Epidermal growth factor receptors in intracranial and breast tumours: their clinical significance

Pathology and molecular genetics of oligodendroglial tumors

Oligodendroglial gliomas are second only to astrocytic gliomas in frequency. The lack of stringent diagnostic criteria cause high interobserver variation in regard to classification and grading of these tumors. Previous studies have described oligodendrogliomas with features that overlap with those of neurocytic tumors, thus further complicating diagnostic decisions. The increasing need for standardized diagnostic criteria in this subset of gliomas is emphasized by the benefit of adjuvant therapies in patients with anaplastic oligodendrogliomas. Characteristic chromosomal aberrations have been successfully determined for oligodendroglial tumors in recent years. In contrast to astrocytomas, however, no genes in the affected regions have been clearly linked to their pathogenesis. However, the molecular findings promise to be helpful for diagnostic and therapeutic decisions. This review compiles clinical, pathological, and molecular genetic findings on WHO grades II and III oligodendrogliomas and oligoastrocytomas.

Molecular alterations in sporadic breast cancer

Breast cancer is a genetic disease. Like other human cancers, it is thought to occur as the result of progressive accumulation of genetic aberrations. These aberrations result in a deviation of the gene expression profiles from that of the normal progenitor cell. In up to 99% of cases, breast cancer is due to solely somatic genetic aberrations without germ-line ones. Considerable progress have already been made in understanding the genetic mechanisms underlying the development and progression of breast cancer. Several extensively studied genes are now well known to be involved. Unfortunately, our ability to make clinically useful interventions on the basis of these data is limited. Because of the involvement of multiple genes and complex pathways in a single cancer cell, the molecular dysfunctioning underlying breast cancer remains to be completely clarified. In a next future, studying the global gene expression of different types of tumors will allow the development of expression profiles unique for a breast cancer, its stage and prognostic category, leading to diagnostic assays and the identification of new therapeutic targets.

PAI-1 and EGFR expression in adult glioma tumors: toward a molecular prognostic classification

PURPOSE

Molecular classification of gliomas is a major challenge in the effort to improve therapeutic decisions. The plasminogen activator system, including plasminogen activator inhibitor type 1 (PAI-1), plays a key role in tumor invasion and neoangiogenesis. Epidermal growth factor receptor (EGFR) is involved in the control of proliferation. The contribution of PAI-1 and EGFR to the survival of gliomas was retrospectively investigated.

METHODS AND MATERIALS

Fifty-nine adult gliomas treated by neurosurgery and conventional irradiation were analyzed, including 9 low-grade (2) and 50 high-grade (3-4) tumors (WHO classification). PAI-1 was measured on cytosols and EGFR on solubilized membranes using ELISA methods.

RESULTS

High PAI-1 levels were strongly associated with high histologic grade (p < 0.001) and histologic necrosis (p < 0.001). PAI-1 also correlated positively with patient age (p = 0.05) and negatively with Karnofsky index (p = 0.01). By univariate analysis of the high-grade population, higher PAI-1 (p < 0.0001) and EGFR values (p = 0.02) were associated with shorter overall survival. Only PAI-1 was an independent factor in multivariate analysis. Grade 3 tumors with low PAI-1 (100% 3-year overall survival rate) presented the same clinical outcome as the low-grade tumors.

CONCLUSIONS

In this prognostic study, PAI-1 and EGFR expression revealed similarities and differences between high-grade gliomas that were not apparent by traditional clinical criteria. These data strongly support that biologic factors should be included in glioma classification and the design of clinical trials to treat more homogeneous populations.

Glioma-associated antigen expression in oligodendroglial neoplasms. Tenascin and epidermal growth factor receptor

