 by FISH and immunohistochemistry (HercepTest) in 81 breast carcinomas. The results showed an overall concordance (correlation coefficient 0.64). In all cases with HercepTest score 0 and 1+, nonamplification of the gene was observed. Gene amplification was found in 20% of cases with a 2+ score and in 77.78% of cases with a 3+ score. Data described in literature for 3+ carcinomas showed a 3% to 10% discrepancy between protein expression and gene amplification, while in this study this difference was up to 22.22%. As a consequence, even if it is usually considered important to analyze only 2+ cases by FISH, 3+ scores nonamplified for HER-2/neu may be a new, interesting subset. Furthermore, the authors investigated the two-variables correlation between chromosome 17 copy number, protein over-expression, gene amplification, and presence of metastatic lymph nodes. Interesting results came from the correlation between the HercepTest score and the HER-2/neu gene amplification evaluation, HercepTest and chromosome 17 aneusomy, and gene amplification and lymph nodes status. In conclusion, the FISH technique can be an important and useful diagnostic tool to integrate the results of the HercepTest and to select patients for immunotherapy.

Suppressor of cytokine signalling 2 (SOCS-2) expression in breast carcinoma

AIMS

To investigate SOCS-2 (suppressor of cytokine signalling 2) protein expression in breast carcinoma samples in relation to biopathological parameters and survival.

METHODS

A polyclonal antibody against SOCS-2 was used to study 50 archival breast carcinoma samples, collected from 1993 to 1995. The presence of SOCS-2 protein was investigated in relation to clinical and biological parameters used in breast cancer pathology. Fluorescence in situ hybridisation (FISH) was used to study whether SOCS-2 expression was related to SOCS-2 gene copy number.

RESULTS

SOCS-2 protein was expressed in 34 of 50 breast carcinoma samples and was positively associated with low grade, low nuclear grade, and p27 protein. SOCS-2 expression was inversely related to Ki-67, cyclin A, retinoblastoma protein (pRb), and the epidermal growth factor receptor (EGFR). No relation with overall survival was demonstrated. SOCS-2 amplification was found in three samples. No relation between the number of FISH signals and SOCS-2 expression was found.

CONCLUSIONS

The significant correlation seen between SOCS-2 expression, grade, nuclear grade, p27, Ki-67, cyclin A, pRb, and EGFR labelling strongly supports the hypothesis that SOCS-2 loss might be related to cell proliferation and tumour growth in breast carcinoma. Gene copy number changes did not seem to play a role in SOCS-2 regulation and expression; other mechanisms might be involved and deserve further study.

Comparison of liquid based cytology and histology for the evaluation of HER-2 status using immunostaining and CISH in breast carcinoma

BACKGROUND

HER-2 amplification is an important prognostic biomarker and treatment determinant in breast carcinoma.

AIMS

To correlate immunocytochemical (ICC) expression of HER-2 and gene amplification determined by chromogenic in situ hybridisation (CISH) using liquid based cytology (LBC) with immunohistochemistry (IHC) and CISH using histological samples of the same breast carcinomas.

METHODS

Frozen sections and cytobrushings of 103 breast carcinomas were analysed. Four techniques were performed on each tumour: two on LBC samples (ICC, and CISH, both graded as positive, indeterminate, or negative) and two on histological samples (IHC and CISH). Two cell lines (MCF-7, negative; BT 474, positive) were used as controls for cytological analysis. A complementary fluorescence in situ hybridisation technique was carried out in histological samples with low amplification (4-10 dots/nucleus).

RESULTS

Interobserver agreement for the four techniques calculated by the kappa coefficient indicated a substantial agreement. Nine cases failed in cytology because of poor cellularity. Among 94 cases, 19 were amplified; 73, 12, and 9 tumours were scored 0 or 1+, 2+, and 3+, respectively by IHC and 75, 13, and 6, respectively, by ICC. CISH found no amplification in 72 tumours. Correlations between the IHC and CISH results in the histological and cytological samples were always significant.

CONCLUSIONS

Her-2 status could be determined in LBC samples and correlated well with reference histological methods using in situ hybridisation. ICC was less reliable because of the presence of the cytoplasmic membrane. However, these results should be confirmed by a large multicentre study.

Polysomy 17 in HER-2/neu Status Elaboration in Breast Cancer: Effect on Daily Practice

PURPOSE

To assess the effect of chromosome 17 copy number on HER-2/neu status determination in breast cancers.

EXPERIMENTAL DESIGN

HER-2/neu gene copy and chromosome 17 centromere numbers were evaluated on 893 breast carcinomas using double color fluorescence in situ hybridization (FISH). The net and chromosome 17 corrected (ratio) HER-2/neu copy numbers were compared and related to immunohistochemistry done according to the Food and Drug Administration (FDA)-approved scoring system (0, 1+, 2+, and 3+) as a first screening step in 584 cases.

