Light and electron microscopical demonstration of c- erB-2 gene product-like immunoreactivity in human malignant tumors

Correlative Fluorescence- and Electron Microscopy of Whole Breast Cancer Cells Reveals Different Distribution of ErbB2 Dependent on Underlying Actin

Epidermal growth factor receptor 2 (ErbB2) is found overexpressed in several cancers, such as gastric, and breast cancer, and is, therefore, an important therapeutic target. ErbB2 plays a central role in cancer cell invasiveness, and is associated with cytoskeletal reorganization. In order to study the spatial correlation of single ErbB2 proteins and actin filaments, we applied correlative fluorescence microscopy (FM), and scanning transmission electron microscopy (STEM) to image specifically labeled SKBR3 breast cancer cells. The breast cancer cells were grown on microchips, transformed to express an actin-green fluorescent protein (GFP) fusion protein, and labeled with quantum dot (QD) nanoparticles attached to specific anti-ErbB2 Affibodies. FM was performed to identify cellular regions with spatially correlated actin and ErbB2 expression. For STEM of the intact plasma membrane of whole cells, the cells were fixed and covered with graphene. Spatial distribution patterns of ErbB2 in the actin rich ruffled membrane regions were examined, and compared to adjacent actin-low regions of the same cell, revealing an association of putative signaling active ErbB2 homodimers with actin-rich regions. ErbB2 homodimers were found absent from actin-low membrane regions, as well as after treatment of cells with Cytochalasin D, which breaks up larger actin filaments. In both latter data sets, a significant inter-label distance of 36 nm was identified, possibly indicating an indirect attachment to helical actin filaments via the formation of heterodimers of ErbB2 with epidermal growth factor receptor (EGFR). The possible attachment to actin filaments was further explored by identifying linear QD-chains in actin-rich regions, which also showed an inter-label distance of 36 nm.

Inhibition of ezrin causes PKCα-mediated internalization of erbb2/HER2 tyrosine kinase in breast cancer cells

Unlike other ErbB family members, HER2 levels are maintained on the cell surface when the receptor is activated, allowing prolonged signaling and contributing to its transforming ability. Interactions between HER2, HSP90, PMCA2, and NHERF1 within specialized plasma membrane domains contribute to the membrane retention of HER2. We hypothesized that the scaffolding protein ezrin, which has been shown to interact with NHERF1, might also help stabilize the HER2-PMCA2-NHERF1 complex at the plasma membrane. Therefore, we examined ezrin expression and its relationship with HER2, NHERF1, and PMCA2 levels in murine and human breast cancers. We also used genetic knockdown and/or pharmacologic inhibition of ezrin, HSP90, NHERF1, PMCA2, and HER2 to examine the functional relationships between these factors and membrane retention of HER2. We found ezrin to be expressed at low levels at the apical surface of normal mammary epithelial cells, but its expression is up-regulated and correlates with HER2 expression in hyperplasia and tumors in murine mammary tumor virus-Neu mice, in human HER2-positive breast cancer cell lines, and in ductal carcinoma in situ and invasive breast cancers from human patients. In breast cancer cells, ezrin co-localizes and interacts with HER2, NHERF1, PMCA2, and HSP90 in specialized membrane domains, and inhibiting ezrin disrupts interactions between HER2, PMCA2, NHERF1, and HSP90, inhibiting HER2 signaling and causing PKCα-mediated internalization and degradation of HER2. Inhibition of ezrin synergizes with lapatinib in a PKCα-dependent fashion to inhibit proliferation and promote apoptosis in HER2-positive breast cancer cells. We conclude that ezrin stabilizes a multiprotein complex that maintains active HER2 at the cell surface.

Immunohistochemical Expression of c-erbB-2 in Human Breast Cancer by Monoclonal Antibody: Correlation with Lymph Node and Er Status

c-erbB-2 Protein expression was investigated in a series of fifty primary breast cancers by means of a specific monoclonal antibody and immunocytochemistry. Specific staining was observed at the plasma membrane level of neoplastic cells, according to the reported localization of c-erbB-2 protein. Sixty-four percent of tumors scored positive, with a variable amount of stained cells. The rate of protein expression was found to exceed the reported gene amplification. No relationship was observed between c-erbB-2 protein staining and age, meno pausal status or histologic subtypes. An inverse association was found between c'erbB-2 protein staining and estrogen receptor content of tumors, assayed by immunocytochemistry. A positive relationship was observed between c-erbB-2 protein expression and presence of axillary node metastasis. These findings suggest that c-erbB-2 protein expression is a marker of tumor aggressiveness and that its prognostic power deserves further investigation both in node-positive and node-negative patients.

Esophageal Cancer: Associated Factors with Special Reference to the Kashmir Valley

Esophageal cancer is one of the most common cancers worldwide. It is a multifactorial disease, and no single agent has been identified so far as the sole cause of the cancer. Many factors like smoking, the consumption of alcohol, fungal-contaminated, spicy and various nitrosamine-containing food stuffs and hot beverages, nutritional deficiency of some vitamins like β-carotene, vitamin A, C and E and minerals like zinc, selenium and molybdenum, the use of opium, HPV infection and various genetic factors have been found associated with the occurrence of the disease worldwide. Wide geographic differences and substantial changes in the incidence of esophageal cancer occurring over time have been suggested. Among the risk factors in India, betel quid chewing carries a relatively high risk. High incidences in Kashmir have been associated with the consumption of hot salted tea, sun-dried, smoked foods, tobacco in the form of hukka and various genetic factors. The exact cause of esophageal squamous cell carcinoma is unknown. Much work has been carried out on the role of various environmental factors, gene mutations, and polymorphisms worldwide, including Kashmir. Although the Kashmir valley is present on the border of the ‘high risk esophageal cancer belt’ and esophageal squamous cell carcinoma represents the most commonly occurring malignancy in Kashmir, the amount of information available on various associated factors is still very little as there is a paucity of various epidemiological and molecular studies being carried out in this field.

HER2 signaling regulates HER2 localization and membrane retention

ErbB2/HER2/Neu is a receptor tyrosine kinase that is overexpressed in 25-30% of human breast cancers, usually associated with amplification of the ERBB2 gene. HER2 has no recognized ligands and heterodimers between HER2 and EGFR (ErbB1/HER1) or HER2 and ErbB3/HER3 are important in breast cancer. Unlike other ErbB family members, HER2 is resistant to internalization and degradation, and remains at the cell surface to signal for prolonged periods after it is activated. Although the mechanisms underlying retention of HER2 at the cell surface are not fully understood, prior studies have shown that, in order to avoid internalization, HER2 must interact with the chaperone, HSP90, and the calcium pump, PMCA2, within specific plasma membrane domains that protrude from the cell surface. In this report, we demonstrate that HER2 signaling, itself, is important for the formation and maintenance of membrane protrusions, at least in part, by maintaining PMCA2 expression and preventing increased intracellular calcium concentrations. Partial genetic knockdown of HER2 expression or pharmacologic inhibition of HER2 signaling causes the depletion of membrane protrusions and disruption of the interactions between HER2 and HSP90. This is associated with the ubiquitination of HER2, its internalization with EGFR or HER3, and its degradation. These results suggest a model by which some threshold of HER2 signaling is required for the formation and/or maintenance of multi-protein signaling complexes that reinforce and prolong HER2/EGFR or HER2/HER3 signaling by inhibiting HER2 ubiquitination and internalization.

