Quantitative Assessment of HER-2/Neu Protein Concentration in Breast Cancer by Enzyme-Linked Immunosorbent Assay

Proteomic-based electrochemical non-invasive biosensor for early breast cancer diagnosis

Breast cancer is the second highest cause of cancer-related mortality in women worldwide and in the United States, accounting for around 571,000 deaths per year. Early detection of breast cancer increases treatment results and the possibility of a cure. While existing diagnostic modalities such as mammography, ultrasound, and biopsy exist, some are prohibitively expensive, uncomfortable, time-consuming, and have limited sensitivity, necessitating the development of a cost-effective, rapid, and highly sensitive approach such as an electrochemical biosensor. Our research focuses on detecting breast cancer patients using the ECM1 biomarker, which has higher expression in synthetic urine. Our study has two primary objectives: (i) Diverse ECM1 protein concentrations are measured using electrochemical impedance spectroscopy and ELISA. Establishing a standard curve for the electrochemical biosensor by calibrating ECM-1 protein levels using electrochemical impedance spectroscopy. (ii) Validation of the effectiveness of the electrochemical biosensor. This aim entails testing the unknown concentration of ECM1 in the synthetic urine to ensure the efficiency of the biosensor to detect the biomarker in the early stages. The results show that the synthetic urine solution's ECM-1 detection range ranges from 1 pg/ml to 500 ng/ml. This shows that by detecting changes in ECM-1 protein levels in patient urine, the electrochemical biosensor can consistently diagnose breast cancer in its early stages or during increasing recurrence. Our findings highlight the electrochemical biosensor's efficacy in detecting early-stage breast cancer biomarkers (ECM-1) in patient urine. Further studies will be conducted with patient samples and develop handheld hardware for patient usage.

Employing Pd nanoparticles decorated on halloysite nanotube/carbon composite for electrochemical aptasensing of HER2 in breast cancer patients

An effective biosensing platform is described based on halloysite nanotube/carbon composite decorated with Pd nanoparticles (HNT/C@Pd NPs). A novel electrochemical aptasensor was designed using the proposed nano-platform to determine human epidermal growth factor receptor 2 (HER2), a breast cancer biomarker. Inherently, aptasensing interfaces provide high sensitivity and selectivity for tumor markers owing to the high specific surface area of HNT/C and good conductivity stems from deposition of Pd NPs into HNT/C composite. With a correlation coefficient of 0.996, the electrochemical aptasensor demonstrated a wide linear range from 0.03 ng/mL to 9 ng/mL. The limit of detection (LOD) of the established assay was 8 pg/mL based on S/N = 3 method. Further, the designed biosensor demonstrated acceptable selectivity, good reproducibility, and high stability. The applicability of the impedimetric sensor in human serum samples was also examined and compared to enzyme-linked immunosorbent assay (ELISA) assay (p-value >0.05). Based on the results, it was found that the proposed methodology can be used in quantification of breast cancer markers for early diagnosis and treatment.

Functional Relationship and Gene Ontology Classification of Breast Cancer Biomarkers

Breast cancer is a complex disease that still imposes a significant healthcare burden on women worldwide. The etiology of breast cancer is not known but significant advances have been made in the area of early detection and treatment. The advent of advanced molecular biology techniques, mapping of the human genome and availability of high throughput genomic and proteomic strategies opens up new opportunities and will potentially lead to the discovery of novel biomarkers for early detection and prognostication of breast cancer. Currently, many biomarkers, particularly the hormonal and epidermal growth factor receptors, are being utilized for breast cancer prognosis. Unfortunately, none of the biomarkers in use have sufficient diagnostic, prognostic and/or predictive power across all categories and stages of breast cancer. It is recognized that more useful information can be generated if tumors are interrogated with multiple markers. But choosing the right combination of biomarkers is challenging, because 1) multiple pathways are involved, 2) up to 62 genes and their protein products are potentially involved in breast cancer-related mechanisms and 3) the more markers evaluated, the more the time and cost involved. This review summarizes the current literature on selected biomarkers for breast cancer, discusses the functional relationships, and groups the selected genes based on a Gene Ontology™ classification.

