Immunocytochemical and biochemical analysis of epidermal growth factor receptor expression in human breast cancer tissues: relationship to estrogen receptor and lymphatic invasion

Anti-epidermal growth factor receptor-antibody therapy for treatment of breast cancer

Recent studies demonstrated that tumors overexpressing the epidermal growth factor receptor (EGF-R, erbB-1) are associated with poor clinical outcome. This led to the development of a variety of monoclonal antibodies targeting the extracellular domain of this receptor tyrosine kinase. The aim of our study was the evaluation of anti-EGF-R antibody EMD 55900 therapy for treatment of breast cancer. On the basis of 299 tumor specimens derived from breast cancer patients, we investigated EGF-R expression and generated a collective of primary xenotransplants in athymic nude mice. The animals received therapy in 2 treatment schedules to investigate the therapeutic response in early stages of tumor formation as well as on well established tumors. Using 6 different tumors with EGF-R expression levels between 10-300 fmol/mg total protein, we found a therapeutic effect when the EGF-R expression of the tumors was at least 40 fMol/mg. On the basis of these experimental data and our EGF-R expression analysis of breast cancer specimens, we conclude that up to 15% of breast cancer patients could benefit from this monotherapy with EMD 55900.

A functional screen for genes inducing epidermal growth factor autonomy of human mammary epithelial cells confirms the role of amphiregulin

To gain better understanding of the molecular alterations responsible for the aggressive growth potential of epidermal growth factor receptor (EGFR)-positive breast cancers, we utilized an expression cloning strategy to seek gene products that mediate the EGF-independent growth of human breast cancer cells. A retroviral cDNA expression library was constructed from the EGFR-positive SUM-149PT cell line, and transduced into growth factor-dependent human mammary epithelial (HME) cells. Recipient cells were functionally selected for their ability to proliferate in serum-free, EGF-free medium. Library cDNAs were recovered from EGF-independent colonies by PCR amplification or by biological rescue. Clone H55a#1 contained a library insert encoding amphiregulin. This EGFR ligand was able to confer EGF independence when transduced into HME cells. SUM-149PT and H55a#1 cells overexpressed amphiregulin transcripts, and secreted moderate EGF-like activity in conditioned media, indicating a possible autocrine loop. EGFR membrane levels and constitutive phosphorylation were consistent with this hypothesis, as well as the sensitivity of the cells to an ErbB-specific kinase inhibitor. Expression of the WT1 Wilms' tumor suppressor gene, a transcriptional activator of amphiregulin, did not parallel amphiregulin transcript levels, suggesting that another factor regulates amphiregulin in SUM-149PT. Our data confirm the importance of amphiregulin in the etiology of breast cancer.

M(R) 77 KDA factor derived from fibroblasts stimulates the invasion ability of breast-cancer cells

Breast-cancer cells frequently invade into the skin. However, few reports have described the mechanisms responsible for this invasion. In this study, we investigated the effects of skin fibroblasts on the invasion ability of breast-cancer cells, using a modification of Boyden's chamber method, and purified an invasion-stimulating factor from fibroblasts. Conditioned medium of skin fibroblasts, DF-1, significantly stimulated the invasion ability of breast-cancer cells, OCUB-1. The invasion-stimulating factor produced from skin fibroblasts was then partially purified and characterized. The soluble invasion-stimulating factor of fibroblasts was a protein of 77 kDa, as calculated by SDS-PAGE. Although TGF-alpha and bFGF stimulated the invasion of OCUB-1, no inhibition of the 77 kDa factor was achieved with neutralizing antibodies against TGF-alpha and bFGF. These findings suggest that the 77 kDa factor derived from skin fibroblasts might be unique, might play an important role in invasion to the skin and might explain the frequent skin invasion in breast carcinoma.

Vascular endothelial growth pattern of endochondral bone graft in the presence of demineralized intramembranous bone matrix--quantitative analysis

OBJECTIVE

To determine the timely ingrowth of new blood vessels of composite endochondral (EC) bone and demineralized bone matrix (DBM) prepared from intramembranous (IM) origin (EC-DBM(IM)) and to compare it with EC bone graft alone.

DESIGN

Thirty-two rabbits with 32 critical-size (10 x 5 mm), full-thickness bony defects in rabbit parietal bone were divided into two groups: composite EC-DBM(IM) group-implanted with composite autogenous EC bone and DBM(IM); EC bone group-implanted with EC bone alone. Two rabbits from each group were sacrificed-1, 2, 3, 4, 5, 6, 7, and 14 days after grafting. Neovascularization was assessed by immunohistochemical staining with antihuman angiogenesis-related endothelial cell antibodies (EN 7/44). Quantitative analysis of neovascularization, represented by percentage area of positive immunohistochemical staining, was performed on 320 sections of the experimental groups by a computer-assisted image analyzer.

RESULTS

Positive immunohistochemical staining was first identified on day 2 post grafting for the composite EC-DBM(IM) group in comparison with day 4 in the EC bone graft group. The composite EC-DBM(IM) bone graft group showed earlier and almost 100% more neovascularization when compared with the EC bone graft group.

CONCLUSION

DBM(IM) enhances healing and integration of EC bone graft by enhancing vascularization as well as increasing the amount of new blood vessels formed. In clinical cases in which EC autogenous bone is used to graft a large defect such as in cleft palate and craniofacial surgery, DBM(IM) should allow better integration and healing of the EC bone graft to the host bone.

