Detection of c-erbB-2 related protein in sera from breast cancer patients. Relationship to ERBB2 gene amplification and c-erbB-2 protein overexpression in tumour

Monitoring Value of Serum HER2 as a Predictive Biomarker in Patients with Metastatic Breast Cancer

Purpose

The aim of this study was to investigate the monitoring value of serum HER2 in patients with metastatic breast cancer.

Patients and Methods

We firstly evaluated the association of serum HER2 levels with tissue HER2 expression and imaging results in 420 breast cancer patients admitted into Tianjin Medical University Cancer Institute and Hospital between April 2016 and December 2018. Secondly, we analyzed serum HER2 levels in breast cancer patients with different metastatic degrees.

Results

There is a higher correlation between serum HER2 and tissue HER2 in breast cancer patients with stage III (κ=0.670, p<0.001) and stage IV (κ=0.464, p<0.001). Serum HER2 levels were significantly associated with imaging results (κ=0.478, p<0.001). The ROC curve analysis showed that serum HER2 was superior to other serum markers for predicting metastatic breast cancer. Multinomial logistic regression revealed that the patients with higher serum HER2 levels would be more likely to have breast cancer metastasis.

Conclusion

Serum HER2 levels in breast cancer patients can partly reflect tissue HER2 expression and tumor imaging changes, and serum HER2 may be used as a biomarker for evaluating metastatic status in patients with breast cancer.

The extracellular domain of Her2 in serum as a biomarker of breast cancer

Breast cancer is a major health problem worldwide. In ~15% of breast cancers, the epidermal growth factor receptor HER2, a transmembrane protein, is overexpressed. This HER2 overexpression is associated with an aggressive form of the disease and a poor clinical prognosis. The extracellular domain (ECD) of HER2 is released into the blood by a proteolytic mechanism known as "ECD shedding". This proteolytic shedding leaves a constitutively active truncated receptor in the membrane that is 10-100-fold more oncogenic than the full-length receptor and promotes the growth and survival of cancer cells. Shedding of the HER2 ECD is increased during metastasis: whereas 15% of primary breast cancer patients have elevated levels of serum HER2 ECD (sHER2 ECD), the levels reach 45% in patients with metastatic disease. Thus, sHER2 ECD has been proposed as a promising biomarker for cancer recurrence and for monitoring the disease status of patients overexpressing HER2. Nevertheless, in 2016, the American Society of Clinical Oncology advises clinicians not to use soluble HER2 levels to guide their choice of adjuvant therapy for patients with HER2-positive breast cancer, because the evidence was considered not strong enough. Currently, biomarkers such as carcinoembryonic antigen and cancer antigen 15-3 are widely used to monitor metastatic breast cancer disease even if the level of evidence of clinical impact of this monitoring is poor. In this article, we review the evidence that sHER2 ECD might be used in some situations as a biomarker for breast cancer. Although this serum biomarker will not replace the direct measurement of tumor HER2 status for diagnosis of early-stage tumors; it might be especially useful in metastatic disease for prognosis, as an indicator of cancer progression and of therapy response, particularly to anti-HER2 therapies. Owing to these data, sHER2 ECD should be considered as a promising biomarker to detect cancer recurrence and metastasis.

Discordant Results Obtained for Different Methods of HER-2/Neu Testing in Breast Cancer – A Question of Standardization, Automation and Timing

Background

HER-2/neu positivity is required for the selection of stage IV breast cancer patients for trastuzumab therapy. We compared the results of the recommended immunohistochemistry (IHC) evaluation with the automated ACIS™ IHC system and with fluorescence in situ hybridization (FISH). These HER-2/neu tissue results were correlated with the serum HER-2/neu (sHER-2/neu) levels at the time of metastatic spread.

Patients and Methods

A total of 61 IHC slides from 30 patients were stained using the HercepTest™. HER-2/neu gene amplification was determined using the Ventana™ FISH assay. sHER-2/neu levels were measured with the Oncogene Science” ELISA kit. The concordance of HER-2/neu results was determined using the concordance index Kappa (κ).

Results

The best concordance between any IHC and FISH was found for the automated ACIS system (88.5%, κ=0.68, category “good”). The comparison between the manual interpretations and the automated IHC was categorized as “very good” (95.1%, κ=0.85). The median sHER-2/neu level of FISH positive patients was significantly higher (67 ng/mL) than that of FISH negative patients (17 ng/mL, p=0.018). The increase in HER-2/neu positivity comparing tissue to stage IV serum was statistically significant (p=0.001).

Conclusions

The concordance between conventional IHC and computerized analysis was very good. The number of patients with stage IV breast cancer with an elevated sHER-2/neu level was much higher than HER-2/neu positivity in tissue. This discrepancy is only partially explained by the influence of tumor load. Patients with an elevated sHER-2/neu level and no tissue overexpression should be considered for retesting of tissue or a new biopsy.

Evaluation of HER2/neu oncoprotein in serum & tissue samples of women with breast cancer

Background & objectives:

The proto-oncogene HER2/neu has been extensively studied in breast cancer patients. Serum levels of HER2/neu by ELISA in breast cancer patients were compared with tissue HER2/neu expression and with other clinicopathological parameters with the aim to investigate whether the serum assay could replace the established tests (IHC/FISH) for HER-2 status.

Methods:

Blood and Tru-cut biopsy samples were collected for determining HER2/neu status in 64 breast cancer patients. The tissue specimens were processed routinely and immunohistochemistry (IHC) for HER2/ER/PR (oestrogen/progesterone receptors) performed. Fluorescence in-situ hybridization (FISH) was performed on all HER2/neu 2 positive cases. Sixty age matched healthy females and females with benign breast disease were taken as controls for ELISA.

Results:

Of the 64 breast cancer cases, 25 (39.1%) had elevated serum HER2/neu levels accompanied with increased tissue expression of HER2/neu receptors. On IHC, HER2/neu score was 3+ in 24 (37.5%) cases, 2+ in three (4.6%), 1+ in 18 (28.1%); while 19 cases (29.7%) showed no HER2/neu expression. Of the three 2+ cases on IHC, two showed amplification on FISH. Twenty one (32.8%) patients were ER positive and 17 (26.6%) were PR positive. There was a significant correlation (P<0.001) of serum HER2 concentration with tumour size, lymph node involvement, stage of disease and histological grade. Serum HER2/neu levels showed a negative correlation with ER status (P=0.047) but no correlation with PR status.

Interpretation & conclusions:

The results suggest that elevated serum HER2 level was associated with a clinicopathological aggressive phenotype of breast carcinoma and was related to tissue HER2 overexpression. Therefore, serum HER2 may be useful for monitoring the course of the disease and response to treatment.