RESULTS

When a ratio > or = 2 was considered as criterion for FISH positivity, 49.3% (440 of 893) of cases showed amplification versus 56.2% (502 of 893) by using a net HER-2/neu gene copy number >4 as a alternative criterion; 14.8% (67 of 453) of cases having a ratio <2 had a net HER-2/neu gene copy number >4 and 1.1% (5 of 440) with a ratio > or = 2 had a net HER-2/neu gene copy number <4. Among discordant cases, 88.8% (64 of 72) were polysomic (>2.25 chromosomes 17/cell) and among polysomic cases, 12.8% (40 of 312) of the low polysomic (2.26-3.75 chromosomes 17/cell) and 36.9% (24 of 65) of the highly polysomic (>3.75 chromosomes 17/cell) cases showed discordance. In cases with a ratio <2, polysomy 17 incidences were 85.7% (6 of 7) in IHC 3+, 42.4% (79 of 186) in IHC 2+, 33.3% (15 of 45) in IHC 1+, and 29.1% (16 of 55) in IHC 0.

CONCLUSION

A net increase in HER-2/neu gene copy number consecutive to polysomy 17 in the absence of specific gene amplification might lead to a strong protein overexpression in a small subset of breast carcinomas. HER-2/neu status determination by FISH is dependent on the criterion considered for positivity in clinical practice.

Overexpression of the HER-2 oncogene does not play a role in high-grade osteosarcomas

The aim of our study was to determine whether or not the tyrosine kinase receptor, HER2 (also known as ErbB2/Her2/neu), is overexpressed in human osteosarcomas (OS). We studied 15 biopsy and 18 resection specimens at the mRNA and protein levels. HER2 status in the OS specimens was assessed by immunohistochemistry (IHC) and quantitative Real-Time Polymerase chain reaction (PCR). In moderately immunopositive cases fluorescent in situ hybridisation (FISH) analysis was used in order to identify any possible gene amplification. 27 samples were evaluable for IHC and only 1 case showed a moderately positive membrane staining. The remaining samples showed no staining or focal cytoplasmic staining (2 samples). In the moderately positive case, FISH analysis showed no HER-2 gene amplification. There was also no overexpression of HER2 mRNA suggesting this sample was a false-positive immunostain. HER2 mRNA expression was present in all samples at a similar level to that in the breast cancer cell line, MCF7, which does not overexpress HER2 and was used as a negative control. In conclusion, this study shows that HER2 mRNA or membranous HER2 protein overexpression is absent in human OS. We noted various inconsistencies in previous published studies, with regard to methodology and the interpretation of the results based on poor methodology. We therefore conclude that the positive data with regard to HER2 overexpression reported in these previous studies is not reliable. Our results suggest that the monoclonal antibody trastuzumab (Herceptin(R)), directed against the HER2-receptor, is not likely to be an effective therapeutic agent in OS.

Amplification of HER2 and TOP2A and deletion of TOP2A genes in breast cancer investigated by new FISH probes

New strategies for improving treatment of patients with breast carcinoma have focused on the HER2 oncoprotein with regard to response to traditional therapy regimes and the effect of a new drug specifically directed against the protein. Furthermore, the status of the topoisomerase IIalpha (TOP2A) gene has been suggested as a predictive marker of anthracycline treatment. In this study of 120 tumours, immunohistochemically detected HER2 overexpression with HercepTest has been compared to the HER2 gene amplification investigated with a new HER2 probe for fluorescence in situ hybridization (FISH). In addition, the HercepTest was evaluated as a screening tool for choosing cases for FISH investigation of TOP2A gene aberrations. The HercepTest score 3+ identified HER2 gene amplification in 27 of 30 amplified tumours (sensitivity of 0.90) with a false-negative rate of 0.10 and a false-positive rate of 0.06. TOP2A gene amplification or deletion was found in 20 cases. Sixteen (80%) of these carcinomas were in the HercepTest 3+ group, but four tumours had alterations in the TOP2A gene with normal HER2 status. Traditionally, in the FISH technique the result has been based on counting 60 cells. However, we found that a much less time-consuming method of counting 60 signals gave equally good results.

Her-2/neu Gene Amplification and Protein Expression in Primary Male Breast Cancer

The role of HER-2/ neu in male breast cancer is not well defined. The purpose of the current study was to measure the frequency of HER-2/ neu expression in primary male breast cancer, to demonstrate HER-2/ neu gene amplification in cases found to be positive for protein overexpression, and to correlate HER-2/ neu positivity with clinicopathological variables. Formalin-fixed, paraffin-embedded archival material from 99 primary male breast carcinomas was evaluated by immunohistochemistry (IHC) using the HercepTest (DAKO Corp., Hamburg, Germany). Scoring was performed according to established guidelines. All cases demonstrating HER-2/ neu staining by IHC (1+/2+ and 3+) were analyzed for HER-2/ neu gene amplification by fluorescence in situ hybridization (FISH) utilizing the PathVysion assay (Vysis Corp., Downers Grove, Illinois) to assess HER-2/ neu amplification status. The immunohistochemical staining of the HER-2/ neu protein revealed HER-2/ neu positivity in 15/99 (15.1%) cases, eight tumors showed 2+ and 7 tumors 3+ staining. HER-2/ neu gene amplification was observed in 11/99 cases (11,1%), and all of the 3+ and 4/8 from the 2+ cases were amplified. HER-2/ neu gene amplification/protein overexpression did not correlate with tumor state, histological grade or estrogen/progesterone receptor status nor the axillary lymph node status. This is the first comprehensive study of HER-2/ neu gene amplification by FISH analysis in primary male breast cancer. Compared to female primary breast cancer the percentage of HER-2/ neu positivity in our study was lower. Our data provide first evidence for HER-2/ neu gene amplification in male breast cancer. Further studies should be addressed on the potential application of the monoclonal rhuMAB HER-2/ neu antibody for treatment of HER-2/ neu positive male breast cancer.