Growth response of breast epithelial cells to estrogen is influenced by EGF

Estrogen-induced growth stimulation has not previously been demonstrated in estrogen receptor (ER) cDNA transfected human cell lines in contrast to breast cancer cell lines expressing endogenous ER. On the contrary, estrogen usually inhibits cell growth of ER transfected cell lines. Growth inhibition by estrogen has also been demonstrated in our cell line, F9, which is an ER transfected subline of HMT-3522 breast epithelial cells derived from fibrocystic disease and propagated in chemically defined medium. By omitting EGF in the medium, we have demonstrated not only an increased transcriptional activity of the ER but also--after an adaptation period--estrogen-dependent growth of the cells, and we have succeeded in establishing a new subline, S3B, that requires 17beta-estradiol (E2) for growth. This is the first example of a nonmalignant, human breast epithelial cell line which is dependent on estrogen for continued growth. The S3B cells express functional ER as measured by transcriptional activity. ER-E2 induced transcription was not inhibited by EGF as in F9 cells. We propose that a growth-stimulatory response of breast epithelial cells in vitro to E2 is dependent on an inactive or down-regulated EGF receptor signaling pathway and it is possible that the effect of estrogen on normal breast epithelium in vivo also is modulated by the EGFR.

Oestrogen receptor: a stable phenotype in breast cancer

Oestrogen receptor (ER) expression in breast cancer is regarded as a phenotype that may change during the natural history of the disease or during endocrine therapy. It has been suggested that in up to 70% of tumours that show acquired resistance the mechanism may be changed in ER status from positive to negative. This paper proposes an alternative hypothesis that ER expression in a stable phenotype in breast cancer. The paper reviews the literature on ER expression during the natural history of breast cancer in patients and also presents data on the effect of endocrine therapy on ER expression. If the alternative hypothesis is true it has important implications for treatment from chemoprevention to acquired endocrine resistance in advanced disease. Equally, if the hypothesis is true, attempts to develop laboratory models of endocrine resistance where ER-positive tumours become ER negative need to be re-evaluated.

Aberrant function of the Ras signal transduction pathway in human breast cancer

Although ras mutations are infrequent (approximately 5%) in breast cancers, there is considerable evidence that suggests that the pathways which Ras services may still be deregulated in breast cancer cells. The recent identification of many of the components of the Ras signal transduction pathway has defined a network of proto-oncogene proteins controlling diverse signaling events that regulate cell growth and differentiation. Consequently, mutations that perturb the function of any one component of this signal pathway may trigger the same oncogenic events as mutation of ras itself. Moreover, several Ras-related proteins have recently been demonstrated to possess the ability to trigger malignant transformation via signaling pathways shared with Ras proteins. Thus, it is possible that the aberrant function of Ras-related proteins may contribute to breast cancer development. Consequently, it is important not to dismiss the Ras pathway in the development of breast cancer merely because of the infrequent detection of mutations in ras itself, but rather to consider the influence of aberrations upstream or downstream of Ras and of certain Ras-related proteins in the development of breast cancer. Finally, the critical importance of components upstream and downstream of Ras provides additional targets for rational drug design approaches to block the aberrant function of Ras signaling in human tumors.

Immunohistochemical assay for epidermal growth factor receptor on paraffin-embedded sections: validation against ligand-binding assay and clinical relevance in breast cancer

Epidermal growth factor receptor (EGFR) has been the subject of much research since it was first described as a prognostic factor in breast cancer. The assay methods used and results obtained vary widely between studies. In this study 88 primary breast cancers were assayed for EGFR using a novel immunohistochemical assay performed on paraffin-embedded sections. The monoclonal antibody used was raised against purified, denatured EGFR, reacts with an epitope on the external domain and does not interfere with ligand binding. Twenty-two per cent of the tumours were EGFR positive using this assay. The results obtained were significantly correlated with those obtained by ligand-binding assay (r = 0.621, P = 0.011). The concordance rate was 82% (P < 0.001). The majority of discordant results could be explained by the presence of benign breast tissue and other non-malignant elements which could be seen to express EGFR on the immunohistochemical assay and were excluded from the score for this, but would be incorporated into ligand-binding assay results. The well-established inverse relationship between EGFR (as measured by this assay) and oestrogen receptor (ER) was seen (chi 2 = 24.9, P < 0.0001). In addition, in this exploratory study on a limited tumour set, EGFR was a significant adverse prognostic factor (on univariate but not multivariate analysis) for both relapse-free survival (P = 0.02) and overall survival (P = 0.03) when measured by this immunohistochemical assay, but was not significant when measured by ligand-binding assay.

Expression of epidermal growth factor receptor messenger RNA in human colorectal carcinomas assessed by non-radioactive in-situ hybridization

No consensus as to the involvement of the epidermal growth factor receptor (EGF-R) in colorectal carcinomas has yet been attained, although they are assumed to play a role in the metastasis to lymph nodes and recurrence of breast carcinoma and bladder carcinoma invasion. Knowing that Dukes' classification of colorectal carcinoma is closely related to prognosis, we examined whether there is a correlation between Dukes' classification and the expression of EGF-R in colorectal carcinoma. If there is a positive correlation, the involvement of EGF-R in the processes may be assumed and the expression of EGF-R may be used as a marker of their prognosis. To this end, the expression of EGF-R mRNA and protein by non-radioactive in-situ hybridization and immunohistochemistry, respectively, were determined on histological preparations of formalin-fixed paraffin-embedded colorectal surgical specimens. In 30 cases of colorectal carcinoma examined, mRNA and/or protein was detected in 33% (two of six) of Dukes' A, in 40% (four of 10) of Dukes' B, in 36% (four of 11) of Dukes' C, in 33% (one of three) of Dukes' D and in 0% of normal colon epithelial cells. Thus, there was no positive correlation between the Dukes' classification and the expression of EGF-R. It is concluded that the expression of EGF-R in colorectal carcinoma is not a promising marker of prognosis. However, the role of EGF-R in EGF-R positive tumours remains to be examined.

Raf-1 protein expression in human breast cancer cells

BACKGROUND

The Raf-1 kinase, a 72-kDa cytoplasmic serine-threonine kinase, plays a central role as a second messenger in signal transduction. After ligand binding to a variety of transmembrane tyrosine kinase growth factor receptors including epidermal growth factor (EGF) receptor, the 72-kDa kinase is activated through phosphorylation to a 74-kDa phosphoprotein. The Raf-1 kinase is constitutively activated in many transformed cells either directly, by mutations within its amino-terminus regulatory region, or indirectly, due to overstimulation by autocrine growth factors or activated proximal oncogenes. The role of Raf-1 kinase in breast cancer has not been studied.

