Epidermal growth factor receptors in cancer tissues of esophagus, lung, pancreas, colorectum, breast and stomach

Activation of growth factor receptors in esophageal cancer--implications for therapy

Esophageal cancer is a highly aggressive disease and is the seventh most common cause of cancer-related death in the western world. Worldwide, it ranks as the sixth most frequent cause of cancer death. Despite advances in surgical techniques and treatment, the prognosis of esophageal cancer remains poor, with very few long-term survivors. The need for novel strategies to detect esophageal cancer earlier and to improve current therapy is urgent. It is well established that growth factors and growth factor receptor-mediated signaling pathways are important components of the transformation process in many forms of cancer, including esophageal cancer. With the recent advances in drug development, there are emerging possibilities to use growth factor signal transduction pathways in targeted therapy. This review provides a summary of the role of growth factors and their receptors in esophageal cancer and discusses their potential roles as biomarkers and as targets in therapy.

The immunocytokine scFv23/TNF targeting HER-2/neu induces synergistic cytotoxic effects with 5-fluorouracil in TNF-resistant pancreatic cancer cell lines

Human pancreatic tumor cells are highly resistant to both tumor necrosis factor (TNF) and to chemotherapeutic agents. HER-2/neu expression has been proposed as a negative prognostic marker in pancreatic intraepithelial neoplasia. Our approach was to utilize HER-2/neu expression on the surface of tumor cells as a therapeutic target employing scFv23/TNF, immunocytokine composed of a single chain Fv antibody (scFv23) targeting the HER-2/neu and the cytokine TNF as the cytotoxic moiety, to deliver TNF directly to TNF-resistant pancreatic tumor cells. Using a panel of human pancreatic cell lines, which overexpress HER-2/neu, we evaluated the in vitro response of cells to TNF, scFv23/TNF, Herceptin, and a combination of scFv23/TNF with various chemotherapeutic agents. We found that all pancreatic cancer cell lines were highly resistant to the cytotoxic effects of TNF and that scFv23/TNF was highly cytotoxic to TNF-resistant HER-2/neu-expressing pancreatic cancer cell lines at levels rivaling that of conventional chemotherapeutic agents. Combination studies demonstrated a synergistic cytotoxic effect of scFv23/TNF with 5-fluorouracil (5-FU) in TNF-resistant pancreatic cancer cell lines. Mechanistic studies demonstrated that the 5-FU plus scFv23/TNF combination specifically resulted in a down-regulation of HER-2/neu, p-Akt and Bcl-2 and up-regulation of TNF-R1. In addition, the combination 5-FU plus scFv23/TNF induced apoptosis and this synergistic effect was dependent on activation of caspase-8 and caspase-3. Delivery of the cytokine TNF to HER-2/neu expressing pancreatic tumor cells, which are inherently resistant to TNF using scFv23/TNF may be an effective therapy for pancreatic cancer especially when utilized in combination with 5-FU.

Mutant p53 protein in the serum of patients with colorectal cancer: Correlation with the level of carcinoembryonic antigen and serum epidermal growth factor receptor

INTRODUCTION

Enzyme-linked immunosorbent assay (ELISA) was used for analysis of serum mutant p53 protein, carcinoembryonic antigen (CEA), and epidermal growth factor receptor (EGFR). Serum samples were obtained from 48 patients with colorectal cancer (CRC) and a control group of twenty healthy individuals.

RESULTS

The results demonstrated a significant increase of serum mutant p53, EGFR, and CEA levels in CRC patients compared to the control group (P<0.001 for each). Mutant p53 protein was significantly different in the different CRC grades (P=0.028). p53, CEA, and EGFR can differentiate successfully between different CRC grades and normal control (P<0.001 for each). Sensitivities of p53, CEA, and EGFR were 39.6, 31, and 71%, respectively. There was no correlation between CEA, EGFR, and p53 indicating that these variables were independent. Positive status of serum CEA and (or) p53 was found in 29 out of 48 (60%) patients. Also, positive status of serum CEA and (or) EGFR was found in 39 out of 48 (81%) patients.

CONCLUSION

Thus, the simultaneous determination of p53 or EGFR combined with the CEA may increase the sensitivity to diagnose CRC patients and may aid in disease prognosis.

Prediction of survival in patients with esophageal carcinoma using artificial neural networks

BACKGROUND

Accurate estimation of outcome in patients with malignant disease is an important component of the clinical decision-making process. To create a comprehensive prognostic model for esophageal carcinoma, artificial neural networks (ANNs) were applied to the analysis of a range of patient-related and tumor-related variables.

METHODS

Clinical and pathologic data were collected from 418 patients with esophageal carcinoma who underwent resection with curative intent. A data base that included 199 variables was constructed. Using ANN-based sensitivity analysis, the optimal combination of variables was determined to allow creation of a survival prediction model. The accuracy (area under the receiver operator characteristic curve [AUR]) of this ANN model subsequently was compared with the accuracy of the conventional statistical technique: linear discriminant analysis (LDA).

RESULTS

The optimal ANN models for predicting outcomes at 1 year and 5 years consisted of 65 variables (AUR = 0.883) and 60 variables (AUR = 0.884), respectively. These filtered, optimal data sets were significantly more accurate (P < 0.0001) than the original data set of 199 variables. The majority of ANN models demonstrated improved accuracy compared with corresponding LDA models for 1-year and 5-year survival predictions. Furthermore, ANN models based on the optimal data set were superior predictors of survival compared with a model based solely on TNM staging criteria (P < 0.0001).

CONCLUSIONS

ANNs can be used to construct a highly accurate prognostic model for patients with esophageal carcinoma. Sensitivity analysis based on ANNs is a powerful tool for seeking optimal data sets.

