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

Progress of PD-1/PD-L1 inhibitor combination therapy in immune treatment for HER2-positive tumors

BACKGROUND

Patients with HER2-positive cancers often face a poor prognosis, and treatment regimens containing anti-HER2 have become the first-line treatment options for breast and gastric cancers. However, these approaches are faced with significant challenges in terms of drug resistance. Hence, it is crucial to explore precise treatment strategies aimed at improving survival outcomes.

ADVANCEMENTS IN TREATMENT

Over the past few years, there has been rapid advancement in the realm of tumor therapy, particularly with the swift progress of immune checkpoint inhibitors, including PD-1/PD-L1 inhibitors. They exert anti-tumor effects by disrupting immune-suppressive factors within the tumor microenvironment. However, monotherapy with PD-1/PD-L1 inhibitors has several limitations. Consequently, numerous studies have explored combinatorial immunotherapeutic strategies and demonstrated highly promising avenues of development.

OBJECTIVE

This article aims to review the clinical trials investigating PD-1/PD-L1 inhibitor combination therapy for HER2-positive tumors. Additionally, it provides a summary of ongoing trials evaluating the efficacy and safety of these combined treatments, with the intention of furnishing valuable insights for the clinical management of HER2-positive cancer.

CONCLUSION

Combinatorial immunotherapeutic strategies involving PD-1/PD-L1 inhibitors hold considerable promise in the treatment of HER2-positive tumors. Continued research efforts and clinical trials are warranted to elucidate optimal treatment regimens that maximize therapeutic benefits while minimizing adverse effects.

Unveiling breast cancer risk profiles: a survival clustering analysis empowered by an online web application

Aim: To develop a shiny app for doctors to investigate breast cancer treatments through a new approach by incorporating unsupervised clustering and survival information. Materials & methods: Analysis is based on the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) dataset, which contains 1726 subjects and 22 variables. Cox regression was used to identify survival risk factors for K-means clustering. Logrank tests and C-statistics were compared across different cluster numbers and Kaplan-Meier plots were presented. Results & conclusion: Our study fills an existing void by introducing a unique combination of unsupervised learning techniques and survival information on the clinician side, demonstrating the potential of survival clustering as a valuable tool in uncovering hidden structures based on distinct risk profiles.

Development of new TAK-285 derivatives as potent EGFR/HER2 inhibitors possessing antiproliferative effects against 22RV1 and PC3 prostate carcinoma cell lines

Epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) protein tyrosine kinases co-expressed in various cancers such as ovarian, breast, colon, and prostate subtypes. Herein, new TAK-285 derivatives (9a-h) were synthesised, characterised, and biologically evaluated as dual EGFR/HER2 inhibitors. Compound 9f exhibited IC₅₀ values of 2.3 nM over EGFR and 234 nM over HER2, which is 38-fold of staurosporine and 10-fold of TAK-285 over EGFR. Compound 9f also showed high selectivity profile when tested over a small kinase panel. Compounds 9a-h showed IC₅₀ values in the range of 1.0-7.3 nM and 0.8-2.8 nM against PC3 and 22RV1 prostate carcinoma cell lines, respectively. Cell cycle analysis, apoptotic induction, molecular docking, dynamics, and MM-GBSA studies confirmed the plausible mechanism(s) of compound 9f as a potent EGFR/HER2 dual inhibitor with an effective antiproliferative action against prostate carcinoma.

Design, Synthesis, Biological Evaluation, and Molecular Dynamics Studies of Novel Lapatinib Derivatives

Co-expression of the epidermal growth factor receptor (EGFR, also known as ErbB1) and human epidermal growth factor receptor 2 (HER2) has been identified as a diagnostic or prognostic sign in various tumors. Despite the fact that lapatinib (EGFR/HER2 dual inhibitor) has shown to be successful, many patients do not respond to it or develop resistance for a variety of reasons that are still unclear. As a result, new approaches and inhibitory small molecules are still needed for EGFR/HER2 inhibition. Herein, novel lapatinib derivatives possessing 4-anilinoquinazoline and imidazole scaffolds (6a-l) were developed and screened as EGFR/HER2 dual inhibitors. In vitro and in silico investigations revealed that compound 6j has a high affinity for the ATP-binding regions of EGFR and HER2. All of the designed candidates were predicted to not penetrate the BBB, raising the expectation for the absence of CNS side effects. At 10 µM, derivatives possessing 3-chloro-4-(pyridin-2-ylmethoxy)aniline moiety (6i-l) demonstrated outstanding ranges of percentage inhibition against EGFR (97.65-99.03%) and HER2 (87.16-96.73%). Compound 6j showed nanomolar IC₅₀ values over both kinases (1.8 nM over EGFR and 87.8 nM over HER2). Over EGFR, compound 6j was found to be 50-fold more potent than staurosporine and 6-fold more potent than lapatinib. A kinase selectivity panel of compound 6j showed poor to weak inhibitory activity over CDK2/cyclin A, c-MET, FGFR1, KDR/VEGFR2, and P38a/MAPK14, respectively. Structure-activity relationship (SAR) that were obtained with different substitutions were justified. Additionally, molecular docking and molecular dynamics studies revealed insights into the binding mode of the target compounds. Thus, compound 6j was identified as a highly effective and dual EGFR/HER2 inhibitor worthy of further investigation.

Variability of predictive markers (hormone receptors, Her2, Ki67) and intrinsic subtypes of breast cancer in four consecutive years 2015-2018

Purpose

Accurate monitoring of predictive markers is of utmost importance as oncological treatment decisions almost entirely depend on these factors. In this study, we conducted a quality control assessment on hormone receptors, Her2 status, Ki67 Labelling Index (LI) and histological grading in breast cancer over 4 years (2015–2018).

Methods

Altogether 2214 consecutive breast cancer cases were included. Data on estrogen (ER) and progesterone receptors (PR), Her2 and Ki67, were available in all cases and were tested mostly on preoperative biopsies, in selected cases on postoperative surgical specimens. ER, PR, and Ki67 were assessed with immunohistochemistry (IHC), Her2 status with IHC and fluorescence in situ hybridization.

Results

ER/PR were positive in 74–79% cases, ER/PR/Her2 negative in 6.16–10.70% and Her2 positive in 11.49–13.88%/year. Ki67 had median values as 15–17.5% in ER/PR-positive cases, 55–60% in triple-negative cases and 30–32.50% in Her2-positive cases. Histological grading distribution for well (G1), moderately (G2) and poorly (G3) differentiated carcinomas was 15.8–19.1% for G1, 54.2–54.8% for G2 and 21.7–23.7% for G3 cases. Variation in yearly distributions was not significant in any of these markers.

Conclusions

Predictive markers displayed a yearly similar distribution in breast cancer cases independently of grading or of intrinsic subtypes. These results point to a qualitative high performance of predictive marker assessment in breast cancer, corresponding to expected on average positivity rate per marker and per year. It is recommended to monitor positivity rate of ER, PR, Ki67 and Her2 yearly or periodically to comply with quality assurance requirements.