Serum Tumor Necrosis Factor-alpha and Interleukin-2 Concentrations in Newly Diagnosed ERBB2 (HER2/neu) Positive Breast Cancer Patients

Aim

Cytokines have been associated with symptoms and adverse outcomes in breast cancer. Overexpression of ERBB2 (c-erb-b2; formerly HER2/neu), which is a member of the epidermal growth receptor family, is associated with involvement of lymph nodes, large tumor size, high grade, steroid receptor negativity, aneuploidy, high proliferation rate, and low overall survival in breast cancer. The aim of the study was to examine whether ERBB2 amplification has any effect on circulating levels of tumor necrosis factor-alpha (TNF-α) and interleukin-2 (IL-2) in breast cancer patients.

Material and methods

Fifty patients with primary breast carcinoma, classified as either ERBB2 (+) or (-) by the fluorescence in situ hybridization (FISH) technique, were included in the study. Cytokines were studied by ELISA according to the procedure described in the commercial kit.

Results

IL-2 levels were found significantly higher in ERBB2+ patients than in controls (p<0.05). A significant negative correlation existed between ERBB2 positivity and estrogen receptor status (p=0.004). Plasma TNF-α and IL-2 levels were positively correlated in ERBB2+ breast cancer patients (p<0.01).

Conclusion

The increase in IL-2 concentrations observed in our study suggests an activation of T cells by ERBB2 peptides.

Inverse prognostic impact of ErbB2 mRNA and protein expression level in tumors of soft tissue sarcoma patients

BACKGROUND

Human epidermal growth factor receptor 2 (ErbB2) is overexpressed in a variety of human malignancies. Moreover, ErbB2 has been reported to influence cancer patient survival and progression of different tumor entities. However, information regarding the prognostic impact of ErbB2 in soft tissue sarcoma (STS) patients is limited and conflicting.

MATERIAL AND METHODS

ErbB2 mRNA and protein levels were defined by quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA), and the prognostic impact of ErbB2 mRNA and protein levels in tumor tissue of 124 soft tissue sarcoma patients were investigated.

RESULTS

The median ErbB2 mRNA expression level in tumor tissue was decreased 3.9-fold compared to non-neoplastic surrounding tissue (p = 0.001). Furthermore, an increased ErbB2 mRNA expression level was associated with an improved tumor-specific survival (p = 0.01, log rank test). Multivariate Cox's proportional hazard regression analyses revealed an increased ErbB2 mRNA expression level as an independent favorable prognostic factor for tumor-specific survival of STS patients (n = 124; RR = 3.0; 95 % CI = 1.6-5.7; p < 0.001). In addition, multivariate Cox's proportional hazard regression analyses showed that an increased ErbB2 protein expression level correlated with poorer recurrence-free survival of STS patients (n = 47; RR = 9.9; 95 % CI = 1.7-59.7; p = 0.012), in particular for STS patients who received postoperative radiotherapy (n = 27; RR = 17.9; 95 % CI = 1.3-247.7; p = 0.031).

CONCLUSION

This study suggests an inverse prognostic value of ErbB2 mRNA and protein expression level.

Expressional correlation of human epidermal growth factor receptor 2, estrogen/progesterone receptor and protein 53 in breast cancer

BACKGROUND

This study aimed to show the localization of estrogen / progesterone receptors, human epidermal growth factor receptor 2 (Her-2) and protein 53 (p53) by immunohistochemistry in a series of consecutive breast cancer patients.

MATERIALS AND METHODS

The study covered invasive breast cancers from 299 patients presenting at the Oncogenetic Clinic and Pathology Centers of Ahwaz Jondishapour University of Medical Sciences Hospital in Iran during the time period from 2009 to 2011. The Scarff-Bloom Richardson scoring method was used.