HER-2 testing and trastuzumab therapy for metastatic breast cancer: a cost-effectiveness analysis

PURPOSE

Trastuzumab therapy has been shown to benefit metastatic breast cancer patients whose tumors exhibit HER-2 protein overexpression or gene amplification. Several tests of varying accuracy and cost are available to identify candidates for trastuzumab. We estimated the cost-effectiveness of alternative HER-2 testing and trastuzumab treatment strategies.

PATIENTS AND METHODS

We performed a decision analysis using a state-transition model to simulate clinical practice in a hypothetical cohort of 65-year-old metastatic breast cancer patients. Outcomes were quality-adjusted life-years (QALYs), lifetime cost, and incremental cost-effectiveness ratio (ICER). Interventions included testing with the HercepTest (DAKO, Carpinteria, CA) immunohistochemical assay alone, fluorescence in situ hybridization (FISH) alone, and both tests, followed by trastuzumab and chemotherapy for patients with positive test results and chemotherapy alone for patients with negative test results.

RESULTS

In the base case, initial HercepTest with FISH confirmation of all positive results had an ICER of $125,000 per QALY gained. The incremental cost-effectiveness of initial FISH was $145,000 per QALY gained. Other strategies yielded the same or poorer effectiveness at a higher cost, or lower effectiveness at a lower cost, but with a less favorable ICER. These findings persisted under a range of assumptions, and only changes in test characteristics substantially altered results.

CONCLUSION

It is more cost-effective to use FISH alone or as confirmation of all positive HercepTest results, rather than using FISH to confirm only weakly positive results or using HercepTest alone. When multiple tests are available to identify treatment candidates, test characteristics may have a substantial impact on the aggregate costs and effectiveness of treatment.

HER2/neu overexpression in the development of muscle-invasive transitional cell carcinoma of the bladder

The mortality from transitional cell carcinoma (TCC) of the urinary bladder increases significantly with the progression of superficial or locally invasive disease (pTa/pT1) to detrusor muscle-invasive disease (pT2+). The most common prognostic markers in clinical use are tumour stage and grade, which are subject to considerable intra- and interobserver variation. Polysomy 17 and HER2/neu gene amplification and protein overexpression have been associated with more advanced disease. Standardised techniques of fluorescence in situ hybridisation and immunohistochemistry, which are currently applied to other cancers with a view to offering anti-HER2/neu therapies, were applied to tumour pairs comprising pre- and postinvasive disease from 25 patients undergoing treatment for bladder cancer. In the preinvasive tumours, increased HER2/neu copy number was observed in 76% of cases and increased chromosome 17 copy number in 88% of cases, and in the postinvasive group these values were 92 and 96%, respectively (not significantly different P=0.09 and 0.07, respectively). HER2 gene amplification rates were 8% in both groups. Protein overexpression rates were 76 and 52%, respectively, in the pre- and postinvasive groups (P=0.06). These results suggest that HER2/neu abnormalities occur prior to and persist with the onset of muscle-invasive disease. Gene amplification is uncommon and other molecular mechanisms must account for the high rates of protein overexpression. Anti-HER2/neu therapy might be of use in the treatment of TCC.

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.

Expression of HER-2/neu gene and protein in salivary duct carcinomas of parotid gland as revealed by fluorescence in-situ hybridization and immunohistochemistry

AIMS

Salivary duct carcinoma is a highly malignant salivary gland tumour with aggressive clinical behaviour, characterized by histological resemblance to invasive ductal carcinoma of the breast. Amplification of HER-2/neu oncogene and over-expression of its gene product have both prognostic and therapeutic implications in breast cancer. Recent report on salivary duct carcinomas for HER-2/neu using immunohistochemistry (IHC) has shown over-expression in most cases. However, correlation between IHC and molecular genetic analysis of HER-2/neu in salivary duct carcinoma has not yet been performed.

METHODS AND RESULTS

We have now evaluated 11 cases of salivary duct carcinomas for HER-2/neu status using IHC and fluorescent in-situ hybridization (FISH). To our knowledge, this is the first molecular genetic analysis of HER-2/neu in salivary duct carcinoma.