Clinical significance of serum and urinary HER2/neu protein levels in primary non-muscle invasive bladder cancer

Objective:

We aimed to compare serum and urinary HER2/neu levels between healthy control group and patients with non-muscle invasive bladder cancer. Additionally, we evaluated relationship of HER2/neu levels with tumor stage, grade, recurrence and progression.

Materials and Methods:

Fourty-four patients with primary non-muscle invasive bladder tumors (Group 2) and 40 healthy control group (Group 1) were included the study. Blood and urinary samples were collected from all patients and HER2/neu levels were measured by ELISA method. Blood and urinary HER2/neu levels and additionally, ratio of urinary HER2/neu levels to urinary creatinine levels were recorded. Demographic data and tumor characteristics were recorded.

Results:

Mean serum HER2/neu levels were similar between two groups and statistically significant difference wasn't observed. Urinary HER2/neu levels were significantly higher in group 2 than group 1. Ratio of urinary HER2/neu to urinary creatinine was significantly higher in group 2 than group 1, (p=0,021). Serum and urinary HER2/ neu levels were not associated with tumor stage, grade, recurrence and progression while ratio of urinary HER2/neu to urinary creatinin levels were significantly higher in high-grade tumors. HER2/neu, the sensitivity of the test was found to be 20.5%, and the specificity was 97.5%, also for the urinary HER2/neu/urinary creatinine ratio, the sensitivity and specificity of the test were found to be 31.8% and 87.5%, respectively.

Conclusions:

Urinary HER2/neu and ratio of urinary creatinine urine were significantly higher in patients with bladder cancer compared to healthy subjects. Large series and controlled studies are needed for use as a tumor marker.

Survey of HER2-neu Expression in Colonic Adenocarcinoma in the West of Iran

BACKGROUND

Overexpression of HER2-neu has been reported in many epithelial malignancies, including cancers of the breast, ovaries, lungs, prostate, bladder, pancreas, colorectum and stomach as well as osteosarcomas. The aim of this study was evaluation of expression of HER2-neu immunohistochemistry (IHC) status and clinicopathologic features in a series of colonic adenocarcinomas.

MATERIALS AND METHODS

In this descriptive and analytical study, we surveyed 211 samples of colon adenocarcinoma from 182 patients (86.3%) undergoing total or partial colectomy and 29 (7.13%) with biopsies by colonoscopy. A sufficient sample size was obtained from all cases and the slides were stained with hematoxylin and eosin and also by IHC (HER2) staining.

RESULTS

The mean age for the patients at diagnosis was 57.9 years (range, 15-88 years). One hundred and twenty one patients (57.3%) were male. Of all patients, 201 samples (95.3%) were conventional adenocarcinomas (159, 29 and 13 cases were well, moderately and poorly differentiated, respectively) and 10 (4.7%) were mucinous type. Out of 211 cases, 171 were checked for lymph nodes metastasis and 64 were positive. There is a correlation between HER2 scores and differentiation, most score 3 cases being well differentiated (P<0.05).

CONCLUSIONS

In patients with advanced colon cancer, surgery alone is not curative and other forms of therapy may be required to prolong patient survival. HER2 overexpression was found in some cases and this could be a guideline to new adjuvant therapy for these patients.

Circulating oncoproteins HER2/neu, EGFR and CAIX (MN) as novel cancer biomarkers

Pharmaceutical companies have developed targeted therapies such as trastuzumab and lapatinib for human epidermal growth factor receptor (HER)2/neu-positive tumors, while others have developed antiepidermal growth factor receptor (EGFR) therapies, such as tarceva and erbitux for EGFR-positive tumors. A drug called rencarex is targeted to an oncoprotein designated carbonic anhydrase IX (CAIX), which is being evaluated in renal cell carcinoma patients. Based on these targeted therapeutic approaches, this review describes clinical research studies performed with enzyme-linked immunosorbent assays specific for the circulating oncoproteins, HER2/neu, EGFR and CAIX. These circulating biomarkers have the potential to be used in conjunction with the specific targeted therapies for patient selection, monitoring and management. With the variety of new therapeutic options, the major challenge ahead will be to select the appropriate therapy or combinations of therapies for each patient. Specific biomarker tests, either alone or in panels, will be needed at the appropriate time in the course of disease to ensure that patients receive the right drug at the right time. These tests will also be valuable in monitoring the efficacy of the targeted therapies. A circulating biomarker such as serum HER2/neu may be able to specifically identify patients with progressing HER2/neu-positive disease and provide the information needed by physicians to choose from the variety of HER2/neu-targeted therapies that will soon be available to cancer patients.

Challenges in the clinical utility of the serum test for HER2 ECD

Approximately 15-30% of breast cancers over-express the HER2/neu receptor. Historically, over-expression of HER2/neu has been identified using IHC or FISH, both of which are invasive approaches requiring tissue samples. Recent evidence has shown that some tumors identified as "negative" using these methods can respond to HER2/neu targeted therapy. Shedding of the extracellular domain (ECD) of the receptor into the circulation has led to the development of a serum test of HER2 ECD as an additional approach to probe HER2/neu overexpression. The serum test will be able to monitor the dynamic changes of HER2 status over the course of disease progression. Some studies further suggest that the serum HER2 ECD level and its change may serve as a biomarker to reflect patients' response to therapy. Yet more than 10years after the first serum HER2 ECD test was approved by the FDA, serum HER2 testing has yet to be widely used in clinical practice. In this article we will review the progress of the serum HER2 ECD test and discuss some obstacles impeding its incorporation into broad clinical practice. We will also discuss recent improvements in the sensitivity and specificity of the assay that offer some hope for the future of serum HER2 test.

Pilot study of the clinical significance of serum and urinary her-2/neu protein in bladder cancer patients

PURPOSE

HER-2/neu overexpression is documented in some bladder cancers. To our knowledge, there are no current studies evaluating urine HER-2/neu levels. Therefore, we examined the clinical significance of serum and urine HER-2/neu protein in bladder cancer.

MATERIALS AND METHODS

Urothelial bladder carcinoma patients (n=38, including 31 men and 7 women) and healthy controls (n=25, including 20 men and 5 women) were included in the study. Urine cytology and serum and urine HER-2/neu levels were measured before the transurethral resection of bladder tumor procedure. Prognostic factors including tumor stage, histologic grade, tumor size, multiplicity, and preoperative urine cytology and their association with urinary HER-2/neu were analyzed by simple and multiple regression analyses.

RESULTS

There was no significant difference in serum HER-2/neu between the two groups (p=0.489). The mean urinary HER-2/neu was 7,586.82 relative luminescence unit (RLU) in bladder cancer patients and 4,245.84 RLU in healthy controls. The mean RLU values of urinary HER-2/neu in the bladder cancer patient group were significantly higher than in healthy controls (p=0.012). An receiver operating characteristic curve was generated, and using the cutoff value of ≥4,800 RLU of urinary HER-2/neu, 71.1% sensitivity and 84.0% specificity were obtained. Among the clinical factors, only positive preoperative urine cytology samples were associated with urinary HER-2/neu levels by both simple and multiple regression analyses.