Epidermal growth factor receptor (EGFR), its variant, EGFRvIII, and tenascin are glioma-associated antigens that are hyperexpressed by neoplastic glial cells relative to normal brain, making them attractive antigenic targets for immunotherapy. Preliminary surveys indicate that oligodendroglial tumors also produce these proteins, although the exact patterns and degrees of reactivity are not known. In this study we examined the immunoreactivity of tenascin among 50 oligodendroglial tumors, including 25 well-differentiated oligodendrogliomas (WDOs) and 12 glioblastomas (GBMs) exhibiting high proportions of oligodendroglia-like cells. We used well-characterized immunoreagents with defined specificities against the target antigens on formalin-fixed, paraffin-embedded archival tissue. The tumors were graded according to WHO guidelines. Immunoreactivity was reported on a 1-3 scale according to staining intensity multiplied by a 1-3 distribution scale distribution within tumor as focal (1), multifocal (2), and diffuse (3) for both the parenchymal and the perivascular components. Although there is considerable overlap in antigen production among the grades of tumor, this study establishes the production of tenascin and wild-type EGFR (but not EGFR vIII) in oligodendroglial neoplasms and supports the concept that antigen production increases with tumor grade.

A constitutively active epidermal growth factor receptor cooperates with disruption of G1 cell-cycle arrest pathways to induce glioma-like lesions in mice

The epidermal growth factor receptor (EGFR) gene is amplified or mutated in 30%-50% of human gliobastoma multiforme (GBM). These mutations are associated usually with deletions of the INK4a-ARF locus, which encodes two gene products (p16(INK4a) and p19(ARF)) involved in cell-cycle arrest and apoptosis. We have investigated the role of EGFR mutation in gliomagenesis, using avian retroviral vectors to transfer a mutant EGFR gene to glial precursors and astrocytes in transgenic mice expressing tv-a, a gene encoding the retrovirus receptor. TVA, under control of brain cell type-specific promoters. We demonstrate that expression of a constitutively active, mutant form of EGFR in cells in the glial lineage can induce lesions with many similarities to human gliomas. These lesions occur more frequently with gene transfer to mice expressing tv-a from the progenitor-specific nestin promoter than to mice expressing tv-a from the astrocyte-specific glial fibrillary acidic protein (GFAP) promoter, suggesting that tumors arise more efficiently from immature cells in the glial lineage. Furthermore, EGFR-induced gliomagenesis appears to require additional mutations in genes encoding proteins involved in cell-cycle arrest pathways. We have produced these combinations by simultaneously infecting tv-a transgenic mice with vectors carrying cdk4 and EGFR or by infecting tv-a transgenic mice bearing a disrupted INK4a-ARF locus with the EGFR-carrying vector alone. Moreover, EGFR-induced gliomagenesis does not occur in conjunction with p53 deficiency, unless the mice are also infected with a vector carrying cdk4. The gliomagenic combinations of genetic lesions required in mice are similar to those found in human gliomas.

Neurofibromatosis type 2: growth stimulation of mixed acoustic schwannoma by concurrent adjacent meningioma: possible role of growth factors. Case report

The authors report the case of a young man suffering from neurofibromatosis type 2 (NF2) who harbored bilateral acoustic schwannomas and a parasellar meningioma. Neuroimaging studies performed during a 4-year follow-up period showed that the bilateral schwannomas had grown very little and at similar rates. However, after the meningioma had infiltrated the tentorium and approached the ipsilateral schwannoma at the incisura, both Schwann cell tumors started to grow rapidly, particularly the one adjacent to the meningioma, of which the percentage of annual growth rate increased by approximately a factor of 10(2). At the same time, magnetic resonance imaging showed that this tumor also changed its features. During surgery, the acoustic schwannoma was firmly adherent to both meningioma and tentorium. Histological examination revealed meningotheliomatous cells in the schwannoma adjacent to the meningioma. Antiphosphotyrosine immunoblotting of PC12 cells was compatible with the presence of an epidermal growth factor (EGF)-like molecule in the cerebrospinal fluid (CSF) of the patient. This factor was not detected in the CSF of five other NF2 patients, two of whom bore associated bilateral acoustic schwannomas and meningioma in remote locations. It is hypothesized that the meningotheliomatous cells infiltrating the schwannoma triggered an autocrine/paracrine growth-stimulatory mechanism that involved an EGF-like factor.