METHODS

To investigate the role of Raf-1 kinase expression and its activation in breast cancer, we studied three human breast cancer cell lines expressing varying amounts of EGF receptor to determine the level of Raf-1 protein and the proportion expressed in the higher molecular weight form. Effects of serum starvation and stimulation with EGF on the Raf-1 protein were studied in T47D, BT474, and MDA-MB231 cells by precipitation of cell lysates with an anti-Raf-1 antibody followed by immunoblotting. [3H]Thymidine incorporation by these cells after EGF stimulation was also determined as a measure of DNA synthesis.

RESULTS

In all three breast cancer cell lines studied, the Raf-1 protein was identified in a 70- and a 74-kDa form. The level of Raf-1 was similar in all three cell lines and appeared unrelated to EGF receptor expression on the cell surface. The majority of the protein was found in the 74-kDa form even after serum starvation. A minor shift from the lower to higher molecular weight form of Raf-1 was apparent in cells treated with EGF, and increased [3H] thymidine incorporation could be demonstrated in two of the cell lines after EGF stimulation.

CONCLUSION

Baseline expression of the 74-kDa or activated form of the Raf-1 kinase appeared to be elevated in the breast cancer cells studied, indicating constitutive activation. Further investigation into the role of Raf-1 protein in the pathogenesis of breast cancer is indicated.

Dual immunocytochemical analysis of oestrogen and epidermal growth factor receptors in human breast cancer

Recent studies have demonstrated a consistent inverse relationship between oestrogen receptor (ER) and epidermal growth factor receptor (EGFR) levels in female human breast cancer. Serial cross-section studies have suggested that separate populations of ER+/EGFR- and ER-/EGFR+ cancer cells exist in tumours deemed by immunocytochemical assay (ICA) to be positive for both. We have developed a dual ICA that is able to stain for both ER and EGFR on a single 5 microns frozen section sample of breast tissue. Twenty-two samples of female human breast cancer tissue that exhibited positivity for ER and EGFR by ER-ICA using the H222 monoclonal antibody and EGFR-ICA using the EGFR1 monoclonal antibody underwent the dual ICA. There was a significant correlation in receptor positivity between the single and dual assays for both ER (rs = 0.801, P < 0.001) and EGFR (rs = 0.831, P < 0.001). Individual cancer cells exhibited one of three staining patterns: nuclear staining only (ER+/EGFR-), membrane-associated and cytoplasmic staining only (ER-/EGFR+) or no staining (ER-/EGFR-). No cancer cells exhibited both nuclear and membrane/cytoplasmic staining. This is the first description of a simultaneous dual immunocytochemical assay system for ER and EGFR in clinical breast cancer specimens. The results suggest that ER and EGFR expression are mutually exclusive within an individual breast cancer cell in vivo with separate populations of ER+/EGFR- cells, ER-/EGFR+ cells and ER-/EGFR- cells coexisting.

Comparison of radioligand assay and immunostaining for epidermal growth factor receptor in human breast cancer

Epidermal growth factor (EGF) receptor status is a useful prognostic indicator in women with breast cancer. Lack of standardization and correlation of methodology for the detection of EGF receptor has hampered its further evaluation. EGF receptor status was ascertained by immunohistochemistry and radioligand assay in 120 breast cancers. Of 52 tumours negative for EGF receptor on radioligand assay, 47 were negative on immunohistochemistry and, of 68 tumours positive for the receptor on assay, 52 were positive on immunohistochemistry. If the more widely evaluated radioligand assay is assumed to be the 'gold standard', immunohistochemistry has a sensitivity of 81 per cent and a specificity of 91 per cent.

A dual immunocytochemical assay for oestrogen and epidermal growth factor receptors in tumour cell lines

A new dual immunocytochemical assay for oestrogen receptor (ER) and epidermal growth factor receptor (EGFR) has been developed. It has been tested in a variety of conditions using cell culture lines and the results correlate well with those obtained from single immunocytochemical assays. MCF-7 and A431 cells and a mixture of the two types of cell were assessed immunocytochemically for ER and EGFR. ER showed immunopositivity of 30% in MCF-7 cells, 10% in the mixture and 0% in A431 cells. EGFR demonstrated immunopositivity of 0% in MCF-7 cells, 70% in the mixture and 100% in A431 cells. Dual immunocytochemical assays using anti-ER followed by anti-EGFR monoclonal antibodies on single histological sections showed similar reactivity to the single assays. Three staining patterns were seen in the mixture: ER+/EGFR- (MCF-7 cells), ER-/EGFR- (MCF-7 cells) and ER-/EGFR+ (A431 cells). ZR-75-1 and MDA-MB-231 cells and their retrovirally transfected counterparts ZR/HERc and MDA/HEGO cells were then analysed. The dual assay revealed the fourth phenotype (ER+/EGFR+) in 40% of ZR/HERc cells and in 10% of MDA/HEGO cells. This is the first description of a dual immunocytochemical assay system for ER and EGFR on single 5 microns frozen section samples. Studies are now underway assessing breast carcinoma sections which may allow investigation of the clonality of human breast cancer.

Growth inhibition of xenotransplanted human carcinomas by a monoclonal antibody directed against the epidermal growth factor receptor

In the athymic nude mice model with xenotransplanted human carcinomas, the effect of a monoclonal antibody (MAb 425), directed against the human epidermal growth factor (EGFR), on tumour growth was studied. Five different solid human breast carcinomas and one vulvar epidermoid cancer cell line (A431) were transplanted in nude mice, and treated with MAb 425 2.2 mg intraperitoneally (i.p.) on day 7 post-transplantation. Tumours with EGFR concentrations of > or = 16 fmol/mg soluble cytosolic protein showed growth inhibition, whereas the growth pattern of EGFR-negative tumours was unaffected. Variation of MAb 425 dosage (1.1 versus 2.2 mg) revealed no difference in the growth inhibiting effect. Different application schedules (application on day 0, 12 or 26) showed different onsets and durations of tumour growth inhibition. Repeated application (1.1 mg, day 0 and 12) was followed by a prolonged inhibitory effect. Our results suggest that growth inhibition of EGFR-positive tumours by MAb 425 may lead to an additional treatment option for patients with EGFR-positive cancer.