CONCLUSIONS

Bladder cancer patients demonstrated significantly higher urinary HER-2/neu than did healthy controls. These findings suggest that urinary HER-2/neu may be valuable as a new urinary marker. The application of urinary HER-2/neu needs additional investigation.

Serum HER2 levels determined by two methods in patients with metastatic breast cancer

BACKGROUND

The role and the optimal measurement method of serum HER2 levels are not defined in patients with metastatic breast cancer (MBC). We prospectively assessed the prognostic value of serum HER2 levels in MBC using two methods, enzyme immunoassay (EIA) and chemiluminescence immunoassay (CLIA).

METHODS

We collected blood samples from patients with MBC at baseline and at subsequent 3- to 4-week intervals up to 12 weeks. Samples were divided, and serum HER2 levels were determined using EIA and CLIA. We also determined whether serum HER2 levels had decreased by ≥20% at first follow-up. These results were evaluated against overall survival, progression-free survival, and tumor response.

RESULTS

We obtained 196 samples from 52 patients. In 59 samples from patients who received trastuzumab, serum HER2 positivity rates were significantly lower for EIA (n = 22) than for CLIA (n = 33, P = 0.042); in 137 samples from patients who did not receive trastuzumab, there was no significant difference in rates of serum HER2 positivity for CLIA (n = 83) and EIA (n = 80). Serum HER2 level at baseline, the level at first follow-up, and a decrease of ≥20% between baseline and first follow-up were not associated with overall survival, progression-free survival, and tumor response.

CONCLUSIONS

Chemiluminescence immunoassay was a more sensitive method than EIA for measuring serum HER2 levels in patients who received trastuzumab. However, because serum HER2 levels did not correlate with patient outcome, we do not currently recommend measuring serum HER2 levels by either method for prognostic evaluation in patients with MBC.

Lapatinib in metastatic breast cancer

Lapatinib is an oral, small-molecule, dual kinase inhibitor that targets both HER2 and the EGF receptor. Lapatinib was approved in June 2008 in Europe for the treatment of advanced HER2-positive breast cancer. Promising results in trastuzumab-refractory metastatic breast cancer were obtained from Phase I, II and III studies in combination with chemotherapy. Diarrhea and rash are the most common side-effects and are mostly moderate and treatable. Cardiac toxicity occurs rarely and mostly as an asymptomatic and reversible decrease of left ventricular ejection fraction. Unlike trastuzumab, some data show that lapatinib could cross the blood-brain barrier, with some evidence of activity in treating or preventing brain metastases. Its evaluation is actively ongoing, in combination with trastuzumab and in the adjuvant setting.

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.

The HER-2 receptor and breast cancer: ten years of targeted anti-HER-2 therapy and personalized medicine

The human epidermal growth factor receptor (HER-2) oncogene encodes a transmembrane tyrosine kinase receptor that has evolved as a major classifier of invasive breast cancer and target of therapy for the disease. The validation of the general prognostic significance of HER-2 gene amplification and protein overexpression in the absence of anti-HER-2 targeted therapy is discussed in a study of 107 published studies involving 39,730 patients, which produced an overall HER-2-positive rate of 22.2% and a mean relative risk for overall survival (OS) of 2.74. The issue of HER-2 status in primary versus metastatic breast cancer is considered along with a section on the features of metastatic HER-2-positive disease. The major marketed slide-based HER-2 testing approaches, immunohistochemistry, fluorescence in situ hybridization, and chromogenic in situ hybridization, are presented and contrasted in detail against the background of the published American Society of Clinical Oncology-College of American Pathologists guidelines for HER-2 testing. Testing issues, such as the impact of chromosome 17 polysomy and local versus central HER-2 testing, are also discussed. Emerging novel HER-2 testing techniques, including mRNA-based testing by real-time polymerase chain reaction and DNA microarray methods, HER-2 receptor dimerization, phosphorylated HER-2 receptors, and HER-2 status in circulating tumor cells, are also considered. A series of biomarkers potentially associated with resistance to trastuzumab is discussed with emphasis on the phosphatase and tensin homologue deleted on chromosome ten/Akt and insulin-like growth factor receptor pathways. The efficacy results for the more recently approved small molecule HER-1/HER-2 kinase inhibitor lapatinib are also presented along with a more limited review of markers of resistance for this agent. Additional topics in this section include combinations of both anti-HER-2 targeted therapies together as well as with novel agents including bevacizumab, everolimus, and tenespimycin. A series of novel HER-2-targeting agents is also presented, including pertuzumab, ertumaxomab, HER-2 vaccines, and recently discovered tyrosine kinase inhibitors. Biomarkers predictive of HER-2 targeted therapy toxicity are included, and the review concludes with a consideration of HER-2 status in the prediction of response to non-HER-2 targeted treatments including hormonal therapy, anthracyclines, and taxanes.

Prognostic value of Her-2/neu and DNA index for progression, metastasis and prostate cancer-specific death in men with long-term follow-up after radical prostatectomy

Abnormal DNA content in tumor cells represents large scale chromosomal alterations and reflects later changes of genetic instability. Her-2/neu oncogene is amplified in 20-30% of breast and ovarian cancer patients and is associated with poor prognosis. Therefore, we evaluated prognostic value of Her-2/neu expression and DNA content measurements in 252 clinically localized PCa patients with long-term follow-up after radical prostatectomy for progression, metastasis and PCa-specific death. Her-2/neu expression was determined by immunohistochemistry and DNA content measurements employed Feulgen-stained cancer nuclei captured using static image cytometry system. Cox proportional hazard regression and Kaplan-Meir plots were used to identify significant prognostic factors for progression, metastasis and PCa-specific death. The proportions of Her-2/neu positive and high %DNA index tumors significantly increased from nonprogressor to progressors without metastasis to progressors with metastasis (p < 0.0001; <0.0001). Further, the proportions of Her-2/neu positive and high %DNA index tumors significantly increased from patients who died from another cause without progression to those who died from another cause with progression to those died with PCa-specific death (p = 0.027; <0.0001). Her-2/neu expression and %DNA index were significant prognosticators for progression (p <or= 0.001), metastasis (p <or= 0.01) PCa-specific death (p <or= 0.04) in univariate analyses. Multivariately, Her-2/neu expression and %DNA index were also significant for progression (p = 0.001), metastasis (p = 0.001) and PCa-specific death (p = 0.02). When all other clinicopathologic information is available, the increment in concordance index by addition of either Her-2/neu or DNA index was approximately 2% and of both biomarkers was approximately 3% for progression, metastasis and PCa-specific death free survival models. Therefore, patients with Her-2/neu positive and high %DNA index are at a higher risk for disease progression, metastasis and PCa-specific death. Further, Her-2/neu expression and %DNA index may be used with clinicopathologic parameters for prediction of long-term prognosis in PCa.

