Serum c-erB-2 levels in monitoring of operable breast cancer patients

Advances in HER2 testing

HER2-positive breast cancer is a particularly aggressive type of breast cancer. Indication of HER2 positivity is essential for its treatment. In addition to a few FDA-approved methods such as immunohistochemical (IHC) detection of HER2 protein expression and in situ hybridization (ISH) assessment of HER2 gene amplification, several novel methods have been developed for HER2 testing in recent years. This chapter provides an overview of HER2 testing with emphasis on those new methods.

High serum HER2 extracellular domain levels: correlation with a worse disease-free survival and overall survival in primary operable breast cancer patients

PURPOSE

High serum human epidermal growth factors receptor-2 (HER2) extracellular domain (ECD) has been identified as an independent prognostic indicator of poor prognosis in metastatic breast cancer. However, its prognostic value in primary operable breast cancer was still controversial. We aim to investigate the correlation between serum HER2 ECD levels and tissue HER2 status, the association between serum HER2 ECD levels and clinicopathological characteristics, and their impacts on disease-free survival (DFS) and overall survival (OS) in primary operable breast cancer.

METHODS

Two hundred and fifty-two primary operable breast cancer patients pretreated from 2002 to 2009 in Sun Yat-Sen University Cancer Center were enrolled in this study. Serum HER2 ECD was measured by chemiluminescent assay, and tissue HER2 status was accessed by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) assay.

RESULTS

There was a significant correlation between serum HER2 ECD levels and HER2 tissue status (P < 0.001, R = 0.36). High serum HER2 ECD levels (≥15 ng/mL) were significantly associated with age (≥35 years) (P = 0.028), postmenopausal status (P < 0.001), stage III (P < 0.001), tumor size (≥2 cm) (P < 0.001), lymph node involvement (P < 0.001), negative estrogen receptor (P = 0.005), and progesterone receptor status (P = 0.001). Multivariate analysis showed that high serum HER2 ECD level was an independent prognostic factor of worse DFS (P = 0.014) and OS (P = 0.014) in primary operable breast cancer patients.

CONCLUSION

Serum HER2 ECD level can reflect tissue HER2 status and can be an independent prognostic indicator for primary operable breast cancer patients.

Current technologies for HER2 testing in breast cancer

BACKGROUND

Molecular techniques play an increasingly important role in breast cancer detection and help in the prediction of prognosis and treatment response. HER-2/neu predicts the sensitivity of breast tumors to trastuzumab and lapatinib. Presently there are several ways to assess HER2 status at the protein level (e.g. ELISA), at the RNA level (RT-PCR, microarray) and at the DNA level (fluorescence in situ hybridization, chromogenic in situ hybridization (ISH), silver in situ hybridization or multiplex ligation-dependent probe amplification).

DESIGN

This paper provides an overview of new developments in HER2 testing.

RESULTS

Although these techniques correlate well in comparative studies, discrepancies remain. Each technique has its own (dis)advantages and thus there is no real gold standard. Not surprisingly, there is no consensus at present on which of the protein- or gene-based techniques is superior, on the use of mono- or duo-probe ISH systems, nor on the use of manual or fully-automated staining- and scoring systems.

CONCLUSION

Until large clinical trials clearly point out one strategy as the best predictive one for trastuzumab response, the choice for a testing strategy will probably be based on local preferences which consider both practical and economic issues. Standardization, proper internal and external quality control assessment, laboratory accreditation and automation of tissue processing (autostainers) and interpretation methods (image analysis) will play an increasingly important role in HER2 testing.

Evaluation of HER2/neu oncoprotein in serum and tissue samples of women with breast cancer: correlation with clinicopathological parameters

BACKGROUND

HER2/neu (HER2) is a proto-oncogen of the EGF Receptor family. The assessment of serum HER2 level is useful for predicting the patients' response to chemotherapy or hormonal therapy and selection of proper patients for treatment with Herceptin. We aimed to compare serum HER2 levels with immunohistochemistry in tumoral tissues and investigate correlation between these levels and various prognostic factors.

MATERIALS AND METHODS

This cross-sectional study was conducted on 75 patients with breast carcinoma referred to surgical ward of Mashhad Imam Reza's hospital from November 2008 to February 2009. Pre-operative serum samples were collected and stored in -20°C. Surgical samples were investigated for the type of carcinoma, tumor size, lymph node metastasis, stage as well as grade of the tumor. Tissue HER2 over-expression was evaluated by immunohistochemistry (IHC) staining and HER2 levels were studied by ELISA method. Statistical analysis was performed by SPSS software.

RESULTS

Serum HER2 cut-off level was 18.4 ng/ml; 46.7% of patients were serum HER2-positive and 43% were IHC positive. There was a high statistical correlation between these two parameters (P=0.018). Statistically, there was no significant correlation between serum HER2 and age, tumor size, stage, grade and metastatic lymph nodes (P>0.05).

CONCLUSION

Serum HER2 level assay can be considered as a complementary method besides tissue methods.

