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

Near infrared photoimmunotherapy of cancer; possible clinical applications

Near-infrared photoimmunotherapy (NIR-PIT) is a new cancer treatment that uses an antibody-photo-absorber conjugate (APC) composed of a targeting monoclonal antibody conjugated with a photoactivatable phthalocyanine-derivative dye, IRDye700DX (IR700). APCs injected into the body can bind to cancer cells where they are activated by local exposure to NIR light typically delivered by a NIR laser. NIR light alters the APC chemical conformation inducing damage to cancer cell membranes, resulting in necrotic cell death within minutes of light exposure. NIR-PIT selectivity kills cancer cells by immunogenic cell death (ICD) with minimal damage to adjacent normal cells thus, leading to rapid recovery by the patient. Moreover, since NIR-PIT induces ICD only on cancer cells, NIR-PIT initiates and activates antitumor host immunity that could be further enhanced when combined with immune checkpoint inhibition. NIR-PIT induces dramatic changes in the tumor vascularity causing the super-enhanced permeability and retention (SUPR) effect that dramatically enhances nanodrug delivery to the tumor bed. Currently, a worldwide Phase 3 study of NIR-PIT for recurrent or inoperable head and neck cancer patients is underway. In September 2020, the first APC and accompanying laser system were conditionally approved for clinical use in Japan. In this review, we introduce NIR-PIT and the SUPR effect and summarize possible applications of NIR-PIT in a variety of cancers.

Near Infrared Photoimmunotherapy; A Review of Targets for Cancer Therapy

Simple Summary

Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that uses an antibody-photoabsorber (IRDye700DX) conjugate (APC) that is activated by NIR light irradiation. A major benefit of NIR-PIT is that only APC-bound cancer cells that are exposed to NIR light are killed by NIR-PIT; thus, minimal damage occurs in adjacent normal cells. NIR-PIT has now been applied to many cancers expressing various cell-surface target proteins using monoclonal antibodies designed to bind to them. Moreover, NIR-PIT is not limited to tumor antigens but can also be used to kill specific host cells that create immune-permissive environments in which tumors grow. Moreover, multiple targets can be treated simultaneously with NIR-PIT using a cocktail of APCs. NIR-PIT has great potential to treat a wide variety of cancers by targeting appropriate tumor cells, immune cells, or both, and can be augmented by other immunotherapies.

Abstract

Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that uses an antibody-photoabsorber (IRDye700DX) conjugate (APC) that is activated by NIR light irradiation. In September 2020, the first APC and laser system were conditionally approved for clinical use in Japan. A major benefit of NIR-PIT is that only APC-bound cancer cells that are exposed to NIR light are killed by NIR-PIT; thus, minimal damage occurs in adjacent normal cells. These early trials have demonstrated that in addition to direct cell killing, there is a significant therapeutic host immune response that greatly contributes to the success of the therapy. Although the first clinical use of NIR-PIT targeted epidermal growth factor receptor (EGFR), many other targets are suitable for NIR-PIT. NIR-PIT has now been applied to many cancers expressing various cell-surface target proteins using monoclonal antibodies designed to bind to them. Moreover, NIR-PIT is not limited to tumor antigens but can also be used to kill specific host cells that create immune-permissive environments in which tumors grow. Moreover, multiple targets can be treated simultaneously with NIR-PIT using a cocktail of APCs. NIR-PIT can be used in combination with other therapies, such as immune checkpoint inhibitors, to enhance the therapeutic effect. Thus, NIR-PIT has great potential to treat a wide variety of cancers by targeting appropriate tumor cells, immune cells, or both, and can be augmented by other immunotherapies.

Diffusion Reflection Measurements of Antibodies Conjugated to Gold Nanoparticles as a Method to Identify Cutaneous Squamous Cell Carcinoma Borders

Diffusion reflectance spectroscopy measurements targeted with gold nanoparticles (GNPs) can identify residual cutaneous squamous cell carcinoma (SCC) in excision borders. Human SCC specimens were stained with hematoxylin and eosin to identify tumor borders, and reflected onto an unstained deparaffinized section. Diffusion reflection of three sites (normal and SCC) were measured before and after GNPs targeting. Hyperspectral imaging showed a mean of 2.5 sites with tumor per specimen and 1.2 tumor-free (p < 0.05, t-test). GNPs were detected in 25/30 tumor sites (sensitivity 83.3%, false-negative rate 16.6%) and 12/30 non-tumor sites (specificity 60%, false-positive rate 40%). This study verifies the use of nanotechnology in identifying SCC tumor margins. Diffusion reflection scanning has high sensitivity for detecting the residual tumor.

