The Oncologist, Vol. 3, No. 4, 237-252,
August 1998
© 1998 AlphaMed Press
The HER-2/neu Oncogene in Breast Cancer: Prognostic Factor, Predictive Factor, and Target for Therapy
Jeffrey S. Rossa,
Jonathan A. Fletcherb
a Department of Pathology and Laboratory Medicine, Albany Medical College, Albany, New York;
b Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
Jeffrey S. Ross, M.D., Department of Pathology and Laboratory Medicine, Albany Medical College, Mail Code 81, 47 New Scotland Avenue, Albany, New York 12208, USA. Telephone: 518-262-5471; Fax: 518-262-3663; e-mail: jeffrey_ross{at}ccgateway.amc.edu
 |
Abstract
|
|---|
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.
Key Words. Breast neoplasms • Proto-oncogene c-erbB2 • HER-2/neu • Prognosis • Therapy
|
Introduction
|
|---|
The proto-oncogene HER-2/neu (C-erbB-2) has been localized to chromosome 17q and encodes a transmembrane tyrosine kinase growth factor receptor. The name for the HER-2 protein is derived from "Human Epidermal growth factor Receptor," as it features substantial homology with the epidermal growth factor receptor (EGFR) [1-2]. HER-2/neu gene amplification has been associated with the development of breast cancer in animal models [1]. The HER-2/neu protein is a component of a four-member family of closely related growth factor receptors, including EGFR or HER-1 (erb-B1); HER-2 (erb-B2); HER-3 (erb-B3) and HER-4 (erb-B4) ( Table 1) [3]. In addition to its association with disease outcome in gastrointestinal, pulmonary, genitourinary and other neoplasms, amplification of the HER-2/neu gene or overexpression of the HER-2/neu protein has been identified in from 10% to 34% of breast cancers [4-50]. To date, a wide variety of clinical studies, including more than 15,000 patients ( Table 2), have evaluated the relationship between HER-2/neu abnormalities and breast cancer outcome, including more than 47 publications concerning the association of gene and/or protein abnormalities with prognosis [4-50]. The techniques used to evaluate HER-2/neu status in breast cancer have included gene-based assays such as Southern and slot blotting, polymerase chain reaction methods, and more recently, in situ hybridization featuring both fluorescent and nonfluorescent techniques [4-50]. Qualitative and quantitative HER-2/neu protein measurements have been performed by immunohistochemistry on frozen and archival tissues, Western blotting, and enzyme immunoassays (ELISA) [4-50].
View this table:
[in this window]
[in a new window]
|
Table 2. Summary of selected studies on the correlation of HER-2/neu gene and protein abnormalities with prognosis in breast cancer
|
|
The results of the breast cancer outcome studies have not been uniform, and a significant discordance between HER-2/neu abnormality detection methods has been described. In particular, when immunohistochemistry has been employed on formalin-fixed paraffin-embedded specimens, there has been a significant lack of agreement with gene amplification detection results on the same tumors and inconsistent success at predicting disease prognosis. In this review, the prognostic significance of HER-2/neu abnormalities in breast cancer is considered and the various methods used to detect HER-2/neu abnormalities discussed in detail. The significance of HER-2/neu abnormalities in ductal carcinoma in situ is also considered, and the potential use of HER-2/neu status in the prediction of response to therapy is presented. A separate section considers the status of serum-based testing for the HER-2/neu protein for the detection and monitoring of breast cancer. The final section of the review presents the results of recent studies of novel breast cancer therapies directed against the HER-2/neu gene and protein, including the use of anti-HER2 antibodies (Herceptin®) in the treatment of metastatic disease.
|
Her-2/neu Abnormalities and Prognosis in Invasive Breast Cancer
|
|---|
A wide variety of morphology-based and molecular-based prognostic factors and tumor markers have been studied as to their potential to predict disease outcome in breast cancer [51-53]. A partial list of prognostic factors commonly used and under consideration for use in the care of breast cancer patients is included in Table 3. Following the original study by Slamon and coworkers [4] in 1987, many investigators have considered the prognostic potential of the HER-2/neu gene and protein in breast cancer. A synopsis of 47 published studies evaluating more than 15,000 patients with breast cancer for abnormalities of the HER-2/neu gene and protein is presented in Table 2.
The original study published by Slamon et al. in 1987 [4] found that HER-2/neu gene amplification determined by Southern analysis independently predicted time to disease relapse and overall survival in 189 patients with breast cancer. Subsequently, Berger et al. reported that HER-2/neu protein overexpression is determined by immunohistochemistry correlated with lymph node status and breast cancer tumor grade [5]. However, an immunohistochemical study by van de Vijver et al. in 1988 [6] failed to show a significant association of HER-2/neu protein immunostaining with disease outcome. In 1990, Heintz et al. reported that the HER-2/neu gene copy number by Southern analysis correlated with mitotic activity and negative estrogen and progesterone receptor status but could not link gene expression with disease outcome [7]. During the next seven years, however, most large studies found substantial correlation of HER-2/neu status with disease outcome. This was especially true for studies using either gene-based analysis or immunohistochemistry with anti-HER-2/neu antibodies having sensitivity in processed tissues and restricting positive cases to those with a characteristic membranous staining pattern ( Fig. 1), [10-12, 14-35, 37, 39-50].