The prognostic value of epidermal growth factor receptor (EGFR) in breast cancer patients. Results of a follow-up study on 149 patients

The expression of epidermal growth factor receptor (EGFR) in breast cancer patients was correlated to the disease-free survival. The study included 149 breast cancer patients. The mean follow-up time was 4.2 years. There was an inverse correlation between EGFR and estrogen receptor (p < 0.003) and progesterone receptor (p < 0.013). Subdivision of EGFR showed that patients with EGFR > or = 0.60%, regarded as EGFR positive, had a worse prognosis than patients with EGFR binding < 0.60%, regarded as EGFR negative (p = 0.004). In the ER negative group, EGFR positive patients had a shorter relapse-free time than patients with EGFR negative cancer (p < 0.009). The same subdivision among ER positive patients showed no statistically significant difference.

Role of epidermal growth factor receptor expression in primary breast cancer: results of a biochemical study and an immunocytochemical study

We have conducted two series of studies, a biochemical study and an immunocytochemical study, to investigate the role of epidermal growth factor receptor (EGFR) expression in primary breast cancer patients. In the biochemical study, a consecutive 115 patients were included and EGFR was measured by a competitive binding assay with multipoint Scatchard analysis. In the immunocytochemical study comprising 126 patients, EGFR status was determined by immunostaining with anti-EGFR antibody EGFR1. Several agreements were found from these two studies. EGFR status was inversely correlated with estrogen receptor (ER) status. No significant correlation was found between EGFR status and tumor size, nodal metastases, or the expression of c-erbB-2 protein. Ki-67 immunoreactivity, a cellular proliferation marker, was enhanced in EGFR positive tumors over EGFR negative tumors, suggesting a linkage of EGFR expression to cellular proliferative activity. Post-operative follow up showed that relapse-free survival for EGFR positive patients was significantly worse than that for EGFR negative patients, particularly in node-positive patients. Multivariate analysis demonstrated a significance of EGFR status as an independent prognostic indicator in primary breast cancer. The group expressing EGFR and c-erbB-2 protein indicated a particularly high risk for relapse.

Effects of lymphocytes and fibroblasts on the growth of human mammary carcinoma cells studied in short-term primary cultures

Breast carcinomas commonly contain varying amounts of fibrous stroma and infiltrates of lymphoid cells. Dickson and Lippman (Endocrine Rev., 8,29, 1987) have proposed a model of growth regulation in breast cancer involving interactions between stroma and carcinoma cells. This model is based on results obtained with established cell lines. In an effort to bring experimentation closer to the clinical situation we have used short-term primary cultures from human breast cancer in co-cultures with lymphocytes and fibroblasts. Cultures were established in a chemically defined serum-free medium (CDM3). Cell types were characterized on the basis of live morphology and expression of vimentin and keratin 18. A semi-quantitative system was developed for measuring growth of epithelial cells, thus defining two indices: maximal growth index (GI-max) and growth rate (GR). Moderate-to-good growth was obtained from 34 out of 46 carcinoma samples (74%) and 30 out of 38 parallel samples of non-cancerous tissue (79%). Success in culture was negatively correlated with the amount of hard stroma but unrelated to age of patient or clinical status. Malignant epithelium was clearly identified in 12 out of 34 (35%) carcinoma samples. For the evaluation of responses of epithelial cells in co-cultures, the cultures from each sample were ranked according to GI-max.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermal growth factor receptor immunohistochemistry in different histological types of infiltrating breast carcinoma

AIMS

To determine the immunohistochemical expression of epidermal growth factor receptor (EGF-R) in high grade, intermediate, and low grade tumours.

METHODS

Specimens from 931 breast carcinomas were partly formalin fixed and paraffin wax embedded, to classify cases, and partly frozen in liquid nitrogen, cryostat sectioned, and immunostained using two monoclonal antibodies from clone 455 and 528 to demonstrate EGF-R positive cells. An avidin-biotin complex and peroxidase method was used after incubation with biotinylated anti-mouse antibody; colour was developed using a diaiminobenzidine solution.

RESULTS

Low grade carcinomas seldom expressed EGF-R (n = 3) compared with 106 high grade infiltrating ductal carcinomas: EGF-R positive cases were much less common in infiltrating lobular than in infiltrating ductal carcinoma. Medullary carcinomas did not differ from infiltrating ductal carcinomas.

CONCLUSIONS

The very low incidence of EGF-R positive cases in the "special type" group of breast carcinomas with a good prognosis is in line with the absence of the homologous c-erbB-2 and p53 oncoproteins, and the rarity of highly proliferating and oestrogen/progesterone negative cases. EGF-R expression in infiltrating lobular carcinoma was in keeping with the intermediate behaviour of this kind of tumour. EGF-R expression in cases of pure medullary carcinoma is the same as that of high grade tumours.

Tumor angiogenesis is an independent prognostic indicator in primary breast carcinoma

Clinical importance of tumor angiogenesis, especially its significance as a prognostic indicator, was examined in 125 primary breast-cancer patients. The grade of neovascularization was assessed by the vessel density which was obtained by immunocytochemical staining for factor VIII antigen. Post-operative survey demonstrated that the vessel density is a statistically significant predictor of relapse-free survival (median follow-up period: 62 months). Patients with over 100 counts of factor-VIII antigen-positive cells per 200 x field in the most active areas of neovascularization showed significantly poorer prognosis than those with less than 100 counts. The prognostic value of the vessel density was also confirmed by another evaluation method using immunocytochemical staining to CD-31 which is a platelet/endothelial cell adhesion molecule. A significant difference in relapse-free survival rate was shown between patients having higher counts of CD-31 positive cells and those having lower counts. Breakdown analysis stratified by nodal status showed that the vessel density was a significant prognostic indicator in node-negative and node-positive patients. Multivariate analysis indicated that the vessel density is an independent prognostic indicator in primary breast-cancer patients.