Expression, regulation and targeting of receptor tyrosine kinases in esophageal squamous cell carcinoma

Esophageal cancer is one of the most common types of cancer, which is a leading cause of cancer-related death worldwide. Based on histological behavior, it is mainly of two types (i) Esophageal squamous cell carcinoma (ESCC), and (ii) esophageal adenocarcinoma (EAD or EAC). In astronomically immense majority of malignancies, receptor tyrosine kinases (RTKs) have been kenned to play a consequential role in cellular proliferation, migration, and metastasis of the cells. The post-translational modifications (PTMs) including phosphorylation of tyrosine (pY) residue of the tyrosine kinase (TK) domain have been exploited for treatment in different malignancies. Lung cancer where pY residues of EGFR have been exploited for treatment purpose in lung adenocarcinoma patients, but we do not have such kind of felicitously studied and catalogued data in ESCC patients. Thus, the goal of this review is to summarize the studies carried out on ESCC to explore the role of RTKs, tyrosine kinase inhibitors, and their pertinence and consequentiality for the treatment of ESCC patients.

Expression, regulation and targeting of receptor tyrosine kinases in esophageal squamous cell carcinoma

Esophageal cancer is one of the most common types of cancer, which is a leading cause of cancer-related death worldwide. Based on histological behavior, it is mainly of two types (i) Esophageal squamous cell carcinoma (ESCC), and (ii) esophageal adenocarcinoma (EAD or EAC). In astronomically immense majority of malignancies, receptor tyrosine kinases (RTKs) have been kenned to play a consequential role in cellular proliferation, migration, and metastasis of the cells. The post-translational modifications (PTMs) including phosphorylation of tyrosine (pY) residue of the tyrosine kinase (TK) domain have been exploited for treatment in different malignancies. Lung cancer where pY residues of EGFR have been exploited for treatment purpose in lung adenocarcinoma patients, but we do not have such kind of felicitously studied and catalogued data in ESCC patients. Thus, the goal of this review is to summarize the studies carried out on ESCC to explore the role of RTKs, tyrosine kinase inhibitors, and their pertinence and consequentiality for the treatment of ESCC 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.

EGFR targeted therapies and radiation: Optimizing efficacy by appropriate drug scheduling and patient selection

The epidermal growth factor receptor (EGFR) plays an important role in tumor progression and treatment resistance for many types of malignancies including head and neck, colorectal, and nonsmall cell lung cancer. Several EGFR targeted therapies are efficacious as single agents or in combination with chemotherapy. Given the toxicity associated with chemoradiation and poor outcomes seen in several types of cancers, combinations of EGFR targeted agents with or without chemotherapy have been tested in patients receiving radiation. To date, the only FDA approved use of an anti-EGFR therapy in combination with radiation therapy is for locally advanced head and neck cancer. Given the important role EGFR plays in lung and colorectal cancer and the benefit of EGFR inhibition combined with chemotherapy in these disease sites, it is perplexing why EGFR targeted therapies in combination with radiation or chemoradiation have not been more successful. In this review we summarize the clinical findings of EGFR targeted therapies combined with radiation and chemoradiation regimens. We then discuss the interaction between EGFR and radiation including radiation induced EGFR signaling, the effect of EGFR on DNA damage repair, and potential mechanisms of radiosensitization. Finally, we examine the potential pitfalls with scheduling EGFR targeted therapies with chemoradiation and the use of predictive biomarkers to improve patient selection.

Systematic review and meta-analysis of immunohistochemical prognostic biomarkers in resected oesophageal adenocarcinoma

BACKGROUND

Oesophageal adenocarcinoma (OAC) is one of the fastest rising malignancies with continued poor prognosis. Many studies have proposed novel biomarkers but, to date, no immunohistochemical markers of survival after oesophageal resection have entered clinical practice. Here, we systematically review and meta-analyse the published literature, to identify potential biomarkers.

METHODS

Relevant articles were identified via Ovid medline 1946-2013. For inclusion, studies had to conform to REporting recommendations for tumor MARKer (REMARK) prognostic study criteria. The primary end-point was a pooled hazard ratio (HR) and variance, summarising the effect of marker expression on prognosis.

RESULTS

A total of 3059 articles were identified. After exclusion of irrelevant titles and abstracts, 214 articles were reviewed in full. Nine molecules had been examined in more than one study (CD3, CD8, COX-2, EGFR, HER2, Ki67, LgR5, p53 and VEGF) and were meta-analysed. Markers with largest survival effects were COX-2 (HR=2.47, confidence interval (CI)=1.15-3.79), CD3 (HR=0.51, 95% CI=0.32-0.70), CD8 (HR=0.55, CI=0.31-0.80) and EGFR (HR=1.65, 95% CI=1.14-2.16).