View larger version (143K):
[in this window]
[in a new window]
|
Figure 1. Overexpression of the HER-2/neu protein by immunohistochemistry. Note the positive membranous staining pattern creating a weaved basket appearance (peroxidase-antiperoxidase).
|
|
In a 1994 study on 442 patients, Muss et al. [33] reported a significant predictive value for HER-2/neu protein overexpression on the response to cytotoxic chemotherapy and overall disease outcome. In 1996, a study of lymph node negative breast cancer by O'Malley and coworkers using a semiquantitative immunohistochemical assessment of HER-2/neu protein levels found an independent prediction with both overall and disease-free survival on multivariate analysis [41]. In another recent study of HER-2/neu protein levels, Hieken et al. found that HER-2/neu protein overexpression measured by an ELISA technique on fresh tumor cytosols independently predicted disease outcome in breast cancer [42]. Another two recent studies reporting adverse prognosis in patients with elevated HER-2/neu protein in tumor cytosols by the ELISA method include the 1997 publications on 115 patients by Dittadi and coworkers [44] and on 100 patients by Eissa et al. [46]. The ELISA method has also been used to measure serum HER-2/neu protein levels (see below).
Several immunohistochemical studies found significant correlation between HER-2/neu protein immunoreactivity and disease outcome on univariate analysis (see section on comparison of HER-2/neu gene and protein detection techniques below) but were unable to demonstrate independent predictive status for immunoreactivity on multivariate analysis [23, 35, 45].
Gene-based studies of HER-2/neu gene amplification in breast cancer include a negative study by Heintz et al. [7] and a 1990 study by Tsuda et al. [8] in which a prognostic impact of the HER-2/neu gene copy number on univariate analysis was absorbed by tumor grade on multivariate analysis. In 1992, however, a study by Babiack et al. [25] reported that the HER-2/neu gene copy number and aneuploidy were predictive of outcome on univariate analysis, and Tiwari et al. reported that gene amplification was associated with nodal metastases [26]. In 1993, Seshadri et al. [30] showed univariate and multivariate significance for HER-2/neu gene amplification as determined by slot-blotting in the prediction of disease recurrence among 1,056 node-negative and node-positive patients. Descotes et al. [31] (using both Southern and slot-blotting methodologies) also reported independent adverse prognostic significance for HER-2/neu gene amplification cases.
Given that Southern and slot-blotting procedures are expensive and time-consuming and require fresh or frozen tissue, the fluorescence in situ hybridization (FISH) technique was implemented to measure HER-2/neu gene copy number on formalin-fixed archival specimens ( Fig. 2). In two previous studies, the FISH method was found to be more sensitive than Southern blotting for the detection of HER-2/neu gene amplification [48, 54]. The FISH technique has out-performed a number of solid matrix blotting techniques designed to detect HER-2/neu DNA and RNA as well as immunohistochemistry designed to detect HER-2/neu protein in formalin-fixed paraffin-embedded tissues [48]. The FISH technique has been described as a rapid, reproducible, and extremely reliable method of detecting HER-2/neu gene amplification [48]. In addition, FISH can readily be performed on archived paraffin blocks stored for long periods and has been successfully applied to fine-needle aspiration biopsies [55].
View larger version (99K):
[in this window]
[in a new window]
|
Figure 2. Amplification of the HER-2/neu gene detected by fluorescence in situ hybridization. Note the numerous bright intranuclear signals seen individually and in clusters (Biotinylated HER-2/neu probe [Oncor, Inc.; Gaithersburg, MD];avidin anti-avidin detection, DAPI counterstain).
|
|
In a study using the FISH method, Xing et al. reported that HER-2/neu gene amplification was more predictive than lymph node status and was the strongest independent predictor of outcome in breast cancer [43]. The recently published study by Press et al. [48] successfully utilized FISH on archived specimens to predict short- and long-term outcome in node-negative breast cancer. This study employed a two-category system of HER-2/neu amplification status: four or fewer signals/nucleus = unamplified, and greater than four signals/nucleus = amplified. A recent study derived from a subset of the cases reported by Press et al. [48] features a three-tiered amplification scoring system with an equivocal borderline amplified group featuring greater than three but fewer than 10 signals/nucleus [49]. The results of the three-tiered system are similar to that of the two-tiered system and confirm the significant association of HER-2/neu gene amplification with early recurrence, recurrence at any time, and disease-related death in node-negative breast cancer initially treated by surgery alone ( Fig. 3). Both the two-tier and the three-tier amplification scoring systems similarly found the adverse impact of HER-2/neu gene amplification to be independent of tumor size, grade, and estrogen receptor status [48-49]. In another study using a two-tier system HER-2/neu gene amplification again predicted disease-related death independent of the original nodal status in a combined series of node-negative and node-positive patients [50].
View larger version (19K):
[in this window]
[in a new window]
|
Figure 3. Kaplan-Meier survival curve for the prediction of disease-related death in lymph node-negative breast cancer by amplification of the HER-2/neu oncogene detected by fluorescence in situ hybridization. Patients with amplified tumors had a significantly increased risk of dying from their disease compared with patients in whom primary tumors were not amplified (p < 0.0001).
|
|
|
Comparison of Methods of Detection of HER-2/neu Abnormalities
|
|---|
Of the 47 studies considering 15,248 patients listed in Table 2 , 30 (64%) employed immunohistochemistry (IHC) on fixed paraffin-embedded tissues to measure HER-2/neu protein overexpression. As seen in Table 4 , 6
(13%) of the studies encompassing 1,222 (8%) of the patients showed no correlation between HER-2/neu status and outcome; 13 (28%) of the studies encompassing 3,884 (25%) of the patients reported prognostic significance on univariate analysis only; and 28 (60%) of the studies encompassing 10,142 (67%) of the patients reported independent prognostic significance on HER-2/neu gene or protein multivariate analysis. Of the six published studies involving 1,222 patients which did not link HER-2/neu abnormalities with prognosis, four (67%) studies of 810 (66%) patients employed IHC on paraffin-embedded tissues as the HER-2/protein detection technique and two (33%) studies involving 412 (34%) patients used gene-based assays. In addition, of the six studies of 2,302 patients in which HER-2/neu abnormalities predicted outcome only on univariate but not on multivariate statistical analysis, five (83%) were IHC-based and one (16%) was based on gene amplification measurements.