Radioimmunohistochemistry of epidermal growth factor receptor in breast cancer

CONTEXT

Conflicting reports of epidermal growth factor receptor (EGFR) expression in breast cancer and inconstant relationships with established prognostic indicators and outcomes suggest difficulties with EGFR measurement.

OBJECTIVE

To compare EGFR measurement in a panel of cell lines and in breast carcinomas by radioimmunohistochemistry (R-IHC), conventional immunohistochemistry (IHC), and a ligand binding (LB) assay.

DESIGN

Eight EGFR-expressing cell lines and 50 primary breast carcinoma specimens were analyzed for EGFR by IHC, R-IHC, and LB assays. A further 153 primary breast cancer specimens were analyzed by R-IHC alone.

RESULTS

All 3 assays were in good agreement for the cell lines. In the subset of the 50 carcinoma specimens, EGFR was detected by LB assays in 19 (38%) and by IHC in 24 (48%). However, R-IHC detected EGFR in 46 (92%) of 50 and in 186 (92%) of all 203 carcinoma specimens. The LB assay agreed poorly with R-IHC of carcinomas, possibly because the LB assay is sensitive to EGFR-expressing nontumor breast parenchyma in the tissue analyzed. Both IHC and R-IHC on carcinoma specimens agreed better, but 26 carcinoma specimens (52%) in which EGFR was not detectable by IHC had a 10-fold range in receptor level detectable by R-IHC.

CONCLUSION

To elucidate the role of EGFR or other growth factor receptors in breast cancer requires accurate, sensitive receptor assays. With its dynamic range, R-IHC returned meaningful results over the entire range of expression actually present in breast cancer, which LB assays and IHC failed to do.

Diet, reflux and the development of squamous cell carcinoma of the oesophagus in Africa

BACKGROUND

Squamous cancer of the oesophagus has reached epidemic proportions in Africa in the past few decades. There are many known associations but as yet no well established theory of causation.

METHODS

Relevant literature was found by manual review of appropriate journals and literature, Medline searches and cross-referencing. Published theories of causation of endemic cancer of the oesophagus were assessed in the light of available evidence. A hypothesis based on that evidence was formulated.

RESULTS AND CONCLUSION

A predominantly maize-based diet is high in linoleic acid, a precursor for gastric prostaglandin synthesis. In combination with low intake of other fatty acids and riboflavin, high levels of prostaglandin E2 are produced in gastric mucosa, leading to reduced gastric acid secretion, relaxation of the pylorus and a reduction in lower oesophageal sphincter pressure. These events result in combined reflux of duodenal and gastric juices low in acidity into the oesophagus. Resulting dysplasia strongly predisposes to local squamous carcinogenesis. This is now a fertile area for research, which may open the way for preventive action.

Technetium-99m labeled epidermal growth factor-tumor imaging in mice

We have shown previously that the epidermal growth factor peptide (EGF) may be radiolabeled with 99mTc at room temperature and neutral pH by using the N-hydroxysuccinimide ester of S-acetyl mercaptoacetyltriglycine (MAG3) as a bifunctional chelator. By a competition binding assay, we found that MAG3-conjugated EGF retained biological activity. Furthermore, the labeled peptide exhibited saturation binding to EGF receptor-positive tumor cell lines which could be inhibited by presaturation of the cells with unlabeled, native EGF. Biodistribution in normal mice at 3 h postadministration showed rapid clearance with minimal retention of the label in sampled organs. We have now investigated the tumor localization properties in mice of this labeled peptide. Nude mice implanted with the EGF receptor-positive tumors A431 and LS-174T were administered labeled EGF and a labeled control peptide (BPTI, aprotinin). Tumor uptake at 12 h postadministration was 0.44% injected dose/g for EGF/g vs. 0.09 for the control. Pretreatment of tumored mice with unlabeled EGF blocked about half the tumor uptake. Animals were also administered an anti-EGF receptor antibody labeled with 99mTc via MAG3. Relative to the antibody, tumor-to-muscle ratios were improved from 6 to 15 and tumor-to-blood ratios from 0.4 to 7 with EGF. These favorable results along with documented evidence of overexpression of the EGF receptor in many human tumors suggest that 99mTc-EGF should be considered further for tumor detection.

Gene amplification of int-2 and erbB in human esophageal cancer: relationship to clinicopathological variables

Gene amplification is a relatively frequent event in human malignant tumors and is believed to play an important role in tumor progression. The int-2 and erbB genes are amplified more frequently than any other genes in human esophageal cancer. In order to investigate the correlation between these two proto-oncogenes and the clinical behavior of esophageal cancer, we examined DNA amplification of int-2 and erbB and analyzed their relationship to clinicopathological variables. Genomic DNA was extracted from 21 esophageal squamous carcinomas and normal esophageal mucosa, as well as from 4 metastatic tumors. We used Southern blot analysis for detection of gene amplification. Amplification of int-2 was observed in 13 of 21 cases (62%) and in all the metastatic tumors (4/4; 100%). We found a significant correlation between amplification of int-2 and the length of the primary lesion. Amplification of erbB was detected in 3 of 18 patients (17%). All patients who showed amplification of erbB also demonstrated amplification of int-2. These results suggest that amplification of int-2 or neighboring genes on 11q may participate in tumor progression and metastasis in patients with esophageal squamous cancer.