C-Erbb-2 Protein Level in Tissue and Sera of Breast Cancer Patients: A Possibly Useful Clinical Correlation

Aims and background

The aims of this study were to assess the clinical utility of circulating preoperative HER-2 extracellular domain p105 detected by enzyme immunoassay (ELISA), to compare the tissue expression of HER-2/neu determined by immunohistochemistry (IHC), to correlate prognostic factors including tumor size, nodal involvement, and hormone receptor status, and to analyze the prognostic significance of the marker in relation to clinical outcome as measured by disease-free and overall survival.

Methods

In this study, we enrolled 108 consecutive patients with breast carcinoma, and obtained serum samples and frozen tumor tissues. We compared them with 57 women with fibroadenoma and 63 healthy women as controls.

Results

Univariate ANOVA analysis showed no relationship between HER-2/neu in tissue and serum. Preoperative serum levels of p105 were significantly higher in breast cancer patients than in women with benign disease or healthy women. Concerning the correlation between p105, HER-2/neu tissue expression, and the other prognostic factors, a statistically significant correlation between high serum p105 levels and ER-negative status in breast cancer patients was found. Kaplan-Meier analysis confirmed that patients with positive HER-2/neu tissue expression had a significantly shorter survival than those with negative expression. Analysis with the Cox model demonstrated that tumor size was the only significant independent prognostic factor.

Conclusions

This research failed to demonstrate a relationship between preoperative tissue overexpression and circulating HER-2/neu, suggesting that p105 does not represent a valid alternative to predict a worsened prognosis in breast cancer, but it could be a diagnostic marker to discriminate healthy subjects from breast cancer patients.

Evaluation of HER-2/neu in Serum and Tissue of Primary and Metastatic Breast Cancer Patients using an Automated Enzyme Immunoassay

Serum HER-2/neu concentrations were evaluated in 172 healthy subjects, 176 primary and 55 metastatic breast cancer patients, employing a new automated assay (Bayer Immuno 1™ serum HER-2/neu). Using 13 ng/mL as the cutoff, abnormal HER-2/neu serum levels were found in 8% (14/176) of primary and 50.9% (28/55) of metastatic breast cancer patients.

Both in primary and metastatic breast cancer a significant relationship was found with the stage of the disease when serum HER-2/neu was considered as a categorized variable (p=0.0003 and p=0.02, respectively), but not when it was taken as a continuous variable (p=0.247 and p=0.146, respectively). Moreover, we evaluated the correlation between Immuno 1™ HER-2/neu and Oncogene Research Products ELISA assay in 53 normal subjects, 46 primary and 34 metastatic breast cancer patients. The correlation was relatively good (p<0.0001), although substantial differences could be found in single cases. The Immuno 1™ assay was also evaluated for the first time in breast cancer tissue. The method, which showed good performance both in terms of imprecision and linearity, was used to measure HER-2/neu protein in 140 cytosol samples from primary breast cancer tissue and in homogenates from 40 matched cases. The correlation between the two matrixes was very close (p<0.0001). By contrast, no correlation was found between serum and matched cytosol (p=0.101) or ho-mogenate samples (p=0.511).

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.

POPDC1 is suppressed in human breast cancer tissues and is negatively regulated by EGFR in breast cancer cell lines

Breast cancer molecular heterogeneity has resulted in disparities in therapeutic response and targeting of molecular subtypes of breast cancer. This necessitates identification and validation of novel therapeutic targets for breast cancer treatment. Suppression of Popeye domain-containing (POPDC) proteins is hypothesized to promote malignant cell behaviour and poor clinical outcomes in various cancers. We aimed to determine whether POPDC proteins are suppressed in human ductal carcinoma tissues and if this correlates to clinical progression and Her2 status. We further assessed if the EGFR regulated POPDC1 in breast cancer. Here we show significant suppression of POPDC1 in malignant breast cancer tissues without correlation to clinical progression. Interestingly, POPDC2 and POPDC3 were highly expressed in malignant breast tissues. Furthermore, HER2+ status significantly correlated with high POPDC2 and POPDC3, but not POPDC1 expression. We further show for the first time that low POPDC1 correlates to high EGFR expression in breast cancer tissues and that EGFR negatively regulates POPDC1 expression in MCF7, MDA231 and SKBR3 breast cancer cells. Furthermore, overexpression of POPDC1 in MCF7, MDA231 and SKBR3 cells attenuated EGF-mediated cell migration and proliferation. These findings show that POPDC1 is suppressed in breast cancer and can potentially be targeted to inhibit EGFR-mediated cell migration and proliferation.

Molecular Mechanisms and Translational Therapies for Human Epidermal Receptor 2 Positive Breast Cancer

Breast cancer is the second leading cause of cancer death among women. Human epidermal receptor 2 (HER2) positive breast cancer (HER2+ BC) is the most aggressive subtype of breast cancer, with poor prognosis and a high rate of recurrence. About one third of breast cancer is HER2+ BC with significantly high expression level of HER2 protein compared to other subtypes. Therefore, HER2 is an important biomarker and an ideal target for developing therapeutic strategies for the treatment HER2+ BC. In this review, HER2 structure and physiological and pathological roles in HER2+ BC are discussed. Two diagnostic tests, immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH), for evaluating HER2 expression levels are briefly introduced. The current mainstay targeted therapies for HER2+ BC include monoclonal antibodies, small molecule tyrosine kinase inhibitors, antibody-drug conjugates (ADC) and other emerging anti-HER2 agents. In clinical practice, combination therapies are commonly adopted in order to achieve synergistic drug response. This review will help to better understand the molecular mechanism of HER2+ BC and further facilitate the development of more effective therapeutic strategies against HER2+ BC.

A meta-analysis on concordance between immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) to detect HER2 gene overexpression in breast cancer

BACKGROUND

We performed this meta-analysis study to evaluate the concordance and discordance between immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in detecting HER2 alteration in human breast cancer.

METHODS

As a meta-analysis, the present study evaluated the available data from previous studies on the HER2 gene detected by IHC and FISH. To indicate the meta-analysis results, a forest plot was used.

RESULTS

We identified 172 citations, for which our inclusion criteria were met by 18 articles, representing 6629 cases. The overall concordance and discordance rate between IHC staining with score 0/1+ and FISH for detection failure of HER2 expression was 96 and 4 %, respectively. The present study showed that the overall proportion of FISH positive and negative rate for IHC score 2+ for detection of HER2 expression was 36 and 64 %, respectively; and 91 and 9 % for 3+ IHC scores.

CONCLUSION

The results of this study show that IHC score 0/1+ and 3+ cannot be completely considered as negative and positive breast cancer test, respectively. Therefore, we suggest a valid and complementary test, the same as FISH, to explore HER2 expression.