HER2: The Neu Prognostic Marker for Breast Cancer

A fundamental mechanism of genetic alteration is amplification of entire gene sequences that results in overexpression of a gene product or protein. If the amplified gene is a member of the oncogene family and/or a regulator of DNA replication or cell cycle progression, overexpression of this oncoprotein may result in enhanced growth advantages for these cells. Amplification of one such oncogene, HER2 (neu, erbB-2), in up to 35% of human breast cancers is associated with a poor prognosis but may predict response to various therapeutic modalities. FDA-approved assays are available to detect the HER2 protein receptor or the HER2 gene sequence to determine eligibility for Herceptin treatment or adriamycin treatment in node positive patients, respectively. As testing for HER2 is becoming more common in the clinical laboratory, we provide an overview of the biology, diagnostic methods, and emerging clinical value of HER2 gene amplification.

Determination of HER2 status using both serum HER2 levels and circulating tumor cells in patients with recurrent breast cancer whose primary tumor was HER2 negative or of unknown HER2 status

Introduction

At the time when metastatic disease is identified, assessment of human epidermal growth factor receptor (HER)2 status might help to optimize treatment decisions if HER2 status was not determined at first diagnosis and if HER2 positivity has been acquired during disease progression. Within this context, determination of serum HER2 or evaluation of HER2 status in circulating tumor cells (CTCs) may be of clinical relevance because metastatic tissue may be difficult to obtain for analysis as a result of its localization. The aim of this study was therefore to determine the HER2 status in serum and corresponding CTCs in patients with metastatic breast cancer whose primary tumors were HER2 negative or of unknown HER2 status.

Methods

Blood samples were obtained from 77 metastatic breast cancer patients with negative (n = 44) or unknown (n = 33) HER2 status. Serum HER2 was determined using a commercial HER2/neu ELISA kit. CTCs were detected by slide-based assay using immunomagnetic enrichment and characterized by phenotyping and genotyping. Alternatively, a commercial kit, based on RT-PCR, was used to detect and characterize CTCs.

Results

Twenty out of 77 patients with metastatic disease had elevated serum levels of HER2. Blood samples could be analyzed for the presence of CTCs in 67 patients. Eight out of 21 patients with detectable CTCs exhibited HER2 amplification. Twenty-three out of 77 patients were HER2 positive using at least one method. Concordance between HER2 status of CTCs and serum HER2 was observed in 15 of 21 patients (71%). In six patients conflicting results were obtained. Three patients with elevated serum HER2 status had HER2-negative CTCs, whereas three patients with HER2-positive CTCs had normal serum HER2 levels.

Conclusion

A subgroup of patients with initially negative or unknown HER2 status can have elevated serum HER2 levels and/or HER2-positive CTCs at the time of development of metastatic disease. Although only a small number of patients were studied, our observations are of clinical relevance because, currently, these patients do not have access to HER2-targeted therapy.

A phase III randomized comparison of lapatinib plus capecitabine versus capecitabine alone in women with advanced breast cancer that has progressed on trastuzumab: updated efficacy and biomarker analyses

PURPOSE

Lapatinib is a small molecule, dual tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor type 2 (HER2). Initial results of a phase III trial demonstrated that lapatinib plus capecitabine is superior to capecitabine alone in women with HER2-positive advanced breast cancer that progressed following prior therapy including trastuzumab. Updated efficacy and initial biomarker results from this trial are reported.

METHODS

Women with HER2-positive, locally advanced or metastatic breast cancer previously treated with anthracycline-, taxane-, and trastuzumab-containing regimens were randomized to lapatinib 1,250 mg/day continuously plus capecitabine 2,000 mg/m(2) days 1-14 of a 21-day cycle or capecitabine 2,500 mg/m(2) on the same schedule. The primary endpoint was time to progression (TTP) as determined by an independent review panel. Relationship between progression-free survival (PFS) and tumor HER2 expression and serum levels of HER2 extracellular domain (ECD) were assessed.

RESULTS

399 women were randomized. The addition of lapatinib prolonged TTP with a hazard ratio (HR) of 0.57 (95% CI, 0.43-0.77; P < 0.001) and provided a trend toward improved overall survival (HR: 0.78, 95% CI: 0.55-1.12, P = 0.177), and fewer cases with CNS involvement at first progression (4 vs. 13, P = 0.045). Baseline serum HER2 ECD did not predict for benefit from lapatinib.

CONCLUSION

The addition of lapatinib to capecitabine provides superior efficacy for women with HER2-positive, advanced breast cancer progressing after treatment with anthracycline-, taxane-, and trastuzumab-based therapy. Biomarker studies could not identify a subgroup of patients who failed to benefit from the addition of lapatinib to capecitabine.

Preoperative Plasma HER2 and Epidermal Growth Factor Receptor for Staging and Prognostication in Patients with Clinically Localized Prostate Cancer

PURPOSE

Human epidermal growth factor receptor-2 (HER2) and epidermal growth factor receptor (EGFR) expression have been associated with disease progression in patients with prostate cancer. We tested the hypothesis that plasma levels of HER2 and/or EGFR are associated with prostate cancer stage and prognosis in patients with clinically localized disease.

EXPERIMENTAL DESIGN

We measured preoperative plasma HER2 and EGFR levels using commercially available ELISAs on banked plasma from 227 patients treated with radical prostatectomy and bilateral lymphadenectomy for clinically localized prostate adenocarcinoma.

RESULTS

Median preoperative plasma EGFR and HER2 levels were 31.4 ng/mL (interquartile range, 19.2 ng/mL) and 10.0 ng/mL (interquartile range, 2.7 ng/mL), respectively. HER2 was elevated in patients with seminal vesicle invasion (P = 0.033). In separate multivariate analyses that adjusted for the effects of standard preoperative predictors, lower EGFR, higher HER2, and higher HER2/EGFR ratio were associated with prostate-specific antigen (PSA) progression (P = 0.003, P < 0.001, and P < 0.001, respectively). In separate multivariate analyses that adjusted for the effects of standard postoperative predictors, lower EGFR and higher HER2/EGFR ratio were associated with PSA progression (P = 0.027 and P < 0.001, respectively). Among the patients who experienced PSA progression, HER2 was significantly higher (P = 0.023) and EGFR was lower (P = 0.04) in those with features of aggressive disease (i.e., development of metastasis, PSA doubling time <10 months, and/or failure to respond to local salvage radiation therapy).