RESULTS

Of the 299, 27% (80/299) were <40, 33% (100/299) were 41-50, and the remaining 40% (119/299) were>50 years old. The highest incidence of breast cancer in this study population was in the group of more than 50 year age, and the most common histological type of breast cancer was the invasive ductal carcinoma, which accounted for 68% (203/299) of the cases. Out of possible total of 207, 6% (13/207), 41% (85/207), and 53% (109/207) were scored as grade ?, ??, ???, respectively.

CONCLUSION

Our findings demonstrated a lack of association between labeling for the markers studied and tumor size and age of the patients. We confirmed an association between ER labeling and nuclear grade of breast cancer. The conflicting results obtained compared with the literature be because of differences in the immunohistochemical techniques applied in the various studies and to the scoring systems used.

Comparison of microarray-based RNA expression with ELISA-based protein determination of HER2, uPA and PAI-1 in tumour tissue of patients with breast cancer and relation to outcome

PURPOSE

Prognostic and predictive markers in breast cancer are currently determined by single analysis of protein amounts. If RNA-based multi-gene analyses enter clinical practice, simultaneous determination of currently established markers like human epidermal growth factor receptor 2 (HER2), urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) would represent an elegant simplification. To investigate the correlation between RNA and protein levels, we assessed HER2, uPA and PAI-1 in patients with breast cancer. In addition, we evaluated the influence of these factors on patient outcome.

METHODS

We collected tumour samples from 133 patients with primary breast cancer. Protein and mRNA levels were measured for HER2, uPA and PAI-1. Protein concentration was measured by ELISA, mRNA expression was analysed by Affymetrix A133U Gene Chip and validated by quantitative PCR.

RESULTS

We were able to demonstrate a statistically significant correlation between mRNA and protein expression for HER2 (r = 0.67, P < 0.001) and uPA (r = 0.7, P < 0.001) but not for PAI-1 (r = 0.27). We observed a prognostic information for PAI-1 mRNA and protein values. Patients with high PAI-1 mRNA expression had a reduced 10-year disease-free survival (DFS) rate (60 vs. 70%, P = 0.071) and 10-year overall survival (OS) rate (68 vs. 79%, P = 0.034). Patients with PAI-1 protein levels above 14 ng/mg protein had a reduced disease-free (10-year DFS rate 54 vs. 71%, P = 0.006) and overall survival rate (10-year OS-rate 63 vs. 83%, P = 0.018). In the patient cohort with no chemotherapy, PAI-1 mRNA levels were the strongest prognostic factor for OS in univariate and multivariate analysis.

CONCLUSIONS

Results of RNA-based multi-gene analyses of the prognostic and predictive markers HER2 and uPA correlate with the corresponding protein levels. This is not the case for PAI-1. However, PAI-1 mRNA expression might reveal new clinically relevant information in addition to PAI protein levels.

Emerging technologies for assessing HER2 amplification

Patients with human epidermal growth factor receptor-2 (HER2)+ breast cancer are eligible for trastuzumab treatment; therefore, accurate assessment of HER2 status is essential. Until recently, only 2 methods were validated for determining the HER2 status of breast tumors in the routine diagnostic setting: immunohistochemical analysis and fluorescence in situ hybridization (FISH). Recently, bright-field in situ hybridization techniques such as chromogenic in situ hybridization (CISH) and silver-enhanced in situ hybridization (SISH), which combine features of immunohistochemical analysis and FISH, have been introduced for the determination of HER2 status. These new techniques use a peroxidase enzyme-labeled probe with chromogenic detection, instead of a fluorescent-labeled probe, allowing results to be visualized by standard bright-field microscopy. Thus, the histologic features and HER2 status of a specimen can be evaluated in parallel. Moreover, signals do not decay over time. This review discusses recent publications regarding CISH and SISH testing, including results scoring and concordance between FISH and immunohistochemical analysis.

