Expression of epidermal growth factor receptor (EGF-R) in non-small cell lung cancer. Use of archival tissue and correlation of EGF-R with histology, tumour size, node status and survival

Missing-in-metastasis B (MIM-B) combined with caveolin-1 promotes metastasis of hepatocellular carcinoma

BACKGROUND

Increasing amounts of evidence indicate that Missing in metastasis B (MIM-B) promotes cancer metastasis. Here, we sought to better understand the mechanism through which MIM-B promotes tumor metastasis in hepatocellular carcinoma (HCC).

METHODS

We performed confocal microscopy analysis to determine the distributions of MIM-B and caveolin-1 and conducted co-immunoprecipitation assays to detect the interactions between MIM-B and caveolin-1 in vitro. We performed transwell assays to analyze the invasive ability of HCC cells. Changes in the expression levels of key genes and some molecular makers were detected by immunohistochemistry and western blotting in HCC tissue samples.

RESULTS

We found that MIM-B co-localizes with caveolin-1 and demonstrated that MIM-B and caveolin-1 interact in vitro. Repressing MIM-B and caveolin-1 expression inhibited the epidermal growth factor receptor signaling pathway. We overexpressed MIM-B and caveolin-1 in Hep3B cells, which enhanced Hep3B cell invasiveness. Furthermore, MHCC97H cell invasiveness was significantly decreased in cells in which MIM-B and caveolin-1 expression was inhibited. Additionally, we found that MIM-B and caveolin-1 were expressed at higher levels in HCC tissues than in paired normal tissues. Moreover, HCC patients with MIM-B and caveolin-1 up-regulation experienced significantly worse outcomes than controls (P < 0.001), and HCC patients with high MIM-B and caveolin-1 expression levels often developed pulmonary metastasis (P < 0.001).

CONCLUSIONS

MIM-B combined with caveolin-1 promotes metastasis of HCC, and elevated MIM-B and caveolin-1 expression levels are associated with a poor prognosis in HCC patients; therefore, MIM-B and caveolin-1 may represent novel targets for the diagnosis and treatment of HCC.

Missense Mutations in Exons 18-24 of EGFR in Hepatocellular Carcinoma Tissues

Epidermal growth factor receptor (EGFR), a transmembrane tyrosine kinase receptor, plays important roles in various cancers. In nonsmall cell lung cancer (NSCLC), EGFR mutations cluster around the ATP-binding pocket (exons 18-21) and some of these mutations activate the kinase and induce an increased sensitivity to EGFR-tyrosine kinase inhibitors. Nevertheless, data of EGFR mutations in HCC are limited. In this study, we investigated EGFR expression by immunohistochemistry and EGFR mutations (exons 18-24) by PCR cloning and sequencing. EGFR overexpression in HCC and matched nontumor tissues were detected in 13/40 (32.5%) and 10/35 (28.6%), respectively. Moreover, missense and silent mutations were detected in 13/33 (39.4%) and 11/33 (33.3%) of HCC tissues, respectively. The thirteen different missense mutations were p.L730P, p.V742I, p.K757E, p.I780T, p.N808S, p.R831C, p.V851A, p.V897A, p.S912P, p.P937L, p.T940A, p.M947V, and p.M947T. We also found already known SNP, p.Q787Q (CAG>CAA), in 13/33 (39.4%) of HCC tissues. However, no significant association was detected between EGFR mutations and EGFR overexpression, tissue, age, sex, tumor size, AFP, HBsAg, TP53, and Ki-67. Further investigation is warranted to validate the frequency and activity of these missense mutations, as well as their roles in HCC tumorigenesis and in EGFR-targeted therapy.

Epidermal growth factor receptor (EGFR) in salivary gland carcinomas: potentials as therapeutic target

AIMS

Epidermal growth factor (EGFR) is involved in angiogenesis, cell differentiation, proliferation and progression of many cancers and is an important therapy target in lung and colorectal cancer. To determine the potential applicability of EGFR targeted therapies, EGFR status of over 800 salivary gland tumors of different entities were analyzed on DNA and protein level by FISH and IHC.

MATERIALS AND METHODS

A tissue microarray was constructed from 721 carcinomas and 205 adenomas of the salivary gland. EGFR expression and EGFR gene copy number was assessed by means of immunohistochemistry and fluorescence in situ hybridization (FISH). EGFR mutation analysis of exon 19 and 21 was performed in a subset of 107 carcinomas.

RESULTS

Positive immunohistochemical staining (definition?) for EGFR was shown in 324 of 663 (48.9%) salivary gland carcinomas. The frequency was dependent on the tumor entity and ranged from 17.9% (30 of 168 cases) positive immunostaining in acinic cell adenocarcinomas to 85.7% (42 of 49 cases) in Warthin tumors. No EGFR amplification was found by FISH. EGFR mutation analysis of Exon 19 and 21 in 107 salivary gland carcinomas revealed mutations in two acinic cell adenocarcinomas.

CONCLUSION

EGFR protein expression is common in salivary gland tumors but is not associated with gene amplification. Activating mutations of EGFR are rare. Nonetheless, selected cases of patients with salivary gland carcinomas might potentially benefit of anti-EGFR therapy.

A translational approach to lung cancer research: From EGFRs to Wnt and cancer stem cells

Lung cancer remains the main cause of all cancer deaths in the United States. The prognosis for non-small cell lung cancer, despite advances in current therapies, is disappointing. Fortunately, we are steadily gaining significant insights into the heterogeneous molecular pathogenesis of lung cancer, which seems to occur in a stepwise manner, mainly secondary to tobacco smoking. With the emerging power of gene expression signatures for individual lung tumors and with the advancing field of stem cell biology and the paradigm of cancer stem cells, we are most certainly paving the way to developing novel tools for the early detection, chemoprevention, and treatment of these vastly morbid pathologies with enormous global burden. We will explore some of these issues and highlight how we are starting to translate them into clinically relevant tools for lung cancer patients.

Annulate Lamellae in a Large Cell Lung Carcinoma Cell Line with High Expression of Tyrosine Kinase Receptor and Proto-Oncogenes

The morphology, karyotype, in vitro growth properties, and expression of tyrosine kinase receptors and proto-oncogenes are reported for a newly established large cell undifferentiated lung carcinoma cell line (RVH-6849). The results were analyzed concomitantly with those for two well-established cell lines from an adenocarcinoma of the lung (A549) and a squamous cell carcinoma (A431). All three cell lines demonstrated common ultrastructural features of epithelial cells, but only RVH-6849 had frequent aggregates of centrioles and annulate lamellae (AL) and was polyploid, having five to seven copies of chromosome 7 by karyotype analysis. All three cell lines expressed transforming growth factor alpha (TGF-alpha), epidermal growth factor receptor (EGFR), c-erb B-2, and c-met genes. RVH-6849 cells, however, expressed the most messenger RNA (mRNA) for TGF-alpha, c-erb B-2, and c-met. Only EGFR mRNA was expressed more in the other two cell lines, especially in A431 cells. AL represent an exaggerated form of the nuclear membrane-pore complex that is found in actively proliferating cells such as germ and some neoplastic cells. AL are suspected to be involved in the deposition or processing of mRNA: The enhanced coexpression of AL and mRNAs of three tyrosine kinase-containing receptors in RVH-6849 cells may represent such a relationship.