Prognostic relevance of epidermal growth factor receptor (EGF-R) and c-neu/erbB2 expression in glioblastomas (GBMs)

Seventeen untreated primary adult glioblastomas were analyzed using immunocytochemistry for the expression of EGF-R, c-neu/erbB2, TGF-alpha, and phosphotyrosine. Patients were divided by median survival into long-term or short-term survivors (LTS, N = 10, median > 4 years; versus STS, N = 7, median 61 weeks). There were no significant differences between the two groups in terms of age, extent of resection, post-operative Karnofsky status, or treatment. Diagnostic sections from each tumor were stained with antibodies to EGF-R, c-neu/erbB2, TGF-alpha and phosphotyrosine. Double-labelling for TGF-alpha and EGF-R was also performed. All 10/10 LTS were considered to be EGF-R negative/scant, while 4/7 STS were EGF-R positive. EGF-R negativity significantly correlated with long-term survival. The differences in c-neu/erbB2 expression did not reach significance. However, 4/7 STS were positive for both proteins and 76% of the 17 cases were either double negative or positive for EGF-R and c-neu/erbB2. TGF-alpha and phosphotyrosine were frequently expressed, but neither were prognostic. Recurrent tumors were studied in 7 STS. EGF-R expression was increased in 4/7 of these cases and c-neu/erbB2 was increased in all 7 cases, compared to the pretreatment baselines. Increased expression of these proteins in glioblastomas may be associated with aggressive clinical behavior and treatment resistance.

Epidermal growth factor receptor in breast cancer: correlation of quantitative immunocytochemical assays to prognostic factors

Immunocytochemical assays for EGFR were performed on frozen sections from breast carcinomas (n = 209). Results were evaluated by computer assisted image analysis to accurately define the percentage of immunostained surface and the mean optical densities. Thirty seven percent (n = 77/209) of the tumors were EGFR positive, but about one third of them were faintly reactive (35%). No significant relationship was observed between EGFR tumor content and patient age, tumor size, histological type, histoprognostic grade, or axillary lymph node status. A negative correlation was observed with the results of estrogen receptor immunocytochemical assays and a positive correlation with immunodetectable cathepsin D and Ki 67 antigen evaluated according the same method. No correlation was found with HER-2/neu protein, aneuploidy, nucleolar organizor region distribution, and nuclear morphometry, also assessed by image analysis. These results suggest that immunocytochemical assays assessed on frozen sections and evaluated by image analysis are suitable for current and standardized evaluation of EGFR which has been previously documented as a prognostic indicator in breast carcinomas.

Prognostic significance of co-expression of c-erbB-2 oncoprotein and epidermal growth factor receptor in breast cancer patients

The expression of c-erbB-2 oncoprotein and epidermal growth factor receptor (EGFR) was examined by immunocytochemical and radioreceptor assays in 115 patients with primary breast cancer. In 48 of 115 patients (42%), the assays were found to be positive for the expression of c-erbB-2 oncoprotein, and, in 44 of 115 (35%) patients, the assays were positive for the expression of EGFR. There was no correlation between the expression of c-erbB-2 oncoprotein and EGFR. Clinical survey demonstrated that both c-erbB-2 oncoprotein expression and EGFR expression have independent prognostic values. Furthermore, when patients were divided into three groups on the basis of the expression of both c-erbB-2 oncoprotein and EGFR, those who were found to be positive for the expression of both c-erbB-2 oncoprotein and EGFR showed a worse prognosis than other groups. These results suggest that the combination of the expression of both c-erbB-2 oncoprotein and EGFR may be important in selecting patients who have a poor prognosis.

Additive effects of c-erbB-2, c-Ha-ras, and transforming growth factor-alpha genes on in vitro transformation of human mammary epithelial cells

MCF-10A cells are a spontaneously immortalized untransformed human mammary epithelial cell line. We have previously shown that overexpression of a human point-mutated c-Ha-ras proto-oncogene, the rat c-neu (c-erbB-2) proto-oncogene, or the human transforming growth factor-alpha (TGF-alpha) gene in MCF-10A cells leads to in vitro transformation of such cells. To ascertain whether the introduction of two of these genes into MCF-10A human mammary epithelial cells induces a completely tumorigenic phenotype, we infected MCF-10A Ha-ras and MCF-10A TGF-alpha cells with a recombinant retroviral vector containing the human c-erbB-2 proto-oncogene and the hygromycin-resistance gene. Ten MCF-10A TGF-alpha/c-erbB-2 (MCF-10A TE) and 10 MCF-10A Ha-ras/c-erbB-2 (MCF-10A HE) hygromycin-resistant clones were randomly selected and expanded into cell lines. MCF-10A TE and MCF-10A HE clones expressed a 10-fold to 40-fold increase in p185 erbB-2 protein levels compared with parental uninfected cells. These cells exhibited a fourfold increase in their growth rate in serum-free medium and showed a strongly reduced mitogenic response to exogenous epidermal growth factor or TGF-alpha compared with MCF-10A cells. Moreover, both MCF-10A TE and MCF-10A HE clones exhibited a fivefold to 20-fold higher cloning efficiency in soft agar than MCF-10A Ha-ras, MCF-10A c-erbB-2, or MCF-10A TGF-alpha clones. However, neither MCF-10A TE nor MCF-10A HE cells were able to grow as tumors in vivo when they were injected into nude mice. These results suggest that c-Ha-ras, c-erbB-2, and TGF-alpha genes have an additive effect on the in vitro transformation of an immortalized human mammary epithelial cell line, but that additional genetic changes such as activation of other proto-oncogenes or inactivation of a tumor suppressor gene may be necessary to elicit a fully tumorigenic phenotype.