Targeting EGFR/HER2 tyrosine kinases with a new potent series of 6-substituted 4-anilinoquinazoline hybrids: Design, synthesis, kinase assay, cell-based assay, and molecular docking

Coexpression of EGFR and HER2 has been found in many tumors such as breast, ovarian, colon and prostate cancers, with poor prognosis of the patients. Herein, our team has designed and synthesized new eighteen compounds with 6-substituted 4-anilinoquinazoline core to selectively inhibit EGFR/HER2 tyrosine kinases. Twelve compounds (8a-8d, 9a, 9c, 9d, 10a, 10c, 11b, 14, and 15) showed nanomolar range of IC50 values on EGFR and/or HER2 kinases. Accordingly, a detailed structure activity relationship (SAR) was established. A molecular docking study demonstrated the favorable binding modes of 8d, 9b, 9d and 10d at the ATP active site of both kinases. A kinase selectivity profile performed for compound 8d showed great selectivity for EGFR and HER2. In addition, 8d, 9c, and 9d exerted selective promising cytotoxic activity over BT-474 cell line with IC50 values of 2.70, 1.82 and 1.95 μM, respectively. From these results, we report analogs 8d, 9c, and 9d as promising candidates for the discovery of well-balanced compounds in terms of the kinase inhibitory potency and antiproliferative activity.

An innovative method for obtaining consistent images and quantification of histochemically stained specimens

Obtaining digital images of color brightfield microscopy is an important aspect of biomedical research and the clinical practice of diagnostic pathology. Although the field of digital pathology has had tremendous advances in whole-slide imaging systems, little effort has been directed toward standardizing color brightfield digital imaging to maintain image-to-image consistency and tonal linearity. Using a single camera and microscope to obtain digital images of three stains, we show that microscope and camera systems inherently produce image-to-image variation. Moreover, we demonstrate that post-processing with a widely used raster graphics editor software program does not completely correct for session-to-session inconsistency. We introduce a reliable method for creating consistent images with a hardware/software solution (ChromaCal™; Datacolor Inc., NJ) along with its features for creating color standardization, preserving linear tonal levels, providing automated white balancing and setting automated brightness to consistent levels. The resulting image consistency using this method will also streamline mean density and morphometry measurements, as images are easily segmented and single thresholds can be used. We suggest that this is a superior method for color brightfield imaging, which can be used for quantification and can be readily incorporated into workflows.

Pharmacophore approaches in protein kinase inhibitors design

Protein kinases constitute a superfamily of therapeutic targets for a number of human and animal diseases that include more than 500 members accordingly to sequencing data of the human genome. The well characterized nature of protein kinases makes them excellent targets for drug development. Pharmacophore approaches have become one of the major tools in the area of drug discovery. Application of pharmacophore modeling approaches allows reducing of expensive overall cost associated with drug development project. Pharmacophore models are important functional groups of atoms in the proper spatial position for interaction with target protein. Various ligand-based and structure-based methods have been developed for pharmacophore model generation. Despite the successes in pharmacophore models generation these approaches have not reached their full capacity in application for drug discovery. In the following review, we summarize the published data on pharmacophore models for inhibitors of tyrosine protein kinases (EGFR, HER2, VEGFR, JAK2, JAK3, Syk, ZAP-70, Tie2) and inhibitors of serine/threonine kinases (Clk, Dyrk, Chk1, IKK2, CDK1, CDK2, PLK, JNK3, GSK3, mTOR, p38 MAPK, PKB). Here, we have described the achievements of pharmacophore modeling for protein kinase inhibitors, which provide key points for further application of generated pharmacophore hypotheses in virtual screening, de novo design and lead optimization.

Classifying patients for breast cancer by detection of autoantibodies against a panel of conformation-carrying antigens

Patients with breast cancer elicit an autoantibody response against cancer proteins, which reflects and amplifies the cellular changes associated with tumorigenesis. Detection of autoantibodies in plasma may provide a minimally invasive mechanism for early detection of breast cancer. To identify cancer proteins that elicit a humoral response, we generated a cDNA library enriched for breast cancer genes that encode membrane and secreted proteins, which are more likely to induce an antibody response compared with intracellular proteins. To generate conformation-carrying antigens that are efficiently recognized by patients' antibodies, a eukaryotic expression strategy was established. Plasma from 200 patients with breast cancer and 200 age-matched healthy controls were measured for autoantibody activity against 20 different antigens designed to have conformational epitopes using ELISA. A conditional logistic regression model was used to select a combination of autoantibody responses against the 20 different antigens to classify patients with breast cancer from healthy controls. The best combination included ANGPTL4, DKK1, GAL1, MUC1, GFRA1, GRN, and LRRC15; however, autoantibody responses against GFRA1, GRN, and LRRC15 were inversely correlated with breast cancer. When the autoantibody responses against the 7 antigens were added to the base model, including age, BMI, race and current smoking status, the assay had the following diagnostic capabilities: c-stat (95% CI), 0.82 (0.78-0.86); sensitivity, 73%; specificity, 76%; and positive likelihood ratio (95% CI), 3.04 (2.34-3.94). The model was calibrated across risk deciles (Hosmer-Lemeshow, P = 0.13) and performed well in specific subtypes of breast cancer including estrogen receptor positive, HER-2 positive, invasive, in situ and tumor sizes >1 cm.

ERBB2 in cat mammary neoplasias disclosed a positive correlation between RNA and protein low expression levels: a model for erbB-2 negative human breast cancer

Human ERBB2 is a proto-oncogene that codes for the erbB-2 epithelial growth factor receptor. In human breast cancer (HBC), erbB-2 protein overexpression has been repeatedly correlated with poor prognosis. In more recent works, underexpression of this gene has been described in HBC. Moreover, it is also recognised that oncogenes that are commonly amplified or deleted encompass point mutations, and some of these are associated with HBC. In cat mammary lesions (CMLs), the overexpression of ERBB2 (27%-59.6%) has also been described, mostly at the protein level and although cat mammary neoplasias are considered to be a natural model of HBC, molecular information is still scarce. In the present work, a cat ERBB2 fragment, comprising exons 10 to 15 (ERBB2_10-15) was achieved for the first time. Allelic variants and genomic haplotype analyses were also performed, and differences between normal and CML populations were observed. Three amino acid changes, corresponding to 3 non-synonymous genomic sequence variants that were only detected in CMLs, were proposed to damage the 3D structure of the protein. We analysed the cat ERBB2 gene at the DNA (copy number determination), mRNA (expression levels assessment) and protein levels (in extra- and intra protein domains) in CML samples and correlated the last two evaluations with clinicopathological features. We found a positive correlation between the expression levels of the ERBB2 RNA and erbB-2 protein, corresponding to the intracellular region. Additionally, we detected a positive correlation between higher mRNA expression and better clinical outcome. Our results suggest that the ERBB2 gene is post-transcriptionally regulated and that proteins with truncations and single point mutations are present in cat mammary neoplastic lesions. We would like to emphasise that the recurrent occurrence of low erbB-2 expression levels in cat mammary tumours, suggests the cat mammary neoplasias as a valuable model for erbB-2 negative HBC.

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.