DISCUSSION

Current methods have not delivered clinically useful molecular prognostic biomarkers in OAC. We have highlighted the paucity of good-quality robust studies in this field. A genome-to-protein approach would be better suited for the development and subsequent validation of biomarkers. Large collaborative projects with standardised methodology will be required to generate clinically useful biomarkers.

Relationship between EGFR over-expression and clinicopathologic characteristics in squamous cell carcinoma of the esophagus: a meta-analysis

Over-expression of epidermal growth factor receptor (EGFR) has been identified as a common feature associated with clinical outcome in many types of cancer, including squamous cell carcinoma of the oesophagus (SCCO). However, the clinical importance of EGFR over-expression in SCCO remains unsettled as conflicting results exist. Therefore we carried out the present meta-analysis of published studies for clarification. A total of 13 studies including 1,150 patients were enrolled. EGFR over-expression was positive in 722 of these cases. With EGFR over-expression, patients had higher depth of invasion, vascular invasion, and poor prognosis. However, expression had no relation with degree of differentiation, histological grade, lymph node metastasis, clinical stage or lymphatic invasion. EGFR over-expression is probably a valuable predictor for the T stage, vascular invasion and OS, and it could be used as a poor prognosis indicator for the esophageal SCC patients. Targeting therapy to EFGR should be considered to the combined treatment in SCCO.

The role of biological markers of epithelial to mesenchymal transition in oesophageal adenocarcinoma, an immunohistochemical study

BACKGROUND

E-cadherin, β-catenin, epidermal growth factor receptor (EGFR), neuronal cadherin (N-cadherin) and Cyclin D1 are involved in epithelial to mesenchymal transition (EMT). However, the prognostic significance of EMT markers in oesophageal adenocarcinoma (OAC) is unknown. Aim of this study was to evaluate the prognostic value of, and the association between different EMT markers in OAC.

METHODS

Tumour cores of 154 patients with OAC were included in a tissue microarray. Scoring criteria was based on immunohistochemical staining intensity.

RESULTS

EMT-associated markers were expressed in OAC: reduced membranous E-cadherin and β-catenin were seen in 11.4% and 51.7%, nuclear β-catenin in 19.1% and EGFR and Cyclin D1 overexpression in 56.5% and 27.4% of tumours. Mesenchymal marker N-cadherin was not expressed in OAC. A positive correlation was seen between membranous β-catenin and E-cadherin expression (R=0.209, p=0.001) and between EGFR and Cyclin D1 (R=0.257, p=0.002). In univariate analysis, EGFR overexpression and membranous β-catenin staining were significantly associated with a poor survival (HR 2.145; 95% CI 1.429 to 3.218, p<0.001 and HR 1.665; 95% CI 1.114 to 2.488; p=0.013). However, Cyclin D1 (HR 1.092; 95% CI 0.702 to 1.698; p=0.697), nuclear β-catenin (HR 1.322; 95% CI 0.799 to 2.189; p=0.277) and E-cadherin (HR 1.012; 95% CI 0.554 to 1.851; p=0.968) were not associated with survival. In multivariate analysis, EGFR overexpression was an independent prognostic factor for poor survival (HR 1.678; 95% CI 1.055 to 2.668; p=0.029) together with T stage (HR 2.759; 95% CI 1.356 to 5.576; p=0.005).

CONCLUSIONS

This study supports the presence of EMT in OAC. Moreover, EGFR overexpression was independently associated with a poor survival.

Chemoprevention of lung cancer: concepts and strategies

Lung cancer develops in a stepwise fashion, with an accumulation of molecular alterations progressing through preinvasive steps to invasive disease. This progression could be arrested or reversed through pharmacologic treatments, which are known as cancer chemoprevention. Preclinical and clinical findings relating to different classes of candidate chemopreventive agents provide support for this strategy as an active and promising approach for controlling this disease.

Epidermal growth factor receptor: an important target in esophageal cancer

INTRODUCTION

Even after complete tumor removal by surgery, the clinical outcomes remain poor in patients with advanced esophageal cancer, justifying the need for new treatment options. Epidermal growth factor receptor (EGFR) is a molecular target for antibody-based therapy in various cancer types, and it may play important roles in the development of esophageal cancer.