Epidermal growth factor receptor in breast cancer: storage conditions affecting measurement, and relationship to steroid receptors

This study investigates the effect of freezing and storage of tissue and subcellular fractions on the measurement of epidermal growth factor receptors (EGF-r); compares competition binding and single saturating dose assays (SSD) for quantitating EGF-r levels; investigates several tissues as potential quality control; and examines the relationship between EGF-r and hormone receptor expression in human breast cancers. Mouse and calf uterine cell membranes were preferred sources of quality control tissue with similar levels of high affinity EGF-r to human breast cancer tissue (less than 150-200 fmol/mg membrane protein). Studies using pooled mouse uterine tissues indicated a loss of 40% in EGF-r activity following a single-20 degrees C freeze/thaw cycle, while a breast cancer tissue showed a 75% loss, independent of storage temperature (liquid nitrogen, -70 degrees C, -20 degrees C). A single freeze/thaw cycle of mouse uterine broken cell pellets (nuclei plus membrane fraction) again indicated a loss of EGF-r irrespective of storage temperature (43% loss at -70 degrees C, 52% loss at -20 degrees C). In most cases irrespective of the tissue type or tissue fraction being stored, the length of storage had little impact on the extent of the loss in activity. A second freeze/thaw cycle of intact tissue, or freezing of broken cell pellets from a previously-frozen tissue, led to a further major or total loss of the remaining EGF-r. Overall these results are commensurate with the published effects of freezing and storage on estrogen receptor measurement. In addition, our studies suggest that the most suitable procedure for assaying frozen breast cancer specimens for EGF-r levels in conjunction with steroid receptor quantitation is to prepare and assay both cytosol and membrane fractions for their respective receptor content without further storage. A concordance of 86% was found in 44 breast cancers assayed for EGF-4 by saturation analysis and SSD. Statistically significant inverse relationships were found between EGF-r and estrogen and progesterone receptor levels in the study of approximately 350 breast cancer patients. No association was found with tumor stage or diameter, axillary node involvement, or patient age.

Immunocytochemistry and in situ hybridisation of epidermal growth factor receptor and relation to prognostic factors in breast cancer

The breast tumour distribution of epidermal growth factor receptor (EGFR) was studied in 193 patients with primary breast cancer by immunocytochemistry on frozen sections. EGFR was correlated (P = 0.0009) with growth fraction assessed by Ki-67, and negatively correlated with oestrogen receptor (ER, P = 0.0001) and progesterone receptor (PR, P = 0.0001) status. In 47 patients, in-situ hybridisation for EGFR mRNA showed good agreement with the immunocytochemically assessed EGFR protein. There were, however, several tumours in which EGFR mRNA could be detected in the absence of EGFR protein and there were differences between the ER and PR status of those tumours in which translation of EGFR mRNA was not seen. The cause of these differences is unclear, but these findings may represent a clue as to the differential control of breast cancer cell receptors.

Epidermal growth factor receptors in human breast cancer: a plea for standardisation of assay methodology

In a prospective study 200 primary human breast cancer specimens were analysed for epidermal growth factor receptor (EGFR) content by means of a multiple point ligand binding assay, proposed by the EORTC Receptor Study Group to be the standard EGFR assay. In 54% of the tumours the presence of saturable high affinity binding sites for epidermal growth factor could be demonstrated. The median EGFR level was 34 fmol/mg of membrane protein, the median Kd 0.50 nmd. Univariate analysis of the EGFR data stratified according to patient age, menopausal status, tumour size, axillary lymph node status, histological tumour type, tumour differentiation grade or the tumours' steroid hormone receptor status showed EGFR to be positively associated with younger age (P = 0.03), tumour dedifferentiation (P = 0.04) and steroid hormone receptor negativity (P less than 0.001). No association between EGFR and menopausal status, tumour size, axillary lymphnode status or histological tumour type could be demonstrated.

Epidermal growth factor receptor expression as a prognostic indicator in breast cancer

The significance of epidermal growth factor receptor (EGFR) status as a prognostic indicator was investigated by a competitive binding assay in 135 primary breast cancer patients. 55 patients (41%) were EGFR positive and EGFR status was negatively correlated with oestrogen receptor (ER) status (P less than 0.01). 5-year postoperative follow-up showed that relapse-free survival for EGFR positive patients was significantly worse than that for EGFR negative patients (P less than 0.05). There was no difference between the two groups in tumour size, axillary node involvement, age and menopausal status. Analysis by axillary node status demonstrated the poor prognosis of the EGFR positive group in node positive patients. As yet, no difference in prognosis has been seen in node negative patients. A higher frequency of haematopoietic relapse was observed in EGFR positive patients. Simultaneous or sequential EGFR measurements in primary tumour and metastatic sites of 34 patients showed that expression of EGFR was more enhanced in metastatic sites.

Clinical significance of the expression of epidermal growth factor and its receptor in esophageal cancer

The epidermal growth factor receptor (EGFR) level in 56 esophageal cancer tissues was measured by 125I-EGF binding assay to elucidate its role in tumor progression. The survival rate of patients with high EGFR level (more than 50 fmol/mg protein) was significantly lower than that of patients with low EGFR level (less than 50 fmol/mg protein, P less than 0.01), although a correlation between EGFR level and the pathologic findings was not observed. The expression of EGF was examined immunohistochemically using anti-EGF monoclonal antibody in 100 esophageal cancer tissues; EGF-positive tumor cells were detected in 92.0%. The immunoreactivity of EGF was classified arbitrarily into four grades according to the number of stained tumor cells. The expression of EGF significantly correlated with the differentiation of esophageal squamous cell carcinoma (P less than 0.01, by chi-square test). The survival rate of patients with high EGF immunoreactivity (Grade 2 or 3) was much lower than in those with lower grade (0 or 1) tumors, (P less than 0.01). Patients with both high EGFR level and EGF immunoreactivity had a much worse prognosis than if both were low. Furthermore, the mitotic index was higher in groups with both high EGFR and EGF than if both were low (16.39 +/- 5.35 versus 6.90 +/- 3.31). These results suggest that EGF and EGFR in the autocrine system may play an important role in tumor progression in esophageal cancer and their expression could be of prognostic significance.