Neurofibromatosis type 2: growth stimulation of mixed acoustic schwannoma by concurrent adjacent meningioma: possible role of growth factors

The authors report the case of a young man suffering from neurofibromatosis type 2 (NF2) who harbored bilateral acoustic schwannomas and a parasellar meningioma. Neuroimaging studies performed during a 4-year follow-up period showed that the bilateral schwannomas had grown very little and at similar rates. However, after the meningioma had infiltrated the tentorium and approached the ipsilateral schwannoma at the incisura, both Schwann cell tumors started to grow rapidly, particularly the one adjacent to the meningioma, of which the percentage of annual growth rate increased by approximately a factor of 102. At the same time, magnetic resonance imaging showed that this tumor also changed its features. During surgery, the acoustic schwannoma was firmly adherent to both meningioma and tentorium. Histological examination revealed meningotheliomatous cells in the schwannoma adjacent to the meningioma. Antiphosphotyrosine immunoblotting of PC12 cells was compatible with the presence of an epidermal growth factor (EGF)-like molecule in the cerebrospinal fluid (CSF) of the patient. This factor was not detected in the CSF of five other NF2 patients, two of whom bore associated bilateral acoustic schwannomas and meningioma in remote locations. It is hypothesized that the meningotheliomatous cells infiltrating the schwannoma triggered an autocrine/paracrine growth-stimulatory mechanism that involved an EGF-like factor.

The epidermal growth factor receptor in breast cancer

The epidermal growth factor receptor (EGFR)3 is a 170 kD transmembrane tyrosine kinase activated by several ligands. It is required for normal mammary development and lactation and is aberrantly expressed in approximately 40% of breast carcinomas, particularly those with a poor prognostic phenotype. Since EGF receptor levels are elevated in a high proportion of many tumor types its potential as a therapy target is being investigated using the EGF receptor to target toxins, as well as drugs that interfere with signaling and anti-receptor antibodies. These approaches are likely to be most effective when used in the adjuvant situation in combination with chemotherapy.

Biodistribution of 125I-MAb 425 in a human glioma xenograft model: effect of chloroquine

Chloroquine has been shown to increase the cellular retention and nuclear incorporation of 125I-labeled monoclonal antibody (MAb) 425, a murine anti-epidermal growth factor receptor monoclonal antibody, in human high-grade glioma cells in vitro. The objective of this study was to examine the effect of chloroquine on the biodistribution of 125I-MAb 425 in an intracerebral xenogeneic transplant of glioma cells. Nude rats were stereotaxically implanted in the right hemisphere with A1207 human high-grade glioma cells. After 14 days, animals were injected i.v. with chloroquine (40 mg/kg) followed 2 h later by an 125I-MAb 425 (9 MBq) infusion. Tissue distributions were performed up to 168 h post 125I-MAb 425 injection. From 24 to 168 h, tumor-to-contralateral left brain ratios increased from 9 to 15 for 125I-MAb 425 alone, and 7 to 13 for the 125I-MAb 425/chloroquine combination, respectively. A single administration of chloroquine did not result in any significant difference in radiolabeled MAb accumulation in either the tumor site or other tissues. We conclude that chloroquine did not increase the amount of 125I-MAb 425 into the tumor; however, it is safe to administer i.v. at the 40 mg/kg dose. Under these experimental conditions, the increased radioactive accumulation observed for in vitro data did not translate into similar in vivo results.

Prospective evaluation of prognostic factors in operable breast cancer

In 215 patients with operable breast cancer (T1-T3, N0-1, M0) and no other or previous cancer, presenting to a single breast unit, sufficient tumour was available for the prospective determination of four putative biochemical markers of prognosis: oestrogen receptor (ER) activity, cathepsin D (cath D), epidermal growth factor receptor (EGFR) activity and cyclic AMP-binding proteins (c-AMP-b). There were significant inter-relationships between ER and EGFR (r = -0.26), c-AMP-b and cath D (r = +0.32) and ER and c-AMP-b (r = +0.14). After follow-up (median 36.2 months), a total of 55 recurrences (18 locoregional only) and 35 deaths were recorded. By univariate analysis, up to 10 of 18 biochemical, clinical and histopathological variables of potential prognostic value were significantly related to disease-free interval or death, but by multivariate analysis only oestrogen receptor concentration and node status contributed significantly to risk of both distant recurrence/death; in addition, tumour size made a small contribution to the risk for a distant recurrence only. Only two parameters, tumour grade and ER concentration, were significantly related to risk of locoregional recurrence by univariate analysis, but by multivariate analysis, only tumour grade was important. It is concluded that tumour ER concentration, axillary nodal status and tumour grade remain as the most important prognostic factors in the early years after presentation of operable breast cancer, with a minor influence of tumour size. At this time, the prognostic significance of quantitative measurements of ER concentration, carefully controlled for the quality of both assay and tumour specimen, is probably greater than is generally appreciated. We have yet to identify other factors, which add significantly to the short-term prognostic value of these key features.