AREAS COVERED

This review evaluates the expression, function, and mechanism of EGFR in esophageal cancer and analyzes its value for the prognosis and therapy of esophageal cancer. Future developments toward the clinical applications of EGFR to cancer treatment are also envisaged.

EXPERT OPINION

EGFR may function as an ideal therapeutic target for esophageal cancer. Further investigation of epidermal growth-factor-receptor-mediated pathways will push insight into the novel strategies of target therapy for esophageal cancer. More clinical trials should be performed to promote the success of therapeutic-clinical use of EGFR and its targets in esophageal cancer.

The role of nitric oxide in the induction of caudal-type homeobox 2 through epidermal growth factor receptor in the development of Barrett's esophagus

OBJECTIVE

The high concentration of nitric oxide (NO) around the gastro-esophageal junction (GEJ) might play an important role in the development of Barrett's esophagus (BE), a precursor of Barrett's adenocarcimona. Although previous studies revealed that the expression of caudal-type homeobox 2 (CDX2), an important marker of BE, might be induced through Epidermal Growth Factor Receptor (EGFR), the roles of NO in this signal transduction remain unclear.

MATERIAL AND METHODS

First, we investigated the expressions of EGFR, CDX2 and nitrotyrosine by immunohistochemical study for BE and squamous epithelium of human specimens. Second, we studied the effect of peroxynitrite, peroxynitrite stimulator, SIN-1, or NO donor, NOC7, on the expression of phosphorylated EGFR and CDX2 in KYSE30, an EGFR-rich human esophageal squamous cell carcinoma cell-line. Specific inhibitors for EGFR, AG1478 and small interfering RNA for EGFR (EGFR-siRNA) were employed to elucidate the role of EGFR in the induction of CDX2.

RESULTS

The immunohistochemical study revealed that the expressions of EGFR, CDX2 and nitrotyrosine in BE were stronger than those in squamous epithelium with positive correlations. Exposure to peroxynitrite, SIN-1 or NOC7 induced EGFR phosphorylation and CDX2 expression in dose- and time-dependent manners. Both EGFR phosphorylation and CDX2 induction were significantly diminished by AG 1478 and EGFR-siRNA.

CONCLUSIONS

We revealed for the first time that extrinsic NO might directly induce CDX2 expression through EGFR phosphorylation. We suggested that NO had an important role in the development of BE from squamous epithelium around GEJ.

Epidermal growth factor expression in esophageal adenocarcinoma: a clinically relevant target?

INTRODUCTION

There has been recent widespread enthusiasm in epidermal growth factor (EGFR) as a molecularly active target in esophageal adenocarcinoma (EAC). However, there is limited data on the extent of EGFR expression in EAC. Thus, the aim of this study was to evaluated EGFR, pErk1/2, and total Erk1/2 expression in malignant and benign specimens.

METHODS

Baseline expression of EGFR in the human normal squamous, Barrett's, and EAC cell lines were determined as well as after bile acid treatment and curcumin pretreatment. In addition, EGFR expression was also evaluated in 60 matched normal and malignant EAC resected specimens.

RESULTS

The in vitro studies in the Het-1a, BarT, and OE19 cell lines failed to show any measurable expression of EGFR via Western blot technique. The marker serving as the positive control for the study, MnSOD, showed expression in each cell line for all three treatment regimens at approximately 24 kDa EGFR, showing moderate staining in the malignant tumor specimens and low staining in the benign tissue specimens. pErk1/2 showed low staining in the malignant tumor specimens and no staining in the benign tissue specimens. Total Erk1/2 showed high staining in both the malignant tumor specimens and benign tissue specimens. The differences in the mean staining scores for the malignant versus benign tissue specimens for pErk1/2 and total Erk1/2 are not statistically significant (p = 0.0726 and p = 0.7054, respectively).

CONCLUSION

Thus, in conclusion, EGFR expression has been confirmed to be limited to non-existent in EAC and thus its use as a clinically active target is limited at best. Prior to the use of these expensive anti-EGFR therapies, confirmation of overexpression should be verified.

Prognosis of esophageal squamous cell carcinoma in patients positive for human epidermal growth factor receptor family can be improved by initial chemotherapy with docetaxel, fluorouracil, and cisplatin

BACKGROUND

The human epidermal growth factor receptor (HER) family, Ki-67 and p53 are important biomarkers for several malignancies. However, few studies have examined the role of these in prognosis and therapeutic sensitivity of esophageal squamous cell carcinoma (ESCC). The efficacy of triple-drug combination therapy with docetaxel, fluorouracil and cisplatin has recently been expected for ESCC.