HER2 expression in Brazilian patients with estrogen and progesterone receptor-negative breast carcinoma

The aim of the study was to evaluate the relationship between clinical and pathological factors and survival in patients with double negative HER2-overexpressing carcinoma and triple negative carcinoma. One hundred and sixty-one (161) patients diagnosed with breast cancer negative for estrogen receptor (ER) and progesterone receptor (PR) were included. Of the total, 58 patients had double negative HER2-overexpressing (ER/PR-negative and HER2-positive) and 103 had triple negative (ER-negative, PR-negative and HER2-negative). ER and PR expression was assessed through immunohistochemistry (IHC) and HER2 expression was measured by immunohistochemistry and Fluorescent in situ Hybridization (FISH) analysis in tissue microarray. More than 80% had stages II and III disease and histologic grade III and nuclear grade 3. Patients with triple negative breast carcinoma had undifferentiated histologic types in 11% of cases and vascular invasion in 14.5%. Both groups had more than 50% visceral metastases. HER2 expression (p=0.42) and vascular invasion (p=0.05) did not interfere with survival. Survival of patients with Stages I-II disease was significantly longer than in those with Stage III disease both for double negative HER2-overexpressing carcinomas (p<0.0001) and triple negative carcinomas (p=0.03). The study shows that hormone receptor-negative breast carcinomas were undifferentiated and diagnosed at advanced stages and that HER2 expression was not associated with overall survival.

Comparison of dual-color dual-hapten brightfield in situ hybridization (DDISH) and fluorescence in situ hybridization in breast cancer HER2 assessment

The most optimal method for assessing HER2 status is still subject to controversy as far as the type of assay used, the optimal method to perform, and the costs of each assay are concerned. The current study was done as a validation study prior to setting up a clinical HER2 testing service using the new commercial dual-color dual-hapten brightfield in situ hybridization (DDISH), but it was felt that our experience may be of interest to other laboratories considering setting up HER2 diagnostic facilities. One hundred and five patients diagnosed with invasive breast cancer were selected. PathVysion FISH and DDISH assays were carried out. Concordance correlation coefficients showed near perfect agreement in average HER2 and centromere-specific signal counts per cell and in HER2/CEN17 ratios between the PathVysion and the DDISH assays, and also the Kappa measure showed near perfect agreement between the two assays (Kappa=0.8712, P<0.0001). Statistical analysis confirmed that the two assays are comparable in terms of detection of HER2 gene amplification and suggests its utilization in routine HER2 diagnostics.

Spontaneous feline mammary intraepithelial lesions as a model for human estrogen receptor- and progesterone receptor-negative breast lesions

Background

Breast cancer is the most frequently diagnosed cancer in women. Intraepithelial lesions (IELs), such as usual ductal hyperplasia (UH), atypical ductal hyperplasia (ADH), and ductal carcinoma in situ (DCIS) are risk factors that predict a woman's chance of developing invasive breast cancer. Therefore, a comparative study that establishes an animal model of pre-invasive lesions is needed for the development of preventative measures and effective treatment for both mammary IELs and tumors. The purpose of this study was to characterize the histologic and molecular features of feline mammary IELs and compare them with those in women.

Methods

Formalin-fixed, paraffin-embedded specimens (n = 205) from 203 female cats with clinical mammary disease were retrieved from the archives of the Purdue University Animal Disease Diagnostic Laboratory and Veterinary Teaching Hospital (West Lafayette, IN), and the Department of Pathology and Veterinary Clinic, School of Veterinary Medicine (Sassari, Italy). Histologic sections, stained with hematoxylin and eosin (HE), were evaluated for the presence of IELs in tissue adjacent to excised mammary tumors. Lesions were compared to those of humans. Immunohistochemistry for estrogen receptor (ER-alpha), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2/neu) and Ki-67 was performed in IELs and adjacent tumor tissues.

Results

Intraepithelial lesions were found in 57 of 203 (28%) feline mammary specimens and were categorized as UH (27%), ADH (29%), and DCIS (44%). Most IELs with atypia (ADH and DCIS) were associated with mammary cancer (91%), whereas UH was associated with benign lesions in 53% of cases. Feline IELs were remarkably similar to human IELs. No ER or PR immunoreactivity was detected in intermediate-grade or high-grade DCIS or their associated malignant tumors. HER-2 protein overexpression was found in 27% of IELs.

Conclusion

The remarkable similarity of feline mammary IELs to those of humans, with the tendency to lose hormone receptor expression in atypical IELs, supports the cat as a possible model to study ER- and PR-negative breast lesions.

Out of the darkness and into the light: bright field in situ hybridisation for delineation of ERBB2 (HER2) status in breast carcinoma

Assessment of ERBB2 (HER2) status in breast carcinomas has become critical in determining response to the humanised monoclonal antibody trastuzumab. The current joint College of American Pathologists and the American Society of Clinical Oncology guidelines for the evaluation of HER2 status in breast carcinoma involve testing by immunohistochemistry and fluorescence in situ hybridisation (FISH). However, neither of these modalities is without limitations. Novel bright field in situ hybridisation techniques continue to provide viable alternatives to FISH testing. While these techniques are not limited to evaluation of the HER2 gene, the extensive number of studies comparing bright field in situ techniques with other methods of assessing HER2 status allow a robust evaluation of this approach. Analysis of the literature demonstrates that, when used to assess HER2 gene status, bright field in situ hybridisation demonstrates excellent concordance with FISH results. The average percentage agreement in an informal analysis of studies comparing HER2 amplification by chromogenic in situ hybridisation with FISH was 96% (SD 4%); kappa coefficients ranged from 0.76 to 1.0. Although a much smaller number of studies are available for review, similar levels of concordance have been reported in studies comparing HER2 amplification by methods employing metallography (silver in situ hybridisation) with FISH. A summary of the advancements in bright field in situ hybridisation, with focus on those techniques with clinical applications of interest to the practicing pathologist, is presented.

Comparison of Pathvysion and Poseidon HER2 FISH assays in measuring HER2 amplification in breast cancer: a validation study

Aims

The current study was done as a validation study prior to setting up a clinical HER2 testing service using the new commercial Poseidon HER2 fluorescence in situ hybridisation (FISH) assay. However, it was felt that the experience of the authors of this study may be of interest to other laboratories when considering setting up a HER2 diagnostic facility.

Methods

122 patients who had been diagnosed with invasive breast cancer were selected. Immunolabelling with HercepTest, PathVysion and Poseidon FISH assays were carried out using tissue microarray blocks.

Results

Concordance correlation coefficients showed near perfect agreement in average HER2 and centromere specific signal counts per cell and in the HER2/CEP17 ratios between the PathVysion and the Poseidon FISH assays. In addition, the κ measure showed perfect agreement (κ 0.9441, p<0.0001), and if only 2+ cases were considered there was substantial agreement (κ 0.7671, p=0.0006), between the two assays. The sensitivity and the specificity of the Poseidon FISH kit were calculated to be 95.2% and 100%, respectively, whereas the positive predictive value (PPV) and negative predictive value (NPV) were 100% and 99%, respectively. With regard to the ability to presume HER2 polysomy, the Poseidon FISH kit had a sensitivity of 93.3% and a specificity of 99.1%, with PPV and NPV of 93.3% and 99.1%, respectively, as assessed with PathVysion classification as the reference.