Evaluation of serum HER2 extracellular domain in early breast cancer patients: correlation with clinicopathological parameters and survival

BACKGROUND

We explored the correlation between serum human epidermal growth factor receptor-2 (HER2) extracellular domain (ECD) and tissue HER2 status, their relationship with clinicopathological parameters and their impact on disease-free survival (DFS) and overall survival in early breast cancer patients.

PATIENTS AND METHODS

This prospective trial included patients with stage I-III breast cancer. Serum HER2 ECD levels were measured by two enzyme-linked immunosorbent assays before surgical treatment. Tissue HER2 status was analyzed by immunohistochemistry (IHC) in all tumors; FISH assay was utilized in HER2 2+ tumors by IHC.

RESULTS

From May 2000 to July 2005, 256 consecutive stage I-III breast cancer patients were included in this study. High serum HER2 ECD levels (>or=15 ng/ml) were reported in 23 patients (9.0%) and HER2-positive status in tumor tissue was observed in 42 patients (16.4%) with a concordance of 87.1%. High HER2 ECD levels were significantly associated with high histological grade (P = 0.003), stage III (P = 0.008), lymph node involvement (P = 0.035) and negativity of both estrogen (P = 0.016) and progesterone (P = 0.007) receptors. At multivariate analysis, high serum HER2 ECD levels were a significant independent prognostic factor of worse DFS (P = 0.009).

CONCLUSIONS

A statistically significant association was observed between high serum HER2 ECD levels and worse DFS in early breast cancer patients.

A monoclonal antibody as an effective therapeutic agent in breast cancer: trastuzumab

Trastuzumab (Herceptin; Genentech, Inc., CA, USA) is a humanized monoclonal antibody developed to target the HER-2/neu receptor, which is overexpressed in 20 - 25% of breast carcinomas. Clinical studies showed that trastuzumab is effective as single-agent therapy and that it has greater antitumour activity in combination with chemotherapy than chemotherapy alone in metastatic breast cancer. The indication for trastuzumab monotherapy and the combination with various chemotherapy agents is country-specific and is largely based on trials of efficacy and safety. Patients with a HER-2/neu overexpression level of 3+, determined by immunohistochemical assay or amplification using fluorescence in situ hybridisation, derive most clinical benefit from trastuzumab. Trastuzumab is generally well-tolerated. Cardiotoxicity is the main concern; thus, monitoring of cardiac function is recommended. Ongoing trials investigate the role of trastuzumab in the adjuvant and neoadjuvant settings.

Adjuvant Therapy with Trastuzumab for HER‐2/neu‐Positive Breast Cancer

Breast cancer is the most common cancer in women in the U.S. and western Europe. Amplification of the her-2/neu gene occurs in approximately 25% of invasive ductal carcinomas of the breast. In experimental models, transfection of the her-2/neu gene results in transformation of mammary epithelial cells. In human breast cancer, amplification of the her-2/neu gene results in protein over expression and poor prognosis. Patients whose tumors have her-2/neu gene amplification have a shorter disease-free survival time than patients whose tumors exhibit a normal her-2/neu gene copy number. her-2/ neu gene amplification identifies a biologically unique subset of aggressive breast tumors that are sensitive to growth inhibition and apoptosis induced by anti-HER-2/neu-targeted therapies. The first HER-2/neu-targeted approach to reach the clinic was trastuzumab, a humanized monoclonal antibody directed against the extracellular domain of the HER-2/neu protein. Trastuzumab therapy prolongs the survival of patients with metastatic HER-2/neu-overexpressing breast cancer when combined with chemotherapy and has recently been demonstrated to lead to dramatic improvements in disease-free survival when used in the adjuvant therapy setting in combination with or following chemotherapy. However, potential cardiotoxicity requires careful patient selection. Here, we review the recently completed clinical trials of adjuvant trastuzumab in the adjuvant setting. HER-2/neu testing, patient selection, cardiotoxicity, duration of therapy, and directions for future research are discussed.