METHODS

Subjects comprised 142 patients with ESCC who underwent operation (OP group, n = 54), neoadjuvant chemotherapy with docetaxel, fluorouracil, and cisplatin (DFP therapy) followed by operation (NAC group, n = 37) or initial systemic DFP therapy (CT group, n = 51) between January 2004 and December 2010. Immunohistochemical expressions of epidermal growth factor receptor (EGFR), HER2, HER3, Ki-67, and p53 were evaluated and compared with prognosis and sensitivity to DFP therapy.

RESULTS

Positive correlations existed between EGFR, HER2, and HER3 expressions. In the OP group, EGFR was independently associated with postoperative recurrence in multivariate analysis (P = .036). In the NAC group, EGFR correlated with pathological response to DFP therapy (P = .004). In the CT group, EGFR, HER2, and HER3 correlated with clinical response to DFP therapy and EGFR was independently associated with favorable prognosis in multivariate analysis (P = .022).

CONCLUSION

EGFR represents a predictor of postoperative recurrence and sensitivity to triple-drug combination therapy including a taxane. EGFR-positive patients may show improved prognosis with taxane combination chemotherapy and molecular targeted therapy for HER family members.

Mutations in epidermal growth factor receptor and K-ras in Chinese patients with colorectal cancer

Background

Mutations of EGFR and K-ras are biomarkers for predicting the efficacy of targeting agents in non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC). Data on the gene mutation status of EGFR and K-ras in Chinese patients with CRC are limited.

Methods

EGFR mutations in exon 18-21 and K-ras mutations in exon 1 and 2 were detected in tumor samples from 101 Chinese patients with CRC by polymerase chain reaction-single strand conformational polymorphism. The relationship between patients' characteristics and survival time and gene mutation status were analyzed using the Statistical Package for the Social Sciences.

Results

Only two samples (2.0%) had EGFR mutations in exon 18 or 21, and 33 of 101 samples (32.7%) had K-ras mutations in codon 12, 13, 45, 69, or 80. Univariate analysis suggested that differentiation might be correlated with K-ras mutations (p = 0.05), which was confirmed by a logistic regression model (p = 0.04). The median overall survival (OS) and median survival after metastasis were 44.0 and 18.0 months, respectively, in the mutant K-ras group, and 53.3 and 19.0 months, respectively, in the wild K-ras group. K-ras mutation was not an independent prognostic factor for OS or survival after metastasis (p = 0.79 and 0.78, respectively).

Conclusions

In Chinese patients with CRC, EGFR mutations were rare, and K-ras mutations were similar to those of Europeans. New mutations in codons 45, 69, and 80 were found in the Chinese population. Poor differentiation was an independent factor related to K-ras mutations.

Integration of targeted agents in the neo-adjuvant treatment of gastro-esophageal cancers

Pre- and peri-operative strategies are becoming standard for the management of localized gastro-esophageal cancer. For localized gastric/gastro-esophageal junction (GEJ) cancer there are conflicting data that a peri-operative approach with cisplatin-based chemotherapy improves survival, with the benefits seen in esophageal cancer likely less than a 5-10% incremental improvement. Further trends toward improvement in local control and survival, when combined chemotherapy and radiation therapy are given pre-operatively, are suggested by recent phase III trials. In fit patients, a significant survival benefit with pre-operative chemoradiation is seen in those patients who achieve a pathologic complete response. In esophageal/GEJ cancer, definitive chemoradiation is now considered in medically inoperable patients. In squamous cell carcinoma of the esophagus, surgery after primary chemoradiation is not clearly associated with an improved overall survival, however, local control may be better. In localized gastric/GEJ cancer, the integration of bevacizumab with pre-operative chemotherapy is being explored in large randomized studies, and with chemoradiotherapy in pilot trials. The addition of anti-epidermal growth factor receptor and anti-human epidermal growth factor receptor-2 antibody treatment to pre-operative chemoradiation continues to be explored. Early results show the integration of targeted therapy is feasible. Metabolic imaging can predict early response to pre-operative chemotherapy and biomarkers may further predict response to pre-operative chemo-targeted therapy. A multimodality approach to localized gastro-esophageal cancer has resulted in better outcomes. For T3 or node-positive disease, surgery alone is no longer considered appropriate and neo-adjuvant therapy is recommended. The future of neo-adjuvant strategies in this disease will involve the individualization of therapy with the integration of molecular signatures, targeted therapy, metabolic imaging and predictive biomarkers.