The scaffolding protein NHERF1 regulates the stability and activity of the tyrosine kinase HER2

We examined whether the scaffolding protein sodium-hydrogen exchanger regulatory factor 1 (NHERF1) interacts with the calcium pump PMCA2 and the tyrosine kinase receptor ErbB2/HER2 in normal mammary epithelial cells and breast cancer cells. NHERF1 interacts with the PDZ-binding motif in PMCA2 in both normal and malignant breast cells. NHERF1 expression is increased in HER2-positive breast cancers and correlates with HER2-positive status in human ductal carcinoma in situ (DCIS) lesions and invasive breast cancers as well as with increased mortality in patients. NHERF1 is part of a multiprotein complex that includes PMCA2, HSP90, and HER2 within specific actin-rich and lipid raft-rich membrane signaling domains. Knocking down NHERF1 reduces PMCA2 and HER2 expression, inhibits HER2 signaling, dissociates HER2 from HSP90, and causes the internalization, ubiquitination, and degradation of HER2. These results demonstrate that NHERF1 acts with PMCA2 to regulate HER2 signaling and membrane retention in breast cancers.

PMCA2 regulates HER2 protein kinase localization and signaling and promotes HER2-mediated breast cancer

In the lactating mammary gland, the plasma membrane calcium ATPase2 (PMCA2) transports milk calcium. Its expression is activated in breast cancers, where high tumor levels predict increased mortality. We find that PMCA2 expression correlates with HER2 levels in breast cancers and that PMCA2 interacts with HER2 in specific actin-rich membrane domains. Knocking down PMCA2 increases intracellular calcium, disrupts interactions between HER2 and HSP-90, inhibits HER2 signaling, and results in internalization and degradation of HER2. Manipulating PMCA2 levels regulates the growth of breast cancer cells, and knocking out PMCA2 inhibits the formation of tumors in mouse mammary tumor virus (MMTV)-Neu mice. These data reveal previously unappreciated molecular interactions regulating HER2 localization, membrane retention, and signaling, as well as the ability of HER2 to generate breast tumors, suggesting that interactions between PMCA2 and HER2 may represent therapeutic targets for breast cancer.

Clinical Significance of erbB-2 (HER-2/neu) Protein

erbB-2 protein is believed to be a cell membrane receptor for the recently identified ligand gp30. When overexpressed, erbB-2 is an indicator of poor prognosis in adenocarcinomas of breast, stomach, lung, and endometrium. Even more important, clinical data suggest that erbB-2 overexpression may be an indicator of poor response to at least some commonly used adjuvant regimens. However, there is preliminary evidence that these tumors might respond as well to doxorubicin regimen as do erbB-2 negative tumors, at least in gastric cancer. The efficacy of doxorubicin-containing regimen in the treatment of tumors with erbB-2 overexpression needs to be explored further by retrospective analysis of finished clinical trials. Combination of chemotherapeutics with reagents that block erbB-2 signal transduction pathway may be another effective approach.

Frequencies of HER-2/neu expression and gene amplification in patients with oesophageal squamous cell carcinoma

The utilisation of antitumour T cells induced by cancer vaccination with HER-2 peptides or antibodies (Herceptin) against HER-2, as immunotherapy for oesophageal cancer, is a novel and attractive approach. It is important to clarify the frequencies of HER-2 expression and gene amplification in patients with oesophageal squamous cell carcinoma (SCC) and to evaluate the relationship between HER-2 status and HLA haplotype, since the candidates for HER-2 peptide-based vaccination are restricted to a certain HLA haplotype. We determined the frequency of HER-2 expression using the HercepTest for immunohistochemistry and HER-2 gene amplification by fluorescence in situ hybridisation (FISH) assay in oesophageal SCC (n=66). HER-2-positive tumours (1+/2+/3+) analysed by a HercepTest were observed in 30.3% of all the patients and HER-2 gene amplification evaluated by FISH was observed in 11.0% of all the patients, in which all HercepTest (3+) tumours were found to have gene amplification and three of six moderately positive (2+) tumours showed gene amplification. Furthermore, HER-2-positive cells were present more diffusely and were larger within each tumour in the patients who were HercepTest 3+ than those who were HercepTest 1+. Moreover, the survival rate in HER-2-positive group was significantly worse than that in HER-2-negative group. Also, the survival rate in the patients with HER-2 gene amplification was significantly worse than that without HER-2 gene amplification. In addition, oesophageal SCC patients with both HLA-A24-positive and HER-2-positive tumours (1+/2+/3+) accounted for 26% of these cases, and both HLA-A2- and HER-2-positive tumours accounted for 18% of them.

ErbB2 growth factor receptor, a marker for neuroendocrine cells?

BACKGROUND/AIMS

The overexpression of ErbB2 in pancreatic cancer has been reported with a varying incidence ranging between 1 and 80%. Our routine examination, however, revealed a consistently strong immunoreactivity of three anti-ErbB2 growth factor receptor antibodies in pancreatic islets and intrapancreatic ganglia. To validate our findings and to understand the reasons for the reported differences in the frequency of ErbB2 overexpression in pancreatic cancer, the following studies were performed.

MATERIALS AND METHODS

Tissue samples from 12 normal pancreata, 7 surgical chronic pancreatitis cases, 21 primary pancreatic adenocarcinomas, 9 metastatic pancreatic adenocarcinomas, and 4 islet cell tumors were subjected to immunohistochemical examination using antibodies from three manufacturers. Cultured human islet cells and pancreatic cancer cell lines, as well as samples from the gastrointestinal tract, the CNS, and the adrenal gland were included in the study. For comparison, mammary cancer tissue and mammary cancer cells, as well as selected tissues from Syrian golden hamsters, were used. To verify the results, Western blot and Northern slot-blot analyses were performed.

RESULTS

Pancreatic cancer cells, in vitro and in vivo, showed a remarkable heterogeneity in the immunostaining of ErbB2, ranging from very faintly to strongly stained. On the other hand, in both humans and hamsters, a consistently strong immunostaining was found in the Langerhans' islets, in the ganglia of intrapancreatic and extrapancreatic nerves, as well as in the CNS, spinal cord and adrenal gland.

CONCLUSIONS

ErbB2 appears to play an important role in neuroendocrine tissues and is probably involved in the development and functional regulation of these cells. The concomitant expression of these factors and islet cell hormones very likely results in the activation of multiple growth-promoting pathways in pancreatic cancer and its aggressive behavior.