CONCLUSION

Preoperative plasma HER2 and EGFR were associated with prostate cancer progression after radical prostatectomy. Plasma HER2 and EGFR may provide a tool for predicting long-term recurrence-free survival and early metastasis.

HER-2/neu diagnostics in breast cancer

HER-2/neu status of the primary breast cancer (PBC) is determined by immunohistochemistry and fluorescent in situ hybridization. Because of a variety of technical factors, however, the PBC may not accurately reflect the metastatic tumor in terms of HER-2/neu status. Recently published guidelines recommend that tumors be defined as HER-2/neu positive if 30% or more of the cells are 3+. Circulating levels of the HER-2 extracellular domain can be measured in serum using a test cleared by the US Food and Drug Administration, and increased serum HER-2/neu levels to above 15 ng/ml can reflect tumor progression. Studies comparing tissue HER-2/neu status of the PBC and HER-2/neu levels above 15 ng/ml in metastatic breast cancer patients are also reviewed.

HER2 testing: a review of detection methodologies and their clinical performance

The ERBB2 proto-oncogene, commonly referred to as the human epidermal growth factor receptor-2 (HER2) gene, encodes a 185 kd receptor tyrosine kinase. Overexpression of the protein leads to constitutive activity of the HER2 receptor and breast tumor development through enhanced cell proliferation, survival, motility and adhesion. Overabundance of the HER2 receptor, typically caused by amplification of the HER2 gene, is present in approximately 10-30% of invasive breast cancers, and is associated with an aggressive disease course and decreased disease-free and overall survival in node-positive patients. Tratuzumab, a humanized murine monoclonal antibody, offers a targeted treatment modality for tumors that over express the HER2 protein. Tratuzumab, shown to be effective and initially approved for treatment of metastatic breast cancer, has recently been shown to be very effective in the adjuvant setting. Thus, to offer prognostic information and to direct appropriate treatment it is important to provide accurate laboratory assessment of the status of HER2. This article provides an overview of the methods currently used to assess HER2.

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.

HER2 status is an important biomarker in guiding personalized HER2 therapy

The human epidermal growth factor receptor (HER)2 oncoprotein has emerged as an important cellular target for the development of a variety of new cancer therapies. The method used to define the HER2 status is a major factor in determining who will receive these targeted therapies. The HER2 status can be determined by using either tissue tests to look at the primary tumor cells, or an enzyme-linked immunosorbent assay (ELISA) that measures the circulating levels of the extracellular portion of HER2 protein. Tissue test (immunohistochemistry and fluorescence in situ hybridization) results indicate that approximately 20–30% of patients with primary breast cancer have a HER2-positive tumor, whereas ELISA results demonstrate that an average of 45% (range: 23–80%) of metastatic breast cancer (MBC) patients can have an abnormally high (> 15 ng/ml) serum HER2 level, which is evidence that a HER2-positive tumor is present. Published studies show that the HER2 status of a breast cancer patient can differ both by the test method used and the time at which HER2 status is assessed. In this review, data will be shown that demonstrates that not all HER2 test results obtained from the primary breast cancer are correct, and that there is a population of patients categorized as HER2 negative by tissue tests that, in fact, have HER2-positive tumors. This observation has important therapeutic implications for breast cancer patients with HER2-positive tumors that are classified as HER2 negative, since they are not eligible for anti-HER2 therapy, such as trastuzumab. If a patient is found to have an elevated (> 15 ng/ml) serum HER2 level in MBC, then either the original tumor should be re-evaluated for HER2 status, or a metastatic lesion should be tested for HER2 positivity, to determine if the patient is eligible for anti-HER2 therapy. Studies have also shown that lack of adequate validation of a testing method can result in false conclusions concerning the HER2 status. If the goal of personalized medicine is to deliver the right treatment to the right patient at the right time then we need to ensure the validity of all test methods, regardless of whether they are for research purposes or are registered as in vitro diagnostics. In the case of establishing HER2 status, it takes more than one type of test to identify patients with HER2-positive tumors. It is highly likely that the introduction of additional targeted drugs to growth factor receptors or to angiogenesis targets will take a variety and combinations of tests to tailor the most appropriate therapy to the patient.

Soluble p185(HER-2) in patients with malignant bone tumours

BACKGROUND

This study was initiated to test the hypothesis that soluble p185(HER-2) could be of value as a diagnostic or predictive marker for patients with malignant bone tumours.

PROCEDURE

Sera of 35 patients with high-grade malignant osteosarcoma (n = 27) and Ewing Sarcoma (n = 8) were tested at the time of diagnosis by ELISA and compared with sera of controls (n = 38) and clinical data.

RESULTS

In patients with osteosarcoma and Ewing Sarcoma, levels of sp185(HER-2) did not differ significantly from levels in controls. These results were irrespective of the type of tumour, survival chemotherapy or other clinical variables.

CONCLUSION

p185(HER-2) serum levels do not appear to be of diagnostic or predictive value for differentiation of high-grade osteosarcoma and Ewing Sarcoma.

HER-2 gene amplification can be acquired as breast cancer progresses

Amplification and overexpression of the HER-2 oncogene in breast cancer is felt to be stable over the course of disease and concordant between primary tumor and metastases. Therefore, patients with HER-2-negative primary tumors rarely will receive anti-Her-2 antibody (trastuzumab, Herceptin) therapy. A very sensitive blood test was used to capture circulating tumor cells (CTCs) and evaluate their HER-2 gene status by fluorescence in situ hybridization. The HER-2 status of the primary tumor and corresponding CTCs in 31 patients showed 97% agreement, with no false positives. In 10 patients with HER-2-positive tumors, the HER-2/chromosome enumerator probe 17 ratio in each tumor was about twice that of the corresponding CTCs (mean 6.64 +/- 2.72 vs. 2.8 +/- 0.6). Hence, the ratio of the CTCs is a reliable surrogate marker for the expected high ratio in the primary tumor. Her-2 protein expression of 10 CTCs was sufficient to make a definitive diagnosis of the HER-2 gene status of the whole population of CTCs in 19 patients with recurrent breast cancer. Nine of 24 breast cancer patients whose primary tumor was HER-2-negative each acquired HER-2 gene amplification in their CTCs during cancer progression, i.e., 37.5% (95% confidence interval of 18.8-59.4%). Four of the 9 patients were treated with Herceptin-containing therapy. One had a complete response and 2 had a partial response.

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.

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.

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.

Trastuzumab and vinorelbine as first-line therapy for HER2-overexpressing metastatic breast cancer: multicenter phase II trial with clinical outcomes, analysis of serum tumor markers as predictive factors, and cardiac surveillance algorithm

PURPOSE

Trastuzumab-based therapy improves survival for women with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer. We conducted a multicenter phase II study to evaluate the efficacy and safety of trastuzumab combined with vinorelbine, and to assess cardiac surveillance algorithms and tumor markers as prognostic tools.