Hsp90 is expressed and represents a therapeutic target in human oesophageal cancer using the inhibitor 17-allylamino-17-demethoxygeldanamycin

Heat shock protein 90 (Hsp90) has been demonstrated to protect oncogenic variants of signalling molecules from degradation and may consequently serve as a therapeutic target for the treatment of oesophageal cancer for which adequate therapy is often lacking. We studied the expression of Hsp90 in tumour tissues of human oesophageal cancer and the impact of Hsp90 inhibition on oesophageal cancer cell lines using the drug 17-allylamino-17-demethoxygeldanamycin (17-AAG). Quantitative immunohistochemistry was performed on formalin-fixed paraffin-embedded tissues from patients with oesophageal cancer. In squamous cell carcinoma, a marked upregulation of Hsp90 could be noted in dysplastic epithelium and invasive cancer compared with normal epithelium. In adenocarcinoma, Hsp90 was expressed in neoplastic epithelium and also in normal non-neoplastic glands weakly. The inhibition of Hsp90 using 17-AAG led to a significant decrease in cell proliferation and viability in human oesophageal cancer cell lines. Using a clonogenic cell survival assay, Hsp90 inhibition significantly sensitised the cells for γ-photon irradiation. Heat shock protein 90 was found to be critical for proper signalling induced by both epidermal growth factor and insulin-like growth factor-1, in which the inhibition of signalling by 17-AAG correlated with the observed reduction in cell proliferation and viability. These results showed that Hsp90 was selectively expressed in oesophageal cancer tissue compared with the corresponding normal tissue, and the inhibition of Hsp90 resulted in decreased proliferation and viability as well as radiosensitisation of oesophageal cancer cells. Heat shock protein 90 represents a potential therapeutic target in the treatment of patients with oesophageal cancer, alone or in combination with radiotherapy.

Anti-angiogenic potential of CoenzymeQ10, riboflavin and niacin in breast cancer patients undergoing tamoxifen therapy

Tumour angiogenesis is a complex mechanism consisting of multi-step events including secretion or activation of angiogenic factors by tumour cells, activation of proteolytic enzymes, proliferation, migration and differentiation of endothelial cells. Both primary and metastatic tumours in the breast are dependent on angiogenesis. In the present study, 84 breast cancer patients were randomized to receive a daily supplement of CoQ(10) 100 mg, riboflavin 10 mg and niacin 50 mg (CoRN), one dosage per day along with tamoxifen (TAM) 10 mg twice a day. Serum pro-angiogenic levels were elevated in untreated breast cancer patients (Group II) and their levels were found to be reduced in breast cancer patients undergoing TAM therapy for more than 1 year (Group III). When these group III breast cancer patients were supplemented with CoRN for 45 days (Group IV) and 90 days (Group V) along with TAM, a further significant reduction in pro-angiogenic marker levels were observed. Supplementing CoRN to breast cancer patients has found to decrease the levels of pro-angiogenic factors and increase the levels of anti-angiogenic factors. A reduction in pro-angiogenic marker levels attributes to reduction in tumour burden and may suggest good prognosis and efficacy of the treatment, and might even offer protection from cancer metastases and recurrence.

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

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

Cetuximab with concurrent chemoradiation for esophagogastric cancer: assessment of toxicity

PURPOSE

To determine the feasibility and toxicity of the addition of cetuximab with paclitaxel, carboplatin, and radiation for patients with esophagogastric cancer on a Phase II study.

METHODS AND MATERIALS

Patients with locoregional esophageal and proximal gastric cancer without distant organ metastases were eligible. All patients received cetuximab, paclitaxel, and carboplatin weekly for 6 weeks with 50.4 Gy radiation.

RESULTS

Sixty patients were enrolled, 57 with esophageal cancer and 3 with gastric cancer. Forty-eight had adenocarcinoma and 12 had squamous cell cancer. Fourteen of 60 patients (23%) had Grade 3 dermatologic toxicity consisting of a painful, pruritic acneiform rash on the face outside of the radiation field. The rates of Grades 3 and 4 esophagitis were 12% and 3%, respectively. Three patients had Grade 3/4 cetuximab hypersensitivity reactions and were not assessable for response. Forty of 57 patients (70%) had a complete clinical response after chemoradiation.

CONCLUSION

Cetuximab can be safely administered with chemoradiation for esophageal cancer. Dermatologic toxicity and hypersensitivity reactions were associated with the addition of cetuximab. There was no increase in esophagitis or other radiation-enhanced toxicity.