Medical management of early-stage breast cancer

With improved screening and education, a greater proportion of breast cancer is detected at an early stage. Although the prognosis for many of these patients is excellent following definitive local therapy alone, some subsets of node-negative patients have a 30% chance of eventually developing metastatic disease that will be incurable with current therapy. Thus, an increasing proportion of early-stage patients are being offered some form of adjuvant therapy, with the expectation of improved relapse-free survival, and possibly improved overall survival. Efforts have been made to base the selection of patients for adjuvant therapy on specific prognostic factors. Meanwhile, the scope and complexity of putative prognostic factors continues to widen, and now includes such items as the presence of occult microscopic metastases, DNA ploidy and proliferative fraction, cytogenetic abnormalities, oncogene expression, growth factor receptors, and expression of hormonally regulated proteins. In addition, there is now a considerable range of options with regard to the composition, dose intensity, and sequence of multimodality therapy. Data regarding the classification, significance, and interpretation of prognostic factors is reviewed together with the development, current status, and recommendations regarding adjuvant therapy for patients with early-stage breast cancer. For 1991, the National Cancer Institute (NCI) has estimated that 175,000 new cases of breast cancer will be diagnosed in American women. It is also estimated that 44,500 women will die of breast cancer. Unfortunately, the age-adjusted death rate from breast cancer has shown no overall change from 1930 through 1987. However, effective screening techniques continue to identify an increasing percentage of early-stage tumors, which should exceed 50% of all new tumors in 1991. Ultimately, our understanding of environmental and genetic risk factors may identify new ways to reduce the impact of this disease. In the interim, development and application of effective systemic adjuvant chemotherapy and hormonal therapy has become increasingly important. There is no question that a greater proportion of patients with less extensive disease are now being offered some form of adjuvant therapy. Meanwhile, selection of patients for adjuvant therapy, and choice among specific adjuvant regimens, has remained controversial. Analysis of multiple prognostic factors is performed not only in the context of cooperative investigational trials, but more often in the offices of individual physicians caring for individual patients. Tumor biopsies can now be routinely sent to specialized laboratories for performance of complex assays with potential prognostic information, although interpretation of these results with reference to a specific patient is often uncertain.(ABSTRACT TRUNCATED AT 400 WORDS)

Clinical significance of the expression of epidermal growth factor and its receptor in esophageal cancer

The epidermal growth factor receptor (EGFR) level in 56 esophageal cancer tissues was measured by 125I-EGF binding assay to elucidate its role in tumor progression. The survival rate of patients with high EGFR level (more than 50 fmol/mg protein) was significantly lower than that of patients with low EGFR level (less than 50 fmol/mg protein, P less than 0.01), although a correlation between EGFR level and the pathologic findings was not observed. The expression of EGF was examined immunohistochemically using anti-EGF monoclonal antibody in 100 esophageal cancer tissues; EGF-positive tumor cells were detected in 92.0%. The immunoreactivity of EGF was classified arbitrarily into four grades according to the number of stained tumor cells. The expression of EGF significantly correlated with the differentiation of esophageal squamous cell carcinoma (P less than 0.01, by chi-square test). The survival rate of patients with high EGF immunoreactivity (Grade 2 or 3) was much lower than in those with lower grade (0 or 1) tumors, (P less than 0.01). Patients with both high EGFR level and EGF immunoreactivity had a much worse prognosis than if both were low. Furthermore, the mitotic index was higher in groups with both high EGFR and EGF than if both were low (16.39 +/- 5.35 versus 6.90 +/- 3.31). These results suggest that EGF and EGFR in the autocrine system may play an important role in tumor progression in esophageal cancer and their expression could be of prognostic significance.

Evidence of an EGF/TGE-alpha--independent pathway for estrogen-regulated cell proliferation

To elucidate the relationship between epidermal growth factor (EGF)/transforming growth factor (TGF-alpha) and estradiol-17 beta (E) in cell proliferation, we examined their effects on the breast cancer cell line, CAMA-1. While E was able to consistently induce cell proliferation under a variety of experimental conditions, EGF/TGF-alpha was without effect. Despite the presence of the receptor (EGFR) gene, mature EGFR protein and mRNA were not detected by radioreceptor assay, 35S Met-labelling, and the Intron Differential RNA/PCR method under conditions in which cells remain responsive to E. Furthermore, TGF-alpha is not an autocrine factor in CAMA-1 cells. We demonstrated unequivocally that EGF/TGF-alpha interaction with EGFR is not an obligatory event in mediating estrogen-stimulated cell proliferation.

Quantitative assay of epidermal growth factor receptor in human squamous cell carcinomas of the oral region by an avidin-biotin method

A quantitative assay method for epidermal growth factor receptors (EGFRs) of human tumor tissues was established, based on enzyme-labeled avidin-biotin (LAB) interaction with anti-human EGFR monoclonal antibody 528IgG. A standard calibration curve for EGFR estimation in human tumor tissues was obtained with A431#8 cells cloned from A431 human epidermoid carcinoma cell line. The coefficient of variance for the standard curve was below 35% in the application to tumor tissues from nude mice implanted with human tumor cell lines. The minimum tissue amount required for the quantitative assay was around 0.1 g (wet weight). Using the LAB method, the correlation between the level of EGFR number and tumor malignancy was examined for 14 human squamous cell carcinomas (SCCs) from the oral region. Seven of the SCCs showed a more than two-fold higher EGFR number compared to normal gingival tissues. Three highly aggressive carcinomas with poor prognosis possessed five to ten times higher levels of EGFR number than normal tissues. The elevated EGFR level in the SCCs seems to correlate to increasing tumor size and the stage of SCCs as clinically classified according to the 1987 UICC TNM system.