Epidermal growth factor receptor immunoreactivity in human laryngeal squamous cell carcinoma

Epidermal growth factor receptor (EGFR) is a transmembrane protein receptor with tyrosine kinase activity. The protein has cysteine-rich sequence repeats in its extracellular ligand-binding domains. Elevated levels of EGFR are associated with malignant transformation of squamous cells and are observed in squamous cell carcinomas from the lung, head, neck, skin, cervix and esophagus. We examined the expression of EGFR in laryngeal squamous cell carcinoma (SCC) (N = 24) and non-neoplastic polyps (N = 7) using streptavidin-biotin immunohistochemistry and a monoclonal antibody (Serotec: MCA-571) to the EGFR protein. The carcinomas were classified as well differentiated (N = 2), moderately differentiated (N = 16) and poorly differentiated (N = 6). Tissues from metastatic tumor deposits in lymph nodes (N = 5) were also studied. Overexpression of EGFR was present, in the form of strong cytoplasmic immunostaining, in the majority of the SCC cases (n = 20; 83%) and in all of the metastatic tumor deposits. In contrast, although some of the vocal cord polyps showed weak (n = 2) to moderate (n = 5) immunoreactivity, none had evidence of strong EGFR immunoreactivity. The differences in EGFR immunoreactivity were significant between primary laryngeal SCC and vocal cord polyps (p = 0.0001; chi 2 test), and between metastatic laryngeal SCC and vocal cord polyps (p = 0.0001; chi 2 test). Laryngeal carcinoma cases which showed EGFR overexpression had a lower median survival period compared to those without overexpression In conclusion, a different extent of EGFR expression is demonstrated in laryngeal squamous cell carcinomas and non-neoplastic vocal cord polyps using an immunohistochemical method. Some trends in the prognostic value of EGFR immunoreactivity in laryngeal carcinomas appear to emerge in this study.

Distribution of epidermal growth factor receptor and ligands during bronchiolar epithelial repair from naphthalene-induced Clara cell injury in the mouse

Clara cells are primary targets for metabolically activated pulmonary toxicants because they contain an abundance of the cytochrome P450 monooxygenases required for generation of toxic metabolites. The factors that regulate bronchiolar regeneration after Clara cell injury are not known. Previous studies of naphthalene-induced bronchiolar injury and repair in the mouse have shown that epithelial cell proliferation is maximal 1 to 2 days after injury and complete 4 days after injury. Proliferation is followed by epithelial re-differentiation (4 to 14 days). In this study, mice were treated with the environmental pollutant naphthalene to induce massive Clara cell injury. The distribution and abundance of three growth-regulatory peptides (epidermal growth factor receptor (EGFR), epidermal growth factor (EGF), and transforming growth factor (TGF)-alpha) was determined immunochemically during repair of this acute bronchiolar injury. EGFR and its ligands were detected at low levels in cells throughout the lung including peribronchiolar interstitial cells, blood vessels, and conducting airway epithelium. Immediately after naphthalene injury (1 to 2 days), EGFR, EGF, and TGF-alpha are expressed in increased abundance in squamous epithelial cells of the injury target zone, distal bronchioles. These immunopositive squamous cells are detected in clumps in the distal bronchioles at the time when cell proliferation is maximal. EGFR protein expression is decreased slightly 4 to 7 days after injury and continues to decrease below control levels of abundance 14 to 21 days after injury. This down-regulation of EGFR is not reflected in a corresponding decrease in EGF and TGF-alpha protein expression, indicating that control of cell proliferation is regulated at the receptor level. Co-localization of EGFR and bromodeoxyuridine-positive proliferating cells in the same bronchiole indicates that EGFR is up-regulated within the proliferative microenvironment as well as in specific proliferating cells within the injury target zone. The coincident localization within terminal bronchioles of EGFR, EGF, and TGF-alpha to groups of squamous epithelial cells 2 days after naphthalene injury suggests that these peptides are important in up-regulating cell proliferation after Clara cell injury in the mouse.

A comparison of epidermal growth factor receptor levels and other prognostic parameters in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) was measured using a competitive radioligand binding assay in membrane preparations from 74 primary human non-small cell lung cancer (NSCLC) tissues and 20 pathologically normal peripheral lung tissues. The mean EGFR level in tumours was 30.38 fmol/mg (+/-41.95 S.D.) of membrane protein (mg.p), significantly higher (P = 0.00016) than in normal tissues (mean, 10.26 +/- 10.02 fmol/mg.p). The mean EGFR concentration was also significantly higher in pathological stage IV tissue than in stages I (P = 0.049) and II (P = 0.040), and the mean EGFR concentration was significantly higher in cases with mediastinal involvement than in cases without it (P = 0.029). The mean EGFR level was higher in DNA aneuploid and multiploid cases than in DNA diploid cases, but there was no significant difference. No significant relationships were found to exist between receptor concentrations and pathological tumour size or histological type, or patient gender or age. From the above findings, a possible prognostic role for EGFR in primary NSCLC should be investigated.

Bromodeoxyuridine: a diagnostic tool in biology and medicine, Part III. Proliferation in normal, injured and diseased tissue, growth factors, differentiation, DNA replication sites and in situ hybridization

This paper is a continuation of parts I (history, methods and cell kinetics) and II (clinical applications and carcinogenesis) published previously (Dolbeare, 1995 Histochem. J. 27, 339, 923). Incorporation of bromodeoxyuridine (BrdUrd) into DNA is used to measure proliferation in normal, diseased and injured tissue and to follow the effect of growth factors. Immunochemical detection of BrdUrd can be used to determine proliferative characteristics of differentiating tissues and to obtain birth dates for actual differentiation events. Studies are also described in which BrdUrd is used to follow the order of DNA replication in specific chromosomes, DNA replication sites in the nucleus and to monitor DNA repair. BrdUrd incorporation has been used as a tool for in situ hybridization experiments.

Bromodeoxyuridine: a diagnostic tool in biology and medicine, Part II: Oncology, chemotherapy and carcinogenesis

This paper follows on from Part 1 of my review of bromodeoxyuridine published earlier this year (Dolbeare, 1995).