Epidermal growth factor receptor signaling in adenocarcinomas with bronchioloalveolar components

BACKGROUND

Epidermal growth factor receptor (EGFR) has gained importance in non-small cell lung cancer given impressive responses to agents targeting this molecule, particularly in bronchioloalveolar carcinoma (BAC) and adenocarcinomas, mixed subtype, with BAC components (adeno/BAC). This study assesses EGFR signaling in these tumors.

METHODS

One hundred fifty tumors were classified as BAC or adeno/BAC. Tumor marker expression was determined by immunohistochemistry. Correlations with expression were examined for all tumors (BAC and adeno/BAC), and by BAC and adeno/BAC subset analyses.

RESULTS

Positive immunophenotype was observed in 40.6% of tumors for EGFR, 51.3% for p-AKT, 58.7% for p-ERK, and 28.0% for PTEN, with increased overexpression of EGFR (p = 0.025) and p-AKT (p < 0.0001) in adeno/BAC. Epidermal growth factor receptor immunophenotype was greater in never-smokers (p = 0.008) and correlated with improved overall survival (p = 0.018). On subset analysis, EGFR correlated with improved overall survival (p = 0.05) and disease-free interval (p = 0.044) only in adeno/BAC. Epidermal growth factor receptor independently predicted improved disease-free interval in adeno/BAC (p = 0.03; hazard ratio, 0.47; 95% confidence interval, 0.23 to 0.94).

CONCLUSIONS

Overexpression of EGFR in lung adenocarcinomas with components of BAC histology correlate with never-smoker status and improved overall survival and disease-free interval. Epidermal growth factor receptor immunophenotype may be a useful predictor of clinical outcomes in this tumor subset.

Novel therapies targeting signaling pathways in lung cancer

Despite advances in chemotherapy, the prognosis for advanced non-small-cell lung cancer (NSCLC) remains dismal. Increasing understanding of the biological processes responsible for lung carcinogenesis has led to development of new therapeutic strategies targeting this disease at a molecular level. This article examines the molecular events believed to lead to cellular changes in lung cancer, and how knowledge of these is used to develop new agents used individually or in combination with available cytotoxic drugs to improve survival. Finally, it explores how a deeper understanding of the embryonic signaling pathways responsible for airway epithelial repair and tumorogenesis, such as Hedgehog (Hh), Notch, and Wingless (Wnt), can lead to the development of newer and more specific therapies for lung cancer.

Activation state EGFR and STAT-3 as prognostic markers in resected non-small cell lung cancer

BACKGROUND

Total EGFR expression by immunohistochemistry (IHC) has failed to demonstrate prognostic importance. We hypothesized that activation (phosphorylated) state of EGFR (p-EGFR) and its activated downstream signal pathway (p-STAT-3) will have prognostic value in NSCLC.

METHODS

145 patients underwent lung resection for NSCLC at University Hospitals from 1998-2002. A database with TNM stage, gender, age, time to recurrence, and survival was established. p-EGFR and p-STAT-3 levels were quantified by IHC. Specimens were divided into negative, 1+, 2+, or 3+ (5-19%, 20-50%, >50% of tumor cells staining respectively). Cox proportional hazard model was used for multivariate analysis.

RESULTS

Median age was 70 years. 58% were female and 54% had adenocarcinoma. Pathologic stage was as follows: stage I: 54%, stage II: 31%, stage III: 15%. 32% were positive for p-EGFR (squamous 36%, adenocarcinoma 29%). p-STAT-3 staining was seen in 38% and was higher in adenocarcinoma (46%) versus squamous cell (27%, p=0.02) and was higher in patients >70 years than compared to those <70 years (p=0.06). There was a trend toward co-expression of p-EGFR and p-STAT-3 (p=0.09). The 5-year Kaplan-Meier probabilities of overall survival were not different amongst patients with activated versus no activation of EGFR and STAT-3.

CONCLUSIONS

Although EGFR is commonly expressed in NSCLC ( approximately 70%), p-EGFR is seen in only 1/3 of patients. p-EGFR and p-STAT-3 were commonly co-expressed in tumors compatible with known signal transduction pathways in lung cancer. However, EGFR and STAT-3 activation status does not provide prognostic information in resected disease.

EGFR expression: associations with outcome and clinicopathological variables in malignant pleural mesothelioma

Malignant mesothelioma (MM) is a fatal tumour of increasing incidence which is related to asbestos exposure. This work evaluated expression in MM of Epidermal Growth Factor Receptor (EGFR) by immunohistochemistry in 168 tumour sections and its correlations with clinicopathological and biological factors. The microvessel density (MVD) was derived from CD34 immunostained sections. Hematoxylin and eosin stained sections were examined for intratumoural necrosis. COX-2 protein expression was evaluated with semi-quantitative Western blotting of homogenised tumour supernatants (n=45). EGFR expression was correlated with survival by Kaplan-Meier and log rank analysis. Univariate and multivariate Cox proportional hazards models were used to compare the effects of EGFR with clinicopathological and biological prognostic factors and prognostic scoring systems. EGFR expression was identified in 74 cases (44%) and correlated with epithelioid cell type (p<0.0001), good performance status (p<0.0001), the absence of chest pain (p<0.0001) and the presence of TN (p=0.004), but not MVD or COX-2. EGFR expression was a good prognostic factor in univariate analysis (p=0.01). Independent indicators of poor prognosis in multivariate analysis were non-epithelioid cell type (p=0.0001), weight loss, performance status and WBC>8.3x10(9)L(-1). EGFR status was not an independent prognostic factor. EGFR expression in MM correlates with epithelioid histology and TN. EGFR may be a target for selective therapies in MM.

Predicting clinical benefit in non-small-cell lung cancer patients treated with epidermal growth factor tyrosine kinase inhibitors

Erlotinib and gefitinib are small-molecule inhibitors of the epidermal growth factor tyrosine kinase. Erlotinib is approved for the treatment of locally advanced or metastatic non-small-cell lung cancer after failure of at least one prior chemotherapy regimen. Although it is active in unselected patients, clinical characteristics and tumor molecular markers associated with enhanced benefit have been identified. Notably, never-smoker status or a positive EGFR FISH test has been consistently predictive of greater erlotinib benefit. Other markers, such as EGFR mutations and EGFR protein expression, as determined by immunohistochemistry, and KRAS mutation status have not proven to be consistently associated with differential benefit.