Breast cancer with neuroendocrine differentiation detected by unique staining pattern of neoplastic cells in hercep test

Hercep Test (DAKO) is an immunohistological screening kit to select cases of advanced breast cancer with indication for treatment with a humanized mouse monoclonal antibody to human epidermal growth factor receptor-2, trasthzumab (Herceptin). We report a case of an 84-year-old female with invasive ductal carcinoma of the right breast, whose neoplastic cells showed a unique staining pattern in Hercep Test. The cells showed an intracytoplasmic fine granular staining pattern, instead of the membranous pattern of typical breast cancer cells. This unique staining pattern suggested some special features of the neoplastic cells. This case was finally diagnosed as invasive ductal carcinoma with focal neuroendocrine differentiation by subsequent imunohistochemical and electron microscopic examinations. The neoplastic cells showed positive reactivity for grimelius stain, chromogranin A, synaptophysin, and neuronspecific enolase, as well as electron-dense neurosecretory granules (up to 150 nm in diameter). This unique staining pattern of the neoplastic cells with Hercep Test is a useful clue to detect breast cancer with neuroendocrine differentiation, which is likely to be missed in routine examination. Clinical and pathologic findings including immunohistochemical and ultrastructural findings of this case are reported, together with a brief review of the literature.

Diverse expression of ErbB receptor proteins during rat liver development and regeneration

BACKGROUND & AIMS

The protein expression and interactions of the ErbB receptors were examined in different liver proliferation models in vivo and in vitro, including ontogeny and regeneration following partial hepatectomy.

METHODS

Expression and tyrosine phosphorylation status of specific ErbB proteins were studied by immunologic methods.

RESULTS

The epidermal growth factor receptor, ErbB2, and ErbB3 were the only ErbB proteins detected in the liver parenchyma on embryonic day 19. ErbB2 disappeared by the third week after birth and could not be appreciably induced in the adult animal by partial hepatectomy. ErbB2 was also detected in multipotent stem (RLE) and hepatoma (H4IIe) cell lines as well as in fetal, but not adult, hepatocyte cultures. Only epidermal growth factor receptor and ErbB3 were detected in adult liver, and both showed circadian variation in protein expression. ErbB4 was not detected in any model. Patterns of ligand-induced ErbB phosphorylation differed between fetal and adult hepatocytes.

CONCLUSIONS

Complex and independent programs regulate the ErbB receptors, with implications for differential cell signaling in hepatic development and regeneration.

Molecular biology of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the predominant histologic subtype of esophageal cancer and characterized by high mortality rate and geographic differences in incidence. With the advances in the field of molecular biology, our understanding of the pathogenesis, epidemiology and behavior of ESCC continues to evolve. The recent development includes research in etiopathogenesis (viruses and cancer susceptibility genes), keratins, tumor related genes (oncogenes, tumor suppressor genes, genes involved in metastasis and apoptosis genes), proliferation-related factors (nuclear proteins, flow cytometry/morphometry, argyrophilic nucleolar organizer region) and factors related to metastases (cell adhesion molecules and enzymes related to degradation of extracellular matrix). There are ranges of molecular techniques potentially available to complement the traditional approaches in the management of ESCC. On the other hand, critics are needed in the interpretation and translation of these research findings from laboratories to clinics. Further investigations, education and collaborations between the various scientific and clinical disciplines are important to successful application of these molecular findings aiming at improving management of patients with ESCC.

Analysis of protooncogene c-erbB-2 in benign and malignant human prostate

In this report, we characterized the c-erbB-2 gene and its product in prostatic cancer cells. Three prostatic cancer cell lines (PC3, DU145 and TSU-Pr1), one primary prostatic cancer and four benign prostatic hyperplasias (BPH) were studied. In reverse transcribed polymerase chain reaction, c-erbB-2 mRNA was demonstrated in all three cell lines and prostatic cancer tissues as well as BPH. The c-erbB-2 protein was expressed higher in prostatic cancer cells and tissues as compared with benign tissue by enzyme immunoassay, but it was not statistically significant. Immunohistochemical study, with the monoclonal antibody SV2-61gamma that recognizes the extracellular domain of c-erbB-2, showed that all the prostatic tissues and cells had reactivity. Antigenicity was mainly in the cytoplasm. Analysis of genomic DNA failed to disclose gene amplifications or rearrangements of c-erbB-2 in both prostatic cancer and BPH. The sequence of amplified c-erbB-2, which corresponds to transmembrane domain, disclosed wild type in all prostatic cancer cells. These results demonstrate that although the number is limited, c-erbB-2 gene and protein are expressed in prostatic cancers and benign prostates. In the previous studies on c-erbB-2 expression in prostatic tissue, mainly conducted by immunohistochemistry, its frequency varies among each study, ranging from less than 0% to 100%. Therefore, to evaluate the c-erbB-2 in prostatic tissue precisely, it is also necessary to detect mRNA of c-erbB-2 as demonstrated in our study.

Expression of c-erbB-2 oncoprotein in gastric carcinoma: correlation with histopathologic characteristics and analysis of Ki-67

Amplification and overexpression of the c-erbB-2 gene has been demonstrated in several tumors and thought to be important determinants of biologic behaviors of carcinomas. In this study, correlation between c-erbB-2 expression und histopathologic parameters, including proliferative activity of gastric carcinomas was evaluated. Paraffin-embedded tissue sections from 62 patients who underwent curative resection of gastric carcinoma were analyzed immunohistochemically for the expression of c-erbB-2 and Ki-67. Strong membrane staining for c-erbB-2 was detected in 11 of 62 gastric carcinomas (17,7%) and no positive reaction was evident in noncancerous tissue. The incidence of c-erbB-2 positivity in intestinal type carcinomas (24,3%) was higher than that of diffuse type carcinomas (4,76%). Positive staining for c-erbB-2 was present in one of the 9 (11,1%) early gastric carcinomas and 10 of 53 (18, 8%) advanced gastric carcinomas. However, no statistically significant relationships were found between c-erbB-2 expression and histopathologic type, depth on invasion, the tumor size or lymph node metastases. Among the metastatic lymph nodes, 3 were positively stained with c-erbB-2 whereas the primary tumors of two cases had been found to be negative. Additionally, no correlation was found between c-erbB-2 reactivity and proliferative activity of carcinoma cells. The results suggest that expression of c-erbB-2 protein may occur selectively in intestinal type of gastric carcinomas. However, c-erbB-2 expression is not a reliable marker of malignant potential in gastric carcinomas.

Expression of c-erbB-2 oncoprotein in human thyroid tumours

AIMS

c-erbB-2 expression has been found to be a potential marker of aggressive biological behaviour in some tumours, but the role played by this oncoprotein in the development and maintenance of thyroid tumours is still controversial. Therefore our objective was to determine whether c-erbB-2 was overexpressed in a large retrospective series of human thyroid tumours, including both from follicular and C-cell differentiation.

METHODS AND RESULTS

We have studied 67 thyroid tumours (10 follicular adenomas, 11 follicular carcinomas, three anaplastic carcinomas, 25 papillary carcinomas and 18 medullary carcinomas and 16 metastases) by immunohistochemistry using an antigen retrieval method for paraffin-embedded material and a specific polyclonal antibody against the intracytoplasmic part of c-erbB-2 oncoprotein. There are marked differences in the pattern of c-erbB-2 immunoreactivity depending on the type of thyroid tumour. Thus, no expression of the oncoprotein has been found in follicular adenomas, follicular carcinomas and anaplastic carcinomas, but 52% of papillary carcinomas (membranous and diffuse cytoplasmic patterns) and all medullary carcinomas (granular cytoplasmic pattern) are immunopositive.