PATIENTS AND METHODS

Patients with HER2-positive (immunohistochemistry [IHC] 3+-positive or fluorescence in situ hybridization [FISH]-positive) metastatic breast cancer received first-line chemotherapy with trastuzumab and vinorelbine to determine response rate. Eligibility criteria were measurable disease and baseline ejection fraction >or= 50%. Serial testing for HER2 extracellular domain (ECD) was performed.

RESULTS

Fifty-four women from 17 participating centers were entered onto the study. The overall response rate was 68% (95% confidence interval, 54% to 80%). Response rates were not affected by method of HER2 status determination (FISH v IHC) or by prior adjuvant chemotherapy. Median time to treatment failure was 5.6 months; 38% of patients were progression free after 1 year. Concurrent therapy was quite feasible with maintained dose-intensity. Patients received both chemotherapy and trastuzumab on 90% of scheduled treatment dates. Two patients experienced cardiotoxicity in excess of grade 1; one patient experienced symptomatic heart failure. A surveillance algorithm of screening left ventricular ejection fraction (LVEF) at 16 weeks successfully identified women at risk for experiencing cardiotoxicity. Other acute and chronic side effects were tolerable. Lack of decline in HER2 ECD during cycle 1 predicted tumor progression.

CONCLUSION

Trastuzumab and vinorelbine constitute effective and well-tolerated first-line treatment for HER2-positive metastatic breast cancer. Patients with normal LVEF can be observed with surveillance of LVEF at 16 weeks to identify those at risk for cardiotoxicity.

ELISA for quantitation of serum C-erbB-2 oncoprotein in breast cancer patients

C-erbB-2 is a protooncogene that is overexpressed in various cancers, either due to its amplification and/or increased transcription, and has been associated with more aggressive disease and a poor clinical prognosis in 20-30% of patients with breast cancer. Besides the prognostic factors such as tumor size, tumor grade, lymph node status, etc., which are significant in the management of breast cancer, C-erbB-2 level might also serve as an additional factor. Immunohistochemistry is the most frequently used method to study the expression of C-erbB-2 in breast cancer. We have generated a panel of monoclonal antibodies against C-erbB-2 oncoprotein with a view to evaluate their application for the diagnosis and therapy of breast cancer. In the present study, a simple, quantitative sandwich ELISA has been developed that uses two monoclonal antibodies directed against the extracellular domain of C-erbB-2 product, designated as CIBCgp185 as the capture antibody and CIBCHER-2 as the detector antibody. C-erbB-2 protein, isolated from BT474 cells, a human breast carcinoma cell line with high expression of C-erbB-2 and purified by Concanavalin A-Sepharose 4B affinity chromatography and HPLC has been used to develop the ELISA procedure. Sera samples of 150 healthy women donors and of 300 breast cancer patients with different histological types of malignancies have been analysed. The control women had serum C-erbB-2 in the range of 4.0-13.2 ng/mL, whereas the 300 breast cancer patients studied had a range of 4.8-75.2 ng/mL with a cut off value of 13.8 ng/mL. Our study showed that 18.6% of breast cancer patients had elevated levels of circulating C-erbB-2. These results might suggest that the serum C-erbB-2 level can be used as a potential tumor marker for breast cancer and that the Sandwich ELISA procedure might serve as an excellent alternative to immunohistochemistry in the near future.

Clinical utility of serial serum c-erbB-2 determinations in the follow-up of breast cancer patients

To evaluate the ability of serum c-erbB-2 protein to (1) indicate occult and manifest metastases and (2) reflect response to first-line therapy, serial serum c-erbB-2 measurements were performed in a retrospective series of 52 primary breast cancer patients who had developed metastatic disease during follow-up. The results were compared with CA 15-3. Preoperatively, 31% (16/52) of the primary breast cancer patients had elevated c-erbB-2 concentrations. The CA 15-3 positivity rate was 13% (7/52). After surgery, 10 of the 52 patients showed either stable but highly elevated or rising c-erbB-2 serum levels indicating serum c-erbB-2 producing minimal residual disease. Increasing CA 15-3 concentrations were seen in only three patients. Elevated serum c-erbB-2 levels predicted manifest metastases in 27 and 50% of the patients at 6 and 3 months, respectively, prior to clinical diagnosis. CA 15-3 was less sensitive. Only 16 and 32% of the patients had increased CA 15-3 serum concentrations at 6 and 3 months, respectively, prior to clinical detection. The positivity rates of c-erbB-2 and CA 15-3 were similar when metastases were clinically diagnosed. Elevated c-erbB-2 concentrations were found in 62% (32/52). The sensitivity of CA 15-3 was 56% (29/52). The association between serum profiles and response to first-line therapy was evaluated in detail for 45 patients. Serial c-erbB-2 and CA 15-3 measurements reflected disease course in 24 and 27 patients, respectively. The serum profiles of c-erbB-2 and CA 15-3 were similar in 17 patients. In summary, our results suggest that serial determinations of serum c-erbB-2 are useful to monitor breast cancer patients.

The Her-2/neu gene and protein in breast cancer 2003: biomarker and target of therapy

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. In this review, the association of HER-2/neu gene and protein abnormalities with prognosis and response to therapy with trastuzumab and to other therapies in breast cancer is presented. By considering a series of 80 published studies encompassing more than 25,000 patients, the relative advantages and disadvantages of Southern blotting, polymerase chain reaction amplification, 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 presented as well as its potential impact on responses to standard and newer hormonal therapies, cytotoxic chemotherapy, and radiation. The review also evaluates the status of serum-based testing for circulating HER-2/neu receptor protein and its ability to predict disease outcome and therapy response.

Association between the ras p21 oncoprotein in blood samples and breast cancer

To assess the potential of using oncoprotein levels in blood as a marker of breast cancer status, we measured ras p21 in blood samples taken from 34 breast cancer cases and 60 non-cancer controls including 26 women with benign breast disease (BBD) and 34 healthy women. Plasma samples drawn before surgery or at routine office visit were analyzed for ras p21 by Western blot with computer aided image analysis to measure staining intensity in integrated pixel units (IPU). We found detectable levels of ras p21 in 53% of the blood samples of cases, in 27% of the BBD controls and 26% of the healthy controls. Comparing cases to the combined control group (n=60) and controlling for known breast cancer risk factors, ras p21 was associated with breast cancer status (odds ratio=5.22, 95% CI=1.58-17.23). The median levels of ras p21 staining were higher in cases (7.04 IPU, P=0.03) compared to BBD controls (0.00 IPU) or healthy controls (0.00 IPU). The sensitivity of the assay for detecting breast cancer was 50% which compares favorably with that seen for erbB-2 ( approximately 10%), a more extensively studied blood-borne tumor marker. Ras p21 may be useful in the early detection of breast tumors and in post-surgical follow-up of patients, giving patients and physicians new tools for managing breast cancer.