Fluorescent silica nanospheres for digital counting bioassay of the breast cancer marker HER2/nue

This paper describes the use of fluorescent silica nanospheres as luminescent signal amplifiers in biological assays based on digital counting of individual particles instead of measuring averaged fluorescence intensity. We recently described a simple method to prepare highly fluorescent mono-dispersed silica nanospheres that avoids microemulsion formulations and the use of surfactants. Modification of the Stöber method was used successfully to prepare fluorescent silica spheres with the inorganic dye dichlorotris(1,10-phenanathroline)ruthenium (II) hydrate encapsulated during the condensation of tetraethylorthosilicate in ethanol and dye aqueous mixtures. Modifications in the ammonia and water content in the reaction mixture resulted in mono-dispersed silica spheres of 65, 440 and 800 nm in diameter. The dye-encapsulating particles emit intense red luminescence when excited at 460 nm. We observed an increased photostability and longer fluorescence lifetime in our particles that we attributed to increased protection of the encapsulated dye molecules from molecular oxygen. The newly prepared fluorescent silica particles were easily modified using trialkoxysilane reagents for covalent conjugation of anti-HER2/neu. We demonstrated the utility of the fluorescent nanospheres to detect the cancer marker HER2/neu in a glass slide based assay. The assay was shown to be simple but highly sensitive with a limit of detection approaching 1 ng/mL and a linear range between 1 ng/mL and 10 microg/mL of HER2/neu.

Analytical validation and interobserver reproducibility of EnzMet GenePro: a second-generation bright-field metallography assay for concomitant detection of HER2 gene status and protein expression in invasive carcinoma of the breast

Fluorescence in situ hybridization (FISH) has both excellent sensitivity and specificity in detecting HER2 gene amplification in invasive breast carcinoma. FISH has not been widely implemented in clinical practice because of reagent costs and the special instrumentation and expertise required to perform and integrate the assay. Immunohistochemistry (IHC) for HER2 protein is widely used, but false-positive and false-negative results are problematic. We developed a bright-field assay to visualize HER2 gene amplification and concomitant HER2 protein expression (EnzMet GenePro). This assay detects HER2 gene amplification via deposition of metallic silver by enzyme metallographytrade mark (EnzMettrade mark, Nanoprobes, Yaphank, NY) combined with HER2 protein detection by IHC using alkaline phosphatase and fast red K substrate visualization (CB11;Ventana, Tucson, AZ). The assay was performed on 94 invasive breast carcinomas, for which FISH (PathVysiontrade mark, Vysis, Downer's Grove, IL), conventional IHC (CB11), and enzyme metallography (EnzMettrade mark) results were known. The EnzMettrade mark component of the assay was scored as either HER2 gene amplified, polysomic, or nonamplified. The IHC component was scored using the conventional FDA scale of 0 to 3+. Concordance of the EnzMet component of the assay versus FISH was assessed and showed an excellent correlation (Pearson coefficient of 0.95; P < 0.001). The combination of gene and protein detection (EnzMet GenePro) displayed a specificity of 100% and an accuracy of 92.6% (95% confidence interval 85.3-97.0), facilitated recognition of gene/protein discordances, and allowed for efficient interpretation of the slide by conventional light microscopy. The interobserver kappa for each component was excellent (IHC, kappa = 0.94; and EnzMettrade mark, kappa = 0.96). EnzMet is the first bright-field ISH assay in our experience that routinely and nonambiguously detects endogenous HER2 signals, essential for a reliable clinical HER2 assay, and in combination with HER2 protein enables improved diagnosis in borderline cases.

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.

Clinical significance of the quantitative assessment of the cytosolic concentration of HER-2/neu protein in breast cancer by immunoenzymatic assay (ELISA)

PURPOSE

Retrospective analysis to assess the prognostic and predictive value of HER-2/ neu expression in breast tumors, quantified by enzyme immunoassay (ELISA).