The prognostic and predictive potential of HER-2/neu protein immunostaining in breast cancer has recently been reviewed by Allred and coworkers [56]. Examples of the IHC-based noncorrelating studies ( Table 2) include the 1994 publication on 81 patients by Jacquemeier et al. [36], showing no association of HER-2/protein staining with response to breast cancer therapy and the 1994 report by Rosen et al. [38] on 440 patients which did not relate immunoreactivity with disease outcome. Examples of gene-based noncorrelating studies include the 1990 Southern analysis of 50 cases by Heintz et al. [7], in which amplification correlated with proliferation and estrogen receptor negative status only, and the 1991 study on 362 patients by Clark et al. [13] in which HER-2/neu gene amplification detected by slot blotting was marginally predictive in node positive patients only. Although only four studies reported to date used the FISH-based gene amplification assay [43, 48-50], four of four (100%) correlated HER-2/neu with outcome on univariate analysis and three of three (100%) showed independent significance when multivariate analysis was performed.
The various methods of determining HER-2/neu gene and/or protein abnormalities in breast cancer specimens are compared in Table 5. Immunohistochemistry has been the predominant method utilized. However, there are significant issues that can impact on IHC, especially when performed on archival, fixed, paraffin-embedded tissues. Many laboratories perform the staining on referred specimens and cannot control the time and nature of tissue fixation, the method of tissue processing, or the temperature of the paraffin embedding procedure, all of which can influence HER-2/neu protein antigen loss. Prolonged storage can also be a problem, and significant loss of tumor-marker immunostaining intensity has been identified, particularly when specimens are stored as unstained slides [57]. The impact of the fixative has been considered and shown to have a significant impact on HER-2/neu immunostaining [58]. Using cell line controls, different antibodies have differing staining patterns depending on how the cells were fixed [58]. Studies of the various commercially available antibodies have also demonstrated a wide variety of sensitivity and specificity for fixed, paraffin-embedded tissues. In a study by Busmanis et al. [59], a panel of six antibodies showed a wide variation in staining patterns including occasional cytoplasmic immunoreactivity (a pattern considered to be nonspecific by most investigators). In a study of a large panel of antibodies, Press et al. similarly reported a wide range of detection rates using a large tissue block containing multiple breast tumors [60]. The use of nonstandardized antigen retrieval (amplification) techniques further compounds the problem and introduces the potential for false-positive staining. The lack of an agreed-upon scoring system for interpreting HER-2/neu protein IHC is another significant issue. Recent attempts to reach consensus on immunohistochemical staining interpretation show promise for dealing with this issue [61]. It should be mentioned that IHC on frozen sections has shown substantial correlation with HER-2/neu gene-based assays [48] and would be an ideal method of detection if not obviously limited by the general lack of availability of fresh or frozen material for this approach. The ELISA technique, when performed on tumor cytosols made from fresh tissue samples, avoids the potential antigen damage associated with fixation, embedding, and uncontrolled storage. In the three published studies including 315 patients listed in Table 2, ELISA-based measurements of HER-2/neu protein in tumor cytosols have uniformly correlated with disease outcome [39, 41, 43]. However, the small size of breast cancers diagnosed in an era of enhanced screening generally precludes tumor tissue ELISA methods because insufficient tumor tissue is available to produce a cytosol. Western blotting can also detect HER-2/neu protein overexpression in both tumor cytosols and archival tissues but is generally cumbersome and impractical for routine specimens.
Southern and slot blotting were the first gene-based HER-2/neu detection methods used in breast cancer specimens. These methods can be significantly hampered when tumor cell DNA extracted from the primary carcinoma sample is diluted by DNA from benign breast tissue and inflammatory cells. The FISH technique allows simultaneous morphologic assessment, such that evaluation of gene amplification can be restricted to invasive carcinoma cells. This approach has proven to be more sensitive than Southern analysis for the detection of HER-2/neu abnormalities in breast cancer [48]. Of the 15 gene-based studies listed in Table 2, the two (13%) noncorrelating studies used Southern (50 patients) and slot- blotting (362 patients) methods. As mentioned above, the FISH-based assays of HER-2/neu gene amplification have uniformly predicted an adverse disease outcome.
In summary, both HER-2/neu gene amplification and protein overexpression have been associated with an adverse outcome in breast cancer, with gene-based methods and protein detection on fresh or frozen samples obtaining the most consistent results. Many of the published studies have used a relatively short clinical follow-up period for a disease prone to late recurrences. Thus, abnormalities of HER-2/neu may actually identify patients at greater risk for early disease relapse, and evidence confirming the ability of the marker to predict overall relapse rates must await continuing long-term studies of tumor outcome.