CONCLUSIONS

Our results indicate that overexpression of c-erbB-2 oncoprotein is easily identifiable by immunohistochemistry in paraffin sections of certain thyroid tumours after applying an antigen retrieval method. This study suggests that c-erbB-2 oncoprotein may play some role in disease progression in papillary and medullary thyroid carcinomas, but the significance of the different immunohistochemical patterns merits further investigations.

C-erbB-2 protein expression in oesophageal squamous epithelium from oesophageal squamous cell carcinomas, with special reference to histological grade of carcinoma and pre-invasive lesions

AIMS

C-erbB-2, an oncogene, is member of the growth factor receptor family. Its role in activation of oesophageal squamous cell carcinoma is poorly understood. The aim of this study was to evaluate the part played by c-erbB-2 in oesophageal squamous cell carcinoma in Hong Kong Chinese patients.

METHODS

We examined the expression of the c-erbB-2 oncoprotein in 104 oesophageal squamous cell carcinomas from 89 men and 15 women, ranging in age from 41 to 89 years (mean 63). C-ercB-2 expression was studied with monoclonal antibody, using an antigen retrieval method.

RESULTS

Focal c-erbB-2 membrane staining was present in 10 (10%) of 104 squamous cell carcinomas. Staining was also noted in the adjacent dysplastic epithelium (n=2) and non-tumour inflamed epithelium (n=2). In carcinomas, the c-erbB-2 membrane staining was identified only in superficial well-differentiated tumour cells and the expression did not predict biological behaviour.

CONCLUSIONS

We conclude that the c-erbB-2 oncoprotein is expressed in a portion of oesophageal squamous cell carcinomas and precursor lesions. This suggests that c-erbB-2 activation plays a certain role, mostly probably during the early stages, in carcinogenesis in oesophageal squamous cell carcinomas from Hong Kong Chinese patients.

Characterization of the progressive sublines derived from a weakly malignant cloned cell line, ER-1, co-inoculated subcutaneously with a foreign body

We previously established an experimental model of tumor progression using a weakly malignant rat mammary carcinoma cell line, ER-1. Using this model, we demonstrated that ER-1 cells converted into highly tumorigenic and metastatic cells, ERpP, by s.c. co-inoculation with plastic plates. We here compared in vitro biological properties associated with malignancy of ER-1 cells with those of ERpP cells which were highly malignant when inoculated into syngeneic rats. In vitro growth rate of ERpP cells was higher than that of ER-1 cells under a low nutrient condition. Invasion capacity of ERpP cells to rat lung endothelial cell monolayer or reconstituted basement membrane, Matrigel, was higher than that of ER-1 cells. Migration of ERpP cells toward fibronectin or laminin was also significantly higher than that of ER-1 cells. There was no difference in gelatinolytic or plasminogen activator activity detected in conditioned media between ER-1 and ERpP cells. Furthermore, we found that ER-1 cells communicated better among themselves and with normal fibroblasts through gap junctions compared to ERpP cells. These results suggest that growth advantage in a poor nutrient condition, enhancement of cell motility, and loss or decrease of junctional communication may be associated with tumor progression of ER-1 cells.

c-neu oncoprotein in developing rostral cerebral cortex: relationship to epidermal growth factor receptor

The c-neu oncoprotein, p185c-neu, is a transmembrane tyrosine kinase that shares structural similarities with the receptor for epidermal growth factor (EGFr). We used immunoblots, immunoprecipitation, and immunohistochemistry 1) to test the hypothesis that p185c-neu and EGFr are coordinately expressed in central nervous system tissue and 2) to assess the spatiotemporal expression of both the c-neu oncoprotein and EGFr in the rostral cerebral cortex. In nondenaturing gels, anti-c-neu antibody identified high molecular weight proteins (about 300-400 kDa) that were reduced by EDTA to a molecular weight of 180-200 kDa. Sodium dodecylsulfate polyacrylamide gel electrophoresis broke down this protein into an array of smaller peptides, which were expressed prenatally, transiently during the first three postnatal weeks, or in the adult. Perinatally, c-neu immunoreactivity was evident in subplate neurons, ascending processes of neurons in the cortical plate, and ventricular zone cells. During the second postnatal week, cells throughout cortex expressed somatodendritic immunostaining, but, in the adult, c-neu immunoreactivity was expressed only by pyramidal neurons in layer V and by glia in the white matter and ependyma. EGFr-positive proteins behaved in the nondenaturing gels as did c-neu-positive oncoproteins, suggesting that both proteins naturally formed dimers. This contention was supported by the EGFr-or c-neu immunolabeling of tissue that was previously immunoprecipitated with anti-c-neu or anti-EGFr, respectively. The pattern of EGFr immunolabeling in the developing and mature cortex was virtually identical to that described for c-neu immunoreactivity. Cortical neurons express the c-neu oncoprotein and EGFr, probably as heterodimers. The specific immunolabeling of layer V neurons in the adult cortex with anti-c-neu and anti-EGFr suggests that the p185c-neu ligand and EGF regulate the activity of corticofugal systems. The expression of different c-neu- and EGFr-positive peptides is developmentally defined and may be related to specific ontogenetic events.

Serum level and tissue expression of c-erbB-2 protein in lung adenocarcinoma

Serum levels of c-erbB-2 protein were measured by an enzyme immunoassay in 64 patients with lung adenocarcinoma. Immunohistochemical staining was performed in 40 of these tumors. The mean serum concentration was 16.5 +/- 8.5 U/mL (range: 3.4 to 49.0) in patients with lung adenocarcinoma, whereas it was 14.0 +/- 3.7 U/mL (range: 6.9 to 20.9) in 15 controls (1 U/mL = 0.61 ng/mL). Elevated concentrations (> or = 22.0 U/mL, control mean + 2 SD) were observed in 17/64 lung adenocarcinoma patients (26.6%), as compared with none of the control subjects (p < 0.05). Patients with stage IIIB or T4 disease had increased serum levels. The serum concentration was decreased significantly by surgical tumor ablation. Tissue overexpression was obtained in 17/40 cases (42.5%), and serum levels in patients with tissue overexpression were higher than in patients without overexpression. Serum c-erbB-2 protein may be a useful indicator of tumor burden in patients with lung adenocarcinoma.

c-erbB-2/neu Oncogene and Ki-67 Analysis in the Assessment of Palatal Salivary Gland Neoplasms

To evaluate the role of the Ki-67 proliferation antigen and c-erbB-2/neu oncogene expression in the clinical assessment of salivary gland tumors, we followed up 71 patients with minor salivary tumors of the palate. All benign neoplasms ( n= 18) showed low Ki-67 scores (< 12%), whereas 26% (14 of 53) of malignant neoplasms manifested high Ki-67 scores (<12%). A significant statistical difference between Ki-67 scores for benign and malignant neoplasms was observed ( p < 0.001). Ki-67 index also correlated significantly with malignant tumor grade ( p = 0.04) and patient survival ( p = 0.02). Only 1 of the 18 benign tumors had c-erbB-2/neu oncogene overexpression. A significant difference between c-erbB-2/neu overexpression in benign and malignant tumors was observed ( p = 0.01). Overexpression of c-erbB-2/neu oncogene was noted in 38% (16 of 42) of malignant tumors and was significantly associated with aggressive tumor behavior ( p <0.001). Multivariate analysis of significant factors revealed that gender, tumor stage, and c-erbB-2/neu oncogene overexpression were jointly predictive of survival. Our data indicate that although the Ki-67 proliferating antigen and c-erbB-2/neu oncogene expression may reflect certain intrinsic biologic properties of these neoplasms, only c-erbB-2/neu overexpression is significantly associated with their biologic aggression.