Expression of epidermal growth factor receptor in normal colorectal mucosa, adenoma, and carcinoma

Using the monoclonal antibody EGF-R1, the expression of epidermal growth factor receptor (EGFR) was investigated immunohistochemically in normal colonic mucosa distant from and adjacent to colonic neoplasms, in 25 adenomas and in 144 unselected colorectal carcinomas. EGFR expression was an inconsistent phenomenon in each of these conditions. It was not expressed in 23/44 non-neoplastic mucosa specimens distant from and in 26/44 mucosae adjacent to colon tumours; 15/25 adenomas and 71 (49.3%) of the carcinomas failed to contain detectable amounts of EGFR. In contrast, large amounts of EGFR were found in 4 non-neoplastic mucosae at both locations, in 3 adenomas and in 11 (7.6%) carcinomas. The remaining cases showed complex patterns of EGFR-expression. In comparing mucosae close to and distant from a colonic tumour, only minor differences in EGFR content were observed. The intra-individual comparison of the mode of EGFR expression in non-neoplastic and neoplastic epithelium revealed an overexpression of EGFR in carcinomas in about one third of the 44 cases examined. One third showed no obvious differences, and one third showed lower levels of EGFR expression within the tumour. We conclude that the mode of EGFR expression in normal and neoplastic colon epithelium is variable and reflective of inter-individual constitutive differences rather than of abnormalities in gene regulation. Statistical analysis failed to reveal correlations between the mode of EGFR expression and tumour grade, type or Dukes stage.

Relationship between epidermal growth factor receptor status and various prognostic factors in human breast cancer

Relationship between epidermal growth factor receptor (EGFR) status and various prognostic factors was investigated in 91 human breast cancer tissues. Epidermal growth factor receptor was measured by biochemical competitive binding assay using iodine 125 epidermal growth factor (125I)-EGF. The EGFR status was not correlated with axillary lymph node involvement, tumor size, stage, and histologic type, but significantly correlated with histologic grading (P less than 0.05) and lymphatic invasion (P less than 0.01). Between EGFR and estrogen receptor (ER) status, a clear inverse relationship was observed (P less than 0.01). The Ki-67-positive stained cell rate, which reveals the proportion of cycling cells, was significantly higher in EGFR-positive tumor tissues than in EGFR-negative cases. Furthermore, preliminary postoperative survey demonstrated a high tendency of recurrence rate of patients with EGFR-positive tumors as compared with those with EGFR-negative tumors. These data suggest that EGFR status may be important for the prediction of biologically high malignant potential.

Growth fractions of breast cancer in relation to epidermal growth factor receptor and estrogen receptor

Growth fractions detected by a monoclonal antibody, Ki-67, were examined in 40 human breast cancer tissues and the results compared with the immunocytochemical reactivities of epidermal growth factor receptor (EGFR) and estrogen receptor (ER). The proportion of proliferating cells displaying Ki-67 positive staining was significantly higher in the EGFR positive tumors than in the EGFR negative tumors (p less than 0.01). The average percentage of Ki-67 positive cells in the EGFR positive tumors was 19.9 per cent, whereas that in the EGFR negative tumors was 8.0 per cent. By contrast, an inverse relationship between the proportion of proliferating cells and ER positive cells detected by anti-ER monoclonal antibody was observed. This data indicated the difference in growth fractions with relation to the EGFR and ER status of breast cancer.

A simplified immuno-enzymetric assay of the epidermal growth factor receptor in breast tumors: evaluation in 282 cases

The epidermal growth factor receptor (EGF-R) is currently being investigated in human clinical oncology, and particularly in breast cancer, as a potential prognostic factor and a biological target for therapy. As an alternative to the 125I-EGF binding assay, we propose a sensitive immuno-enzymetric assay (IEMA) suitable for EGF-R assay in breast cancer. The assay is performed on solubilized extracts of the 105,000 g pellet of a tumor homogenate, allowing estrogen (ER) and progesterone (PR) assays to be made on the cytosol. The IEMA is performed on 96-well plates coated with the monoclonal anti-EGF-R antibody RI, through an anti-mouse IgG2b bridge. Trapped EGF-R in the samples is covered by a second monoclonal antibody (MAb), 528, and revealed by an anti-IgG2a-peroxidase complex. The sensitivity is 1 fmol/mg membrane protein, and the asay can be performed on tissue samples down to 50 mg. Two hundred and twenty primary ductal breast carcinomas assayed by this method showed a log normal distribution with a modal value of 8 fmol/mg prot., a mean at 18 and a median at 13 fmol/mg prot. EGF-R-rich tumors (greater than 20 fmol/mg prot.) were highly correlated with the absence of estrogen receptors and/or with a high histological grade (SBR III). Our data demonstrate the validity of the IEMA assay of EGF-R in human breast tumors.

Growth factors and oncogenes in human solid tumors: clinical aspects

Growth factors, growth factor receptors and oncogenes have been extensively studied in human tumors for some years. The purpose of this paper is to review the clinical results obtained in human cancers and their predisposing conditions or high risk groups as well as their relation with clinical, pathological characteristics and their prognosis.

Antineoplastic effect of erbstatin on human mammary and esophageal tumors in athymic nude mice

The growth of MCF-7, a human mammary carcinoma, in athymic nude mice was inhibited by intraperitoneal administration of erbstatin for 14 days in combination with an iron chelator, foroxymithine, which inhibits the decomposition of erbstatin. Another human mammary carcinoma, Br-10, was not affected. Foroxymithine alone had no anti-tumor activity. In four esophageal tumors, erbstatin retarded tumor growth. There were no side-effects in any erbstatin-treated group. Levels of epidermal growth factor receptors were not changed throughout treatment with erbstatin at any dose. Erbstatin, a tyrosine kinase inhibitor, may have an antineoplastic effect against human mammary and esophageal tumors.