Epidermal growth factor receptor immunoreactivity in gallbladder and extrahepatic biliary tract tumours

Elevated levels of epidermal growth factor receptor (EGFR), a transmembrane protein tyrosine kinase receptor, are found in carcinomas from various sites of the body. We investigated the expression of EGFR in carcinoma of the gallbladder (n = 13), common bile duct (n = 7) and ampulla of Vater (n = 9). Non-malignant conditions investigated include chronic cholecystitis (n = 11), gallbladder dysplasia (n = 3) and adenoma (n = 1), and ampullary carcinoma in situ (CIS) (n = 2). Routine immunohistochemistry was employed using a monoclonal antibody against the EGFR protein. Immunostaining was assessed according to both intensity and extent of staining of cells. There was strong immunoreactivity for all gallbladder carcinoma and adenoma, the majority of common bile duct (n = 6; 86%) and ampullary (n = 6; 67%) carcinoma. In contrast, all cases of gallbladder dysplasia, the majority of cases of chronic cholecystitis (n = 7; 64%) and ampullary CIS (n = 2; 67%) had only weak to moderate immunoreactivity. The pattern of immunoreactivity was one of diffuse cytoplasmic and membranous staining. In conclusion, EGFR expression is increased in both gallbladder, common bile duct and ampullary carcinomas but not in non-malignant conditions of the gallbladder and biliary tract. These findings suggest that EGFR overexpression occurs late in the sequential development of gallbladder and biliary tract cancers.

Clinical significance of epidermal growth factor (EGF), EGF receptor, and c-erbB-2 in human gastric cancer

The EGF stimulation system for growth regulation is implicated in normal and neoplastic cell proliferation. The role of EGF, the EGF receptor, and c-erbB-2 in human gastric cancer is reviewed on the basis of several reports, which have been mainly oriented toward their clinical significance. EGF has been shown immunohistochemically to be present in 26% of gastric cancers (n = 395). The presence of EGF in gastric cancer is correlated with the degree of gastric wall invasion and lymph node metastasis. The 5-year survival of patients with EGF-positive tumors is worse than that of patients with EGF-negative tumors. The presence of EGF in human gastric cancer may therefore represent a higher malignant potential. Fifteen percent of gastric cancers (n = 352) were also shown to be positive for both EGF and the EGF receptor immunohistochemically, and the simultaneous occurrence of EGF and the EGF receptor suggests that these tumors grow in an autocrine fashion. Tumors exhibiting EGF and the EGF receptor simultaneously show a greater degree of local invasion and lymph node metastasis. Increased expression of EGF receptor protein in gastric cancer appears to be related to biologic aggressiveness, although gene amplification has occurred only to a small extent. Twelve percent of gastric cancers (n = 486) were found to be positive for c-erbB-2. This type of tumor has a frequent metastasis, and patients with c-erbB-2-positive cancer have a poorer prognosis than those with c-erbB-2-negative tumors. Selective blockade of the EGF receptor and c-erbB-2 from their ligands with monoclonal antibodies (MoAbs) inhibits the growth of human gastric cancer xenografts. These MoAbs may therefore be effective antitumor agents against gastric cancer showing overexpression of EGF receptors or c-erbB-2.

Cellular and subcellular localization of transforming growth factor-alpha and epidermal growth factor receptor in normal and diseased human and hamster pancreas

Four normal pancreas, 8 chronic pancreatitis specimens, and 30 non-endocrine pancreatic tumors from humans and 6 normal and 6 induced pancreatic cancers in hamsters were examined immunohistochemically by antibodies against human transforming growth factor-alpha (TGF-alpha) and epidermal growth factor receptor (EGFR). Two normal pancreas and two pancreatic cancer specimens from each species were also studied immunoelectron microscopically by the immunogold method. In chronic pancreatitis, the reactivity and intensity of the staining with both antibodies were much greater in ductal/ductular cells than in the normal pancreas. All 30 pancreatic cancers reacted with both antibodies with a variable degree of reactivity and staining intensity. No correlation was found between the histological type of tumors, the degree of tumor differentiation, and the incidence and patterns of reactivity of either antibody. Immunoelectron microscopically, both EGFR and TGF-alpha were demonstrated primarily on the basal membrane. In the normal hamster pancreas, TGF-alpha was overexpressed in the alpha-cells but not in any other islet cells. Both TGF-alpha and EGFR were marginally detectable in the exocrine pancreas and in induced pancreatic lesions. This is the first demonstration of subcellular localization of TGF-alpha and EGFR in the normal and diseased human and hamster pancreas.

Adaptation of EGF receptor signal transduction to three-dimensional culture conditions: changes in surface receptor expression and protein tyrosine phosphorylation

A431 cells grown as three-dimensional spheroids show growth stimulation in response to nanomolar concentrations of EGF in contrast to monolayer cultures that show inhibition. In investigating the alterations in EGF signal transduction that underlie this modification of the proliferative response, we have compared the expression of EGF receptors on A431 cells under these conditions and related our findings to tyrosine phosphorylation and the growth response. EGF receptors were measured by 125I-EGF binding to trypsin-dispersed cells. Unexpectedly, dispersion of the monolayers caused an 80% decrease in surface EGF receptor, although, after dispersion, EGF receptor was digested by trypsin with a half-life of 69 +/- 32 min. No evidence for a comparable loss of cellular EGF receptor was seen on trypsin dispersion of spheroids. After allowing for this effect, we found that the receptor density on nondispersed monolayers (5 x 10(6) per cell) was twentyfold greater than that on spheroids (0.25 x 10(6) per cell). EGF-induced tyrosine phosphorylation was confined to the outermost cells of the spheroid, although the presence of surface-expressed EGF binding sites could be demonstrated throughout the structure and the number of EGF receptors/cell on dispersed spheroid cells showed a single distribution peak by flow cytometry, with no evidence for more than one population. Using RCM-lysozyme as a substrate, tyrosine phosphatase activity in spheroids lay within the range observed in monolayer cultures. Autophosphorylation of the EGF receptor following EGF stimulation in monolayer cultures of A431 cells rose rapidly in the first 10 seconds and then slowly increased for at least 3 h. In spheroids, it reached a maximum within 10 seconds and then declined over 3 h. Since the microenvironment within a tumor resembles that in a spheroid, a similar reduction in surface EGF receptor expression may be expected in tumors relative to monolayer cultures, together with corresponding growth stimulation in response to EGF.