METHODS

Quantification of HER-2/neu was performed on cytosolic extracts from 914 cases of primary invasive breast carcinomas. Relapse-free and overall survival data were available from 889 patients. The prognostic value of HER-2/neu levels was assessed considering them as a continuous, dichotomic or quartile variable.

RESULTS

Cytosolic HER-2/neu levels ranged widely in breast carcinomas (median: 746.5 NHU/mg; range: 2.8-80,000 NHU/mg protein). HER-2/neu protein levels were significantly higher in either moderately or poorly differentiated tumors, as well as in those showing a ductal histological type, aneuploidy or a high S-phase fraction. There was a significant and positive association between cytosolic and membranous HER-2/neu levels (n=162, r sub S=0.53; P<0.0001). In addition, cytosolic HER-2/neu level correlated weakly with progesterone receptors but not with estrogen receptors. Elevated cytosolic HER-2/neu levels (> or =1,400 NHU/mg protein) were associated with a high probability of both shortened relapse-free survival and overall survival. This same cut-off value was obtained when we divided the overall group of patients in a training set. However, this HER-2/neu value did not achieve any statistical significance in a validation set used to make sure that the cut-off was correct. Nevertheless, when we divided the obtained data into three different groups with respect to the quartile values (Q) of the intratumoral oncoprotein levels (< or = Q1 vs Q1-Q2 vs > Q3), we observed that patients with either low HER-2/ neu levels (< or = Q1) or high HER-2/neu levels (> Q3) had shorter both relapse-free survival and overall survival curves than those patients with intermediate HER-2/neu levels. On the other hand, high HER-2/neu levels predicted a poor response to adjuvant chemotherapy but not to adjuvant hormonal therapy with tamoxifen.

CONCLUSIONS

The results of the present investigation indicate that by quantitatively determining the content of HER-2/neu oncoprotein, groups of high-risk breast cancer patients could be identified, for a more effective clinical management.

Serum HER2 extracellular domain in metastatic breast cancer patients treated with weekly trastuzumab and paclitaxel: association with HER2 status by immunohistochemistry and fluorescence in situ hybridization and with response rate

PURPOSE

We explored the relationship between circulating HER2 extracellular domain (ECD) and tissue HER2 status as determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). We also examined its predictive value in a cohort of metastatic breast cancer patients treated with weekly trastuzumab and paclitaxel.

METHODS

Eligible patients had pre- and post-treatment stored serum specimens and were treated on a previously reported phase II trial. Retrospective analysis evaluated: the association between pretreatment serum HER2 ECD and tissue HER2 status by IHC and FISH; and the association between change in serum HER2 ECD after 12 weeks of therapy and response proportion.

RESULTS

Stored serum samples were available for 55/95 (58%) patients. Statistically significant associations were found between HER2 status as assessed by IHC and FISH, and baseline serum HER2 ECD level. Patients whose ECD normalized after 12 weeks of therapy had a higher response proportion compared with patients with persistently high ECD levels (68% versus 15%, P=0.005). A relative decline of over 55% from baseline HER2 ECD predicted response to therapy.

CONCLUSION

A statistically significant association was observed between pretreatment serum HER2 ECD and tissue HER2 status as assessed by IHC and FISH. A decrease in serum HER2 ECD level was a significant predictor of response to trastuzumab-based therapy.