Clinical significance of serum and urinary c-erbB-2 levels in colorectal cancer

In this study we measured serum and urinary c-erbB-2 levels in 63 patients with colorectal cancer and 29 healthy controls, assessing their role in cancer-specific survival and the effects of resectional surgery. Serum and urinary c-erbB-2 levels were measured by an enzyme-linked immunosorbent assay, preoperatively and 7 days following tumor resection. Preoperative serum c-erbB-2 concentrations were significantly higher in the cancer patients and correlated with disease stage and the presence of liver metastases. Urinary c-erbB-2 was detected more often in cancer patients, although levels did not differ from controls and there was no association with any clinicopathological variable. Serum c-erbB-2 levels decreased significantly in those patients resected for cure and were an independent prognostic factor for cancer-specific survival with higher preoperative concentrations correlating with worse overall survival. These findings suggest that serum assessment of c-erbB-2 concentration may be valuable in defining colorectal cancer prognosis.

Resistance to trastuzumab: a necessary evil or a temporary challenge?

The aim of this review article is to examine the potential mechanisms of resistance to trastuzumab. In the clinical setting, when trastuzumab is given as a single agent for first-line treatment of HER2-overexpressing metastatic breast cancer, it is associated with a 40% objective response rate. In the remaining cases, no tumor regression is observed, although HER2 protein is overexpressed and/or the corresponding gene is amplified. Hence, some other factors besides HER2 must play a role in determining the level of sensitivity to trastuzumab. The identification of the potential mechanisms of resistance to trastuzumab can be very helpful for the development of new compounds, which might overcome that resistance and/or have additive/synergistic antitumor effect when given in association with trastuzumab. Moreover, thorough understanding of the HER2 pathway is essential to the identification of new predictive markers of response to trastuzumab that will help to better define the patients who are most likely to benefit from this drug.

Non-small cell lung cancer clinical trials with trastuzumab: their foundation and preliminary results

The overexpression of HER2, a transmembrane glycoprotein tyrosine kinase, has been implicated in mitogenesis, cell survival, invasion and angiogenesis. Preclinical evidence suggests that HER2 overexpression contributes to tumor progression in non-small cell lung cancer (NSCLC) and retrospective clinical correlative studies show that it is probably associated with poor clinical outcome. Trastuzumab (Herceptin, Genentech Inc., South San Francisco, CA) is a recombinant humanized monoclonal antibody that targets HER2 and is currently approved for use in the treatment of patients with HER2-overexpressing metastatic breast cancer. Two primary mechanisms proposed for the activity of trastuzumab are downregulation of HER2 and induction of antibody-dependent cell-mediated cytotoxicity. Evidence from preclinical studies of trastuzumab in NSCLC and other cell lines, the presence of HER2 overexpression in NSCLC clinical specimens and the clinical benefit derived from trastuzumab in phase II and III metastatic breast cancer trials have led to the development of clinical trials of trastuzumab in NSCLC. Phase II studies of trastuzumab in patients with stage IIIB or IV NSCLC are being conducted to test the efficacy of trastuzumab as a single agent or in combination with chemotherapy. Preliminary results show combinations of chemotherapy plus trastuzumab are well tolerated, with encouraging response rates of 21-40%. A randomized phase II trial of chemotherapy with or without trastuzumab showed promise in a small subgroup of patients with 3+ HER2 overexpression by immunohistochemistry or HER2 DNA amplification by fluorescence in situ hybridization. Taken together, these data indicate that trastuzumab warrants further investigation in a clinical study in selected patients with NSCLC.

The HER2 extracellular domain as a prognostic and predictive factor in breast cancer

The HER2/neu proto-oncogene encodes a 185-kd transmembrane receptor with tyrosine kinase activity. Amplification of HER2 with overexpression of the p185HER2 receptor occurs in 20%-30% of breast cancers and has been established as an independent prognostic factor in numerous studies. Increasing evidence suggests that HER2 may be a predictive marker for response to chemotherapy and hormonal therapy. HER2 overexpression has provided a new target in breast cancer therapy, as evidenced by the development of trastuzumab (Herceptin(R)), a monoclonal antibody targeted against HER2. Detection of HER2 in the clinical setting is performed by immunohistochemistry or fluorescence in situ hybridization in tissue, and by detection of the shed extracellular domain in serum or plasma. Differences in methodology, reagents, and scoring systems have led to varying results in different patient cohorts, contributing to the debate on the role of HER2 as a prognostic and predictive factor. This review focuses on the prognostic and predictive value of serum HER2 detection in the management of HER2-positive breast cancer.

Status of c-erbB-2 in gastric adenocarcinoma: a comparative study of immunohistochemistry, fluorescence in situ hybridization and enzyme-linked immuno-sorbent assay

c-erb-2 amplification and overexpression are currently attracting a great deal of attention because a new adjuvant therapy using an antibody against the c-erbB-2 gene product, trastuzumab (Herceptin; Genentech, Inc., South San Francisco, CA), has proved effective in treating breast cancer with amplification and/or overexpression of c-erbB-2. Aberrations of c-erbB-2 have also been detected in ovarian, endometrial and gastric carcinomas at varied frequencies. Amplification of the c-erbB-2 locus (17q12-q21.32), overexpression of c-erbB-2 protein (p185) and serum levels of soluble c-erbB-2 protein fragments (p105) were examined in gastric cancer patients using fluorescence in situ hybridization (FISH), immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), respectively. Overexpression of c-erbB-2 protein was found in 29 (8.2%) of the 352 gastric carcinomas analyzed. In FISH analysis, all tumors with 3+ immunostaining and 1 of 5 tumors with 2+ staining showed high-level amplification of c-erbB-2. Pre-operative serum p105 was quantified in serum specimens from 129 patients with gastric cancer and 28 patients with benign diseases. There were no significant differences in the serum p105 levels among 11 patients with c-erbB-2-overexpressing carcinomas, 118 patients with c-erbB-2 non-overexpressing carcinomas and 28 controls, although a single case of gastric carcinoma overexpressing c-erbB-2 with extensive liver metastasis had a higher level than the cut-off value. The mechanisms of overexpression of p185 and high-level amplification of c-erbB-2 in gastric adenocarcinomas seem similar to those well-established in breast cancers. Patients having gastric adenocarcinoma with c-erbB-2 amplification are potential candidates for a new adjuvant therapy using humanized monoclonal antibody.