Selective toxicity of TGF-alpha-PE40 to EGFR-positive cell lines: selective protection of low EGFR-expressing cell lines by EGF

The sensitivity of human breast and lung cancer cell lines to TGF-alpha-PE40, a novel chimeric recombinant cytotoxin composed of two independent domains, (i) TGF-alpha and (ii) a 40 kDa segment of the Pseudomonas exotoxin protein, PE-40, was investigated. Toxicity varied widely, correlated with epidermal growth factor receptor (EGFR) levels (P = 0.01) and was greatly reduced by EGF, indicating that binding of TGF-alpha-PE40 to EGFR is important in mediating toxicity. Cell lines expressing low EGFR levels were most highly protected by EGF, indicating that normal (low EGFR-expressing) tissue may be selectively protected by EGF in vivo. P-glycoprotein did not confer resistance to TGF-alpha-PE40, and toxicity was unaffected by multidrug resistance-modulating agents (cyclosporin A, tamoxifen, verapamil), indicating a role for TGF-alpha-PE40 in the clinical management of drug-resistant tumours.

Detection of epidermal growth factor receptor gene amplification in human squamous cell carcinomas using fluorescence in situ hybridization

The gene for epidermal growth factor receptor (EGFR) is associated with development of certain human cancers. In this study, we employed the improved fluorescence in situ hybridization technique to detect EGFR gene amplification in cell lines and tissue sections from human squamous cell carcinomas. We detected multiple distinct signals as arrayed amplicons on metaphase chromosomes and interphase nuclei of tumor cells. Our results provide a basis for rapid and quantitative DNA diagnosis of the EGFR gene amplification in individual cells of tumor specimens.

Immunohistochemical investigation of epidermal growth factor receptor expression in ameloblastomas

Immunohistochemical analysis was performed to determine the localization of epidermal growth factor receptor (EGFR) in ameloblastomas. Ameloblastoma samples were classified into follicular, plexiform, and basal cell types. The number of cases in each category was 17, 19 and 3, respectively. Ameloblastomas, disregarding their histological type, consist of two cell forms: peripheral columnar cells and central stellate cells. The frequency of EGFR expression was much higher in the latter than in the former (P < 0.005). On analysis with respect to histological types, the frequency of EGFR expression in columnar cells was not significantly different between the follicular and the plexiform types, but was observed more frequently in the stellate cells in the follicular than in the plexiform ameloblastomas (P < 0.05). This pattern of EGFR expression was not consistent with the PCNA staining pattern, but was similar to that of keratin expression which we have reported previously. The present study suggests that EGFR expression in ameloblastomas is closely associated with tumour differentiation, and squamous differentiation in particular.

EGF receptor expression, regulation, and function in breast cancer

Epidermal growth factor receptor (EGFR) overexpression correlates with both loss of estrogen receptor (ER) and poor prognosis in breast cancer. Interestingly, in normal breast EGFR appears to be expressed more frequently than in malignant tissue, and there may be a different relationship between ER and EGFR. A variety of cellular regulators, such as EGF, TGF alpha, phorbol esters, and steroid hormones, are capable of altering the level of EGFR expression in breast cells. However, much work remains to be done on the mechanistic details of EGFR regulation in this disease. The significance of EGFR as an oncogene in breast cancer is compounded by its potential interactions with other oncogenes such as c-erbB-2 and c-myc. Additionally, several recent studies have placed EGFR prominently in the signal transduction pathway, demonstrating that the EGFR-ligand system may play important roles throughout the course of malignant progression in breast cancer.

Precise mapping of the EGF receptor gene on the human chromosome 7p12 using an improved fish technique

The gene for epidermal growth factor receptor (EGFR) has been localized to the p14-p12 region of human chromosome 7 by somatic cell hybridization and radioisotope in situ hybridization techniques. In this paper, we report the precise mapping of the EGFR gene to the band p12 of chromosome 7 using a novel method in which fluorescence images from in situ hybridization and Q-banding are computer graphically merged. The novel procedure is described in detail.

Carcinoma of the esophagus and tylosis. A lethal genetic combination

Hyperkeratosis of the palms and soles (tylosis) is an uncommon genetic disorder. A small number of English families, however, have been described in which it is associated with carcinoma of the esophagus. The current report is of the first American family described with this condition. Members of those families affected with tylosis have at least a 90% risk of esophageal carcinoma by age 65 years. The paired conditions have an autosomal dominant mode of transmission and probably are controlled at a single genetic locus. The actual pathologic state might be mediated through an increase in epidermal growth factor receptors in the abnormal tissues.

Hormonal therapy of pancreatic carcinoma. Rationale and perspectives

Exocrine pancreas carcinoma is still diagnosed at a relatively late stage, so that only a few cases can be cured by surgery. Therefore, it is desirable that an effective medical therapy be found first to stall the development of the disease and second to improve the life conditions of patients. On the basis of recent discoveries, a new therapeutic approach seems to derive from hormone manipulation. The growth of pancreatic carcinoma appears to be stimulated by various factors, such as Epidermal Growth Factor (EGF) and Insulin-like Growth Factor I (IGF-I), and by various hormones, such as androgens and cholecystokinin. Several studies performed on cell lines and on animal models of pancreatic carcinoma demonstrated an antitumoral effect of certain antihormones and of somatostatin. Taking such studies as a premise, the first clinical studies were finally started in patients suffering from nonoperable pancreatic cancer. Results are still partial and contradictory, but such research is certainly worthy of further study along the lines already taken.