Epidermal growth factor receptor mutations in non-small cell lung cancer: a basic science discovery with immediate clinical impact

A large body of preclinical work suggested that the epidermal growth factor receptor (EGFR) would be a successful target for therapy against non-small cell lung cancer (NSCLC), and this led to the development of oral, selective EGFR tyrosine kinase inhibitors (TKI) that improve symptoms and survival in patients with advanced NSCLC. However, not all patients benefit from this treatment, and there has been great interest in identifying the molecular correlates that predict for response to these agents. The recent detection of somatic mutations in EGFR that predict for response to the EGFR tyrosine kinase inhibitors has excited the scientific community. This discovery has far-reaching implications, not only for lung cancer patients treated with an EGFR TKI but also for future drug development in all malignancies.

Survival impact of epidermal growth factor receptor overexpression in patients with non-small cell lung cancer: a meta-analysis

BACKGROUND

It is thought that overexpression of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) might compromise patient survival, presumably by promoting tumour growth by an autocrine mechanism. However, conflicting results have been reported from various laboratories, and the clinical importance of EGFR overexpression remains unsettled.

METHODS

A meta-analysis of previous studies was performed to quantitatively review the effects of EGFR overexpression on survival in patients with NSCLC using a DerSimonian-Laird random effects model. Eighteen studies including 2972 patients were subjected to final analysis.

RESULTS

Overall, positivity for EGFR overexpression differed between histological types: 39% in adenocarcinomas, 58% in squamous cell carcinomas, 38% in large cell carcinomas, and 32% in cancers in a miscellaneous category (p<0.0001). The combined hazard ratio (HR) was 1.14 (95% CI 0.97 to 1.34; p = 0.103), indicating that EGFR overexpression has no significant impact on survival. When only the 15 immunohistochemistry based studies were considered, the combined HR was 1.08 (95% CI 0.92 to 1.28; p = 0.356), again suggesting that EGFR overexpression has no impact on survival. Heterogeneity testing indicated that there was heterogeneity between studies but publication bias was absent, which suggests that the summary statistics obtained may approximate the actual average.

CONCLUSIONS

EGFR overexpression was not associated with poorer survival in patients with NSCLC. Specific mutations of the EGFR gene will need further study in terms of survival implications.

Small tumor size and limited smoking history predicts activated epidermal growth factor receptor in early-stage non-small cell lung cancer

STUDY OBJECTIVE

Epidermal growth factor receptor (EGFR) signaling has been implicated in the pathogenesis of bronchial dysplasia and overt non-small cell lung cancer (NSCLC). We hypothesized that assaying for EGFR activity using an antibody that recognizes phosphorylated EGFR (pEGFR) may identify a subset of patients whose tumor cells are dependent on EGFR signaling. We also hypothesized that EGFR activity may be prognostic for early-stage NSCLC.

DESIGN

We constructed high-density tissue microarrays using tissues from 193 surgically resected stage I NSCLCs. These arrays were immunostained with a pEGFR antibody, and the intensity of staining was correlated with clinicopathologic variables, as well as disease-free and overall survival (OS). Staining was scored by intensity and the percentage of positively stained tumor cells in triplicate.

MEASUREMENTS AND RESULTS

We found the expression of pEGFR (with > 50% of tumor cells staining positive) in 51% of tumor tissues. We found an inverse correlation between pEGFR, and both tumor size and the degree of tobacco smoking. In addition, we found a trend in which pEGFR expression was inversely correlated with disease stage (IA higher than IB). There was no correlation with sex, histology, or disease-free or OS.

CONCLUSIONS

Our results suggest that pEGFR levels are present in early-stage NSCLC, especially in patients with small tumors and in those with short smoking histories, but there is no prognostic impact on a patient's disease course. Targeting EGFR may therefore have more promise in chemoprevention or in patients with smaller early-stage NSCLCs compared with those with more advanced disease.

Current Management of Advanced Non-Small Cell Lung Cancer: Targeted Therapy

Lung cancer is one of the most frequent causes of cancer-related death in the United States. For patients with advanced non-small cell lung cancer (NSCLC), chemotherapy, alone or in combination with radiation therapy, is considered the standard treatment. Although this treatment may result in a modest improvement in patient survival, overall prognosis of these patients remains dismal, and the treatment is nonspecific, nonselective, and toxic. Therefore, new therapeutic strategies are needed. During the past decade, several molecules that contribute to lung cancer progression and metastasis have been identified. Growth factors and proangiogenic factors have been the focus of intense research in cancer since therapeutic approaches for their inhibition do exist. The role of these factors was studied in different organs and tumors and was found to be phenotypically distinct. Several molecular targeted therapies have shown efficacy and had been approved for treatment of specific cancers. Most advanced in clinical research for lung cancer are targeted therapies that inhibit the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor (VEGF) signaling pathways. Others are signaling pathway inhibitors. The first targeted therapy for lung cancer is gefitinib, an EGFR inhibitor, which was approved in several countries in 2003. Goals of molecular targeted therapy studies include the following: better understanding of the exact role of particular growth factors in specific tumors; establishment of new clinical study designs for biological agents; and tailoring appropriate combinations of conventional chemotherapy and/or radiotherapy with biological therapy for specific patients. Achievement of these goals will hopefully lead to incorporation of biological therapy into the current anticancer arsenal, for the benefit of lung cancer patients.

Clinical significance of biological differences between cavitated and solid form of squamous cell lung cancer