Epidermal growth factor receptor expression in oligodendroglial tumors

A series of 13 oligodendrogliomas (WHO grade II) and 20 anaplastic oligodendrogliomas (WHO grade III) was studied for gene amplification and expression of the epidermal growth factor receptor gene (EGFR). EGFR gene amplification was found in only one case of anaplastic oligodendroglioma, which additionally showed a deletion/rearrangement at the 5' end of the gene. Northern blot analysis, however, revealed increases of EGFR mRNA expression relative to non-neoplastic control brain in 6 of 13 oligodendrogliomas and 10 of 18 anaplastic oligodendrogliomas. All cases with increased mRNA expression showed strong immunoreactivity for EGFR protein. Our findings thus indicate that increased expression of EGFR mRNA and protein is common in low-grade and high-grade oligodendroglial tumors and in the vast majority of cases is not caused by gene amplification.

In vitro growth inhibition of growth factor-stimulated meningioma cells by calcium channel antagonists

Studies have shown that a majority of meningiomas contain receptors for platelet-derived growth factor and epidermal growth factor and that these growth factors promote the proliferation of meningioma cells in culture. Although the mechanism of action has not been elucidated, intracellular calcium appears to be part of the signal transduction mechanism. Because alterations in intracellular calcium could interrupt this pathway and decrease cellular proliferation, we investigated the effects of calcium channel-blocking agents on the growth of meningioma cells in vitro. Primary meningioma cell cultures were established, and the cells were characterized by light and electron microscopy and by immunohistochemical studies. Then, the cultures were given growth factors and/or various calcium channel antagonists, and growth rates were measured. A dose-response decrease in cell growth was seen when verapamil, nifedipine, or diltiazem (voltage-dependent calcium channel-blocking agents) was added to serum-containing media. Also, these drugs blocked the growth stimulation of epidermal growth factor and platelet-derived growth factor in a similar fashion. Dantrolene, which inhibits the release of sequestered intracellular calcium, was also an effective blocker of the mitogenic stimulation of these growth factors.

Prognostic factors in early breast carcinoma

Several investigators, the SEER data, and the ECOG/Intergroup study have shown that patients with small tumors (< 0.5 cm) have a recurrence rate of less than 2%, compared to 20-25% for large tumors (> or = 5 cm). Nuclear grade and tumor differentiation are established indicators; however, the interobserver lack of concordance has thwarted their use in clinical trials. The presence of peritumoral lymphatic and blood vessel invasion (PLBI) is associated with a relative risk of recurrence of 4.7. The predictive value of the presence of hormone receptors in tumors is associated with a favorable disease free and overall survival difference of 8-10%; however, this advantage is being eroded by the early appearance of other factors, such as the epidermal growth factor receptor (EGFR), proliferative capacity (S-phase), nuclear grade, and HER-2/neu oncogene. Concordance among the different methods of hormone-receptor assay (immunocytochemical, sucrose gradient, and dextran-coated charcoal) is essential to refine the true value of these factors. DNA flow cytometry measurements of ploidy (DNA content) and S-phase fraction are the most characterized of the prognostic factors. There are conflicting reports regarding the clinical significance of ploidy status, while measurements of S-phase fraction clearly indicate a robust association with disease free and overall survival. Our data continue to show that S-phase, but not ploidy, can predict time to recurrence significantly in untreated patients, even when data are stratified for tumor size. HER-2/neu oncogene is expressed in about 50% of ductal carcinoma in situ and 14% of invasive ductal carcinoma. The presence of this oncogene at high copy number may be a useful independent marker of poor prognosis and may be associated with drug resistance and correlated with tumor recurrence and shorter survival. EGFR could be measured in most breast tumors, and the level of its expression has inversely correlated with estrogen receptor protein expression. The value of EGFR as a predictor of prognosis remains controversial and is still being investigated. Cathepsin-D provides a provocative biologic rationale but is hindered by different and incongruent methods of analysis. The majority of large studies with more than 3-years' follow-up suggests that high cathepsin-D levels may be predictive of greater recurrence and lower survival. Angiogenesis has been implicated as a critical component of the metastatic process. Early studies show that tumor angiogenesis is an independent and highly significant prognostic indicator, and its presence may suggest the selection of "anti-angiogenic therapy."(ABSTRACT TRUNCATED AT 400 WORDS)

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.