|
HER-2/neu Abnormalities in Ductal Carcinoma In Situ (DCIS)
|
|---|
HER-2/neu protein overexpression was first reported in in situ breast cancer by van de Vijver et al. in 1988 and was associated with the comedocarcinoma variant [6]. As seen in Table 6, numerous subsequent studies confirmed this relationship between HER-2/neu protein immunoreactivity and the high-grade and comedo subtypes of DCIS as well as with other unfavorable prognostic factors [62-73]. HER-2/neu protein expression has been associated with DCIS extent [68, 73], negative staining for hormone receptor proteins [65, 67, 71], high cell proliferation rates [64, 67], DNA aneuploidy [65], p53 protein overexpression [64, 67, 71], and association with invasive disease [63]. Given the increased incidence of the diagnosis of DCIS on breast biopsies generated by the detection of small lesions on mammography, there has been significant recent interest in prognostic markers that could further subtype the disease and guide follow-up therapy. As seen in Table 6, HER-2/neu abnormalities appear to identify a particularly virulent form of DCIS featuring a tendency for a high nuclear grade and comedo-type necrosis. Further evaluation of the HER-2/neu status in these lesions appears warranted to confirm whether this marker can be clinically useful in stratifying patients into low-risk groups which may be followed conservatively and high-risk groups that may require extensive post-biopsy surgical procedures to prevent recurrence and to rule out invasive disease with an aggressive phenotype.
|
HER-2/neu Abnormalities in Other Types of Breast Malignancies and Proliferative Disease
|
|---|
HER-2/neu gene expression has generally not been specifically implicated in the progression or prognosis assessment of lobular breast cancer [74]. HER-2/neu protein overexpression has been a consistent feature of both mammary and extramammary Paget's disease [75]. Studies of ductal carcinoma in situ and Paget's disease extension patterns have led some researchers to suggest that the HER-2/neu protein may function both as a growth factor receptor and as a cell motility factor. HER-2/neu protein overexpression has been associated with an absence of neuroendocrine breast cancer differentiation [76]. Immunohistochemical staining for HER-2/neu protein has varied in reports considering benign breast disease, such as fibrocystic mastopathy and fibroadenoma. In general, when staining interpretation is limited to a membranous staining pattern, the staining of benign or proliferative breast tissue both in cancer-free patients and patients with adjacent infiltrating and in situ breast carcinomas has been absent to weak in intensity [77-79]. When Southern blot analysis was performed on both benign female breast tissue and male breast tissue showing gynecomastia, no significant amplification was identified [79].
|
HER-2/neu Status in Male Breast Carcinoma
|
|---|
Male breast cancer comprises approximately 0.05% of new breast cancer diagnoses per year in the United States (1,000 new cases). A variety of prognostic markers have been studied in male breast cancer, including routine histologic parameters of size, grade, and lymph node status, as well as newer molecular markers of disease progression. In a study by Gattuso and coworkers [80], HER-2/neu protein overexpression measured by immunohistochemistry was present in 35% of male breast carcinoma patients and emerged as a statistically significant predictor of disease outcome on univariate analysis. Similarly, a study by Joshi and coworkers in 1996 found HER-2/neu protein immunostaining to predict shortened survival in male breast cancer [81]. However, three additional IHC studies found a similar range of overexpression as seen in female breast cancer but could not correlate immunostaining with disease outcome [82-84]. In another immunohistochemical study of HER-2/neu expression in male breast carcinoma, the expression rate was found to be half (17%) of that in women (33%) [85]. In the latter study, it was commented that male breast carcinomas are often characterized by large tumor cells similar to the type associated with HER-2/neu gene amplification in women. Although male breast carcinoma is a relatively rare form of malignancy, it appears that further studies of HER-2/neu gene and protein status in male breast carcinoma are warranted to determine whether this oncogene has clinical utility for the management of patients with this disease.
|
HER-2/neu Status and the Prediction of Response of Breast Cancer to Therapy
|
|---|
In addition to the considerable interest in the HER-2/neu gene and protein as prognostic factors, investigators have also evaluated potential applications of HER-2/neu testing for predicting response of breast cancer to therapy. However, compared with the prognostic studies, the reports of therapy response prediction are fewer, involve smaller patient groups, and have been generally less well controlled [32, 33, 86-102]. Table 7 lists 20 published studies involving more than 4,500 patients, tumor cell lines, and xenografts that used a variety of detection techniques to test the relationship between HER-2/neu abnormalities and response to therapy. The most common association of HER-2/neu protein overexpression with therapy response, reported in nine of the studies, is the apparent resistance of these tumors to hormone therapy alone [86-88, 90, 92, 97, 99]. Several studies found that HER-2/neu-overexpressing tumors were specifically resistant to tamoxifen therapy [92, 97]. However, in a recent IHC-based study including 200 patients, HER-2/neu protein staining failed to predict tamoxifen resistance in estrogen-receptor positive cases [100]. This was also the case in a previously published study using an ELISA technique to determine the HER-2/neu protein status [94]. In a twenty-year update of an adjuvant chemotherapy trial from Italy, not only did HER-2/neu protein overexpression predict resistance to tamoxifen treatment, HER-2/neu-positive patients treated with tamoxifen actually had an adverse outcome compared with untreated patients [101]. In an initial report of the SWOG Biological Correlative Study, patients with HER-2/neu protein overexpressing tumors appeared more responsive to cytotoxic chemotherapy with a CAFT regimen than when treated with tamoxifen alone, although this relationship could not achieve complete statistical significance [102]. HER-2/neu protein overexpression has also been linked to CMF resistance in clinical specimens (cytoxan, methotrexate, 5-fluorouracil) [32, 87, 88] and taxol resistance in cell lines [91]. However, another study found that HER-2/neu positive tumors were three times more sensitive to taxol [95], and HER-2/neu overexpression has also been associated with enhanced response rates to chemotherapy regimens containing adriamycin [16]. HER-2/neu immunostaining has successfully predicted local recurrence in patients receiving surgery and radiation alone [93]. Recently, an artificial neural network approach utilized HER-2/neu status along with other prognostic markers to successfully predict response to adjuvant chemotherapy and radiation [98]. It appears that although strong trends have been presented in the published studies, such as the resistance to tamoxifen and sensitivity to adriamycin for HER-2/neu-positive tumors, more studies are needed using appropriate control arms to confirm these important associations. Should this be accomplished, it would seem likely that HER-2/neu testing would be of even greater value in the management of breast cancer patients and possibly achieve status as a standard of practice similar to hormone receptor testing.