Conclusions

Statistical analysis confirmed that the two FISH assays are comparable in terms of detection of HER2 gene amplification. Proceeding from these findings, the genetic diagnoses obtained with the Poseidon kit can be considered to be as valuable as the results from the Food and Drug Administration approved PathVysion assay, and its utilisation in routine HER2 diagnostics is proposed.

An alternative and reliable real-time quantitative PCR method to determine HER2/neu amplification in breast cancer

The overexpression of HER-2/neu is an independent prognostic factor of clinical outcome of breast cancer, therefore determination of HER-2/neu status is now an integral part of the clinicopathologic workup. The ways of measuring the copy number of the HER-2/neu gene in tumor cells comprise in situ hybridization techniques and real-time polymerase chain reaction (PCR). Quantitative real-time PCR is a relatively new technique for assessing HER-2/neu gene amplification with high sensitivity. However, the HER-2/neu Quantification Kit developed by Roche designed for a LightCycler 1.5 platform had been withdrawn from the commercial market; therefore, we were encouraged to design an alternative LightCycler-based method that offers the desired level of reliability. One hundred breast cancer cases with known HER-2/neu status have been examined with the original Roche developed HER-2/neu Quantification kit and the custom real-time PCR assay. The newly developed, custom PCR showed sensitivity of 91.43%, specificity of 90.63%, and accuracy of 90.91% taking fluorescence in situ hybridization results as the end point. We have described a novel real-time PCR technique for the relative quantification of the HER2/neu gene on a LightCycler 1.5 platform. We have determined that our method is eligible and ideal for the supplement of regular fluorescence in situ hybridization reactions, concerning its high sensitivity and reliability.

Radiolabeling of HER2 specific Affibody(R) molecule with F-18

The presence of human epidermal growth factor type 2 (HER2) on 20-30% of human breast cancer is a prognostic indicator of more rapid disease progression and a therapeutic indicator for anti-HER2 monoclonal antibodies. Because the literature has demonstrated some discordance between primary and metastatic tumors in the same patient for expression of the HER2 marker, we set out to develop an imaging agent that could be used to assess the marker concentration in vivo in an individual patient. The pharmaceutical company Affibody AB has optimized the specificity of Affibody molecules for HER2. Two Affibody molecules, a 7 kD and an 8 kD protein, were designed with a single carboxy terminal cysteine in order to provide a specific location for the purposes of labeling for various types of imaging. We have prepared N-[2-(4-[(18)F]fluorobenzamido)ethyl]maleimide utilizing a coupling reaction between [(18)F]fluorobenzoic acid and aminoethylmaleimide. We then optimized the conjugation of this radiolabeled maleimide to the free sulfhydryl of cysteine by incubating at pH 7.4 in phosphate buffered saline containing 0.1% sodium ascorbate. An overall uncorrected yield of radiolabeled Affibody molecule of approximately 10% from [(18)F]fluoride was achieved in a 2 h synthesis. These conjugated Affibody molecules were obtained with a specific activity of 2.51 +/- 0.92 MBq/microg. Characterization of the product by HPLC-MS supported the conjugation of [(18)F]FBEM with the Affibody molecule. The radiolabeled Affibody molecule retained its binding specificity as demonstrated by successful imaging of xenografts expressing HER2.

The epidermal growth factor receptor family in breast cancer

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

The role of human epidermal growth factor receptor 2 in the survival of women with estrogen and progesterone receptor-negative, invasive breast cancer: the California Cancer Registry, 1999-2004

BACKGROUND

Breast cancers that are negative for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) (triple negative [TN]) have been associated with high-grade histology, aggressive clinical behavior, and poor survival. It has been determined that breast cancers that are negative for ER and PR but positive for HER2 (double negative [DN]) share features with TN breast cancers. In this report, the authors quantified the contribution of HER2 as well as demographic and tumor characteristics to the survival of women with TN tumors, DN tumors, and other breast cancers (OBC).

METHODS

In total, 61,309 women who were diagnosed with invasive breast cancer between 1999-2004 were identified in the California Cancer Registry. Demographic and tumor characteristics of women with TN tumors were compared with those from women with DN tumors and women with OBC. A compound proportional hazards regression analysis (PHPH) (a generalization of the Cox proportional hazards model) was used to model these characteristics.

RESULTS

Women with TN tumors were younger, African American, Hispanic, and of lower socioeconomic status (SES), whereas women with DN tumors were slightly older; African American, and Asian/Pacific Islander. Women with TN and DN tumors presented with larger, higher grade, and higher stage than women with OBC. Survival among women with TN tumors was poorer compared with that among women with OBC but was nearly the same as that of women with DN tumors. Results of the regression analysis indicated that disease stage, tumor grade, SES, and race/ethnicity were significant risk factors for survival. Negative ER and PR status was associated with an increased risk of death. There was a small but significant difference in both long-term and short-term survival patients who had TN tumors compared with patients who had DN tumors.

CONCLUSIONS

Patients with TN tumors shared many clinical, demographic, and tumor features and had survival that was very similar survival to that of patients with DN tumors, and survival for both groups contrasted greatly with survival for patients with OBC. Disease stage, tumor grade, SES, race/ethnicity, negative ER and PR status, rather than negative HER2 status, were risk factors for survival.

[18F]FBEM-Z(HER2:342)-Affibody molecule-a new molecular tracer for in vivo monitoring of HER2 expression by positron emission tomography

PURPOSE

The expression of human epidermal growth factor receptor-2 (HER2) receptors in cancers is correlated with a poor prognosis. If assessed in vivo, it could be used for selection of appropriate therapy for individual patients and for monitoring of the tumor response to targeted therapies. We have radiolabeled a HER2-binding Affibody molecule with fluorine-18 for in vivo monitoring of the HER2 expression by positron emission tomography (PET).

MATERIALS AND METHODS

The HER2-binding Z(HER2:342)-Cys Affibody molecule was conjugated with N-2-(4-[18F]fluorobenzamido)ethyl]maleimide ([18F]FBEM). The in vitro binding of the resulting radioconjugate was characterized by receptor saturation and competition assays. For in vivo studies, the radioconjugate was injected into the tail vein of mice bearing subcutaneous HER2-positive or HER2-negative tumors. Some of the mice were pre-treated with non-labeled Z(HER2:342)-Cys. The animals were sacrificed at different times post-injection, and the radioactivity in selected tissues was measured. PET images were obtained using an animal PET scanner.