Recently, Kolodziejski et al. [Kołodziejski LS, Dyczek S, Duda K, Goralczyk KJ, Wysocki MW, Lobaziewicz W. Cavitated tumor as a clinical subentity in squamous cell lung cancer patients. Neoplasma 2003;50:66--73] have shown, that patients with cavitated form of squamous cell lung cancer (c-SqCLC) treated by surgery had shorter survival than patients with solid form (s-SqCLC) despite having similar stage, histological features and causes of deaths. Therefore, we decided to check if tumour biological features are responsible for the difference in patients' response. The aim of the study was to assess tumour proliferation rate (MIB-1 labelling index, MIB-1 LI), tumour proliferation pattern and expression of epidermal growth factor receptor (EGFR labelling index, EGFR LI) in solid and cavitated SqCLCs. A total of 81 patients with SqCLC were analysed; 18 c-qCLC (with cavity identified at X-ray examination) and 63 s-SqCLC. Expression of Ki-67 protein (MIB-1 LI) and proliferation pattern based on this staining and EGFR LI was visualized in formalin-fixed paraffin-embedded sections, using immunohistochemistry. s-SqCLC showed faster proliferation than c-SqCLC. Mean MIB-1 LI for the first group was higher-39.2% (range, 12.7--65.6) than for the second group--26.1% (range, 7.1--45.6) (P=0.000). In c-SqCLC subgroup, eight tumours with intermediate type of proliferation, six with random and four with mixed pattern were identified. However, in the s-SqCLC there were 18 with intermediate, 22 with random and 22 with mixed type of proliferation. The difference between architecture of proliferation and histological grade was seen (P=0.040). Mean EGFR LI did not differ between c-SqCLC (31.1%) and s-SqCLC (29.3%); however, median value was non-significantly lower for c-SqCLC (14.0%) than in s-SqCLC (21.0%). Univariate Kaplan-Meier analysis revealed that patients with s-SqCLC and a lower pTNM, faster tumour proliferation (MIB-1 LI>39%) and 13%</=EGFR LI<80% had significantly longer survival. Cox multivariate analysis performed for the whole analysed group showed that proliferation rate, expression of EGF receptor (EGFR LI); pTNM and form of SqCLC were significant in respect of patients' survival. However, when the analysis was performed separately for s-SqCLC and c-SqCLC it appeared that biological parameters (EGFR LI and proliferation pattern) were significant only for solid and not for cavitated SqCLC form. For the latter, only clinical (TNM) and pathological stage (pTNM) appeared to be important and therefore adjuvant systemic chemotherapy after surgery may be more indicated.

Epidermal growth factor receptor as a target to improve treatment of lung cancer

Despite considerable efforts to reduce tobacco use, lung cancer remains the most common cancer in both men and women. Recent advances in radiation therapy and chemotherapy for lung cancer have yielded encouraging results, but survival in patients with locally advanced non-small-cell lung cancer (NSCLC) remains poor. As more and more molecular changes and their importance in malignant tissues continue to be characterized, approaches to target those aberrant pathways are being actively explored. The epidermal growth factor receptor (EGFR) is commonly overexpressed in NSCLC, particularly squamous cell carcinoma, and has been implicated in the development and progression of this disease, although a clear correlation with prognosis has not been established. Several different strategies have been developed to target and block the EGFR and its downstream effects, and some of them have been intensively studied in preclinical and clinical studies as a single-agent approach or in combination with radiation therapy or chemotherapy. In this article, we review the role of EGFR in lung cancer, as well as preclinical and clinical data on strategies to interfere with EGFR signaling alone or in combination with chemotherapy, radiation, or both.

The role of new agents in the treatment of non-small cell lung cancer

Lung cancer is one of the most frequent causes of cancer deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for approximately 80% of cases and no curative treatment is available for the advanced stages of disease (stages III and IV), which comprise the majority of cases. Current treatment regimens with standard chemotherapy offer only a limited survival benefit, and, therefore, the development of new therapeutic strategies is needed. Novel chemotherapeutic drugs such as the epothilones, MEN 10755 and S-1 are being studied in patients with advanced stages of disease. Furthermore, a large number of therapies targeted against critical biological abnormalities in NSCLC are being investigated in clinical trials. The latter approach includes inhibition of growth factors, interference with abnormal signal transduction, inhibition of angiogenesis and gene replacement therapy. Promising results have thus far been obtained with some of these therapies. This review describes the role of new therapeutic agents in the treatment of NSCLC.

Phosphorylated tyrosine-containing proteins in primary lung cancer correlates with proliferation and prognosis

To determine the usefulness of tyrosine phosphorylation in evaluating biological characteristics, we attempted to evaluate the relationship between the amount of phosphorylated tyrosine-containing proteins and clinicopathological factors, cell proliferation and outcome in non-small cell lung cancer. To evaluate phosphorylated tyrosine-containing proteins we used 96 surgically resected materials of non-small cell lung cancer and normal peripheral lung, while immunohistochemical evaluation was performed. Cell proliferating ability was evaluated using the labelling index of proliferating cell nuclear antigen-positive nuclear staining cells. There were statistically significant differences between the expression levels of phosphorylated tyrosine-containing proteins of normal and cancerous tissues (P<0.0001). Evaluations based on clinicopathological factors apart from histopathological differentiation, showed no statistically significant differences of phosphorylated tyrosine-containing proteins expression. However, phosphorylated tyrosine-containing proteins correlated with cell proliferation activity evaluated (P((Low, High))<0.0001; P((Low, Int)) <0.0001; P((Int, High))<0.0001). Furthermore, non-small cell lung cancer cases with high expression and intermediate expression of phosphorylated tyrosine-containing proteins had a significantly shorter disease-free postoperative survival than those with low expression of phosphorylated tyrosine-containing proteins using log-rank analysis (P((Low, Int)) <0.0028; P((Low, High))=0.0002). Furthermore, phosphorylated tyrosine-containing proteins expression level statistically contributed to disease-free survival in Cox's proportional hazard model. Therefore, phosphorylated tyrosine-containing proteins in non-small cell lung cancer tissues seem to reflect its biological malignancy, and this evaluation may be valuable for constructing the most appropriate therapeutic strategy.

Epidermal growth factor receptor family in lung cancer and premalignancy

Lung cancer, like many other epithelial malignancies, is thought to be the outcome of genetic and epigenetic changes that result in a constellation of phenotypic abnormalities in bronchial epithelium. These include morphologic epithelial dysplasia, angiogenesis, increased proliferative rate, and changes in expression of cell surface proteins, particularly overexpression of epidermal growth factor receptor (EGFR) family proteins. The EFGR family is a group of four structurally similar tyrosine kinases (EGFR, HER2/neu, ErbB-3, and ErbB-4) that dimerize on binding with a number of ligands, including EGF and transforming growth factor alpha. Epidermal growth factor receptor overexpression is pronounced in virtually all squamous carcinomas and is also found in > or = 65% of large cell and adenocarcinomas. It is not expressed in situ by small cell lung carcinoma. Overexpression of EGFR is one of the earliest and most consistent abnormalities in bronchial epithelium of high-risk smokers. It is present at the stage of basal cell hyperplasia and persists through squamous metaplasia, dysplasia, and carcinoma in situ. Recent studies of the effect of inhibitors of receptor tyrosine kinases suggest that patterns of coexpression of multiple members of the EGFR family could be important in determining response. Intermediate endpoints of such trials could include monitoring of phosphorylation levels in signal transduction molecules downstream of the receptor dimers. These trials represent a new targeted approach to lung cancer treatment and chemoprevention that will require greater attention to molecular endpoints than required in past trials.