Construction of immunoradiometric assay for circulating c-erbB-2 protooncogene product in advanced breast cancer patients

The human c-erbB-2 protooncogene product (erbB-2 protein) is a 185 kilodalton glycoprotein closely related to epidermal growth factor receptor protein. In this study, we measured the concentration of circulating erbB-2 protein in cancer patients by means of a new immunoradiometric assay (IRMA). Two monoclonal antibodies (MoAbs), SV2-61 gamma and 6G10, recognize erbB-2 protein but bind to separate epitopes. SV2-61 gamma was used as an immunoadsorbent and 6G10 as an 125I-labeled probe. A serum was considered positive for erbB-2 protein if the percent binding exceeded the mean of the normal group by more than 3 standard deviations. Eleven of 21 patients with advanced breast cancer and 1 of 15 with advanced gastric cancer were positive. Serum erbB-2 protein levels correlated well with the therapy and the status of the patients with breast cancer. On the contrary, all patients with advanced colon, ovarian, or pancreatic cancers, showed levels below the cut-off value. These results suggest that circulating erbB-2 protein can be measured using the newly constructed IRMA. Since c-erbB-2 protooncogene amplification and overexpression are accepted as a good marker of aggressiveness, relapsing potency, and poor prognosis, this IRMA should be a promising tool with which to help manage breast cancer patients.

Epidermal growth factor receptor in breast cancer. Comparison with non malignant breast tissue

Epidermal growth factor receptors were measured using a radioligand binding assay in membrane preparations from 67 cancer and 25 non-malignant tissues. The binding characteristics of EGFr were similar in tumour and normal breast membranes. The concentrations were significantly higher in non-malignant tissue than in cancer. EGFr concentrations were directly correlated with steroid receptors in non-malignant tissue, whereas in cancer an inverse correlation between EGFr and steroid receptors was found.

Epidermal growth factor receptor in odontogenic cysts and tumors

The expression of epidermal growth factor receptor (EGFR) was investigated in 67 cases of odontogenic cysts and 35 cases of odontogenic tumors using monoclonal antibody to EGFR (Biomarker, Israel) to determine the presence and significance of this transmembrane growth factor receptor. The cystic epithelial cells of odontogenic cystic lesions (keratocyst 60%; primordial cyst 75%; radicular cyst 35%; and follicular cyst 47.4%) were positive to EGFR staining. Cytochemical characterization of EGFR in those cystic epithelium was cell membrane positive type as in the normal epithelium. No expression of EGFR was found in the odontogenic tumors. This diversity of EGFR represents no binding activity of EGF, or loss of EGFR in the tumor cell upon EGFR mediated growth in odontogenic tumors was suggested a different tumor cell growth factor status or microenvironment in cell proliferation mechanism at the cellular level in cysts and tumors of odontogenic origin.

Expression of transforming growth factor-alpha in gastric carcinoma and normal gastric mucosa cells

The presence of transforming growth factor-alpha (TGF-alpha) was studied in a total of 120 consecutive patients with gastric carcinomas. This immunohistochemical study found TGF-alpha expression in 60% (n = 72) of carcinomas. It also was detected in normal gastric epithelial mucosa in 36% (n = 43) of specimens. There was no significant statistical correlation between TGF-alpha expression and clinical features (e.g., patient age and sex) or pathologic features (e.g., tumor stage, grade, and localization or growth pattern according to an earlier histologic classification). Expression of TGF-alpha by these tumor cells had no influence on prognosis. It was neither a histopathologic marker of high malignancy nor a useful prognostic tool. It had no influence on the invasive growth pattern of gastric carcinoma.

Autocrine growth factors and solid tumor malignancy

The ability of malignant cells to escape the constraint that normally regulate cell growth and differentiation has been a primary focus of attention for investigators of cancer cell biology. An outcome of this attention has been the discovery that the protein products of oncogenes play a role in the activation of growth signal pathways. A second outcome, possibly related to abnormal oncogene expression, has been the discovery that malignant cells frequently show an ability to regulate their own growth by the release of autocrine growth modulatory substances. Most important, the growth of certain malignant cell types has been shown to depend on autocrine growth circuits. A malignant tumor whose continued growth depends on the release of an autocrine growth factor may be vulnerable to treatment with specific receptor antagonists or immunoneutralizing antibodies designed to break the autocrine circuit. Information is rapidly emerging concerning autocrine growth factors in selected human solid tissue malignancy.

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.

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.

Immunohistochemical demonstration of epidermal growth factor receptor and ceruloplasmin in thyroid diseases

The expression of epidermal growth factor receptors (EGFR) and ceruloplasmin (CP) in thyroid diseases was investigated by immunohistochemical methods, and the results were compared with the expression of thyroglobulin (TG). Eighty-eight surgical specimens of thyroid diseases, including follicular carcinoma (7 cases), papillary carcinoma (20 cases), follicular adenoma (29 cases), adenomatous goiter (10 cases), diffuse hyperplasia (20 cases) and chronic thyroiditis (2 cases), were studied. All cases of follicular carcinoma and 18 cases (90%) of papillary carcinoma expressed the EGFR immunoreaction in the cytoplasm with a moderate to strong staining intensity. A weak immunoreaction for EGFR was noted in some benign thyroid diseases. CP showed various degrees of positivity in all cases of follicular carcinoma and 19 cases (95%) of papillary carcinoma. The benign thyroid lesions were consistently negative for this antigen, not counting one case of Hürthle cell adenoma. There was a positive correlation between EGFR and CP immunostaining intensity in thyroid carcinomas, representing higher expression of EGFR accompanied by a stronger staining intensity of CP. Except for two cases of papillary carcinoma, all cases showed immunoreaction for TG. The results indicate the enhanced expression of EGFR and CP in thyroid carcinomas. EGFR and CP thus appear to be valuable tools for differential diagnosis between benign and malignant thyroid neoplasms.