RESULTS

In vitro experiments indicated specific, high-affinity binding to HER2. PET imaging revealed a high accumulation of the radioactivity in the tumor as early as 20 min after injection, with a plateau being reached after 60 min. These results were confirmed by biodistribution studies demonstrating that, as early as 1 h post-injection, the tumor to blood concentration ratio was 7.5 and increased to 27 at 4 h. Pre-saturation of the receptors with unlabeled Z(HER2:342)-Cys lowered the accumulation of radioactivity in HER2-positive tumors to the levels observed in HER2-negative ones.

CONCLUSION

Our results suggest that the [18F]FBEM-Z(HER2:342) radioconjugate can be used to assess HER2 expression in vivo.

Prognostic value of HER2 gene amplification detected by chromogenic in situ hybridization (CISH) in metastatic breast cancer

After so many years of research, clinical value of HER2 (Human epidermal growth factor receptor 2) is unclear. Perhaps the main reason is variability of testing methods that produce controversial results. There is a lack of studies regarding prognostic value of CISH especially in metastatic breast cancer (MBC) when risk evaluation is based on different parameters than for primary breast cancer. Aim of this study was to compare prognostic relevance of HER2 status in MBC tested by two different methods i.e. immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH). HER2 status of the same group of 107 MBC patients was determined by IHC (protein overexpression) and by CISH (gene amplification). HER2 results obtained by IHC and CISH showed significant correlation, beside the existence of discrepancies. Beside the significant correlation in two methods, there was a difference in prognostic values of compared methods during the course of metastatic disease. There was a significant difference in progression-free interval (PFI) between HER2 non-amplified and HER2 amplified cases determined by CISH, in postmenopausal subgroup and node-positive subgroup, but no significant difference for IHC stratified MBC patients. CISH seems to be accurate and more informative method than IHC regarding prognostic value of HER2 in metastatic breast cancer.

Regulation of transcription by synthetic DNA-bending agents

Gene expression is regulated by a complex interplay between binding and the three-dimensional arrangement of transcription factors with RNA polymerase and DNA. Previous studies have supported a direct role for DNA bending and conformation in gene expression, which suggests that agents that induce bends in DNA might be able to control gene expression. To test this hypothesis, we examined the effect of triple-helix-forming oligonucleotide (TFO) bending agents on the transcription of luciferase in an in vitro transcriptional/translational system. We find that transcription is regulated only by a TFO that induces a bend in the DNA. Related TFOs that do not induce bends in DNA have no effect on transcription. Reporter expression can be increased by as much as 80 % or decreased by as much as 50 % depending on the phasing of the upstream bend relative to the promoter. We interpret the results as follows: when the bend is positioned such that the upstream DNA is curved toward the RNA polymerase on the same DNA face, transcription is enhanced. When the upstream DNA is curved away, transcription is attenuated. These results support the hypothesis that DNA-bending agents might have the capability to regulate gene expression, thereby opening up a previously undervalued avenue in research on the artificial control of gene expression.

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

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

Proteomics in human cancer research

Proteomics is now widely employed in the study of cancer. Many laboratories are applying the rapidly emerging technologies to elucidate the underlying mechanisms associated with cancer development, progression, and severity in addition to developing drugs and identifying patients who will benefit most from molecular targeted compounds. Various proteomic approaches are now available for protein separation and identification, and for characterization of the function and structure of candidate proteins. In spite of significant challenges that still exist, proteomics has rapidly expanded to include the discovery of novel biomarkers for early detection, diagnosis and prognostication (clinical application), and for the identification of novel drug targets (pharmaceutical application). To achieve these goals, several innovative technologies including 2-D-difference gel electrophoresis, SELDI, multidimensional protein identification technology, isotope-coded affinity tag, solid-state and suspension protein array technologies, X-ray crystallography, NMR spectroscopy, and computational methods such as comparative and de novo structure prediction and molecular dynamics simulation have evolved, and are being used in different combinations. This review provides an overview of the field of proteomics and discusses the key proteomic technologies available to researchers. It also describes some of the important challenges and highlights the current pharmaceutical and clinical applications of proteomics in human cancer research.

c-erbB-2 (HER-2/neu) immunohistochemistry in invasive breast cancer: is there concordance between standard sections and tissue microarrays?

AIMS

Immunohistochemical detection of the 185-kDa transmembrane glycoprotein product of the proto-oncogene c-erbB-2 (also known as HER-2/neu), located on chromosome 17q21, is a well established method of evaluation in invasive breast cancer. This investigation is currently performed on standard sections cut from the tumour containing paraffin block. It is uncertain if concordant results can be obtained on tissue microarray (TMA) sections, a high throughput technique that is particularly advantageous in research and validation protocols. Our aim in this study was to compare the results of c-erbB-2 immunoexpression in standard sections of invasive breast cancers with those of TMAs.

METHODS

Standard sections and TMAs constructed from archival paraffin-embedded breast cancers of 184 patients who had surgery in Singapore General Hospital during the period 1998-2002 were subjected to immunohistochemistry using the commercial antibody (A0485, Dako). c-erbB-2 over-expression was evaluated according to cytoplasmic membrane staining intensity, which was defined as 2+ and 3+ staining.

RESULTS

Over-expression of c-erbB-2 protein was found in 21.2% (39/184) and 18.6% (34/183) of cases on standard sections and TMAs, respectively. There was substantial agreement between these two types of sections (k = 0.724) when positive and negative staining was considered.

CONCLUSION

Immunohistochemistry on TMAs for c-erbB-2 expression in breast cancer is a reliable alternative to that performed on routine standard sections, as it is both cost effective and time efficient, especially in a research setting.

[Molecular protocol for HER2/neu analysis in breast carcinoma]

BACKGROUND

The HER2/neu proto-oncogene is frequently over-expressed in breast cancer and serves as a biological target for trastuzumab therapy. However, there is no consensus regarding the technical aspects to be used to define HER2/neu status in clinical practice.

METHODS

The present study was conducted to address this critical issue by prospectively analysing a large cohort of breast cancer patients (n = 222) and using a variety of methods. To define HER2/neu expression, detection of its encoded protein (p185) was performed by comparative immunohistochemical (IHC) analysis using two mouse monoclonal antibodies (mAb CB11 and mAb TAB250). To assess HER2/neu gene amplification, fluorescent in situ hybridisation (FISH) assays with gene-specific probes were conducted. All procedures were applied to de-paraffinised tissue sections of breast tumour samples.

RESULTS

Results showed that mAb CB11 had increased sensitivity and specificity (62.5% and 93.4%, respectively) compared to mAb TAB250 (40% and 76.4%, respectively) in defining HER2/neu amplification. We conclude that HER2/neu measurement by IHC using mAb CB11 is an appropriate strategy which provides a high negative predictive value (95.5%) for HER2/neu amplification in cases with low or undetectable p185 expression. Conversely, mAb CB11 has a high positive predictive value (96.2%) for HER2/neu amplification in cases with p185 overexpression. However, cases with moderate p185 expression need to be considered as inconclusive. In such cases, it is necessary to use FISH measurement to evaluate HER2/neu amplification. It is also advisable to conduct FISH if there is discordance between p185 expression and the histopathology classification of the lesion, or molecular profile of the tumour. Finally, even though the false positive rate of IHC assay is <5%, the toxicity and cost of trastuzumab therapy suggest that FISH be used systematically prior to implementation of treatment.