Indium-111-labeled anti-EGFr-425 scintigraphy in the detection of malignant gliomas

BACKGROUND

The monoclonal antibody anti-epidermal growth factor receptor (EGFr) antibody-425, against the epidermal growth factor receptor, has the potential to bind specifically to gliomas and not normal brain tissue. A prospective study was conducted (1986-1988) to evaluate the use of Indium-111 (111In)-labeled anti-EGFr-425 in the localization of gliomas before radioimmunotherapy with Iodine-125 (125I)-labeled anti-EGFr-425.

METHODS

Twenty-eight patients with intracranial neoplasms were injected intravenously with an average dose of 2.2 mCi 111In-labeled anti-EGFr-425. Planar and single-photon emission computed tomography scans were performed after 48 and 72 hours. Control studies also were performed in two cases with 111In-labeled Co 17-1A (an antibody to colorectal cancer) and in one case with unlabeled 111In chloride.

RESULTS

The immunoscintigraphic findings were generally in good agreement with computerized tomographic findings. The definitive diagnosis was established by biopsy findings: 23 gliomas (1 Grade I, 5 Grade II, 6 Grade III, and 11 Grade IV), 1 meningioma, and 4 metastatic lesions. The localization of gliomas with 111In-labeled anti-EGF-425 had a sensitivity of 0.96, a specificity of 0.60 and an accuracy of 0.90.

CONCLUSION

Immunoscintigraphy with 111-In labeled anti-EGFr-425 can be useful in the management of malignant gliomas, especially before radioimmunotherapy with 125I-labeled anti-EGFr-425.

The epidermal growth factor receptor as a prognostic marker: results of 370 patients and review of 3009 patients

Epidermal growth factor receptor (EGFR) and estrogen receptor (ER) were assayed by ligand binding in tumors from 370 patients with primary breast carcinoma with a median follow up of 18 months. Forty seven percent (175/370) and 57% (210/370) of tumors had > 20 fmol/mg and > 10 fmol/mg of EGFR and ER respectively. There was a highly significant inverse relationship between EGFR and ER (p = 0.0032). There was also a significant association between EGFR and patient age (p = 0.0006) but not correlation between EGFR and lymph node status, tumor grade, or tumor size (p = 0.104, p = 0.198, and p = 0.085 respectively). In a univariate analysis of all patients, EGFR expression was not associated with a significant reduction in overall survival (OS). However, there was a significant decrease in relapse-free survival (RFS) and OS in node negative EGFR positive patients (p = 0.03 and p = 0.05 respectively). In a multivariate analysis (Cox proportional hazard model) of all patients, lymph node status was an independent prognostic indicator for OS and RFS (p < 0.00005) and p = 0.00005 respectively), ER status for RFS (p = 0.0006), and EGFR (in the node negative model) for RFS (p = 0.03). When all patients were stratified for EGFR and ER, there was a significant difference in RFS and OS such that EGFR positive and ER negative had the worst prognosis (p = 0.0034 and p = 0.005 respectively).

The prognostic significance of transforming growth factors in human breast cancer

Transforming growth factor alpha (TGF alpha) and Transforming growth factor beta-1 (TGF-beta 1) are growth regulatory for breast cancer cell lines in vitro and several studies have suggested that levels of the receptor for TGF alpha, the epidermal growth factor (EGFR) in tumour biopsies predict relapse and survival. We have examined the prognostic significance of TGF alpha, TGF-beta 1 and EGFR mRNA expression in a series of patients with primary breast cancer with a median follow up period of 60 months. In 167 patients the expression of TGF-beta 1 was inversely correlated with node status (P = 0.065) but not ER status, tumour size or menopausal status. Patients with high levels of TGF-beta 1 had a longer disease free interval with a significantly longer probability of survival at 80 months although the overall relapse free survival was not increased. EGFR mRNA expression was measured in 106 patients and was inversely correlated with ER status (P = 0.018). EGFR levels did not predict for early relapse or survival. TGF alpha mRNA levels were measured in 104 patients, no correlation was seen tumour size, node status, Er status, or clinical outcome.