|
Serum HER-2/neu Antigen Levels as a Tumor Marker
|
|---|
Antibodies similar to those used for HER-2/neu protein detection in breast tumor tissues have been applied to human serum samples to test whether circulating HER-2/neu receptor protein levels can predict the progression of breast cancer [88, 94, 99, 103-112]. Table 8 is a summary of 12 published studies on 1,960 patients featuring HER-2/neu serum protein enzyme-based immunoassays. Seven of the studies (1,330 patients) found a significant correlation of serum HER-2 protein levels with either disease recurrence, metastasis, or shortened survival [103, 106, 98, 109-111]. Two studies (379 patients) reported no significant association of serum levels with prognosis [104, 107]. Of the studies in which serum HER-2 protein levels predicted response to therapy, three studies found that elevated serum HER-2/neu protein predicted therapy resistance [98, 103, 106], whereas three studies did not demonstrate this association [94, 107, 109]. Interestingly, elevated serum HER-2/neu levels correlate with decreased survival and absence of clinical response to hormonal therapy, even when estrogen receptor assays are positive [98]. However, in a recent study, serial serum HER-2/neu protein levels did not correlate with the clinical course in a group of patients with metastatic breast carcinoma treated with second-line hormonal therapy [107].
|
New Therapies in Breast Cancer Directed at the Her-2/neu gene and Protein
|
|---|
Table 9 lists a series of studies in which the HER-2/neu receptor protein served as a therapeutic target. Although most of the listed studies were performed in vitro using cell lines and xenografts [112, 113, 115, 117-120] the preliminary results of clinical trials in humans have been promising [114, 116, 121, 122]. Baselga and coworkers have reported a phase II study of 45 women with HER-2/neu overexpressing metastatic breast cancer resistant to multiple previous therapies, in which 11.6% and 37% of patients developed objective response and disease stabilization, respectively, when treated with monoclonal antibody rhuMAB HER-2 (Herceptin®) directed toward the HER-2/neu protein [116]. Herceptin® has a favorable toxicity profile and has recently achieved a significant overall response rate of 15% when given alone in metastatic breast cancer [121]. Most recently, the results of a randomized multinational controlled phase III clinical trial using Herceptin® in combination with first-line chemotherapy in metastatic breast cancer have been reported [122]. In 469 patients with HER-2/neu overexpressing primary tumors, Herceptin® increased the time to disease progression and response rate when given in combination with either adriamycin-cytoxan or paclitaxel [122]. Although the adverse event incidence in this study was not increased by Herceptin® therapy, the incidence of myocardial toxicity classically associated with adriamycin was slightly increased in patients who received the drug [122]. If the preliminary results can be confirmed on large patient groups, then the use of anti-HER-2/neu antibody therapy may have significant potential as a new method of breast cancer treatment whether given alone or in combination with other conventional treatment modalities. At the time of this review, similar clinical trials are in progress at multiple centers. Additional approaches to anti-HER-2/neu therapy, under preliminary investigation, include the use of antisense "gene therapy" probes [117] and anti-HER-2/neu protein vaccination [123, 124].
|
Other Uses of HER-2/neu in Breast Cancer.
|
|---|
Antibodies to the HER-2/neu protein have been used for radionucleotide imaging in breast cancer. In a 1994 study, Allan and coworkers used Tc99m-labeled monoclonal antibodies to HER-2 protein and reported encouraging results [125]. In addition to a potential use as a detector of occult metastasis, this approach may also allow for antibody-targeted chemo or radiation therapy in patients with recurrent or metastatic disease.
|
Conclusions
|
|---|
The preponderance of evidence indicates that HER-2/neu gene amplification and protein overexpression are associated with an adverse outcome in breast cancer. Although controversy exists over the best detection method for measuring abnormalities of HER-2/neu, the majority of data favor the conclusion that assays of gene amplification such as the FISH technique and immunohistochemistry on frozen sections or enzyme immunoassays on fresh tumor cytosolic protein produce more consistent results than immunohistochemistry on formalin-fixed, paraffin-embedded tissue sections. Although requiring further statistical confirmation, evidence also indicates that breast cancers with HER-2/neu gene or protein abnormalities are resistant to treatment with tamoxifen alone and relatively more sensitive to cytotoxic therapy regimens containing adriamycin. Based on the promising new information concerning the response of metastatic breast cancer in patients with HER-2/neu overexpressing primary tumors to treatment with anti-HER-2 antibodies (Herceptin®), it appears that further basic and clinical research studies of this gene and protein will likely continue well into the 21st Century.
|
Acknowledgments
|
|---|
Dr. Ross and Dr. Fletcher are consultants for Oncor, Inc., Gaithersburg, Maryland.