Analysis of c-erbB2 protein content of human glioma cells and tumor tissue

This study was designed to determine whether or not overexpression of the c-erbB2 protein plays a role in the etiology of human gliomas. The c-erbB2 gene codes for a 185 kDa cell membrane glycoprotein (gp185c-erbB2), which is similar to the receptor for epidermal growth factor. In initial studies, four human glioma cell lines (A-172, U118MG, U138MG and SW608) were used to develop techniques for detecting and quantifying gp185c-erbB2, using immunofluorescence microscopy, immunoblot analysis and flow cytometry. A-172 cells were found to have the highest content of gp185c-erbB2. More detailed studies utilizing A-172 cells indicated that cellular gp185c-erbB2 content changed little in response to conditions affecting cellular proliferative status, including serum deprivation, growth in low glucose medium and treatment with dimethyl sulfoxide. Ten human glioma specimens were then analyzed for cellular gp185c-erbB2 fluorescence and DNA content, using A-172 cells as a biological standard. Results indicated that gp185c-erbB2 was expressed at levels comparable to that of A-172 cells in many specimens, and at a very high level in one specimen. These data reiterate the problem of the molecular heterogeneity of human gliomas and indicate that gp185c-erbB2 may have a role in at least a subset of malignant glial tumors.

Analysis of cerbB2 expression using a panel of 6 commercially available antibodies

Results are presented of a study comparing cerbB2 (neu or Her2) expression as assessed immunohistochemically in breast neoplasia using a panel of 6 commercially available antibodies. The antibodies were examined utilizing conventional formalin fixed paraffin embedded tissue, and compared with molecular analysis of gene amplification. The aim was to determine the practical utility of each antibody, assessing ease of use, specific and non-specific staining characteristics, and expense, thus allowing a specific recommendation as to antibody of choice for immunohistochemical assessment of cerbB2 expression. Reassuringly, amongst the 38 breast lesions (36 carcinomas, 2 fibroadenomas) subjected to immunohistochemically (IHC) with the panel of 6 antibodies (Ab), no gross discrepancy of staining pattern was seen. Of the 38 cases, 10 were positive (26%), where at least one Ab demonstrated clear cytoplasmic membrane staining. Of a total of 45 breast lesions (43 carcinomas, 2 fibroadenomas), including all those examined by IHC, the total number of cases showing cerbB2 amplification by DNA analysis was 14 (31%). Using the DNA amplification as a base line for comparison, one Ab (No. 4) was found to stain 6 of the 14 cases of breast carcinoma that were assessed as showing amplification at the DNA level. Four Abs (1,3,5,6) stained 5 of these cases. However, Abs 3,4 and 6 displayed artefactual cytoplasmic staining (in the absence of membrane staining) that precluded the practical use of these reagents. Therefore, based on additional considerations of cost and ease of use, Ab No. 1 was finally chosen for recommendation from the 6 Ab panel.

Significance of erbB-2 gene product as a target molecule for cancer therapy

The new monoclonal antibodies (MoAbs) E401, E811, E907 and E919 were prepared and characterized. These recognized an extracellular domain (amino acids No. 292-370) on the human c-erbB-2 gene product. Utilizing MoAb E811 and MoAb E919, a double determinant immunoassay (DDIA) was established to detect the soluble and the shed forms of the c-erbB-2 molecule. The levels of circulating erbB-2 antigen in the sera of patients with benign diseases and healthy controls were very low. The incidence of positivity for shed c-erbB-2 antigen in gastric cancer, colonic cancer, gall-bladder cancer, pancreatic cancer and other cancers were 7.4%, 4.2%, 0%, 6.7% and 0%, respectively. Four of 54 patients with gastric carcinoma showed high levels of serum c-erbB-2 antigen. They belonged to clinical stage IV and their histological types were all well differentiated adenocarcinomas (two papillary and two tubular adenocarcinomas). Furthermore, the incidence of positive staining in gastric cancer was 34.6%; higher than that for shedding erbB-2 antigen. Most of the cases which showed erbB-2 expression on cells were well-differentiated adenocarcinomas. Meanwhile, the distribution of erbB-2 antigen was limited in normal tissues. The results suggest that the expression of erbB-2 antigen is largely restricted to adenocarcinoma cells. It may not shed easily from these cells, and therefore it may be a very useful target molecule for passive immunotherapy.

Prognostic value of DNA ploidy and c-erbB-2 oncoprotein overexpression in adenocarcinoma of Barrett's esophagus

BACKGROUND

During the last two decades, a rising incidence of adenocarcinoma of the esophagus has been observed in the Western world. The prognostic relevance of tumor-biological factors, such as DNA ploidy or c-erbB-2 overexpression, for overall survival following complete resection is still unknown.

METHODS

In a retrospective study of 80 patients with adenocarcinoma of Barrett's esophagus, the prognostic significance of flow cytometric DNA ploidy determination was investigated. Overexpression of c-erbB-2 oncoprotein was studied by immunohistochemical alkaline phosphatase-antialkaline phosphatase staining of formalin fixed, paraffin embedded tissue sections of the primary tumor.

RESULTS

The rate of aneuploidy was 86%. Aneuploidy was significantly correlated with lymph node metastases only. c-erbB-2 oncoprotein overexpression of the primary tumor was detected in 15 patients (19%). A significant correlation was seen between c-erbB-2 overexpression and depth of tumor invasion, lymph node involvement, distant metastases, and status of residual tumor after resection (R category, International Union Against Cancer [UICC], 1987). All primary tumors with c-erbB-2 oncoprotein overexpression were aneuploid. In a multivariate Cox regression analysis for overall survival of those 62 patients (78%) whose tumor resection was macroscopically and microscopically complete (R0-UICC), depth of invasion, distant metastases, and c-erbB-2 overexpression were independent prognostic factors. The relative risk of death due to recurrence was nearly identical for patients with either c-erbB-2 oncoprotein overexpression or distant metastases: 4.06 (1.4-11.8) and 3.94 (1.6-9.5). In a multivariate Cox regression analysis of the subgroup of lymph node-negative patients (n = 26), the ploidy status of the primary tumor (defined as near-diploid plus tetraploid versus aneuploid plus multiploid) was the only independent prognostic factor for overall survival.