Value and Limitations of Measuring HER-2 Extracellular Domain in the Serum of Breast Cancer Patients

The human epidermal receptor-2 (HER-2) is overexpressed or amplified in 15% to 25% of breast cancers. Determination of HER-2 tumor status offers clinically useful information, as it selects patients who may benefit from treatment with trastuzumab, the monoclonal antibody against HER-2. Currently approved methods for HER-2 testing include immunohistochemistry or fluorescent in situ hybridization using tumor tissue. A fragment of HER-2 composed of its extracellular domain (ECD) can also be detected in the serum of some patients with breast cancer. As an easily accessible tumor marker, it could offer additional useful prognostic or predictive information. This review will briefly address the biology of the circulating HER-2 ECD and discuss the evidence to support the role, if any, for measuring HER-2 ECD levels in women with breast cancer. In particular, we focus on the value and limitations of serum ECD in both early and advanced breast cancer in the following clinical contexts: as a marker of HER-2 tumor tissue status; clinical implications of raised levels in women who have a tumor not overexpressing HER-2; as a prognostic indicator and as a predictor of response to treatment; and as a monitoring tool for early recurrence. On the basis of our review of the literature, we conclude that there is currently insufficient evidence to support the use of serum HER-2 ECD in the routine management of individual patients with breast cancer. This conclusion is in agreement with the 2007 American Society of Clinical Oncology guidelines on the use of biomarkers in breast cancer.

Utility of serum HER2 extracellular domain assessment in clinical decision making: pooled analysis of four trials of trastuzumab in metastatic breast cancer

PURPOSE

Trastuzumab is a humanized monoclonal antibody directed against human epidermal growth factor receptor 2 (HER2). Trastuzumab alone or in combination with chemotherapy has been shown to be effective in patients with HER2-positive early and metastatic breast cancer. The extracellular domain (ECD) of the HER2 protein may be shed into the serum and is detectable using an enzyme-linked immunosorbent assay. Correlations have been reported between raised baseline ECD levels and response to trastuzumab, suggesting that serum ECD levels may be useful in making treatment decisions in patients with HER2-positive breast cancer. We investigated this relationship, and also the effect of trastuzumab and chemotherapy on ECD levels, in patients with advanced breast cancer.

METHODS

This study analyzed sequential ECD determinations on 322 patients treated with six different treatment regimens in four clinical trials.

RESULTS

Baseline values were available in 296 patients, and of these, 205 (69%) had raised levels (> 15 ng/mL). No clear relationship was found between baseline ECD levels and tumor response. After initiating combination therapy, ECD levels declined irrespective of treatment received and tumor response. For trastuzumab monotherapy, some trend between changes in ECD levels in early cycles and best response was discernable, but the overlap was too broad to be clinically useful. Disease progression was not reliably predicted by rising ECD levels in the majority of patients.

CONCLUSION

Based on our data, we cannot recommend using serum HER2 ECD levels to make trastuzumab or other treatment decisions for individual patients with advanced/metastatic breast cancer.

Serum c-erbB-2 protein is a useful marker for monitoring tumor recurrence of the breast

C-erbB-2 oncogene protein (ErbB-2/HER-2) overexpression is a prognostic marker of breast carcinoma. The purpose of this study was to evaluate serum ErbB-2 for monitoring tumor recurrence of operable breast carcinoma patients. The subjects were 86 breast carcinoma patients with stage I-IIIB. Sera were collected at preoperative and postoperative periods from 1996 to 2000. The cutoff value was set at 5.4 ng/ml for preoperative patients and at 6.5 ng/ml for postoperative patients. Twenty-nine patients (34%) had higher preoperative serum ErbB-2 levels (>or=5.4 ng/ml). A higher preoperative serum ErbB-2 was associated with higher clinical stage, larger tumor size, nodal metastasis, higher histologic grade and lymphatic invasion, but not with vascular invasion, hormonal receptor status or other tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 15-3 (CA15-3). As of April 2005, 27 patients (31%) had recurrence and 18 (62%) of them had a higher preoperative serum ErbB-2. Seventeen patients died of tumor progression. The recurrence-free survival rates at 7 years after breast surgery were 84% in 57 patients with a normal preoperative serum ErbB-2 and 41% in 29 patients with a higher preoperative serum ErbB-2 (p < 0.0001). The overall survival rates at 7 years were 93% and 55% (p < 0.0001), respectively. A multivariate analysis revealed that preoperative serum ErbB-2 was an independent prognostic factor for recurrence-free survival and overall survival in breast carcinoma patients. The specificities and sensitivities of postoperative tumor markers (CEA, CA15-3 and ErbB-2) were 91%, 100% and 85%, and 40%, 30% and 70%, respectively. Serum ErbB-2 is a preoperative prognostic marker and may be useful for monitoring tumor recurrence of the breast.