|
References
|
|---|
-
Slamon DJ, Clark GM. Amplification of C-ERB-B2 and aggressive breast tumors? Science 1988;240:1795-1798.[Free Full Text]
-
De Potter CR. The neu oncogene: more than a prognostic indicator? Hum Pathol 1994;25:1264-1268.[Medline]
-
Lupu R, Cardillo M, Harris L et al. Interaction between ERB-receptors and heregulin in breast cancer tumor progression and drug resistance. Sem Cancer Biol 1995;6:135-145.[Medline]
-
Slamon DJ, Clark GM, Wong SG et al. Human breast cancer: correlation of relapse and survival with amplification of the Her-2/neu oncogene. Science 1987;235:177-182.[Abstract/Free Full Text]
-
Berger MS, Locher GW, Saurer S et al. Correlation of c-erb B2 gene amplification and protein expression in human breast carcinoma with nodal status and nuclear grading. Cancer Res 1988;48:1238-1243.[Abstract/Free Full Text]
-
van de Vivjer MJ, Peterse JL, Mooi WJ et al. Neu-protein overexpression in breast cancer. N Engl J Med 1988;319:1239-1245.[Abstract]
-
Heintz NH, Leslie KO, Rogers LA et al. Amplification of the c-erb B-2 oncogene in prognosis of breast adenocarcinoma. Arch Pathol Lab Med 1990;114:160-163.[Medline]
-
Tsuda H, Hirohashi S, Shimosato Y et al. Correlation between histologic grade of malignancy and copy number of c-erbB-2 gene in breast carcinoma. A retrospective analysis of 176 cases. Cancer 1990; 65:1794-1800.[Medline]
-
Borg A, Tandon AK, Sigurdsson H et al. HER-2/neu amplification predicts poor survival in node-positive breast cancer. Cancer Res 1990;50:4332-4337.[Abstract/Free Full Text]
-
Paik S, Hazan R, Fisher ER et al. Pathologic findings from the nations' surgical adjuvant breast and bowel project: prognostic significance of erb B2 protein overexpression in primary breast cancer. J Clin Oncol 1990;8:103-112.[Abstract/Free Full Text]
-
Battifora H, Gaffey M, Esteban J et al. Immunohistochemical assay of neu/c-erb B-2 oncogene product in paraffin-embedded tissues in early breast cancer: Retrospective follow-up study of 245 stage I and II cases. Modern Pathol 1991;4:466-474.[Medline]
-
Kallioniemi OP, Holli K, Visakorpi T et al. Association of C-erb B2 protein over-expression with high rate of cell proliferation, increased risk of visceral metastasis and poor long-term survival in breast cancer. Int J Cancer 1991;49:650-655.[Medline]
-
Clark GM, McGuire WL. Follow-up study of HER-2/neu amplification in primary breast cancer. Cancer Res 1991;51:944-948.[Abstract/Free Full Text]
-
Lovekin C, Ellis IO, Locker A et al. C-erb B2 oncoprotein expression in primary and advanced breast cancer. Br J Cancer 1991;63:439-443.[Medline]
-
McCann AH, DeDervan TA, O'Regan M et al. Prognostic significance of C-erb B2 and estrogen receptor status in human breast cancer. Cancer Res 1991;51:3296-3303.[Abstract/Free Full Text]
-
Dykens R, Corbett IP, Henry J et al. Long term survival in breast cancer related to overexpression of the C-erb B2 oncoprotein: an immunohistochemical study using monoclonal antibody NCL-CB11. J Pathol 1991;163:105-110.[Medline]
-
Rilke F, Colnaghi MI, Cascinelli N et al. Prognostic significance of HER-2/neu expression in breast cancer and its relationship to other prognostic factors. Int J Cancer 1991;49:44-49.[Medline]
-
Winstanley J, Cooke T, Murray GD et al. The long term prognostic significance of C-erb B2 in primary breast cancer. Br J Cancer 1991;63:447-450.[Medline]
-
O'Reilly SM, Barnes DM, Camplejohn RS et al. The relationship between C-erb B2 expression, and s-phase fraction in prognosis in breast cancer. Br J Cancer 1991;63:444-446.[Medline]
-
Paterson MC, Dietrich KD, Danyluk J et al. Correlation between C-erb B2 amplification and risk of recurrent disease in node-negative breast cancer. Cancer Res 1991;51:556-567.[Abstract/Free Full Text]
-
Toikkanen S, Helin H, Isola J et al. Prognostic significance of Her-2 oncoprotein expression in breast cancer: a 30-year follow up. J Clin Oncol 1992;10:1044-1048.[Abstract]
-
Molina R, Ciocca DR, Candon AK et al. Expression of HER-2/neu oncoprotein in breast cancer: a comparison of immunohistochemical and western blot techniques. Anticancer Res 1992;12:1965-1991.[Medline]
-
Noguchi M, Koyasaki M, Ohta N et al. c-erb B-2 oncoprotein expression versus internal mammary lymph node metastases as additional prognostic factors in patients with axillary lymph node-positive breast cancer. Cancer 1992;69:2953-2960.[Medline]
-
Allred DC, Clark GM, Tandon AK et al. HER-2/neu node-negative breast cancer: prognostic significance of overexpression influenced by the presence of in-situ carcinoma. J Clin Oncol 1992;10:599-605.[Abstract/Free Full Text]
-
Babiak J, Hugh J, Poppeme S. Significance of c-erb B-2 amplification in DNA aneuploidy. Analysis in 78 patients with node-negative breast cancer. Cancer 1992;70:770-776.[Medline]
-
Tiwari RK, Borgen PI, Wong GY et al. HER-2/neu amplification and overexpression in primary human breast cancer is associated with early metastasis. Anticancer Res 1992;12:419-426.[Medline]