Co-expression of epidermal growth factor receptor and transforming growth factor-alpha is independent of ras mutations in lung adenocarcinoma

The interaction of epidermal growth factor receptor (EGFR) and its ligand transforming growth factor-alpha (TGF-alpha) leads to an autocrine activation of the ras signaling pathway and putatively its oncogenic activity. It is thus hypothesized that the co-overexpression of EGFR-TGFalpha will be redundant hence rare in tumors with oncogenic ras mutations. To test this hypothesis, we studied by immunohistochemistry the expression of EGFR and TGF-alpha in primary non small cell lung cancers. Such putative EGFR autocrine loop activation was found in 73% of squamous cell carcinomas that rarely develop ras mutations. In contrast, EGFR-TGFalpha co-expression occurred with equal frequency in adenocarcinomas irrespective of their ras genotype. The results indicate that EGFR autocrine loop activity in adenocarcinoma may have alternative signaling activities aside from the activation of ras-MAP kinase pathway.

C-erbB-2 expression and its relationship with ploidy, p53 abnormalities and epidermal growth factor receptor content in human non-small cell lung cancer

This study attempts to clarify the role of c-erbB-2 overexpression in human non-small cell lung cancer (NSCLC) and relate it with the p53 alterations, DNA index (D.I.) and epidermal growth factor receptor (EGFR) content in sixty four patients with NSCLC. c-erbB-2 and EGFR quantification were carried out from tissue homogenates using quantitative ELISA procedures. p53 alterations were determined by immunohistochemical (IHC) detection with the monoclonal antibody DO-7 and analysis for p53 mutations on exons 4 to 8 by single strand conformation polymorphism (SSCP). The D.I. was performed by flow cytometry. c-erbB-2 hyperexpression was found in 13 of 58 LC (22%), and it was closely associated with hyperdiploid tumors (D.I. >1.3; P = 0.00). The p53 abnormalities detected by SSCP were statistically more frequent in hyperdiploid tumors (16/25; P = 0.015) than in diploid ones (8/30). No relationship between the results of IHC p53 and SSCP was found. The patients with c-erbB-2 hyperexpressing tumors were prone to have frequent relapses (P = 0.03), although the patients with hyperdiploid NSCLC are the ones with the highest relapse rate (P = 0.008). From the results obtained in this study the following conclusions can be drawn: (a) c-erbB-2 hyperexpressing NSCLC are associated with abnormalities in other biological markers and with a greater rate of relapses; (b) SSCP seemed to be more specific that IHC to detect p53 molecular abnormalities; and (c) the D.I. is the parameter more tightly related with relapse.

Do molecular markers predict survival in non-small-cell lung cancer?

Patients with non-small-cell lung cancer (NSCLC) survive for variable lengths of time, even when adjustment is made for pathological stage. Numerous reports suggest that biological markers predict survival in patients undergoing surgery for NSCLC with curative intent, but many of these claims are unconfirmed or conflicting. We postulated that the use of multiple putative markers might provide greater power in predicting survival. We studied 101 consecutive patients with NSCLC who underwent exploratory thoracotomy and who were followed for at least 2 yr. We assessed mutations in the p53 tumor suppressor gene (exons 5-8) and the K-ras oncogene (codons 12 and 13) by polymerase chain reaction amplification and single strand conformation polymorphism of the product. We identified 19 K-ras mutations (all adenocarcinomas except for two) and 40 p53 mutations among the 101 cases. We also evaluated p53 protein, bcl-2 protein, c-erbB-1 protein, c-erbB-2 protein, and MIA-15-5 antigen by standard immunocytochemical techniques, and we found that all of these antigens were variably expressed. As expected, we found a strong inverse association between surgical tumor stage and survival. Of the molecular markers studied, only MIA-15-5 antigen expression correlated strongly with survival by univariate analysis (p = 0.001) and it remained a significant predictor by multivariate analysis (p = 0.01). However, in this study, overexpression of MIA-15-5 antigen predicted an improved survival, whereas the original report showed a worse prognosis (N. Engl. J. Med. 1992;327:14). We conclude the multiple cell markers are not clinically useful in predicting survival among patients undergoing surgery for NSCLC. Differences between our results and prior reports may be due to chance, to true population differences, or to other factors.

Relationship of p53 molecular abnormalities with flow cytometry and growth factor receptor content in lung cancer

This study attempts of clarify the oncological significance of the p53 molecular abnormalities and p53 expression in lung cancer (LC) and their relationship with flow cytometry (FC) parameters and epidermal growth factor receptor (EGFR). The study includes 65 samples taken from both LC and normal lung (NL). The p53 molecular abnormalities of exons 4-8 were studied by single strand conformation polymorphisms (SSCP) and the loss of heterozygosity (LOH) of exon 4 by the Metzler method. P53 protein was detected by Western blot. EGFR was determined by a radioligand assay using [125I]EGF. The FC parameters S phase fraction (SPF), DNA index (D.I.), G1G0 and growth rate (G2M + SPF) were evaluated from cellular monosuspensions. The LC with SSCP p53 molecular abnormalities have a significantly higher EGFR content (P < 0.001), SPF (P < 0.007), D.I. (P < 0.017) and a lower proportion of G1G0 cells (P < 0.04) than LC with no molecular abnormalities. No relationship between p53 molecular abnormalities and tumor TN or evolutive events was found. Neither the relationship between the molecular results and p53 expression detected by Western blot nor that of the p53 expression detected by Western with FC parameters or EGFR could be shown. In NL the growth fraction cells decrease significantly (P < 0.05) with the intensity of p53 expression. The lack of biological functionality of p53 with molecular abnormalities seemed to relate to fast growing LC whereas p53 expression detected by Western seemed more related to the wild type of p53.

Epidermal growth factor receptor (EGFR) and EGFR mutations, function and possible role in clinical trials

The epidermal growth factor receptor (EGFR) is a growth factor receptor that induces cell differentiation and proliferation upon activation through the binding of one of its ligands. The receptor is located at the cell surface, where the binding of a ligand activates a tyrosine kinase in the intracellular region of the receptor. This tyrosine kinase phosphorylates a number of intracellular substrates that activates pathways leading to cell growth, DNA synthesis and the expression of oncogenes such as fos and jun. EGFR is thought to be involved the development of cancer, as the EGFR gene is often amplified, and/or mutated in cancer cells. In this review we will focus on: (I) the structure and function of EGFR, (II) implications of receptor/ligand coexpression and EGFR mutations or overexpression, (III) its effect on cancer cells, (IV) the development of the malignant phenotype and (V) the clinical aspects of therapeutic targeting of EGFR.