The nature of the head and neck cancer

Squamous cell carcinoma of the head and neck is a disease predominantly of males and is due to a variety of known environmental irritants, notably cigarette smoke. Dietary, viral and immunological factors may also be relevant. Head and neck squamous cancers express epidermal growth factor receptors and some show weak levels of oestrogen receptor activity, but a reliable serum marker of tumour burden remains to be identified. The prognosis is found to be less favourable in females, in those with advanced T stage, in association with multiple node involvement, especially where extracapsular spread is present and where the T4/T8 ratio is elevated. Administration of heterologous blood during therapy may also have an adverse effect on prognosis. Interested clinicians must remember that most cases are preventable.

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 receptors and oestrogen receptors in the head and neck

We report a pilot study of the levels of epidermal growth factor receptors (EGFR) in normal and neoplastic tissues of the head and neck. Specimens from 20 consecutive patients undergoing major head and neck surgery showed that squamous cell carcinomas had detectable but widely varying levels of EGFR. EGFR expression was greater in normal salivary gland tissue than in benign salivary neoplasms. Oestrogen receptors were not detected in clinically significant amounts in any of the tumours assayed.

Epidermal growth factor receptor activity and clinical outcome in glioblastoma and meningioma

Epidermal growth factor receptor (EGF-r) activity in patients with glioblastoma multiforme (GBM: n = 27) and meningioma (n = 18) was compared with clinical outcome. All patients with GBM were followed up to time of death. In patients with GBM there was no significant relationship between EGF-r activity and either patient survival time or age. EGF-r activity in patients with meningioma was neither related to age nor, at a median of 40 months after surgery, to clinical outcome. These results suggest that routine estimation of EGF-r activity in these intracranial tumours is not indicated.

Expression of epidermal growth factor receptor in human meningiomas and meningeal tissue

The aim of this study was to examine meningeal tissue under normal, reactive, and neoplastic conditions for expression of epidermal growth factor receptor (EGFR) using an improved histochemical method, namely biotinylated epidermal growth factor. EGFR was found in all the examined meningiomas (12 benign and three anaplastic) and in neonatal rat meninges, whereas normal and injured adult human and rat meninges did not exhibit detectable EGFR. These observations indicate that EGFR is involved in the development of meningeal tissue. Further, EGFR is abnormally expressed in meningeal tumours, indicating a role of EGFR in the neoplastic process of these tumours. The regular expression of EGFR in human meningiomas suggests EGFR as a tumour marker for this tumour type.

Overexpression of multiple oncogenes related to histological grade of astrocytic glioma

The expression of the c-erbB-1, c-myc, Ha/N-ras and c-fos oncogenes was investigated in 62 astrocytomas of low, intermediate and high grades by immunogold silver histochemistry. Elevated expression of c-erbB-1 was observed in 95%, 48% and 86% of low, intermediate and high grade tumours respectively, c-myc in 5%, 33% and 76% respectively, Ha/N-ras in 0, 43% and 71% respectively and c-fos in 55%, 48% and 52% respectively. Controls included normal brain and tumour sections immunoreacted with pre-immune serum or with antisera absorbed with synthetic peptides. Analysis of co-overexpression revealed that low grade tumours co-overexpressed a maximum of two of these genes, intermediate grade tumours a maximum of three of these genes, while co-overexpression of all four genes was observed in some high grade tumours. Co-overexpression of c-erbB-1 and c-fos was frequently observed in low grade astrocytomas and may be predictive of non-progression. On the other hand, there was a statistically significant increase in the number of tumours overexpressing Ha/N-ras or c-myc with increasing grade of tumour, suggesting that overexpression of these two oncogenes may be indicative of progression.