CONCLUSIONS

These findings demonstrate that DNA ploidy as well as c-erbB-2 oncoprotein overexpression are valuable prognostic factors in patients with adenocarcinoma of Barrett's esophagus after complete tumor resection.

Overexpression of c-erbB-2 protein in gastric cancer. Its correlation with long-term survival of patients

BACKGROUND

Overexpression of c-erbB-2 protein in breast cancer has been reported to be associated with poor prognosis. However, clinical significance of c-erbB-2 protein overexpression has not been demonstrated clearly in gastric cancer.

METHODS

Immunohistochemical reactivity to c-erbB-2 protein was examined in formalin-fixed, paraffin-embedded tissue sections from patients with gastric cancer.

RESULTS

First, primary stomach cancers in 106 patients were examined. Among 58 cases of papillary or well- to moderately differentiated tubular adenocarcinoma, staining of c-erbB-2 protein was positive on the plasma membrane of cancer cells in 8 cases (14%). Conversely, among 47 cases of poorly differentiated adenocarcinoma or signet ring cell carcinoma, positive staining of c-erbB-2 protein was detected in one case only (2%), where the histopathologic type was poorly differentiated adenocarcinoma with a cohesive structure. Among tubular adenocarcinomas, no significant association was shown between overexpression of c-erbB-2 protein and the depth of tumor invasion, extent of lymph node metastasis, or tumor location. To investigate the correlation between the staining of c-erbB-2 protein and prognosis in gastric cancer, an additional 108 cases of papillary or well- to moderately differentiated tubular adenocarcinoma invasive as far as the muscularis propria were examined immunohistochemically for expression of c-erbB-2 protein. Twelve cases (11%) showed positive staining on the plasma membrane, and their survival curve showed a significantly poorer prognosis (P < 0.01).

CONCLUSIONS

These results suggest that overexpression of c-erbB-2 protein occurs selectively in cohesive gastric cancer, and it can be considered an important prognostic indicator.

Relationship of C-erbB-2 protein expression and gene amplification to invasion and metastasis in human gastric cancer

BACKGROUND

Amplification and/or overexpression of the C-erbB-2 gene has been demonstrated in breast and gastric cancer and is thought to be involved in the process of gastric cancer metastasis.

METHODS

The expression of C-erbB-2 protein in human gastric cancer was examined by immunohistochemistry and amplification of the C-erbB-2 gene by Southern blot hybridization.

RESULTS

C-erbB-2 protein was located on the cell membrane of cancer cells in formalin-fixed, paraffin-embedded sections. Fourteen percent of specimens were positive for C-erbB-2, and no positive reaction was evident in noncancerous tissue. The presence of C-erbB-2 in gastric cancer was correlated with the depth of invasion, histologic type, growth pattern, and presence of liver metastasis. C-erbB-2 was found more often in advanced cancers (P < 0.05), papillary adenocarcinoma (P < 0.01), nonscirrhous cancer (P < 0.05), and cancers with liver metastasis (P < 0.01). The incidence of C-erbB-2 positivity in lymph nodes with metastasis was higher than in primary sites (P < 0.01) and was significantly higher in differentiated adenocarcinoma (P < 0.01). Patients with C-erbB-2-positive tumors had poorer survival rates those with C-erbB-2-negative tumors in the early stages (P < 0.001), but not in the advanced stages. Amplification of the C-erbB-2 gene was detected at the primary site and in metastatic nodes in the same case, and expression of the protein was also evident.

CONCLUSIONS

The expression and/or gene amplification of C-erbB-2 is related to invasion and nodal involvement in differentiated adenocarcinoma of the human stomach.

Comparative clinical evaluation of biochemical and genomic tumor markers

The clinical utilities of established biochemical tumor markers and of emerging genomic markers are compared by six formal criteria: [1] tests negative in health or benign disease, [2] produced exclusively by specific tumor cells, [3] present frequently in the targeted malignancy, [4] detectable in occult disease, [5] degree of expression reflects tumor burden and prognosis, and [6] degree of expression correlates with therapeutic result. Evaluation of eight widely accepted marker systems combining a biochemical indicator with a specific cancer, on the one hand, and five representative genomic marker-target combinations involving chromosomal translocation, gene amplification and mutation, on the other hand, produces three main conclusions: First, specified applications are sufficiently well documented for the best biochemical markers to now tailor analytical performance goals to these uses. Second, further clinical trials of genomic markers are needed to document the useful linkage of specific indicators with specific clinical problems. Third, the different profiles of marker characteristics defining the two classes of indicators suggest some mutually complementary uses.

An immunohistochemical study of the c-erbB-2 oncogene product in intraductal mucin-hypersecreting neoplasms and in ductal cell carcinomas of the pancreas

BACKGROUND

Intraductal mucin-hypersecreting neoplasm of the pancreas (IMHN) is a unique tumor that has a tendency to spread intraductally. The clinical outcome of IMHN generally is far better than that of pancreatic ductal cell carcinoma. Because of the presence of various cell atypia within the same tumor, it sometimes is difficult to make an accurate histopathologic diagnosis and, therefore, predict its biologic behavior. It has been shown that overexpression of c-erbB-2 protein in breast cancer with lymph node metastases is related to a poor prognosis. Overexpression of c-erbB-2 protein has been reported as an infrequent event in pancreatic ductal cell carcinoma, but little is known in the case of IMHN.

METHODS

The expression of c-erbB-2 protein was immunohistochemically investigated in the formaldehyde-fixed, paraffin-embedded tissues of 17 cases of IMHN, and 14 cases of pancreatic ductal cell carcinoma (8 cases with lymph node metastasis), using polyclonal and monoclonal c-erbB-2(p185) antibodies by the avidin-biotin method.

RESULTS

Both the polyclonal and monoclonal antibodies showed similar immunostaining for the c-erbB-2 product. Overexpression of the c-erbB-2 product was observed frequently in IMHN (13/17), especially in that with moderate- to high-grade cell atypia (12/12), whereas it was detected in only 1 of 14 cases of pancreatic ductal cell carcinoma (1/14). Among eight cases of pancreatic ductal cell carcinoma with lymph node metastases, overexpression of the c-erbB-2 product in metastatic lesions was detected in two, one of whose primary lesions also overexpressed the oncogene product.

CONCLUSIONS

These observations suggest the genetic expression of c-erbB-2 is related to the pathogenesis of IMHN.

An immunohistochemical and molecular biological study of c-erbB-2 amplification and prognostic relevance in gallbladder cancer

Forty-three cases of gallbladder cancer were investigated for c-erbB-2 gene amplification and c-erbB-2 protein over-expression using a combined polymerase chain reaction (PCR) and immunohistochemical approach. Thirty out of 43 cases (69.6%) demonstrated c-erbB-2 gene amplification, the positive rates being 50% and 77.4% for twelve early cancers and thirty-one advanced cancers, respectively (P < 0.05). However, there was no statistically significant correlation between c-erbB-2 gene amplification and histologic grade of differentiation or lymph node metastasis. Fourteen out of 43 cases (32.6%) showed positive immunoreactivity reflecting c-erbB-2 protein over-expression but again no statistically significant correlation was found with grade of differentiation, invasion or lymph node metastasis. Neither the c-erbB-2 gene nor the protein revealed any close relation to prognosis. In contrast, histopathologic findings for histologic grade of differentiation, invasion grade and lymph node metastasis showed good correlations to prognosis and between themselves. In conclusion, while c-erbB-2 gene and protein in gallbladder cancers might be related to invasiveness, they are not applicable as predictive factors for prognosis.