CONCLUSIONS

In immunohistochemistry, over-expression of HER-2/neu protein was identified as distinct membrane staining in most carcinoma cells in all our salivary duct carcinoma cases, while only four cases revealed an amplification of HER-2/neu gene by means of FISH analysis. Both amplified and non-amplified salivary duct carcinomas with strong immunohistochemical staining for HER-2/neu protein were associated with poor clinical outcome for the patients. Apparently, HER-2/neu protein over-expression could also be controlled by mechanisms other than gene amplification. In the group of salivary gland tumours other than salivary duct carcinoma, strong over-expression was detected only in three cases of carcinoma ex pleomorphic adenoma. Thus, over-expression of HER-2/neu protein is also a useful marker of malignant transformation in pleomorphic adenomas.

Variation of the prognostic significance of HER-2 expression in breast cancer according to tumor size

The prognostic importance of HER-2 status in breast cancer has been investigated extensively, but findings have not been uniform across immunohistochemical studies using fixed, paraffin-embedded specimens. We speculate that studies with an overrepresentation of large tumors might not produce evidence for an independent effect of a single marker because breast tumors of larger size tend to exhibit multiple adverse attributes as the malignancy advances through the metastatic cascade. Further, it has been posited that results from certain studies of biologic markers might be generalizable only to larger tumors because tumor repositories tend to house a disproportionate number of larger tumors. To test our hypothesis that the prognostic effect of HER-2 status might be modified by the size of the tumor, we conducted a survival analysis of a nested case-case sample of 156 women diagnosed with primary breast cancer from 1983 to 1995. Relative risks (RRs) and confidence intervals (CIs) for recurrence in relation to HER-2 status were estimated using a multivariate Cox proportional hazards model. Immunohistochemistry of archival tissue was used to detect HER-2 expression. Positive HER-2 status was associated with recurrence (RR = 4.24, 95% CI 1.30-13.78) among patients with axillary lymph node-positive involvement. This analysis identified an interaction (p < 0.01) between tumor size and overexpression. Stratification by tumor size revealed an increased risk of recurrence associated with HER-2-positive tumors that were <or=2 cm in size (RR = 13.68, 95% CI 1.06-175.76), whereas no such association was observed among patients with HER-2-positive tumors larger than 2 cm. Eligible patients without available tumor tissue tended to have smaller tumors compared to study participants. Our results might partly explain the variation in evidence across HER-2 prognostic studies using fixed tissue and might apply to other putative markers of prognosis 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.

Amplification and expression of genes from the 17q11 approximately q12 amplicon in breast cancer cells

Amplification of a portion of 17q11 approximately q12 involving the human epidermal growth factor receptor-2 (HER-2/neu) gene is common in solid tumors. HER-2/neu amplification in breast cancer is associated with a poor prognosis and may predict response to therapeutic interventions. The molecular complexity and informative content of the 17q11 approximately q12 amplified DNA remain largely unknown. Study of available sequence information in public database allowed us to construct a contig in bacterial artificial chromosome that covers this region. We have identified a several hundred kilobase core segment from this region that is amplified in three out of three breast cancer cell lines with HER-2/neu amplification. There is striking correlation between amplification and overexpression of genes from this region. Amplified and overexpressed genes, in addition to HER-2/neu, may play functional roles in the pathogenesis of breast cancer and may serve as additional targets for therapy. Published by Elsevier Science Inc.

Detection of c-erbB-2 (HER-2/neu) amplification in breast carcinoma by fluorescence in situ hybridization on tissue sections and imprinted cells

Abnormalities in c-erbB-2 have attracted a great deal of attention. Treatment using an antibody against the c-erbB-2 gene product is effective against breast cancers with amplification and/or overexpression of c-erbB-2. There is an urgent need to establish methodology for selecting patients who would benefit from this therapy. A total of 235 breast carcinomas were examined for c-erbB-2 protein overexpression by immunohistochemistry. Tissue sections with discernible immunostaining from 52 tumors, 70 negative tumors and smear imprints from 35 patients were examined by dual-color fluorescence in situ hybridization (FISH) using probes specific for c-erbB-2 and the centromeric region of chromosome 17. The concordance between gene amplification and protein overexpression was 95.7%. When the findings of the two FISH preparation techniques were compared, no discrepancies were found in 24 of the tumors. However, differences were seen in eight cases. In six of these cases the differences did not affect the presence or absence of amplification, but in the other two cases, considered to show low-level amplification on paraffin sections, polysomy 17 was detected instead. It was concluded that FISH is an excellent tool to detect gene amplification in particular, and FISH on touch imprints is a useful adjunct to differentiate between low-level amplification and polysomy 17.

Trastuzumab: hopes and realities

Despite improvements in care of patients with breast cancer, up to half develop refractory or resistant disease. There is therefore a need for new, modified anticancer therapies with greater effectiveness, tolerability to patients, and tumour specificity. Trastuzumab (Herceptin) is the first clinically available oncogene-targeted therapeutic agent for treatment of solid tumours. Clinical trials in patients positive for HER2 (human epidermal-growth-factor receptor 2) show that trastuzumab is effective and well tolerated; as a single-agent second-line or third-line treatment, the drug produced durable tumour responses. First-line trastuzumab in combination with chemotherapy, particularly paclitaxel, significantly improved time to disease progression, duration of response, and time to treatment failure. Combination therapy resulted in a 25% improvement in overall survival compared with chemotherapy alone. Patients with HER2 gene amplification, high overexpression of HER2 (3+ on immunohisto-chemistry), or both features, obtained the greatest clinical benefit. Trastuzumab is the first monoclonal antibody with efficacy in breast cancer and the first gene-product-targeted therapy to produce a significant survival advantage in this disease. Trastuzumab is likely to find its ultimate role in the adjuvant setting. Its development provides a model for the integration of other gene-targeted therapies into breast-cancer management to improve survival and quality of life.