Role of tyrosine specific phosphorylation of cellular proteins, especially EGF receptor and p125FAK in human lung cancer cells

To clarify the role of tyrosine phosphorylation of cellular proteins in human lung cancer cells, phosphotyrosine (PTYR)-containing proteins in lung cancer cell lines and in paired tissues resected from cancerous and normal lungs were studied by immunoblotting with an anti-PTYR antibody. We found that the profiles of protein phosphorylation were very similar among those cell lines which had different histological features. The major PTYR-containing proteins (180-190 KDa, 120-130 KD, and 95-100 KDa) were detected in lung cancer cell lines. The expression of EGF receptor (EGF-r) (p185) and o-erb B2 protein, and tyrosine phosphorylation of p125FAK were examined in cancerous lung tissues and normal lung tissues. In surgical specimens, approximately half of the samples of lung cancer tissues showed clear elevation of tyrosine phosphorylation. In these cancerous tissues, no clear amplification of EGF-r and c-erb B2 protein expression was observed. However, elevation of tyrosine phosphorylation of p125FAK was observed in cancerous lung tissues but not in normal lung tissues, and its phosphorylation was closely correlated with the nodal involvement of cancer and disease-free survival time. These results suggested that the intracellular signaling pathway via tyrosine phosphorylation plays a role in the generation and immortalization of lung cancer, and assessment of tyrosine phosphorylation of cellular proteins. especially p125FAK, may be available clinically as a prognostic factor.

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.

Tyrosine phosphorylation of 100-130 kDa proteins in lung cancer correlates with poor prognosis

To search for the signalling pathways in lung cancer relevant to its aggressive behaviour, we studied tyrosine phosphorylated proteins in lung cancer cell lines and surgical specimens. We found that the profiles of protein phosphorylation were closely matched among these cell lines and cancer tissues of different histological origins, and 100-130 kDa proteins were the major components of phosphorylated proteins. In surgical specimens, approximately half of the cases showed tyrosine phosphorylation of these proteins in a tumour-specific manner, and phosphorylation of these proteins showed good correlation with the survival length of patients after operation. By immunoprecipitation with specific antibodies, we found that p125FAK, p120 and beta-catenin were the major components of tyrosine-phosphorylated proteins in the surgical specimens. These results suggest that tyrosine phosphorylation of these proteins may play a role in tumour relapse and is available as a clinical marker.

Lack of prognostic significance of epidermal growth factor receptor and the oncoprotein p185HER-2 in patients with systemically untreated non-small-cell lung cancer: an immunohistochemical study on cryosections

The prognostic role of the epidermal growth factor receptor (EGFR) and the related receptor p185HER-2 in lung cancer is as yet undefined. We investigated the immunohistochemical expression of EGFR (monoclonal antibody R1; Amersham) and p185HER-2 (polyclonal antibody A485; Dako) in cryosections. A total of 186 unselected and systemically untreated patients with non-small-cell lung cancer (NSCLC) diagnosed and treated at Odense University Hospital, Denmark, were included. Median follow-up period was 66 months. EGFR and p185HER-2 was highly expressed in 55% and 26% of cases respectively. Expression of EGFR was independent of p185HER-2 expression. The expression of EGFR was higher in squamous cell carcinomas whereas the level of p185HER-2 staining was higher in adenocarcinomas. Expression of either or both receptors was not correlated with age, histological grading, stage and prognosis. We conclude that immunohistochemical detection of these growth factor receptors failed to demonstrate a prognostic significance in patients operated on for NSCLC.

Expression and activation of erbB-2 and epidermal growth factor receptor in lung adenocarcinomas

ErbB-2 and EGFR (epidermal growth factor receptor) are expressed in lung adenocarcinomas and associated with a poor prognosis. Immunocytochemical analysis revealed erbB-2 and EGFR coexperession as a characteristic feature of most lung adenocarcinomas, and at levels of receptor expression present in bronchial epithelial cells. In primary lung tumours and cell lines, erbB-2 detected using Western blot analysis demonstrated low-level phosphotyrosine staining of the 185 kDa band, as compared with breast cancer cell lines. A549 and A427 lung adenocarcinoma cells treated with neu differentiation factor (NDF) showed increased erbB-2 phosphotyrosine staining, but to a much lesser extent than breast cancer cells. The lung cells were examined for expression of the potential autocrine growth factors NDF and transforming growth factor alpha (TGF-alpha) by Northern blot analysis. Both NDF and TFG-alpha mRNA were abundantly expressed in the A549 cells. NDF mRNA was highest during active cell proliferation and decreased in confluent cells or after treatment with the growth-inhibitory steroid dexamethasone. Primary tumours and cell lines expressed EGFR, showing higher basal level phosphotyrosine staining than erbB-2. Treatment with NDF and EGF (epidermal growth factor) stimulated cell growth, and in A549 cells the presence of both factors provided an additive increase in cell growth. The growth stimulus that ligand-activated erbB-2 and EGFR provides to lung adenocarcinoma cells may establish a background of continued cell proliferation over which other critical transforming events may occur.

Epidermal growth factor receptor (EGFr) expression in non-small cell lung carcinomas correlates with metastatic involvement of hilar and mediastinal lymph nodes in the squamous subtype

Epidermal growth factor receptor (EGFr) levels were evaluated in paraffin-embedded tumour specimens of non-small cell lung cancer (NSCLC) from 176 patients who underwent surgical resection. The EGFr expression was evaluated by immunocytochemical assay using a monoclonal antibody which recognises the external domain of the receptor. EGFr immunoreactivity was significantly higher in squamous than in non-squamous cell carcinomas (P = 0.0009). Hilar and/or mediastinal nodal involvement was found in 29 of 105 (27.4%) squamous cancers, and in this group of patients, the mean of EGFr positive cells was significantly higher than that of patients without nodal involvement (P = 0.01). No significant correlations were found between the expression of EGFr and other clinicopathological or biological parameters such as T-status, grading, proliferative activity. EGFR is suggested to represent a useful indicator of nodal metastasis in NSCLC.

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.

[Epidermal growth factor receptor in non-small cell cancer of the lung]

In this study we determined the concentration of epidermic growth factor receptors (EGFr) in non-small cell carcinoma of the lung (NSCCL) and analyzed its relation to the anatomical, pathological and clinical factors of these neoplasms. The concentration of EGFr in 62 tumor tissue samples was 9.9 +/- 14 fmol/mg, higher than that found in 14 tissue samples from cases of spontaneous pneumothorax (3.9 +/- 3.6 fmol/mg) (p = 0.005). EGFr concentration in lung tissue with no signs of neoplasm was 6.5 +/- 10 fmol/mg. In 21 (33%) cases of NSCCL the concentration exceeded the normal threshold of 10 fmol/mg. EGFr concentration was higher in cases of epidermoid carcinoma than in other tissue samples (p = 0.042). No significant association was found between EGFr levels and status of tumor node metastasis, degree of differentiation and mitotic index. The probability of remaining free of tumor recurrence and of survival after 24 months among patients whose tumoral EGFr concentration was below 10 fmol/mg was 34 and 40%, respectively. The rates for patients with concentrations that exceeded the threshold were 20% (p = 0.32) and 25% (p = 0.26), respectively. The results seem to indicate that the study of EGFr concentration alone does not yield practically important information for the management of patients with NSCCL who have undergone surgery. The concentration of EGFr marks degree of differentiation in NSCCL and has prognostic implications derived from its association with other factors.