Expression of the epidermal growth factor receptor in astrocytic tumours is specifically associated with glioblastoma multiforme

Epidermal growth factor and its receptor (EGFR) constitute an important and well-characterized mitogenic system in various ectodermal tissues including glial cells. Over-expression of the EGFR due to gene amplification has been reported in primary brain tumours of glial origin. Using a monoclonal antibody to the EGFR and immunohistochemical analysis, we examined the expression and distribution of EGFR in 103 astrocytic tumours. In addition, selected tumours were studied by Western blotting using a polyclonal antibody to EGFR and by Southern blot analysis. Glioblastomas (WHO grade IV) showed EGFR expression in 37% of cases, whereas pilocytic (WHO grade I), low-grade (WHO grade II) or anaplastic astrocytoma (WHO grade III) were invariably EGFR negative. Generally, there was a close correlation between the presence of EGFR gene amplification and over-expression of receptor protein. Different patterns of immunoreactive cells and significant intratumour heterogeneity of EGFR expression were observed in glioblastomas. The specific association of EGFR over-expression with glioblastoma may provide a useful diagnostic tool for distinguishing anaplastic astrocytoma (WHO grade III) and glioblastoma multiforme (WHO grade IV).

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.

A new monoclonal antibody for detection of EGF-receptors in western blots and paraffin-embedded tissue sections

The prognostic significance of the epidermal growth factor receptor status (EGF-R-status) for certain human tumors requires the development of antibodies useful for clinical application. We used purified receptor preparations to generate monoclonal antibodies immunoreactive with the EGF-R purified from placenta membranes and A431 tumors. Four of the hybridomas contained antibodies (R2, R3, R5, and R9) which recognized both antigens. Antibody R3 was shown to display the following properties: it binds with a KD value of about 10(-9)-10(-10) M to the receptor, a half maximal inhibition of EGF-binding is achieved at 5 x 10(-8) M, and in Western blots of cell membranes R3 specifically detects the EGF-R at 0.1 micrograms/ml. R3 inhibits EGF-dependent clonogenic growth of NRK cells and completely blocks EGF stimulated autophosphorylation of the receptor. Moreover, R3 also detects EGF-R in paraffin-embedded tissue sections taken from human salivary gland, term placenta, and adult skin and mammary carcinomas. Thus, R3 can be used in retrospective diagnostic clinical studies and might help to develop new immunotherapeutic intervention.

Proliferating cell nuclear antigen in breast lesions: Correlation of c-erbB-2 oncoprotein and EGF receptor and its clinicopathological significance in breast cancer

Monoclonal anti-proliferating cell nuclear antigen (PCNA PC10), which is directed against a 36 kDa auxiliary protein for DNA polymerase delta specific for the S-phase of cell cycle, was used to measure tumour cell proliferation in 4 lactating breasts and 98 benign and malignant breast tumours. The percentage of PCNA-positive cells determined by point counting was significantly lower in the lactating breast [mean 3.6%, standard deviation (SD) 0.67, n = 5] than in fibroadenoma and mastopathy (mean 23.7, SD 5.0, n = 2). Primary breast carcinoma showed a PCNA index ranging from 2% to 36% (mean 12.3, SD 9.3, n = 50), whereas in recurrent carcinoma the index was mean 28.5, SD 4.0. A high index was correlated with c-erbB-2 and epidermal growth factor (EGF) receptor membrane reactivity, worsening histological grade, poor survival and disease-free survival. The expression of c-erbB-2 and EGF receptor was associated with poor survival and disease-free survival in primary breast cancer patients.

The epidermal growth factor receptor in human pancreatic cancer

The epidermal growth factor receptor (EGFR) and its ligands are thought to be important in the control of proliferation of many epithelial systems, including the exocrine pancreas. Abnormalities in expression of two of the known ligands of the EGFR, transforming growth factor alpha and epidermal growth factor, occur frequently in ductal adenocarcinoma of the human pancreas. We have examined an archival series of cases of pancreatic pathology for expression of the EGFR using the anti-EGFR antiserum 12E and found that there is almost ubiquitous overexpression of EGFR in pancreatic cancer and in chronic pancreatitis. Southern blot analysis showed no evidence of amplification or rearrangement of the EGFR gene. We conclude that an autocrine loop involving the EGFR system may be involved in the genesis of both neoplasia and reactive hyperplasia of pancreatic ductal epithelium.