Anti-human epidermal growth factor receptor 2 monoclonal antibody therapy for breast cancer

BACKGROUND

Advances in molecular biology and improved understanding of tumour biology have led to the development of novel treatments for cancer. Trastuzumab (Herceptin; Genentech, San Francisco, California, USA) is a monoclonal antibody directed against human epidermal growth factor receptor (HER) 2 protein, which is overexpressed in a wide variety of human cancers, including 20-30 per cent of human breast cancers. HER-2 plays an important role in oncogenic transformation, tumorigenesis and metastatic spread. Overexpression is associated with a poor prognosis and predicts a poor response to several treatment modalities.

METHOD

Literature relating to the monoclonal antibody was identified by a Medline literature search and by cross-referencing from the references of seminal articles on the subject. Four major clinical trials were identified and reviewed.

RESULTS AND CONCLUSION

In clinical trials approximately 15-20 per cent of patients with HER-2-overexpressing tumours benefited from treatment with trastuzumab. In sensitive patients the antibody appeared to have intrinsic anticancer activity when given as a single agent. In combination chemotherapy it appeared to act synergistically with other agents. Ongoing research is evaluating trastuzumab in combination with numerous standard chemotherapy regimens and with other novel chemotherapeutic agents. Clinical trials have also revealed several serious side-effects of monoclonal antibody therapy. Most notable is an unpredictable cardiotoxicity, especially when used in combination with anthracycline-based chemotherapy regimens.

Amplification of Her-2/neu gene in Her-2/neu-overexpressing and -nonexpressing breast carcinomas and their synchronous benign, premalignant, and metastatic lesions detected by FISH in archival material

Amplification of Her-2/neu in breast carcinoma is associated with poor prognosis, short disease-free interval, and short survival time in both node-negative and -positive patients. Little is known about the starting point of amplification of Her-2/neu and how it progresses from benign to malignant breast lesions. We attempted to address these questions by evaluating amplification of Her-2/neu in benign, premalignant, and malignant lesions using fluorescence in situ hybridization (FISH). Twenty-six patients with Her-2/neu-overexpressing invasive ductal carcinomas (as judged by strong immunoreactivity with Her-2/neu antibody) and coexisting lesions of ductal hyperplasia (DH), atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS) in the vicinity of the invasive tumor (as judged by review of the hematoxylin and eosin-stained sections), as well as metastatic carcinoma in axillary lymph nodes (mets) were selected for this study. In the primary carcinomas, a close relationship was present between overexpression as detected by immunohistochemistry (IHC) and amplification as demonstrated by FISH (85% concordance). Among these patients, amplification of Her-2/neu in ADH was demonstrated in 7 of 13 cases with ADH, and in DCIS, in 21 of 22 cases with DCIS. There was no amplification in DH or normal ductal epithelium. Significantly, in all 12 patients with synchronous positive axillary lymph nodes, there was concordant amplification of Her-2/neu in the primary and metastatic carcinoma. Amplification was consistent in multifocal metastases, despite morphological heterogeneity in some patients. Amplification ratios increased from ADH to DCIS to invasive carcinoma (P <.01, ADH versus DCIS; P <.05, DCIS versus invasive cancer), but there was no difference in amplification ratios between primary cancers and synchronous axillary metastases (P >.05). We also evaluated Her-2/neu amplification in 21 patients without Her-2/neu overexpression in their primary carcinomas (as judged by absent immunoreactivity with Her-2/neu antibody). Three showed amplification in both primary and metastatic lesions, with a low amplification ratio (approximately 2). One patient had amplification in the primary tumor but not in an axillary metastasis. Two patients exhibited slight amplification in the metastatic carcinoma (ratios 1.6 and 2), but not in their primary cancers. This FISH study indicates that amplification of Her-2/neu can emerge de novo in any stage of the disease process, from ADH to metastatic lesions, but most often appears first in ADH or DCIS. The degree of Her-2/neu amplification increases with progression to invasive carcinoma, there being no further increase in synchronous metastasis. Our data suggest that amplification of Her-2/neu appears to be mainly involved in initiation of breast oncogenesis and that its role in progression of breast cancers is uncertain.