An immunohistologic evaluation of C-erbB-2 gene product in patients with urinary bladder carcinoma

BACKGROUND

Amplification or overexpression of the c-erbB-2 gene have been reported to correlate with poor patient prognosis in human breast, gastric, and ovarian cancer. Recently, the c-erbB-2 gene product was found to be expressed frequently in the urinary bladder carcinoma. In the current study, the presence of the c-erbB-2 gene product in urinary bladder carcinomas was compared with patient outcome to evaluate whether c-erbB-2 gene product could identify a subset of patients who are destined to have a poor prognosis.

METHODS

Immunohistologic study of the c-erbB-2 gene product was done in formaldehyde-fixed paraffin-embedded tissue specimens obtained from 88 transitional cell carcinomas of the human urinary bladder. Eighty-three patients who underwent complete tumor resection by total cystoprostatectomy (30 patients) or by bladder-preserving operations such as transurethral surgery (50 patients) or partial cystectomy (3 patients) entered a follow-up study. The other five patients did not enter the follow-up study because of lost follow-up (2 patients) or distant metastasis at the time of surgery.

RESULTS

The c-erbB-2 gene product was expressed in 23 of 88 patients (26%), showing an increase in the expression rate corresponding to the advancement of tumor grade (P < 0.05) and tumor stage (P < 0.2). The 5-year disease-free survival rate was 48.5% for patients with c-erbB-2 negative tumors versus 9.7% for those with c-erbB-2 positive tumors (P < 0.01). The 5-year actuarial survival rate was 65.5% for patients with c-erbB-2 negative tumors versus 41.8% for those with c-erbB-2 positive tumors (P < 0.05). Multivariate analysis using Cox regression model showed that the c-erbB-2 gene product tissue status was a significant prognostic factor independent of grade and stage of the tumor.

CONCLUSIONS

The results suggest that the c-erbB-2 gene product could be a tumor marker to identify a malignant subgroup in bladder carcinomas.

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

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

Expression of c-erbB-2 protein and epidermal growth factor receptor in normal tissues of the female genital tract and in the placenta

The c-erbB-2 (HER-2/neu) protein is a membrane glycoprotein growth factor receptor that has molecular homology with the epidermal growth factor receptor (EGFR). To investigate the relationship between the expression of c-erbB-2 protein and EGFR in the tissues of the human female genital tract and in the placenta, we examined the immunohistochemical reactivity of monoclonal antibodies against both of these proteins. In the müllerian-derived genital tract, epithelial cells of the fallopian tube, endometrium, and endocervix showed reactivity for c-erbB-2 protein, whereas reactivity for EGFR was distributed mainly in the stromal cells throughout the menstrual cycle and during pregnancy. In addition, the staining intensity for EGFR in the endometrial stroma increased with its decidualization. In the exocervical squamous epithelium, basal cells were c-erbB-2 protein-negative and EGFR-positive, but the more differentiated squamous cells of the intermediate layer were c-erbB-2 protein-positive and EGFR-negative. In the placental tissues, cytotrophoblasts and syncytiotrophoblasts of the chorionic villi were c-erbB-2 protein-negative and EGFR-positive. In contrast, intermediate trophoblasts in the extravillous space were c-erbB-2 protein-positive and EGFR-negative. Thus, there is an inverse relationship between the expression of c-erbB-2 protein and EGFR in the tissues of the female genital tract and in the placenta. This suggests that there may be a regulatory mechanism(s) for the expression of both proteins that is associated with the differentiation and/or function of cells in the female genital tract and the placenta.

Differential expression of the neu oncogene in mouse liver and pancreatic cell lines

To study the tissue-specific expression of neu oncogene, we used two mouse tumor cell lines derived from liver, Hep1-a, and pancreatic, 266-6, tumors as a model system. The endogenous neu gene is expressed in Hep1-a but not in 266-6 cells. We demonstrate in this report that differential expression of the neu gene in these two cell lines is mainly regulated at transcriptional level. The neu promoter sequence responsible for the differential regulation is localized within a 90 bp region and it is possibly due to lack of a specific positive transcription factor(s) interacting with this region in 266-6 cells.

Clinicopathological significance of c-erbB-2 protein expression in human gastric carcinoma

One hundred seventy-nine primary human gastric tumors not associated with early cancer or noncurative resection were examined immunohistochemically for the expression of c-erbB-2 protein. Positive staining, regarded as an indication of gene amplification, was evident in 22(12%) of the tumors. Of various clinicopathological factors considered, a statistically significant difference in association with frequency of expression was noted only for histological differentiation, as follows: 39% positive staining in papillary, 17% in well differentiated, 5% in moderately differentiated, and 4% in undifferentiated adenocarcinomas (P greater than 0.01). The 5-year survival rates of patients with positive and negative c-erbB-2 staining were 57% and 59%, respectively. These findings indicate that, in the case of human gastric adenocarcinoma, expression of c-erbB-2 protein is correlated with tumor histological differentiation. Our results also suggest that the presence or absence of c-erbB-2 protein may not serve as a prognostic indicator, particularly in cases of adenocarcinoma of the stomach.

Amplification and overexpression of the c-erbB-2 protooncogene in human gastric cancer

The c-erbB-2 protooncogene encodes a possible growth factor receptor. This gene has been studied as to whether it can be regarded as a prognostic indicator in human breast carcinoma. As amplification and overexpression of the gene have been reported in several adenocarcinomas, 24 specimens of human gastric cancers were examined by immunohistochemical staining (24 cases), by Southern blotting (23/24) and by Northern blotting (16/24). Amplification of the gene was detected in two moderately differentiated tubular adenocarcinomas (8.7%), and overexpression of c-erbB-2 mRNA was detected in three moderately differentiated tubular adenocarcinomas (18.8%). By immunohistochemical staining of paraffin-embedded tissues using a polyclonal antibody to c-erbB-2 gene products, the cell membrane was stained positively in three cases of gastric cancers which overexpressed c-erbB-2 mRNA. Peritoneal metastases were found in six gastric cancers, including two moderately differentiated tubular adenocarcinomas in which amplification of c-erbB-2 occurred. These results suggest that amplification and overexpression of c-erbB-2 may be correlated with metastases in differentiated adenocarcinoma of the stomach.