Expression of epidermal growth factor receptor in esophageal and esophagogastric junction adenocarcinomas: association with poor outcome

BACKGROUND

The prognosis for patients with esophageal and esophagogastric junction (EGJ) adenocarcinoma remains poor, even after surgical resection. Pathologic assessment of depth of invasion and lymph node status are the primary prognostic factors in these patients. In patients with esophageal squamous cell carcinoma, increased epidermal growth factor receptor (EGFR) expression has been associated with a worse prognosis. It is not known whether EGFR plays a similar role in esophageal and EGJ adenocarcinomas.

METHODS

To address this issue, the authors studied tumor specimens from 103 patients with surgically resected esophageal and EGJ adenocarcinomas (9 patients with stage I disease, 23 patients with stage II disease, 57 patients with stage III disease, and 14 patients with stage IV disease). The expression of EGFR was assessed by immunohistochemical analysis of tissue microarrays. Tumors were considered positive for EGFR expression when >5% of tumor cells were stained and negative when <or=5% of tumor cells were stained.

RESULTS

EGFR was expressed in 33 of 103 adenocarcinomas (32%) and was correlated with higher pathologic tumor (T) classification (P = .02), the presence of lymph node metastasis (P = .01), and higher pathologic tumor, lymph node, metastasis classification (P = .02). EGFR expression also was correlated with shorter disease-free and overall survival in univariate analyses (P = .001 and P = .004, respectively), and there was a trend toward a correlation between EGFR expression and shorter disease-free survival in multivariate analyses (P = .07 and P = .08). The results demonstrated that EGFR expression in esophageal adenocarcinomas was correlated with advanced pathologic tumor classification and lymph node metastasis. EGFR expression also was correlated with poor disease-free and overall survival, but that correlation was not independent of T classification.

CONCLUSIONS

The current findings suggested that EGFR expression correlates with poor prognostic factors and may be used to predict patient outcomes.

Epidermal growth factor receptor is a critical mediator of ultraviolet B irradiation-induced signal transduction in immortalized human keratinocyte HaCaT cells

Epidermal growth factor receptor (EGFR) is a critical mediator of several types of epithelial cancers. Skin cancer arising from exposure to ultraviolet B irradiation (UVB) from the sun is a prominent form of human cancer. Recent data indicate that in addition to cognate ligands, EGFR is activated by UVB irradiation. We used pharmacological and genetic approaches to investigate the function of EGFR in mediating UVB-induced signal transduction in human skin keratinocyte HaCaT cells. Pharmacological inhibition of EGFR tyrosine kinase significantly inhibited UVB-mediated induction of ERK, p38, and JNK MAP kinases, and their effectors, transcription factors c-Fos and c-Jun. Inhibition of UVB activation of EGFR also suppressed activation of AKT-, PKC-, and PKA-dependent signal transduction pathways. B82 mouse L cells devoid of EGFR were used to further investigate EGFR dependence of UVB-induced signal transduction. UVB failed to induce ERK, and JNK activation was reduced 60% in B82 cells compared to B82K+ cells, which express EGFR. In addition, UVB induced both c-Fos and c-Jun proteins in B82K+ cells, whereas neither were induced in B82 cells. Taken together, these data demonstrate that EGFR is required for UVB-mediated induction of multiple signaling pathways that are known to mediate tumor formation in skin.

Gefitinib (ZD1839) combined with weekly epirubicin in patients with metastatic breast cancer: a phase I study with biological correlate

PURPOSE

Epidermal growth factor receptor (EGFR) is overexpressed in approximately 50% of invasive breast carcinomas and it is correlated with hormone resistance and poor prognosis. EGFR suppression by gefitinib, a quinazoline derivative that inhibits phosphorylation of the specific receptor, represents a novel therapeutic strategy. A dose-finding study was performed to evaluate the combination of gefitinib with weekly epirubicin in patients with pretreated metastatic breast cancer.

METHODS

Fifteen patients were enrolled at four sequential dose levels. Gefitinib was administered orally, at the fixed daily dose of 250 mg. The starting dose of epirubicin was 20 mg/m2. Escalating dose levels of epirubicin were planned by increments of 5 mg/m2 per level, up to the maximum tolerated dose (MTD). Pharmacodynamic studies were performed by determining serum and tissue ERBB2 and EGFR.

RESULTS

At the first three dose levels tested no patient experienced a dose-limiting toxicity (DLT). In cohort 4, two patients experienced DLTs (grade 4 dyspnea and asthenia, grade 3 diarrhea and thrombocytopenia) identifying the MTD of epirubicin as 35 mg/m2. Of the 14 cases assessable for response, partial response was documented in two patients, and stable disease in seven, giving an overall disease control rate of 64.2%. The comparison of pre- and post-therapy ERBB2 and EGFR values was not statistically significant between the subgroups of patients regarding responsiveness to treatment.