Detection of urokinase plasminogen activator receptor and c-erbB-2 in sera of patients with breast and ovarian carcinoma

The role of urokinase plasminogen activator receptor (uPAR) and c-erbB-2 in breast and ovarian cancer was investigated. Eighty patients of breast and ovarian cancer and benign lesions, as well as twenty normal controls were evaluated for the expression of c-erbB-2 by Western blotting and uPAR levels by ELISA. The c-erbB-2 and uPAR showed a significant increase in both types of cancer investigated compared to normal control and benign lesions. The frequency of c-erbB-2 was significantly higher in breast cancer lesions (p < 0.01). Levels of CA15.3 in breast cancer and CA125 in ovarian cancer were significantly higher in cases expressing c-erbB-2 (p < 0.01) than in negative c-erbB-2 cases. The uPAR showed a significant positive correlation with advanced stages of breast cancer (r = 0.7971) and ovarian cancer (r = 0.83662), while significant correlations were found for CA15.3 in breast cancer (r = 0.64967) and CA125 in ovarian cancer (r = 0.83996). Taken together, our data suggest that the c-erbB-2 and uPAR in the sera of ovarian and breast cancer act as valuable markers for the evaluation of the patients preoperatively.

Monitoring the Circulating Levels of the HER2/neu Oncoprotein in Breast Cancer

The HER2/neu oncoprotein is a major target for the development of new cancer therapies and is similar to the estrogen receptor, which guides hormone therapy. The HER2/neu status is used to guide therapy decisions in patients with HER2/neu-overexpressing breast cancer tumors. The HER2/neu oncogene, or c-erbB-2, encodes a transmembrane receptor protein that is expressed on normal epithelial cells and can be overexpressed in breast cancer cells. Studies have shown that the extracellular domain (ECD) of the HER2/neu oncoprotein is released from the cell and can be measured in the circulation of women with breast cancer. Enzyme-linked immunosorbent assay methods used to measure the circulating HER2/neu ECD have shown that the prevalence of elevated ECD levels is approximately 18.1% in women with primary breast cancer and approximately 45.6% in women with metastatic breast cancer (MBC). Many studies have monitored the circulating ECD levels after surgery and indicate that increasing ECD levels can indicate recurrence of breast cancer earlier than clinical diagnosis. Studies in women with MBC showed that serial changes in circulating HER2/neu ECD levels paralleled the clinical course of disease, regardless of the treatment regimen. Several studies identified a subgroup of patients with MBC who had HER2/neu-negative disease by tissue testing but developed elevated ECD levels with MBC. In contrast to tissue testing, which is a one-time event, monitoring the circulating levels of the HER2/neu ECD in patients with breast cancer provides a real-time assessment of the HER2/neu status and provides important information for managing the therapy of patients with MBC.

Potential clinical utility of serum HER-2/neu oncoprotein concentrations in patients with breast cancer

BACKGROUND

The HER-2/neu oncogene and its p185 receptor protein are indicators of a more aggressive form of breast cancer. HER-2/neu status guides Herceptin therapy, specifically directed to the extracellular domain (ECD) of the HER-2/neu oncoprotein. The HER-2/neu ECD is shed from cancer cells into the circulation and is measurable by immunoassay.

METHODS

We performed a systematic review of the peer-reviewed literature on circulating ECD with respect to prevalence, prognosis, prediction of response to therapy, and monitoring of breast cancer.

RESULTS

The prevalence of increased ECD in patients with primary breast cancer varied between 0% and 38% (mean, 18.5%), whereas in metastatic disease the range was from 23% to 80% (mean, 43%). Some women with HER-2/neu-negative tumors by tissue testing develop increased ECD concentrations in metastatic disease. Increased ECD has been correlated with indicators of poor prognosis, e.g., overall survival and disease-free survival. Increased ECD predicts a poor response to hormone therapy and some chemotherapy regimens but can predict improved response to combinations of Herceptin and chemotherapy. Many studies support the value of monitoring ECD during breast cancer progression because serial increases precede the appearance of metastases and longitudinal ECD changes parallel the clinical course of disease.

CONCLUSIONS

The monitoring of circulating HER-2/neu ECD provides a tool for assessing prognosis, for predicting response to therapy, and for earlier detection of disease progression and timely intervention with appropriate therapy.

Serum HER-2/neu in the management of breast cancer patients

The clinical role of HER-2/neu, a 185 kD epithelial transmembranous protein, has evolved after the approval of the anti-HER-2/neu targeted monoclonal antibody trastuzumab (Herceptin) for the therapy of metastatic breast cancer. The extracellular domain of HER-2/neu undergoes proteolytic cleavage from the full-length protein by metalloproteases, and is shed into the blood as a circulating antigen. While HER-2/neu gene amplification and/or protein overexpression are detected in approximately 25% of primary breast cancers, serum HER-2/neu levels are elevated beyond the upper limit of normal in 50 to 60% of stage IV breast cancer patients. HER-2/neu in serum can be detected by enzyme immunoassays (manual and automated versions). It has been shown to have prognostic and predictive information in breast cancer patients. Monitoring for recurrence by serum HER-2/neu reaches a high sensitivity for HER-2/neu positive tumors. Longitudinal follow-up of patients during any kind of systemic therapy allows for monitoring of the therapeutic success. When utilized in these applications, serum HER-2/neu testing is complementary to HER-2/neu tissue results and to the determination of classical tumor markers such as CA 15-3, CA 27.29 and CEA, which are not targeted by specific forms of systemic therapy.