Prognostic value of a solubilized fraction of EGF receptors in primary breast cancer using an immunoenzymatic assay--a retrospective study

In a retrospective study of 319 primary breast cancers, we show that an immunoenzymatic assay of a solubilized fraction of EGF receptors indicates a prognostic value for EGFR which is in contradiction with some (but not all) other studies. It appears that different methodological approaches of measuring EGFR are not equivalent in terms of prognostic power. We emphasize the need for rigorous multicentric standardization and quality control of assays, followed by multistep validation of parameters oriented towards clinical use.

The prognostic value of epidermal growth factor receptor (EGF-R) in primary breast cancer: results of a 10 year follow-up study

In a study on 214 patients with primary breast cancer (median follow-up 8.5 yr, maximum follow-up 15 yr), EGF-R was negatively correlated to estrogen receptor and progesterone receptor, whereas no association was found with age, lymph node status, and tumor size. Initially, after a follow-up of 5 yr, there was a tendency to a significant association between EGF-R levels and tumor recurrence rate (p = 0.08). Patients with tumors containing intermediate levels of EGF-R experienced a longer relapse-free survival (RFS) than did patients with tumors possessing lower or higher levels of EGF-R. This effect was most pronounced in the subgroup of patients with positive axillary lymph nodes. However, after 10 yr follow-up, this association appears to be lost (p = 0.28) as shown in this update. A similar phenomenon was observed for the ER. While at 5 yr follow-up ER status had significant prognostic value (p = 0.01), at 10 yr follow-up this significance also appears to be lost (p = 0.40). However, tumor size, lymph node status, grade, and PgR status maintained significant prognostic value by univariate analysis. Based on 40 separate studies comprising 5232 patients, the mean percentage of EGF-R positivity reported in breast cancer is 45% (range 14-91%). Nine out of 15 different studies showed in some way a significant negative association between EGF-R and RFS by univariate analysis, and 2 others showed a tendency to such a relationship. Of 7 studies applying multivariate analysis, two demonstrated an independent prognostic value of EGF-R for RFS and two others a tendency to a significant correlation, whereas three did not. It may be concluded that EGF-R status has more or less prognostic value in patients with primary breast cancer, but the prognostic power decreases with longer follow-up. Of great clinical significance is the association of EGF-R with hormone resistance. Therefore EGF-R status can be used for selection of type of treatment. Finally, EGF-R might be useful as a target for new treatment modalities.

Modulation of the immunophenotype of ovarian cancer cells by N,N-dimethylformamide and transforming growth factor-beta 1

Exposure of HOC-7 ovarian adenocarcinoma cells to regulators of cell differentiation caused inducer-dependent alterations of the antigenic pattern of the cells. Immunocytochemistry revealed that N,N-dimethylformamide (DMF) elevated the membrane staining for epidermal growth factor (EGF)-receptor and for desmoplakins I and II. DMF also stimulated cytoplasmic and surface labeling for CA 125 and the deposition of fibronectin into the extracellular matrix. Stimulation of fibronectin was also seen after addition of transforming growth factor (TGF)-beta 1. These responses were quantified using a fixed-cell, enzyme-linked immunosorbent assay (ELISA) and revealed that DMF dose-dependently induced expression of EGF-receptor, CA 125, fibronectin, and desmoplakins I and II. TGF-beta 1 stimulated fibronectin and desmoplakins I and II only. Production of EGF and TGF-alpha was not affected by these inducers. Immunocytochemistry, ELISA and Western blotting showed that both inducers caused down-regulation of myc oncoproteins. DMF was more effective in changing the immunophenotype of HOC-7 cells than TGF-beta 1. Desmoplakins I and II demonstrated elevated epithelial differentiation, whereas fibronectin indicated stimulation of extracellular matrix formation. Elevated EGF-receptor could not compensate for the growth inhibition induced by DMF. The expression of myc oncoproteins was inversely related to cell proliferation. CA 125, however, seems to be unrelated to cell growth.

Different propensity for spontaneous differentiation of cell clones isolated from the human ovarian surface epithelial cell line HOC-7

Limiting dilution culture of cell fractions obtained by discontinuous density gradient centrifugation was used to establish six different cell clones from HOC-7 ovarian adenocarcinoma cells (D1-D3, N1-N3). Clones D1-D3 revealed a phenotype similar to that seen in parental cells exposed to differentiation inducers such as dimethyl sulfoxide (DMSO, 0.8% [v/v]). They were flattened, slowly growing cells (doubling times: 42-46 h). The cells developed long cytoplasmic extensions and adopted a complicated growth pattern. Fixed-cell enzyme-linked immunosorbent assay (ELISA) and Western blotting demonstrated that these cells contained high levels of epidermal growth factor-receptor (EGF-R), carbohydrate antigen 125 (CA 125), fibronectin and desmoplakin, but low levels of myc oncoproteins. However, untreated parental cells and clones N1-N3 were fast-growing (doubling times: 23-28 h), regularly shaped, polygonal cells ("cobblestone" monolayer) with low levels of EGF-R, CA 125, fibronectin and desmoplakin, but relatively higher amounts of myc oncoproteins. The similarity of the sublines to either untreated or inducer-treated parental cells indicated that clones D1-D3 represented spontaneously differentiated HOC-7 cells, whereas clones N1-N3 originated from less-differentiated cells. The features examined in this model cell system proved to be closely related to ovarian cancer cell proliferation and differentiation. The observation of a tumor-inherent propensity for spontaneous differentiation suggests that exogenous stimulation of existing differentiation pathways may represent an alternative approach for tackling the problem of growth control and differentiation in malignant tissues.