Increased epidermal growth factor receptors in seborrheic keratoses and acrochordons of patients with the dysplastic nevus syndrome

Seborrheic keratoses and acrochordons may change in biologic behavior with pregnancy or during treatment with sex steroids. Because epidermal growth factor receptor localization may change in hyperproliferative skin diseases, we compared epidermal growth factor receptor immunolocalization in seborrheic keratoses and acrochordons from women who were or were not pregnant or taking oral sex steroid hormones. Epidermal growth factor receptor was further investigated in growing and quiescent seborrheic keratoses and acrochordons from women with and without the dysplastic nevus syndrome. The epidermal growth factor receptor concentration was strikingly elevated in suprabasilar keratinocytes of growing seborrheic keratoses and acrochordons from patients with the dysplastic nevus syndrome who were pregnant or taking sex steroid hormones and less elevated in growing seborrheic keratoses from other patients. In contrast, the epidermal growth factor receptor distribution pattern in acrochordons did not correlate as well with the history of growth of these lesions in normal patients. These data suggest sex steroids may affect epidermal growth factor receptor metabolism in benign epidermal hyperproliferative lesions, particularly in patients with the dysplastic nevus syndrome.

Expression of several growth factors and their receptor genes in human colon carcinomas

We have examined the expression of mRNAs for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), EGF receptor (EGFR), PDGF-A chain (PDGFA), PDGF-B chain (PDGFB) and PDGF receptor (PDGFR) genes in seven human colorectal carcinoma cell lines and 18 human colorectal carcinomas. In surgically resected specimens of the 18 colorectal tumors, TGF-alpha, EGFR, PDGFA, PDGFB and PDGFR mRNAs were detected at various levels in 15 (83%), 9 (50%), 18 (100%), 8 (44%) and 12 (67%), respectively. They were also detected in normal tissues. Interestingly, EGF mRNA was detected in only five (28%) of the tumors, but not in normal mucosa. Expression of EGF was also confirmed immunohistochemically in tumor cells. Of the five tumors expressing EGF, four expressed EGFR mRNA and showed a tendency to invade veins and lymphatics. All the colorectal carcinoma cell lines expressed TGF-alpha mRNA, and five cell lines expressed EGFR mRNA simultaneously. Production of TGF-alpha protein by DLD-1 and CoLo320DM cells was confirmed by TGF-alpha specific monoclonal antibody binding assay. The spontaneous 3H-thymidine uptake by DLD-1 was suppressed by an anti-TGF-alpha monoclonal antibody. PDGFA and PDGFB mRNA were also expressed in four cell lines, but PDGFR and EGF mRNA was not detected. These results suggest that human colorectal carcinomas express multi-loops of growth factors and that TGF-alpha produced by tumor cells functions as an autocrine growth factor in human colonic carcinoma.

Growth factors and oncogenes in pancreatic cancer

There are abnormalities in the structure and/or function of several oncogenes and growth factors in human pancreatic cancer, notably the EGF receptor and its ligand TGF alpha, c-erb B-2 proto-oncogene, Ki-ras oncogene and the tumour suppressor gene p53. The temporal sequence of their activation and the nature of the aetiological agents responsible for their activation are not yet clear. In vitro pancreatic culture systems and transgenic animal experiments are needed to reconstruct and define those molecular events that are necessary and sufficient for the neoplastic phenotype.

TPA induces repression of EGF receptor gene expression

Epidermal growth factor receptor gene expression in response to the tumor promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) was analyzed in the A549 human lung adenocarcinoma cell line using DNA transfection. After 8 h of treatment a definite repression (45%) of EGF receptor gene transcription could be seen. Repression was maintained for up to 24 h. Little or no induction of transcription could be seen prior to the onset of repression for potential enhancer regions both upstream and downstream of the translation start site. The cis-element(s) responsible for repression were localized between residues -384 and -151 of the EGF receptor gene promoter region using a deletion plasmid series.

Composition and production of pancreatic tumor related antigens

Large numbers of specific and highly purified antibodies that react with tumor-associated antigens (TAAs) have been produced over the last decade as a result of the hybridoma technology that was developed during the previous decade. The availability of monoclonal antibodies (MAbs) rapidly led to studies of their clinical applicability. It has recently become apparent that further characterization of TAAs at the molecular level is needed before the MAbs, which react with TAAs, can have extensive use in the diagnosis and treatment of pancreatic cancer. The information that is currently available concerning the molecular composition and production of pancreatic TAAs is summarized in this presentation.

Epidermal growth factor labeled beta-amanitin-poly-L-ornithine: preparation and evidence for specific cytotoxicity

Poly-L-ornithine with an average molecular weight of 32K was reacted with beta-amanitin hydroxysuccinimide ester to form an amide-linked toxin conjugate. Loading of the polymeric chain with amanitin was high, corresponding to up to 35% of the total weight. To this amatoxin vehicle we attached a targeting molecule, human recombinant leucine-21 epidermal growth factor (hrEGFL), via a disulfide-containing linker moiety. A typical average stoichiometry of the hrEGFL labeled toxin conjugate was (L-Orn)164(beta-amanitin)19(COC2H4SSC2H4CO-hrEGFL)2. The affinity for EGF receptors of hrEGFL bound in this conjugate was tested by using A 431 cells. The affinity was eight times lower than that of unsubstituted hrEGFL but regarded as high enough for studying specific toxicity effects with cells bearing EGF receptors. We found that beta-amanitin in the labeled conjugate was able to inhibit the growth of A 431 cells at a concentration of 28 nM, 80 times lower than for native beta-amanitin and 20 times lower than for poly-L-ornithine-bound beta-amanitin without the hrEGFL label. The approximately 20-fold enhancement of cytotoxicity suggests a specific internalization of the toxin conjugate mediated by the hormone label. This idea is supported by the fact that also in another transformed fibroblast cell line, with an increased though smaller number of EGF receptors than A 431 cells, the corresponding enhancement of cytotoxicity was demonstrable but less pronounced (7-fold). The hormone-mediated increase in cytotoxicity of EGF labeled poly-L-ornithine-beta-amanitin conjugates, combined with their moderate toxicity in the mouse, encourages further examination of such compounds in tumor model systems in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of EGF receptor expression with proliferating cells and of ras p21 expression with differentiating cells in various skin tumours