Novel bright field molecular morphology methods for detection of HER2 gene amplification

Profiling the amplification and over-expression of the HER2 gene is a key component for defining the prognosis and management of invasive breast carcinoma. Clinical laboratory testing for HER2 gene amplification and over expression has been complicated by an unacceptably high rate of false positive immunohistochemistry (IHC) results, poor reproducibility for the '2+' category of IHC scoring, and reluctant acceptance of alternative testing by fluorescence in situ hybridization (FISH) by the diagnostic pathology community. Novel chromogenic in situ hybridization (CISH) assays have been developed that utilize bright field microscopy and a conventional light microscope for interpretation, but the analytical sensitivity of first generation CISH systems has been problematic. Novel second generation in situ hybridization detection methods based upon polymerized lg detection chemistry, autometallography or enzyme metallography, have been developed that routinely detect endogenous HER2 signals in normal cells (on slide hybridization control) and HER2 signals in both non-amplified and amplified patterns of HER2 genomic signatures. By combining the strength of polymerized peroxidase-labeled antibodies and metallography for gene amplification, with the detection of expression of HER2 encoded protein by IHC on the same slide, both HER2 gene amplification and protein over-expression can be simultaneously evaluated on a cell-by-cell basis in each microscopic field of carcinoma.

Circulating biomarkers from tumour bulk to tumour machinery: promises and pitfalls

In this paper, we provide a working classification for circulating biomarkers according to their potential clinical application. We broadly divided biomarkers into four groups: (i) biomarkers of cancer risk, (ii) biomarkers of tumour-host interactions, (iii) biomarker of tumour burden, and (iv) function-related biomarkers. We hope this classification will provide a framework to which the results of future studies can be added. We also discuss the promises and pitfalls in the optional use of biomarkers in oncology.

HER2 polymorphism and breast cancer risk in Portugal

Breast cancer is a major public health problem around the world, and its carcinogenesis is not yet well understood. The human epidermal growth factor Receptor 2 (HER2) seems to play an important role in the development of this neoplasia, and genetic alterations in this gene, such as point mutations and polymorphisms have been detected in breast cancer patients. We analysed the frequency of a single nucleotide polymorphism in the HER2 gene in blood samples from 152 breast cancer patients and 146 healthy controls using the polymerase chain reaction methodology, followed by restriction fragment length polymorphism (PCR-RFLP). We found a twofold increase in risk of breast cancer in women who are carriers of a Val allele genotype-Ile/Val and Val/Val genotypes [odds ratio (OR)=2.00; 95% confidence interval (CI) 1.23-3.25; P=0.005]. Our results indicate an association between the presence of the Val allele in the HER2 polymorphism and the risk of breast cancer. Further studies are needed to evaluate the role of this polymorphism in the behaviour of breast cancer.

Targeted therapy in breast cancer: the HER-2/neu gene and protein

The HER-2/neu oncogene, a member of the epidermal growth factor receptor or erb gene family, encodes a transmembrane tyrosine kinase receptor that has been linked to prognosis and response to therapy with the anti-HER-2-humanized monoclonal antibody, trastuzumab (Herceptin, Genentech, South San Francisco, CA) in patients with advanced metastatic breast cancer. HER-2/neu status has also been tested for its ability to predict the response of breast cancer to other therapies including hormonal therapies, topoisomerase inhibitors, and anthracyclines. This review includes an analysis of 80 published studies encompassing more than 25,000 patients designed to consider the relative advantages and disadvantages of the various methods of measuring HER-2/neu in clinical breast cancer specimens. Southern blotting, PCR amplification detection, and fluorescence in situ hybridization assays designed to detect HER-2/neu gene amplification are compared with HER-2/neu protein overexpression assays performed by immunohistochemical techniques applied to frozen and paraffin-embedded tissues and enzyme immunoassays performed on tumor cytosols. The significance of HER-2/neu overexpression in ductal carcinoma in situ and the HER-2/neu status in uncommon female breast conditions and male breast cancer are also considered. The role of HER-2/neu testing for the prediction of response to trastuzumab therapy in breast cancer is reviewed along with the current studies designed to test whether HER-2/neu status can predict the response to standard and newer hormonal therapies, cytotoxic chemotherapy, and radiation. The review will also evaluate the status of serum-based testing for circulating HER-2/neu receptor protein and its ability to predict disease outcome and therapy response.