CONCLUSION

We suggest the use of a molecular protocol for HER2/neu analysis in this type of tumor.

Synthesis and testing of a triaza-cyclopenta[b]phenanthrene scaffold as a DNA binding agent

A novel DNA binding agent based upon a triaza-cyclopenta[b]phenanthrene scaffold, compound 1, has been synthesized. dsDNA binding analysis of this compound using the ethidium bromide displacement assay indicated a preference for GC-rich sequences. However, equilibrium dialysis experiments against a variety of nucleic acids showed that the target compound bound about 20-fold tighter to G-quartet DNA than to dsDNA under physiological salt concentrations. The binding of 1 to G-quartet DNA was verified by the ability of the compound to promote the formation of the quartet and to compete with TmPyP4 for binding to the quadruplex. Given the importance of G-quartet binding agents in the treatment of cancer and in the understanding of drug-DNA interactions, 1 and its related analogs should find utility as a new class of G-quartet specific agents.

HER-2 codon 655 polymorphism in cervical carcinogenesis

HER-2 codon 655 polymorphism together with human papillomavirus (HPV) types were examined in a total of 279 cervical smear samples. Forty-nine patients with high-grade squamous intraepithelial lesion had higher frequency of high-risk HPV than 167 patients with low-grade squamous intraepithelial lesion and 63 controls. There was no statistical difference in the frequencies of HER-2 Ile/Ile, Ile/Val, and Val/Val genotypes between squamous intraepithelial lesions (SILs) and controls. When the Ile/Ile genotype was compared to the Ile/Val + Val/Val genotypes, there was also no statistical difference in the genotype prevalence between SILs and controls either in 91 or 188 patients with or without high-risk HPV, respectively. These results suggest that the HER-2 polymorphism at codon 655 in cervical cell samples is unlikely to be associated with HPV status and the onset of cervical cancer in a Japanese population.

Pharmacodiagnostic testing in breast cancer: focus on HER2 and trastuzumab therapy

Pharmacogenomics is defined as research into inherited genetic variations that determine an individual's response to therapeutic agents. In oncology, pharmacogenomics based on somatic molecular alterations inherited by subsequent cancer cell generations forms the basis of molecular targeting of novel therapeutic agents. What has emerged from clinical experience with such agents is the need for appropriate pharmacodiagnostic approaches to ensure the drugs are correctly targeted. Given the broad range of pharmacogenomic agents currently under evaluation for cancer therapy, it appears that a rapid extension of pharmacodiagnostic profiling will be required in the next 5-10 years, if not sooner. If this is to be successfully achieved, lessons learned in the past, particularly during the development of HER2 (ERBB2) testing for directing trastuzumab therapy in breast cancer, may provide a valuable framework for the development of future pharmacodiagnostic assays system. This article reviews the biological and clinical rationale for targeting breast cancer with trastuzumab and the steps taken to validate and improve pharmacodiagnostic procedures for testing tumor HER2 protein expression and HER2 gene amplification. Attention is given to quality assurance and reproducibility of testing approaches and the optimal selection of patients for response to trastuzumab. This approach serves as a paradigm for the future development of pharmacodiagnostic tests in oncology.

A French national survey on infiltrating breast cancer: analysis of clinico-pathological features and treatment modalities in 1159 patients

BACKGROUND

Despite the approximate 42,000 yearly new cases of breast cancer in France, there have been very few exhaustive studies on the clinicopathological features and treatment options of this disease.

METHODS

Thus, a prospective, non-selective, nationwide survey on infiltrating breast cancer (IBC) was conducted in France from September 2001 to April 2002, in order to assess the epidemiological features of newly diagnosed disease, the prognostic and predictive variables with a special emphasis on hormone receptors, and the current approaches to therapy in everyday clinical practice.

RESULTS

In total, 1159 patients were evaluable (median age 57 years); two-thirds of women were postmenopausal and 38% had undergone hormonal replacement therapy (HRT). Ductal and lobular infiltrating cancers represented 82.3% and 11.6% of cases, respectively. Most tumours expressed oestrogen (79.7%) and progesterone (69.7%) receptors. Overexpression of the human epidermal growth factor receptor-2 oncogene was found in 20.6% of the assessed cases. IBC diagnosed in women under HRT presented significantly better clinico-pathological features than in non-users. All patients underwent surgery as first treatment: 77.5% breast-conserving surgery (BCS) and 22.5% mastectomy; 1024 patients also underwent axillary surgery. The overall axillary lymph-node involvement rate was 44.4%. Radiotherapy was proposed in 98% and 83% of the women who had undergone BCS and mastectomy, respectively. Adjuvant chemotherapy was delivered in 58.7% of patients and hormonal treatment was provided in 76.5% of patients; tamoxifen was the most widely used hormonal treatment.

CONCLUSIONS

This study showed a trend for global downstaging of IBC (with favourable clinico-pathological features), leading to a high rate of BCS. Postoperative treatments were widely used, in accordance with national and international guidelines. Use of aromatase inhibitors and taxanes was limited, but is likely to rise in the future.

Cyclic GMP-dependent protein kinase regulates CCAAT enhancer-binding protein beta functions through inhibition of glycogen synthase kinase-3

The CCAAT enhancer-binding protein (C/EBPbeta) plays an important role in the regulation of gene expression during cell proliferation, differentiation, and apoptosis. We previously showed that C/EBPbeta participates in cGMP-regulated transcription of c-fos in osteoblasts (Chen, Y., Zhuang, S., Cassenaer, S., Casteel, D. E., Gudi, T., Boss, G. R., and Pilz, R. B. (2003) Mol. Cell. Biol. 23, 4066-4082). In the present work, we show that cGMP/cGMP-dependent protein kinase (PKG) induced dephosphorylation and activation of C/EBPbeta by inhibiting glycogen synthase kinase-3beta (GSK-3beta). Phosphorylation of GSK-3beta on Ser9 negatively regulates the enzyme activity, and we found that PKG phosphorylated this site both in vitro and in vivo; the in vivo phosphorylation occurred rapidly and preceded C/EBPbeta dephosphorylation. Previous studies with GSK-3 inhibitors suggest that GSK-3beta is a C/EBPbeta kinase in resting cells. We determined that GSK-3beta phosphorylated C/EBPbeta in vitro on Thr189, Ser185, Ser181, and Ser177; C/EBPbeta was phosphorylated on these same sites in intact, unstimulated osteoblasts, and phosphorylation was decreased in cGMP-treated cells. Mutation of the GSK-3 phosphorylation sites in C/EBPbeta prevented C/EBPbeta phosphorylation in resting cells, enhanced C/EBPbeta DNA binding, and led to increased target gene transactivation, mimicking the stimulatory effects of cGMP on C/EBPbeta. cGMP regulation of C/EBPbeta was disrupted by a mutant GSK-3beta(Ala9) resistant to cGMP/PKG phosphorylation and inhibition. We conclude that cGMP increases the DNA binding potential of C/EBPbeta by preventing the negative effects of GSK-3 phosphorylation.