Serum level and tissue expression of c-erbB-1 and c-erbB-2 proto-oncogene products in patients with squamous cell carcinoma of the head and neck

The proto-oncogene products erbB-l (EGF-Receptor) and erbB-2 (HER-2/neu), distinct members of the epidermal growth factor receptor family, are frequently overexpressed in squamous cell carcinoma of the head and neck (SCCHN). The accumulation of these transmembrane proteins may lead to significant amounts of the respective extracellular receptor domains (ECD) that are shed from the tumour cell surface and enter blood circulation, thus representing potential serum tumour markers. For erbB-l and erbB-2, we determined the ECD serum levels with enzyme-linked immunosorbent assays and evaluated the protein expression in tumour tissue by immunohistochemistry. The present study included 49 patients (37 untreated, 12 recurrences) and the same number of age- and sex-matched healthy controls. In 24 patients ECD serum levels were determined before and 6 weeks after surgery. Mean ECD serum levels for erbB-1 and erbB-2 were 54.8+/-1.6 and 153.7+/-6.1 fmol/ml in cancer patients, and 54+/-1.5 and 147.9+/-4.5 fmol/ml in healthy controls, respectively. There was no significant difference between untreated and recurrent disease. Serum ECD follow-ups 6 weeks after surgery revealed a significant 12.3% decline of erbB-1 but no change of erbB-2 values. Immunohistochemistry showed strong staining for erbB-1 in 78% and erbB-2 in 47% of the SCCHN specimens. No correlation was detectable between receptor ECD serum levels and receptor tissue expression, tumour stage, and tumour differentiation. Hence, ECD serum levels of erbB-1 and erbB-2 are not considered to be valuable tumour markers in SCCHN.

ErbB2 immune response in breast cancer patients with soluble receptor ectodomain

Investigation of ErbB2 immunity in human breast cancer employing recombinant expression sources in immunoblot analysis revealed ErbB2-specific antibodies of the IgG isotype in sera of 14 of 71 cancer patients and 1 of 31 normal donors. Reactivity was confirmed on ErbB2-specific immunoprecipitates. Independent evidence of existing ErbB2 immunity was obtained after in vitro transformation of peripheral blood leukocytes from six positive patients. Furthermore, in vitro immortalization of B-lymphocytes unmasked existent ErbB2 immunity in 1 of 8 patients negative for ErbB2 serum antibodies. Determining shed ErbB2 extracellular domain as an indirect measure of tumor burden in ErbB2-positive malignancy, elevated serum levels were observed in 16 of 71 breast cancer and 1 of 31 normal donor sera. Strikingly, existing ErbB2 immunity correlated significantly with elevated shed ErbB2 ectodomain among the patients analyzed. Incidence of both ErbB2 immunity and elevated ErbB2 extracellular domain increased with a progressed disease stage and was significantly associated with metastatic breast cancer. These observations implicate soluble ErbB2 amounts in vivo in the development of ErbB2 immunity in breast cancer. They further project serum analysis of ErbB2 immunity and soluble ectodomain as potential markers of disease progression in ErbB2-positive malignancy.

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

BACKGROUND

Various methods and criteria are used to determine protein overexpression of c-erbB-2 and the clinical utility of c-erbB-2 is under investigation. We have reported previously that the levels of cytosol c-erbB-2 in breast cancer were significantly different between the clinical stages.

METHODS

The levels of c-erbB-2 protein were determined in sera from 210 breast cancer patients using a sandwich enzyme immunoassay between November 1996 and March 1998. The cut-off level was set at 5.4 ng/ml for healthy female blood donors.

RESULTS

First, serum c-erbB-2 levels were analyzed in 73 preoperative breast cancer patients with stage I-IIIB disease. The range and median values were 2.3-32.3 and 4.8 ng/ml, respectively. The positive rate was 38%. Overexpression of serum c-erbB-2 was significantly associated with tumor size, clinical stage, histological grade, lymphatic invasion, nodal status and overexpression of cytosol c-erbB-2, but not with hormonal receptor status and other clinico-pathological factors. Second, c-erbB-2, CEA and CA15-3 in sera were examined in 157 postoperative breast cancer patients. In the 137 disease-free patients, specificities of c-erbB-2, CEA and CA15-3 were 72, 93 and 99%, respectively, but in the 20 first recurrent patients, these sensitivities were 80, 25 and 25%, respectively.

CONCLUSIONS

These results suggest that serum c-erbB-2 protein is a useful marker for predicting aggressive behavior and first recurrence of breast cancer.

Circulating tumor markers in breast cancer: accepted utilities and novel prospects

Detecting and/or monitoring changes in circulating tumor markers might assist in evaluating cancer risk, diagnosis, prognosis, or response to treatment. Several categories of circulating tumor markers have been investigated in breast cancer. These categories include classical tumor-associated antigens, such as CEA and CA 15-3, markers of tumor biology, including markers of angiogenesis, adhesion, and invasion, and antibody response to tumor-associated antigens such as HER2/neu and p53. We used a recently proposed Tumor Marker Utility Grading System to evaluate the use of several circulating tumor markers for different clinical utilities in breast cancer. While there are no tumor markers with established clinical utilities for most uses, tumor-associated antigens can be used for monitoring patients with metastatic disease. In addition, markers of tumor biology such as the circulating extracellular domain of HER2/neu might be useful in determining not only prognosis, but also response to specific treatments. However, further investigations are required to further assess the utility of individual tumor markers for specific clinical uses.

The HER-2/neu oncogene in breast cancer: prognostic factor, predictive factor, and target for therapy

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. HER-2/neu has been widely studied in breast cancer. In this review, the association of HER-2/neu gene and protein abnormalities studied by Southern and slot blotting, immunohistochemistry, enzyme immunoassays, and fluorescence in situ hybridization with prognosis in breast cancer is studied in depth by review of a series of 47 published studies encompassing more than 15,000 patients. The relative advantages of gene amplification assays and frozen/fresh tissue immunohistochemistry over paraffin section immunohistochemistry are discussed. 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 potential value of HER-2/neu status for the prediction of response to therapy in breast cancer is presented in the light of a series of recently published studies showing a range of impact on the outcome of patients treated with hormonal, cytotoxic, and radiation therapies. The evidence that HER-2/neu gene and protein abnormalities in breast cancer predict resistance to tamoxifen therapy and relative sensitivity to chemotherapy regimens including adriamycin is presented. The review will also evaluate the status of serum-based testing for circulating the HER-2/neu receptor protein and its ability to predict disease outcome and therapy response. In the final section, the review will briefly present preliminary data concerning the use of antibody-based therapies directed against the HER-2/neu protein and their potential to become a new modality for breast cancer treatment. The recently presented phase III clinical trial evidence that systemic administration of anti-HER2 antibodies (Herceptin), alone and in combination with cytotoxic chemotherapy in patients with HER-2/neu overexpressing primary tumors, can increase the time to recurrence and overall response rates in metastatic breast cancer is reviewed.