-
Gusterson BA, Gelber RD, Goldhirsch A et al. Prognostic importance of C-erb B2 expression in breast cancer. J Clin Oncol 1992;10:1049-1056.[Abstract]
-
Bianchi S, Paglierani M, Zampi G et al. Prognostic significance of C-erb B2 expression in node negative breast cancer. Br J Cancer 1993;67:625-629.[Medline]
-
Press MF, Pike MC, Chazin VR et al. Her-2/neu expression in node-negative breast cancer: direct tissue quantification by computerized image analysis and association of overexpression with increased risk of recurrent disease. Cancer Res 1993;53:4960-4970.[Abstract/Free Full Text]
-
Seshadri R, Firgaira FA, Horsfall DJ et al. Clinical significance of Her-2/neu oncogene amplification in primary breast cancer. J Clin Oncol 1993;11:1936-1942.[Abstract/Free Full Text]
-
Descotes F, Pavy J-J, Adessi GL. Human breast cancer: correlation study between Her-2/neu amplification and prognostic factors in an unselected population. Anticancer Res 1993;13:119-124.[Medline]
-
Giai M, Roagna R, Ponzone R et al. Prognostic and predictive relevance of C-erb B2 and ras expression in node-positive and negative breast cancer. Anticancer Res 1994;14:1441-1450.[Medline]
-
Muss HB, Thor AD, Berry DA et al. Cerb-B2 expression and response to adjuvant therapy in women with node-positive early breast cancer. N Engl J Med 1994;330:1260-1266.[Abstract/Free Full Text]
-
Tetu B, Brisson J. Prognostic significance of Her-2/neu oncogene expression in node-positive breast cancer. The influence of the pattern of immunostaining and adjuvant therapy. Cancer 1994;73:2359-2365.[Medline]
-
Hartmann LC, Ingle JN, Wold LE et al. Prognostic value of CerbB2 overexpression in axillary lymph node-positive breast cancer. Results from a randomized adjuvant treatment protocol. Cancer 1994;74:2956-2963.[Medline]
-
Jacquemier J, Penault-Llorca P, Viens P et al. Breast cancer response to adjuvant chemotherapy in correlation with erb B2 and p53 expression. Anticancer Res 1994;14:2773-2778.[Medline]
-
Marks JR, Humphrey PA, Wu K at al. Overexpression of p53 and Her-2/neu proteins as prognostic markers in early stage breast cancer. Ann Surg 1994;219:332-341.[Medline]
-
Rosen PP, Lesser ML, Arroyo CD et al. Immunohistochemical detection of Her-2/neu expression in patients with axillary lymph node-negative breast carcinoma. A study of epidemiologic risk factors, histologic features and prognosis. Cancer 1995;75:1320-1326.[Medline]
-
Quenel N, Wafflart J, Bonichon F et al. The prognostic value of c-erbB2 in primary breast carcinomas: a study on 942 cases. Breast Cancer Res Treat 1995;35:283-291.[Medline]
-
Sundblad AS, Pellicer EM, Ricci L. Carcinoembryonic expression in stages I and II breast cancer; its relationship with clinicopathologic factors. Hum Pathol 1996;27:297-300.[Medline]
-
O'Malley FP, Saad Z, Kerkvliet N et al. The predictive power of semiquantitative immunohistochemical assessment of p53 and C-erbB2 in lymph node-negative breast cancer. Hum Pathol 1996;27:955-963.[Medline]
-
Hieken TJ, Mehta RR, Shilkaitis A et al. Her-2/neu and p53 expression in breast cancer: valid prognostic markers when assessed by direct immunoassay, but not by immunochemistry. Proc Annu Meet Am Soc Clin Oncol 1996;15:113a.
-
Xing W-R, Gilchrist KW, Harris CP et al. FISH detection of HER-2/neu oncogene amplification in early onset breast cancer. Breast Cancer Res Treat 1996;39:203-212.[Medline]
-
Dittadi R, Brazzale A, Pappagallo G et al. ErbB2 assay in breast cancer: possibly improved clinical information using a quantitative method. Anticancer Res 1997;17:1245-1247.[Medline]
-
Fernandez-Acenero MJ, Farina Gonzalez J, Arangoncillo Ballesteros P. Immunohistochemical expression of p53 and c-erbB-2 in breast carcinoma: relation with epidemiologic factors, histologic features and prognosis. Gen Diagn Pathol 1997;142:289-296.[Medline]
-
Eissa S, Khalifa A, el-Gharib A et al. Multivariate analysis of DNA ploidy, p53, c-erbB-2 proteins, EGFR, and steroid hormone receptors for short-term prognosis in breast cancer. Anticancer Res 1997;17:3091-3097.[Medline]
-
Charpin C, Garcia S, Bouvier C et al. c-erbB-2 oncoprotein detected by automated quantitative immunocytochemistry in breast carcinomas correlates with patients' overall and disease-free survival. Br J Cancer 1997;75:1667-1673.[Medline]
-
Press MJ, Bernstein L, Thomas PA et al. Her-2/neu gene amplification characterized by fluorescence in situ hybridization: poor prognosis in node-negative breast carcinomas. J Clin Oncol 1997;15:2894-2904.[Abstract]
-
Ross JS, Muraca PJ, Jaffe D et al. Multivariate analysis of prognostic factors in lymph node negative breast cancer. Mod Pathol 1998;11:26a.
-
Depowski PL, Brien TP, Sheehan CE et al. Prognostic significance of p34cdc2 cyclin dependent kinase and MIB1 overexpression, and HER-2/neu gene amplification detected by fluorescence in-situ hybridization in breast cancer. Mod Pathol 1998;11:18A.