Aneusomy 17 in breast cancer: its role in HER-2/neu protein expression and implication for clinical assessment of HER-2/neu status

HER-2/neu protein overexpression in breast cancer is mostly caused by HER-2/neu gene amplification. However, it is unclear whether aneusomy 17 may also play a role. Using immunohistochemistry assay (IHC) with DAKO antibody and manual quantitation, 189 specimens were selected from archival invasive breast cancer specimens, including most IHC-positive and some IHC-negative cases (n = 158 and 31, respectively). They were then analyzed by PathVysion fluorescence in situ hybridization (FISH) assay (Vysis, Inc., Downers Grove, IL) and by an image analyzer (ACIS; ChromaVision Medical Systems, Inc., San Juan Capistrano, CA)-assisted IHC quantitation. Ninety-two cases contained disomy 17 (chromosome 17 centromere, 1.76-2.25 signals per cell) whereas 97 cases had aneusomy 17, including 82 with low polysomy (2.26-3.75 signals per cell), 10 with high polysomy (> or =3.76 signals per cell), and 5 with hypodisomy (> or =1.75 signals per cell). HER-2/neu protein expression had the highest correlation with HER-2/neu gene dosage (copy number; r =.826), followed by the HER-2/neu gene to chromosome 17 ratio (r =.733). The lowest correlation was with the chromosome 17 copy number (r =.307), on which the 10 cases with high polysomy 17 had a disproportionately high impact. The FISH assay using the PathVysion criterion for HER-2/neu gene amplification (HER-2/neu gene to chromosome 17 ratio, > or = 2.00) achieved higher concordance with ACIS IHC than did an alternative FISH criterion (absolute HER-2/neu gene copy number, > or = 4.00 signals per cell). Most ACIS IHC-PathVysion FISH-discordant cases contained disomy or low polysomy 17, whereas all 10 cases with high polysomy 17 had no such discordance. However, two cases with monosomy 17 had ACIS IHC-PathVysion FISH discordance, i.e., with gene amplification, but no protein overexpression. Both cases would have had no gene amplification if the alternative FISH criterion had been used. In conclusion, aneusomy 17 is common in breast cancer. Except in a certain subset of cases, aneusomy 17 probably is not a significant factor for HER-2/neu protein expression or for clinical assessment of HER-2/neu status.

Testing for HER2 status

Incorporation of a new biological marker such as HER2 into routine clinical practice requires proof that it provides reproducible information independent of, and better than, conventional pathologic criteria, and that it influences treatment decisions. In breast cancer, HER2 amplification/overexpression predicts for a poor clinical outcome and an enhanced survival benefit from the HER2-targeted therapy, Herceptin, and may predict for resistance to some conventional therapies. Thus, HER2 is considered to be a clinically important molecule and testing for HER2 abnormalities is already part of routine patient assessment in many parts of the world. There is currently no gold standard for HER2 testing. The main challenge is to standardize and technically validate HER2 testing methodologies. Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are the most common HER2 tests used, and show a high level of concordance. HER2 testing approaches based on the polymerase chain reaction (PCR) are under extensive investigation and appear promising. A Canadian HER2 testing algorithm designed to increase the validity and reproducibility of HER2 testing has been compiled. HER2-positive cases are defined as those with >10% of tumor cells with moderate/strong, complete membrane staining in the invasive component, by IHC. Confirmatory HER2 testing using either FISH or quantitative PCR is recommended for indeterminate cases. Additional studies are required to calibrate HER2 testing results to clinical outcome.

The predictive value of HER2 in breast cancer

Measurement of molecular markers predictive of response to therapy should enable more selective and effective utilization of anticancer agents. The predictive value of HER2 remains a complex and inconclusive subject. In metastatic breast cancer, HER2-positive, ER-positive patients can show responses to endocrine treatment, but experience shorter time to progression and survival than HER2-negative patients. In the adjuvant setting, weak, retrospective evidence suggests that tamoxifen is potentially harmful in HER2-positive patients and that there is no benefit from prolonged tamoxifen therapy. It has not yet been demonstrated conclusively that HER2 positivity increases resistance to adjuvant cyclophosphamide, methotrexate, 5-FU (CMF), but there are indications that HER2-positive patients benefit more from adequately dosed anthracyclines than from CMF. The greatest value of HER2 as a predictive marker lies in the prediction of response to therapies that target HER2, such as Herceptin. Patients with strongly HER2-positive breast cancer derive significant clinical benefit from single-agent and combined Herceptin therapy. HER2 testing has become an integral part of the optimal management of the breast cancer patient. Best current practice in adjuvant breast cancer therapy based on the current knowledge of the potential predictive power of HER2 constitutes not denying tamoxifen to HER2-positive, ER-positive patients or CMF to HER2-positive patients. Outside of clinical trials, adequately dosed anthracycline-based chemotherapy is the current preferred adjuvant treatment option for HER2-positive patients.