Expression of epidermal growth factor receptors by odontogenic jaw cysts

The expression of epidermal growth factor receptor (EGFr) by odontogenic epithelium was studied in odontogenic cysts (n = 35), ameloblastoma (n = 6), and periapical granulomas containing proliferating epithelial rests of Malassez (n = 7) using a panel of monoclonal antibodies to EGFr (clone E30, F4 and C11) known to react with formalin-fixed, paraffin-embedded sections. Odontogenic epithelium in all specimens demonstrated immunoreactivity with all three antibodies. Clone E30 consistently gave the most intense, membrane located staining pattern of the three antibodies tested. Generally, staining of epithelial cells progressively diminished with movement away from the basal cell layers toward the most superficial layers of cystic lining or centre of epithelial rests and tumour islands. Developmental odontogenic cysts (odontogenic keratocysts, n = 13; dentigerous cysts, n = 11) and ameloblastoma (follicular type, n = 5; unicystic type, n = 1) expressed a higher level of EGFr staining than inflammatory cysts (radicular cysts, n = 11) and the proliferating epithelial rests in periapical granulomas. However, foci of weak EGFr staining of odontogenic keratocyst lining, similar to that seen in radicular cysts, were found in areas associated with inflammation. In addition, epithelial rests not associated with inflammatory cell infiltrates exhibited stronger reactivity for EGFr than proliferating rests within periapical granulomas. These results indicate that the level of EGFr expression by odontogenic cysts and rests is related to the presence of inflammation within adjacent connective tissue and that there is no detectable difference in receptor expression between developmental cysts and ameloblastoma.

Expression of transforming growth factor-alpha in mid-gestation human fetal lung

Transforming growth factor-alpha (TGF-alpha), a member of the epidermal growth factor (EGF) family, is a potent mitogen for several cell types. To investigate the possible role of TGF-alpha in the development of midgestation human fetal lung, we studied its distribution with immunohistochemistry and determined levels of steady-state TGF-alpha mRNA by Northern analysis of cellular RNA isolates from lung. Lung was obtained from fetuses at 10 to 22 wk of gestation (n = 14) and immunostained for TGF-alpha. TGF-alpha was localized in epithelial cells at all gestational ages examined. Immunostaining was particularly prominent in bronchiolar epithelial cells. TGF-alpha immunoreactivity was also associated with arterial smooth muscle cells, as well as with nerves. Occasional chondrocytes were also associated with TGF-alpha immunoreactivity. Total cellular RNA was isolated from lung tissue obtained from additional fetuses at gestational ages 10 to 24 wk (n = 22). TGF-alpha mRNA was present in RNA extracts of all fetal lungs studied. We conclude that TGF-alpha is probably produced in human fetal lung during mid-gestation. The prominent immunostaining of bronchiolar epithelial cells for TGF-alpha is consistent with its playing a role in distal airway formation.

Comparative analysis of the effects of dimethyl sulfoxide and retinoic acid on the antigenic pattern of human ovarian adenocarcinoma cells

HOC-7 malignant ovarian surface epithelial cells have been exposed to differentiation promoters like dimethyl sulfoxide (DMSO) and retinoic acid (RA) and the resulting cell phenotypes were characterized immunologically. Immunocytochemistry revealed that DMSO caused elevation of membrane-associated staining for epidermal growth factor-receptor (EGF-R) and for desmoplakins I and II (DPI+II). DMSO also stimulated cytoplasmic and surface labelling for CA 125 and extracellular deposition of fibronectin (FN). A fixed-cell ELISA system was used for quantification of these differentiation-like responses and revealed that DMSO efficiently induced expression of EGF-R, CA 125, FN and DPI+II in dose-dependent manner. Immunocytochemistry, ELISA and Western blotting additionally demonstrated that both DMSO and RA caused down-regulation of myc oncoproteins. Densitometer evaluation of electrophoresed proteins revealed a 50% DMSO- and a 25% RA-induced myc reduction. Apart from growth reduction, which was seen for both inducers, inhibition of myc gene expression was the only response of HOC-7 cells to RA-treatment. The extent of myc down-regulation seems, therefore, to be crucial for the initiation of maturational processes in the cells. Subsequent phenotypic differentiation of HOC-7 cells causes elevated levels of EGF-R, CA 125, FN and DPI+II. This cell model might be useful for the distinction between induced growth reduction and differentiation of ovarian cancer cells.

Growth control by epidermal growth factor and transforming growth factor-alpha in human lung squamous carcinoma cells

Although EGF receptor expression is generally elevated in human lung squamous carcinoma, the biological significance of this phenomenon and the role of EGF and TGF-alpha in this disease are poorly understood. We have investigated three human lung squamous carcinoma cell lines (NX002, CX140 and CX143) and have shown, using an antibody (EGFR1) directed against the EGF receptor, that the majority of cells in all three lines express the EGF receptor. Using a ligand binding assay, Scatchard analysis indicated high concentrations (1,300-2,700 fmol mg-1 protein) of a single low affinity binding site (Kd = 3-5 nM) within these lines. Addition of EGF or TGF-alpha at concentrations greater than 0.1 nM resulted in growth inhibition of all three lines and this was associated with an accumulation of cells in the G2/M phase of the cell cycle. Growth inhibitory effects were not explained by an enhancement of cellular differentiation as monitored by involucrin expression and the ability to form cornified envelopes. While the presence of EGF could not be detected in medium conditioned by the NX002 cell line, mRNA for TGF-alpha was detected in all three lines suggesting the possibility of an autocrine loop. These results together with reports of growth inhibition by EGF and TGF-alpha in other systems suggest that EGF and similar molecules might have a growth regulatory role in lung cancer cells and modulation of such may have therapeutic potential.

Immunohistochemical studies on oncogene products (EGF-R, c-erbB-2) and growth factors (EGF, TGF-α) in human breast cancer: their relationship to oestrogen receptor status, histological grade, mitotic index and nodal status

In this investigation, 83 human mammary carcinomas were examined for the expression of oestrogen receptor (ER), epidermal growth factor receptor (EGF-R), epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), c-erbB-2, histological grade, mitotic index and nodal status, all of which are reportedly prognostically significant factors (Bloom and Richardson 1957; Baak et al. 1985; Wright et al. 1989). ER expression was biochemically recognized in 43.4% of mammary carcinomas, and EGF-R, EGF, TGF-alpha and c-erbB-2 were histochemically recognized in 25.3, 14.5, 27.7 and 18.0% of mammary carcinomas examined respectively, using conventional sections of buffered formalin-fixed, paraffin-embedded tissue and monoclonal or polyclonal antibodies. There were significant relationships between negative ER and positive EGF-R or TGF-alpha; positive EGF-R and TGF-alpha; positive EGF-R and c-erbB-2; and positive c-erbB-2 and TGF-alpha. The single changes which were the negative ER and the positive c-erbB-2 correlated with histological grade and mitotic index. Co-expression of EGF-R and TGF-alpha correlated with positive nodal status. Therefore, the present investigation indicates that the negative ER, single expression of c-erbB-2 and co-expression of EGF-R and TGF-alpha are important markers which contribute indirectly to prognosis, which reconfirms previous findings on the former two while adding the new finding that immunohistochemical demonstration of expression of EGF-R and TGF-alpha may provide useful information for selecting the appropriate treatment.