-
Page DL. Prognosis and breast cancer. Recognition of lethal and favorable prognostic types. Am J Surg Pathol 1991;15:334-349.[Medline]
-
Porter-Jordan K, Lippman ME. Overview of the biologic markers in breast cancer. Hematol Oncol Clin North Am 1994;8:73-100.[Medline]
-
McGuire WL, Tandon AK, Allred DC et al. How to use prognostic factors in axillary node-negative breast cancer patients. J Natl Cancer Inst 1990;82:1006-1015.[Free Full Text]
-
Pauletti G, Godolphin W, Press MF et al. Detection and quantitation of HER-2/neu gene amplification in human breast cancer archival material using fluorescence in situ hybridization. Oncogene 1996;13:63-72.[Medline]
-
Sauter G, Feichter G, Torhorst J et al. Fluorescence in-situ hybridization for detecting ERBB-2 amplification in breast tumor fine needle aspiration biopsies. Acta Cytol 1996;40:164-173.[Medline]
-
Allred DC, Harvey JM, Berardo M et al. Prognostic and predictive factors in breast cancer by immunohistochemical analysis. Mod Pathol 1998;11:155-168.[Medline]
-
Jacobs TW, Prioleau JE, Stillman IE et al. Loss of tumor marker-immunostaining intensity on stored paraffin slides of breast cancer. J Natl Cancer Inst 1996;88:1054-1059.[Abstract/Free Full Text]
-
Penault-Llorca F, Adelaide J, Houvenaeghel G et al. Optimization of immunohistochemical detection of ERBB2 in human breast cancer: impact of fixation. J Pathol 1994;173:65-75.[Medline]
-
Busmanis I, Feleppa F, Jones A et al. Analysis of C-erb B2 expression using a panel of six commercially available antibodies. Pathol 1994;26:261-267.
-
Press MF, Hung G, Godolphin W et al. Sensitivity of Her-2/neu antibodies in archival tissue samples: potential source of error in immunohistochemical studies of oncogene expression. Cancer Res 1994;54:2771-2777.[Abstract/Free Full Text]
-
vanDiest PJ, vanDam P, Henzen-Logmans SC et al. A scoring system for immunohistochemical staining: consensus report of the Task Force for Basic Research of the EORTC-GCGC. J Clin Pathol 1997;50:801-804.[Free Full Text]
-
Lodato RF, Maguire HC, Greene MI et al. Immunohistochemical evaluation of cerb B2 oncogene expression in ductal carcinoma in situ and atypical ductal hyperplasia of the breast. Mod Pathol 1990;3:449-454.[Medline]
-
Allred DC, Clark GM, Molina R et al. Overexpression of Her-2/neu and its relationship with other prognostic factors changed during progression of in-situ to invasive breast cancer. Hum Pathol 1992;23:974-979.[Medline]
-
Zafrani B, Leroyer A, Fourquet A et al. Mammographically-detected ductal in-situ carcinoma of the breast analyzed with a new classification. Sem Diagn Pathol 1994;11:208-214.
-
Brower FT, Ahmed S, Tartter P et al. Prognostic variables in invasive breast cancer: Contribution of comedo versus non-comedo in-situ component. Ann Surg Oncol 1995;2:440-444.[Abstract]
-
Leal CB, Schmitt FC, Bento NJ et al. Ductal carcinoma in-situ of the breast. Histologic categorization and its relationship to ploidy and immunohistochemical expression of hormone receptors, p53 and C erb B-2 protein. Cancer 1995;75:2123-2131.[Medline]
-
Bobrow WLG, Happerfield LC, Gregory WM et al. Ductal carcinoma in-situ: assessment of necrosis in nuclear morphology and their association with biological markers. J Pathol 1995;176:333-341.[Medline]
-
DePotter CR, Schelhout AM, Verbeeck P et al. neu overexpression correlates with extent of disease in large cell ductal in situ carcinoma of the breast. Hum Pathol 1995;26:601-606.[Medline]
-
Inaji H, Koyama H, Motomura K et al. Differential distribution of erb B2 and pS2 proteins in ductal carcinoma in-situ of the breast. Breast Cancer Res Treat 1996;37:89-92.[Medline]
-
Albonico G, Querzoli P, Ferretti S et al. Biophenotypes of breast carcinoma in-situ defined by image analysis of biological parameters. Pathol Res Pract 1996;192:117-123.[Medline]
-
Bose S, Lesser ML, Norton L et al. Immunophenotype of intraductal carcinoma. Arch Pathol Lab Med 1996;120:81-85.[Medline]
-
Moreno A, Lloveras B, Figueras A et al. Ductal carcinoma in-situ of the breast: Correlation between histologic classification and biologic markers. Mod Pathol 1997;10:1088-1092.[Medline]
-
Mack L, Kerkzelit N, Doig G et al. Relationship of a new histological categorization of ductal carcinoma in-situ of the breast with size and the immunohistochemical expression of p53, C-erb B2, bcl2 and ki-67. Hum Pathol 1997;28:974-979.[Medline]
-
Porter PL, Garcia R, Moe R et al. cerb B2 oncogene protein in in-situ and invasive lobular breast neoplasia. Cancer 1991;68:331-334.[Medline]
-
Wolber RA, DuPuis BA, Wick MR. Expression of cerb B2 oncoprotein in mammary and extramammary Paget's disease. Am J Clin Pathol 1991;96:243-247.[Medline]
-
Lilleng R, Hagmar BM, Nesland JM. cerb B2 protein and neuroendocrine expression in intraductal carcinomas of the breast. Mod Pathol 1992;5:41-47.[Medline]
-
Yeh I-T, Keykhah S, Selig AM et al. Expression of erb B2 gene in the benign and proliferative breast tissue. Surg Pathol 1993;5:109-120.
-
Hanna W, Kahn HJ, Andrulis I et al. Distribution and patterns of staining of neu oncogene product in benign and malignant breast diseases. Mod Pathol 1990;3:455-461.[Medline]
-
Odagiri E, Kanda N, Jibiki K et al. Reduction of telomeric-linked cerb B2 gene amplification in human breast cancer, fibroadenoma, and gynecomastia. Relationship to histologic grade and clinical parameters. Cancer 1994;73:2978-2984.[Medline]
Top
Abstract
Introduction