Expression of the neu proto-oncogene by Schwann cells during peripheral nerve development and Wallerian degeneration

The neu gene, which encodes a putative tyrosine kinase growth factor receptor termed p185neu, was originally identified as a dominant transforming gene in neurogliomas and schwannomas induced by transplacental treatment of rat embryos with ethylnitrosourea. The present studies were undertaken to determine the expression pattern of the neu gene in peripheral nerve. Northern blot analysis of total RNA isolated from rat sciatic nerves demonstrated prominent neu mRNA expression on postnatal days 1 and 7, with substantially lower expression up to adulthood. Immunohistochemical studies confirmed expression of p185neu by Schwann cells (SC) in developing sciatic nerve and minimal p185neu immunoreactivity in adult nerves. However, neu mRNA and p185neu protein progressively increased following sciatic nerve transection in adult animals. In addition, neu mRNA and p185neu were found in neonatal rat sciatic nerve SC and several SC-derived cell lines. In resting SC, neu mRNA was expressed at a low level, but was greatly increased by treatment with forskolin and glial growth factor. These studies demonstrate that the neu gene and its protein product, p185neu, are expressed by SC both in vivo and in vitro and suggest that p185neu plays a role in the regulation of SC proliferation or differentiation.

Prognostic value of c-erbB-2 protein expression in human lung adenocarcinoma and squamous cell carcinoma

203 primary human lung tumours, of which 119 were adenocarcinoma and 84 were squamous cell carcinoma, were investigated immunohistochemically for the expression of c-erbB-2 protein. Positive staining was evident in 33 (28%) of adenocarcinomas and 2 (2%) of squamous cell carcinomas. In cases of adenocarcinoma, c-erbB-2 was present in 18% of those with stage I disease. In stage IIIA, stage IIIB and stage IV cases, c-erbB-2 was present in 39%, 50% and 60%, respectively (I vs. IIIA and I vs. IIIB: P less than 0.05, I vs. IV: P less than 0.01). The 5-year survival rates of c-erbB-2 positive patients and those who were negative were 30% and 52%, respectively, with a statistically significant difference (P less than 0.01). These observations suggest that when the expression of c-erbB-2 correlates with invasiveness of the tumour, this correlation may serve as a prognostic indicator, particularly in cases of adenocarcinoma of the lung.

Expression of c-erbB-2 gene product in urinary bladder cancer

Expression of the c-erbB-2 gene product and the epidermal growth factor receptor (EGF-R) was investigated in 54 cases of human bladder cancer immunohistologically and by Western blot analysis. For detection of the c-erbB-2 product, two specific antibodies, a rabbit polyclonal antibody directed to the intracellular domain and a murine monoclonal antibody recognizing an epitope in the extracellular domain, were used. Seventeen cases of bladder cancer were stained by the anti-c-erbB-2 polyclonal antibody, while 20 cases were stained by the monoclonal antibody, with good correlation on both stainings (p less than 0.01). There were four c-erbB-2 positive cases in 26 G1 tumors, four in 15 G2 tumors, and nine in 13 G3 tumors. There were also eight erbB-2 positive cases in nine muscle-invasive tumors, nine of 45 superficial tumors, four of five with lymph node metastasis, and seven of 14 without metastasis, as revealed by staining with the polyclonal antibody. Thus, the c-erbB-2 gene product was more frequently expressed in high grade tumors (p less than 0.01), in high stage tumors (p less than 0.01), and nodal metastatic tumors (N.S. by Chi-square test). Twenty-two of the 54 tumors were stained by an anti-EGF-R monoclonal antibody, 528 IgG. The expression of EGF-R was independent of histological grading, tumor stage, and nodal status, and no correlation was observed between expression of the c-erbB-2 product and EGF-R. The c-erbB-2 product may be applicable as a tumor marker for evaluation of malignant potential, invasiveness, and probably metastatic potential of human bladder cancer.

Ultrastructural localization of c-erbB-2 gene product in transitional cell carcinoma of the urinary tract

The c-erbB-2 gene product was demonstrated immunoelectron microscopically in human transitional cell carcinomas of the urinary tract. Two antibodies specific for the c-erbB-2 gene product were used: a polyclonal antibody directed to the intracellular domain and a monoclonal antibody recognizing an epitope in the extracellular domain. The immunoreaction with the polyclonal antibody was observed on cell membranes and the cytoplasmic area beneath membranes with particularly strong reaction on microvilli. The immune reaction with the monoclonal antibody was confined to cell membranes with a linear pattern. Amorphous deposits in the intercellular spaces were also immunoreactive with the monoclonal antibody directed to an extracellular epitope, suggesting that a part of the c-erbB-2 gene product may be released from the cancer cell membranes into the extracellular space.

Correlation between the presence of microvilli and the growth or metastatic potential of tumor cells

We used an electron microscope to examine microvilli which appear on the surfaces of various tumor cells with high or low growth potential and/or metastatic ability. The results show that a greater number of microvilli appeared on the surfaces of tumor cells (QRpP and ERpP) which possess high growth potential than on tumor cells (QR and ER) with low growth potential. We also observed that microvilli were more abundant on the surface of highly metastatic clone cells, i.e. c-SST-2 (cl-2), mouse B16 melanoma (F-10) and human colon carcinoma (KM12SM) than on weakly metastatic clone cells, c-SST-2 (cl-4-2), B16 (F-1) and (KM12C). At the same time, more microvilli were observed on the surface of B16 BL6 cells, which were obtained from the metastatic site of the B16 F10 cells, than on the surface of the parent B16 F10 cells. Immunoelectron microscopy revealed that the c-neu oncogene product, which is closely related to an epidermal growth factor receptor, was positively stained in the microvilli of tumor cells (ERpP) with high growth potential and high metastatic ability, whereas the tumor cells (ER) with low growth potential and weak metastatic ability were not stained. These findings suggest that the increased presence of microvilli correlates closely with the growth potential and metastatic ability of tumor cells.

The c-erb B-2 proto-oncogene in human pancreatic cancer

The c-erb B-2 oncogene encodes a 190 kD transmembrane growth factor receptor which is closely related to the EGF receptor and has been found to be amplified and overexpressed in a number of human adenocarcinomas, particularly of the breast. We have analysed, by immunocytochemistry using the 21N antibody, expression of c-erb B-2 in a retrospective series of pancreatic adenocarcinoma, chronic pancreatitis, and examples of histologically normal pancreas. In three cases (21 per cent) of chronic pancreatitis, there were focal areas of cytoplasmic immunoreactivity in regenerating epithelium. In 15 cases (17 per cent) of pancreatic adenocarcinoma, cytoplasmic immunoreactivity was seen, while in two cases (2 per cent) strong membrane staining of tumour cells was seen which could be blocked by peptide controls. c-erb B-2 immunoreactivity was also demonstrated using a second antibody, 20N, which recognizes another peptide sequence of the c-erb B-2 protein. There was no relationship between immunoreactivity and histological subtype or grade, but there was absolute concordance between staining in primary and metastatic deposits. Since the rat homologue (neu) of the c-erb B-2 oncogene may be activated by a specific point mutation in its transmembrane region, we have analysed 23 cases from this series for mutations by polymerase chain reaction amplification and sequence-specific oligonucleotide hybridization. We were unable to identify activity mutations in this series. These data suggest that there is abnormal expression of c-erb B-2 oncogene in nearly 20 per cent of cases although mutational activation of this gene is not seen in human pancreatic adenocarcinoma.