Protein overexpression and gene amplification of c-erbB-2 in breast carcinomas: a comparative study of immunohistochemistry and fluorescence in situ hybridization of formalin-fixed, paraffin-embedded tissues

We evaluated 173 consecutive breast carcinomas for c-erbB-2 using a combination of immunohistochemistry (IHC) with a commercial polyclonal antibody (Nitirei) and dual-color fluorescence in situ hybridization (FISH) using the c-erbB-2-specific probe and the chromosome 17 centromere-specific probe from Vysis (Downers Grove, IL) and compared the results with the histologic characteristics of intraductal spread, cancer invasion, and intratumoral heterogeneity. With correction for chromosome 17 copy number, c-erbB-2 amplification was observed in 26 tumors (13.5%): high-level amplification in 23 tumors, and low-level amplification in 3. The gene amplification was positively correlated with c-erbB-2 protein overexpression, defined as 2+ or 3+ immunostaining, on a case-by-case basis (P < .000001). All 3+ immunostaining tumors (19 tumors) showed high-level amplification, although gene amplification was found in only 5 of 27 2+ immunostaining tumors. Although the rates of overexpression and gene amplification did not differ in ductal carcinomas in situ and invasive carcinomas (P = .46 and .53, respectively), they were significantly higher in invasive carcinomas with intraductal spreading (P < .0001). Intratumoral heterogeneity of c-erbB-2 amplification was found in only 1 case; however, in 17 invasive carcinomas, intraductal components expressed c-erbB-2 more intensely than invasive components. We conclude that in breast carcinomas, c-erbB-2 overexpression occurs mostly in tumors with high-level gene amplification, and such overexpression appears to endow carcinoma cells with the capacity for intraductal spreading. The best method for detecting breast carcinomas with c-erbB-2 aberrations using archival tissues is to screen cases by IHC; however, follow-up FISH assays are indispensable for excluding false-positive results.

Her-2/neu gene amplification in low to moderately expressing breast cancers: possible role of chromosome 17/Her-2/neu polysomy

Overexpression of the Her-2/neu (HER2) oncogene is known to confer important prognostic and predictive value to patients with breast cancer. Controversy exists as to the best method for its determination caused primarily by the variable sensitivities of the different antibodies and interobserver differences, particularly in the group of breast cancers with borderline levels of expression of the protein product. This study was therefore designed to determine the status of the HER2 gene amplification in a group of breast carcinomas with low levels of overexpression. After an initial validation of our procedures, a series of 52 consecutive cases of formalin-fixed, paraffin-embedded breast cancers with low levels of overexpression and a series of 22 cases with no expression by immunohistochemistry were analyzed by fluorescence in situ hybridization (FISH), and the results correlated statistically. Amplification of the HER2 gene was observed in 16% of equivocal to weakly positive cases. Those that were amplified showed low levels of amplification with ratios less than 4.5 and a characteristic scattered pattern of distribution of HER2 signals in the FISH assay. In addition, heterogeneity was noted in two cases in the amplification of the HER2 gene within the same tumor samples with pockets of amplified tumor cells amidst nonamplified tumor cells. In cases without amplification, a statistically significant number showed chromosome 17 polysomy. In conclusion, equivocal to low levels of HER2 overexpression in breast cancers are associated, in the majority of cases, with chromosome 17 polysomy and a corresponding increase in the HER2 gene numbers. True gene amplification is present in only a minority of cases. FISH analysis should be used for confirmation of gene amplification. Prior screening and selection of appropriate immunohistochemistry-positive areas for FISH analysis may prove beneficial.

c-erbB-2 (HER-2/neu) gene amplification is a better indicator of poor prognosis than protein over-expression in operable breast-cancer patients

Our aim was to compare the prognostic value of c-erbB-2 gene amplification analyzed by Southern blot with that of protein (p185) over-expression measured by immunohistochemistry in 172 patients with operable breast cancer (BC). Amplification and p185 over-expression were found in 31 (18%) and 51 (30%) BCs, respectively. All but 1 of the tumors showed both amplification and over-expression, while 21 (12%) tumors displayed over-expression without amplification. The risk of death associated with c-erbB-2 gene amplification and p185 over-expression was evaluated by multivariate analysis, taking into account tumor size, histoprognostic grade, hormone receptors and axillary node status. During a mean follow-up of 9.5 (+/-2) years, node involvement (p < 0.001), c-erbB-2 gene amplification (p = 0.02) and negative hormone receptors (p = 0.02) were found to be independent prognostic indicators of the risk of death. Over-expression of p185 with no amplification was not correlated with this risk. When the risk of death associated with c-erbB-2 amplification was studied according to chemo- and hormone therapy, no significant difference was observed between subgroups of subjects. Amplification was also associated (p = 0.02) with the risk of multifocal distant metastases (i.e., metastases detected concomitantly in at least 2 sites) and, thus, with BC aggressiveness. These data show the importance of c-erbB-2 gene amplification in predicting the long-term outcome of patients and in selecting eligible patients for c-erbB-2-targeted therapies.

Her-2/neu analysis in archival tissue samples of human breast cancer: comparison of immunohistochemistry and fluorescence in situ hybridization

PURPOSE

The objective of our study was to compare the methods used in the literature to analyze HER-2/neu status on archival breast cancer tissue. Therefore, a series of antibodies was evaluated to assess their immunohistochemical (IHC) sensitivity in correlation to gene amplification determined by fluorescence in situ hybridization (FISH).