The localization of DNA replicating cells, epidermal growth factor (EGF) receptor-expressing cells and ras oncogene product p21 (p-21ras) positive cells were examined in various skin tumours to elucidate the role of EGF receptor and p21ras in the epidermis. Normal skin, keratoacanthoma (KA), solar keratosis (SK), Bowen's disease (BD), squamous cell carcinoma (SCC), basal cell carcinoma (BCC) and extramammary Paget's disease (PD) were studied. EGF receptors were seen in proliferating layers, where DNA replicating cells localize, but p21ras was found in the more differentiated layers. We conclude that EGF receptor expression is closely associated with cellular proliferation, but p21ras may play a role in the differentiation of cells in various skin tumours.

EGF and TGF-alpha, the ligands of hyperproduced EGFR in human esophageal carcinoma cells, act as autocrine growth factors

In order to ascertain autocrine growth factors in esophageal carcinomas, we analysed expression of mRNAs and proteins for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha) and epidermal growth factor receptor (EGFR) in 6 esophageal carcinoma cell lines. Gene alterations were also examined. All of the esophageal carcinoma cell lines expressed mRNA for EGFR and TGF-alpha genes. Interestingly, EGF mRNA of about 5.0 kb was also detected in TE-1, TE-2, and TE-8 cells. Production of protein was also confirmed by binding assay and ELISA on 3 of the 6 cell lines. The cells had a relatively high number of EGFRs and produced TGF-alpha and EGF protein at the same time. Furthermore, anti-EGF (KEM-10) and anti-TGF-alpha (WA-3) monoclonal antibodies (MAbs) inhibited spontaneous uptake of tritiated thymidine (3H-TdR) by TE-1 cells which expressed EGF, TGF-alpha and EGFR mRNA and protein. These results strongly suggest that EGF and/or TGF-alpha produced by carcinoma cells function as autocrine growth factors for human esophageal carcinomas.

Growth factors in progression of human esophageal and gastric carcinomas

Human esophageal and gastric carcinomas express multi-autocrine growth factors and hormones including epidermal growth factor (EGF), transforming growth factor (TGF)-alpha and beta, platelet-derived growth factor (PDGF), insulin-like growth factor (IGF) and sex hormones. Overexpression of EGF, TGF-alpha and EGF receptor (EGFR) by tumor cells is closely correlated with the tumor invasion and patient prognosis. This is substantiated by the facts that EGF and TGF-alpha act as autocrine growth factors and then induce the expression of mRNAs for multi-growth factors and their receptors (EGF, TGF-alpha, EGFR, ERBB2, PDGF). Moreover, they stimulate the expression of metalloproteinase genes suggesting that EGF and TGF-alpha successively evoke cascade phenomena which are most convenient for tumor progression, invasion and metastasis. On the other hand, multiple oncogene alterations take place in the process of tumor progression. HST-1 and INT-2 genes which is a member of fibroblast growth factor gene family, are amplified in approximately 50% of primary tumors and all the metastatic tumors of esophageal carcinomas. The amplification of ERBB2 gene in metastatic gastric carcinomas is detected more frequently than in primary carcinomas. Overexpression of multi-growth factor-receptor systems might lead to genetical alterations. Scirrhous gastric carcinoma has vast fibrous stroma with rapid and extensive growth and exhibits high malignancy. Its fibrous stroma may account for synchronous overexpression of EGF, TGF-alpha, PDGF, IGF and TGF-beta by tumor cells. Most of well differentiated adenocarcinomas show overexpression of p 185ERBB2 and coexpression of p 185ERBB2, and EGFR evidently correlates with high malignancy. In conclusion, the accumulation and interaction of several growth factors produced by tumor cells are necessary for the progression of human esophageal and gastric carcinomas. They may be attributed to genetic changes including activation of oncogenes, inactivation and deletion of anti-oncogenes and transcriptional regulatory sequences.

Expression of epidermal growth factor, transforming growth factor-alpha and their receptor genes in human gastric carcinomas; implication for autocrine growth

The expressions of mRNA for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha) and EGF receptor (EGFR) genes were examined in 7 human gastric carcinoma cell lines and 15 gastric carcinoma tissues and the corresponding normal mucosas. All of the gastric carcinoma cell lines expressed mRNA for EGFR and TGF-alpha genes. TMK-1 and MKN-28 cells also expressed EGF mRNA. Production of EGF, TGF-alpha and EGFR protein by gastric carcinoma cell lines was also confirmed by EGF and TGF-alpha specific monoclonal antibody binding. As for surgical specimens, EGFR and TGF-alpha mRNA were detected at high levels in all the tumor tissues. Interestingly, EGF mRNA was detected in 5 (33.3%) of the 15 gastric carcinomas but it was not detected in normal tissues. Moreover, anti-EGF and anti-TGF-alpha monoclonal antibodies inhibited the spontaneous 3H-TdR uptake by gastric carcinoma cells. These results suggest that EGF and/or TGF-alpha produced by tumor cells act as autocrine growth factors for gastric carcinomas.