Re-evaluation of HER2 status in metastatic breast cancer and tumor-marker guided therapy with vinorelbine and trastuzumab

BACKGROUND

HER2 is overexpressed in 20-30% of breast cancers. Compared to chemotherapy alone, chemotherapy with trastuzumab improves clinical outcome in patients with HER2-positive metastatic breast cancer (MBC). In general, HER2 status in a primary lesion predicts the status of metastases, so that biopsy of metastatic lesions appears unnecessary.

CASE REPORT

A 39-year old woman was diagnosed with primary breast cancer in November 2000. Using the method and scoring system of the DAKO Hercep Test, the tumor has shown low HER2 expression (DAKO score 1+). After failure of several chemotherapy regimens for metastatic disease (liver, skeletal), the patient underwent CT-guided needle biopsy of the liver which showed HER2 positive adenocarcinoma (DAKO score 3+). In consequence, the patient was treated with vinorelbine (30 mg/m2 d1,8,15 q4w) and trastuzumab (4 mg/kg loading dose, 2 mg/kg weekly). During a treatment period of 4 months imaging results as well as tumor marker kinetics indicated an excellent response with sustained decrease of tumor markers. A retrospective analysis of the HER2 shed antigen in metastatic stage revealed excessively increased serum levels and supports HER2 overexpression observed in liver metastasis. The kinetics of the HER2 shed antigen during therapy for metastatic disease were found to be in phase with the kinetics of CEA and CA15-3.

CONCLUSION

This case report demonstrates that re-evaluation of the HER2 status may be helpful in single patients not sufficiently responding to treatment of metastatic disease. Determination of HER2 overexpression may be facilitated by a determination of the HER2 shed antigen level in peripheral blood.

Global search for chromosomal abnormalities in infiltrating ductal carcinoma of the breast using array-comparative genomic hybridization

Array-comparative genomic hybridization (a-CGH) is a molecular cytogenetic technique for detection of multiple chromosomal abnormalities in genomic DNA samples. Using an a-CGH with 287 probes, we examined 14 cases of breast infiltrating ductal carcinoma (IDCA) that had previously been classified by fluorescent in situ hybridization (FISH) as either human epidermal growth factor receptor-2 positive (HER2+) or HER2- and analyzed the data by hierarchical, K-means, and principal component analyses. The aim of the study was to identify the genetic abnormalities that are present in breast IDCAs and determine if the global status of 287 cytogenetic locations could be used as a more objective method for breast IDCA classification. Concordance between FISH and a-CGH at the HER2 locus was 78.6% (11/14). In general, a-CGH detected more abnormalities in HER2+ cases. In HER 2+ cases, chromosomes 1, 2, 3, 7, 9, 17, and 20 had more regions that showed statistically significant (P < or = 0.01) changes in DNA copy number. Among all the aberrant cytogenetic locations detected, 20q13, 7p12.3 approximately p12.1, and 17q23.2 approximately q25.3, which contain among others, genes for TNFRSF6B, EGFR, and TK1 showed statistically significant gains (P < or = 0.01) in 83, 66.7, and 50% of the HER2+ IDCA cases, respectively. Chromosome location 8q24.12 approximately q24.13 was the only region that showed consistent amplification in approximately 50% of the HER2- cases. Unsupervised hierarchical and K-means cluster analyses and principal component analysis using the DNA copy number status of 287 cytogenetic locations or the 177 cytogenetic locations that showed statistically significant differences revealed a cluster consisting of mainly HER2- IDCA cases. Even though this study demonstrates the usefulness of a-CGH in the rapid identification of aberrant DNA regions in tumor samples, we conclude that an array-CGH with more than 287 probes will be needed for a more precise mapping of DNA aberrations at the global level.

Real-time quantitative PCR of microdissected paraffin-embedded breast carcinoma: an alternative method for HER-2/neu analysis

We studied the feasibility of using real-time quantitative PCR to determine HER-2 DNA amplification and mRNA expression in microdissected formalin-fixed, paraffin-embedded breast tumors and compared this with standard immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) methods. Study cases (27 carcinomas and 3 ductal breast carcinoma in situ (DCIS) cases) showed varying Her-2 expression as determined by IHC (HercepTest). In carcinomas, there was a good correlation between HER-2 DNA amplification and strong HER-2 protein expression detected by FISH and IHC, respectively. A single DCIS case was amplified in FISH, but not in IHC. Both HER-2 gene amplification and expression could be quantified in microdissected paraffin-embedded tumors using real-time PCR, DNA and RNA being successfully detected in 146 of 150 (97%) and 141 of 150 (94%) samples, respectively. PCR analysis for HER-2 DNA amplification using the LightCycler HER2/neu DNA Quantification kit (Roche Molecular Biochemicals, Mannheim, Germany) correlated fairly well with IHC and FISH. All IHC HER-2 3+ tumors were amplified according to the kit, as was the FISH-amplified DCIS case. DNA-PCR identified five additional tumors as being amplified. Interestingly, all these scored 2+ with the HercepTest, but were negative using FISH. We believe that real-time quantitative PCR analysis of HER-2 DNA amplification following microdissection represents a useful supplementary or perhaps even an alternative technique for establishing HER-2 status in paraffin-embedded tumors.

HER-2/neu (c-erbB-2) Evaluation in Primary Breast Carcinoma by Fluorescent In Situ Hybridization and Immunohistochemistry With Special Focus on Intratumor Heterogeneity and Comparison of Invasive and In Situ Components

We have studied the intratumor HER-2/neu heterogeneity in 78 consecutive and population-based primary invasive breast carcinomas. Within the invasive component, heterogeneity was detected in only 1 of 78 tumors. In 48 tumors (62%), we found both in situ and invasive components in analyzed tissue sections. Twelve of these 48 tumors had a difference of at least 2 arbitrary units in the in situ compared with the invasive part of the tumor with regard to the HER-2/neu status analyzed by HercepTest (immunohistochemistry). Eight of these 12 tumors were reanalyzed with fluorescent in situ hybridization and immunohistochemistry with and without a new Automated Cellular Imaging System. In this limited material, immunohistochemistry in combination with the Automated Cellular Imaging System seemed to have a better correlation with fluorescent in situ hybridization than immunostaining analyzed manually. In conclusion, HER-2/neu expression is not seldom heterogeneous in invasive compared with in situ components within a tumor. This finding should be considered in the choice of evaluation method. To avoid heterogeneity as a confounding factor in HER-2/neu analyses, detection methods such as immunohistochemistry and fluorescent in situ hybridization, which can provide evaluation in a preserved tissue architecture, should be used. Perhaps the intratumor HER-2/neu heterogeneity can explain some of the unexpected failures of trastuzumab therapy.