MATERIALS AND METHODS

HER-2/neu overexpression was studied on paraffin sections of 85 invasive breast cancers using a panel of five monoclonal (9G6, 3B5, CB11, TAB250, GSF-HER2) and two polyclonal antibodies (A8010, A0485) in addition to the HercepTest (DAKO, Glostrup, Denmark). HER-2/neu gene amplification was determined by FISH using a dual-color probe (PathVysion; Vysis, Stuttgart-Fasanenhof, Germany).

RESULTS

HER-2/neu overexpression was demonstrated in 26% (9G6, TAB250, GSF-HER2), 27% (3B5, CB11), 33% (A8010) and 42% (A0485, HercepTest) of the tumors. FISH on paraffin sections identified gene amplification in 28% of the tumors. Strongly positive IHC results (3+) were always associated with gene amplification. Among the 16 tumors presented with weakly positive IHC results (2+) using the HercepTest, 12 (75%) lacked gene amplification.

CONCLUSION

The comparison of IHC and FISH demonstrated an excellent correlation of high-level HER-2/neu overexpression (3+) with gene amplification; ie, FISH does not provide further information in these tumors. However, weakly positive IHC results (2+) obtained with the HercepTest share only a minor association with gene amplification.

Strong correlation between results of fluorescent in situ hybridization and immunohistochemistry for the assessment of the ERBB2 (HER-2/neu) gene status in breast carcinoma

ERBB2 (HER-2/neu) amplification and/or overexpression are associated with poor prognosis in node-positive breast carcinoma. Its prognostic value in node-negative cases and its predictive value for response to chemotherapy remain controversial. This may be related to the use of molecular methods, which are sensitive to dilution of tumor material by normal cells, or the use of nonstandardized immunohistochemistry (IHC) procedures, for the determination of the ERBB2 gene status. In addition, new therapeutic approaches that target the cells overexpressing ERBB2 are under development. These perspectives necessitate a reliable evaluation of the status of ERBB2 in individual tumors before the application of specific therapeutic strategies. Fluorescent in situ hybridization (FISH) and IHC allow the evaluation of the ERBB2 status specifically in tumor cells on archival material. We have analyzed a series of 100 invasive ductal breast carcinomas without lymph node invasion both by IHC, using the CB11 monoclonal antibody and a sensitive Auidin Biotin Complex (ABC) immunodetection system, and by FISH, using the Oncor Inform HER-21neu (ERBB2) gene amplification detection system as reference technique. Complete concordance between the results of FISH and IHC was seen in 98% of the cases. ERBB2 amplification (more than four signals per nucleus) was observed in 12 of the 100 cases, and all but one showed an overexpression of the protein (membrane staining) by IHC. Conversely, ERBB2 expression was present in one case without gene amplification. In conclusion, ERBB2 overexpression detected by IHC is highly correlated to gene amplification detected by FISH. Thus, under standardized conditions, IHC is a reliable and economical test to assess the ERBB2 status in tumors. The use of FISH could be limited to the verification of the status of tumors displaying a weak membrane immunostaining.

The significance of histological determination of HER-2 status in breast cancer

Since the identification of the novel transforming gene neu in rat neuroblastomas in 1981, and the subsequent cloning of the human equivalent HER-2, there have been considerable developments concerning the role and value of HER-2 in human breast cancer. Early studies found gene amplification in 20-30% of breast carcinomas, with most studies linking this to poorer survival. Numerous antibodies have been generated against the oncoprotein and in many instances overexpression, as defined by membrane staining of breast cancer cells, correlated with gene amplification. Many studies, but not all, have found an association between HER-2 reactivity and poor prognosis. HER-2 can also be detected in high-grade ductal carcinoma in situ. HER-2 status can also aid prediction of response to hormonal and chemotherapy, but the present interest lies in the humanized monoclonal antibody against HER-2 (Herceptin) that has been developed. This is only of value if there is over-expression of HER-2 by a breast cancer, and so a reliable, accurate method of determination of HER-2 status is required. Immunohistochemistry is widely used and is relatively simple, with no major equipment requirements. However, there are variations in results with different antibodies and standardized methods, with controls for evaluating extent of reactivity required. Fluorescent in situ hybridization, which detects gene amplification, is an alternative approach that can be used with fixed embedded tissue but the technique is less widely available. HER-2 is the first oncoprotein involved in breast cancer in which there has been direct translation from the laboratory to the patient.

Assessment of HER2 status in breast cancer: why, when and how?

Human epidermal growth factor receptor 2 (HER2) is overexpressed, usually as a result of HER2 proto-oncogene amplification, in 20-30% of breast cancers. A HER2-positive status is generally associated with more aggressive disease and a worse prognosis. Furthermore, a positive HER2 status may predict the likelihood of resistance to some conventional therapies, as well as probably being predictive of sensitivity to anthracycline dose intensification. In addition to this prognostic/predictive value, HER2 is a target for specific therapy, with anti-HER2 monoclonal antibody therapy available in the USA. This article reviews the different assays used to determine HER2 status, discussing their relative advantages/disadvantages and the need for their standardisation before integration alongside other pathological indices into the clinical management of breast cancer.