CONCLUSIONS

The recommended dose of epirubicin for phase II studies is 30 mg/m2 in combination with gefitinib at the daily dose of 250 mg. Pharmacodynamic studies did not identify any biomarker predictive of response.

Combined expression of p53, cyclin D1 and epidermal growth factor receptor improves estimation of prognosis in curatively resected oral cancer

p53, cyclin D1 and epidermal growth factor receptor (EGFR) are molecular markers that regulate the cell cycle or cell growth and play important roles in tumor development and progression. In this study, we examined the impact of immunohistochemical expression of these markers on tumor progression in 140 oral cancers. p53, cyclin D1 and EGFR were expressed in 64 cases (46%), 54 cases (39%) and 54 cases (39%), respectively, but there was no inter-relationship between any two of these markers. In the association of these markers with clinicopathological features, EGFR expression alone was significantly associated with poor differentiation (P=0.0008) and invasive growth pattern (P=0.0003). Any of these markers, including EGFR, had no significant impact on survival. Coexpression of all these markers, however, was significantly associated with invasive growth pattern (P=0.0149) and shortened survival (P=0.0181), and was a significant and independent unfavorable prognostic factor (P=0.0002), along with tumor size (P=0.0040), nodal metastasis (P=0.0137) and growth pattern (P=0.0017) in a multivariate analysis. Simultaneous coexpression of these markers in oral cancers might prove to be a useful indicator for identification of low- or high-risk patients.

Diffuse EGFR staining is associated with reduced overall survival in locally advanced oesophageal squamous cell cancer

Squamous cell carcinoma of the oesophagus (SCCO) is still a pathology of bad prognosis. Specific therapies are now developed against epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2, c-kit receptor (CD117), vascular endothelial growth factor (VEGF) and p53 protein. This study was aimed at assessing their expression in a large series of SCCO, as well as their potential therapeutic interest in this pathology. Immunohistochemical expression of these factors was assessed retrospectively in 107 cases of SCCO with primary surgery, as well as their relationships to recurrence, metastasis and overall survival on a long-term follow-up. Human epidermal growth factor receptor 2 and CD117 were expressed in less than 3% of the cases. Epidermal growth factor receptor and p53 were overexpressed in 68.2 and 66.4% of the cases, and VEGF in 38.3%. Epidermal growth factor receptor overexpression was significantly related to vascular invasion (P=0.023). Its diffuse positivity was significantly related in multivariate analysis to higher local recurrence (P=0.006) and lower overall survival (P=0.003), in a subgroup of patients of poor outcome who had received postoperative adjuvant treatment. These results highlight the great potential prognostic and therapeutic interest of evaluating EGFR diffuse positivity in locally advanced SCCO.

Correlation between laminin-5 gamma2 chain and epidermal growth factor receptor expression in esophageal squamous cell carcinomas

OBJECTIVES

Laminin-5 gamma2 chain (LN-5 gamma2) is an extracellular matrix protein that plays an important role in cell migration and tumor invasion. We evaluated the association of LN-5 gamma2 and epidermal growth factor receptor (EGFR) expression in esophageal squamous cell carcinoma (SCC).

METHODS

LN-5 gamma2 and EGFR expression was evaluated in 110 esophageal SCC patients by immunohistochemistry, and was confirmed using esophageal SCC cell lines by Western blot analysis.

RESULTS

LN-5 gamma2 expression in the invasive front of the tumor was correlated with the depth of invasion (p = 0.0001), lymph node metastasis (p = 0.0011) and pathological stage (p = 0.0001). The strong expression of EGFR was also correlated with lymph node metastasis (p = 0.0456) and the pathological stage (p = 0.0055). In patient survival, LN-5 gamma2 positivity and/or strong EGFR expression showed a significantly low survival rate as compared with those with lesser expression of LN-5 gamma2 and EGFR. Immunohistochemically, LN-5 gamma2 expression was significantly correlated with EGFR expression (p < 0.0001). Western blot analysis also confirmed the correlated expression of LN-5 gamma2 and EGFR in SCC cell lines except 2 of the 5 cell lines.

CONCLUSIONS

This study suggests that coexpression of LN-5 gamma2 and EGFR is closely related to the progression and poor prognosis of esophageal SCC.

Pathological determinants of survival in node-negative oesophageal cancer

Background

Many studies have analysed prognostic factors following oesophagectomy, but few have examined survival determinants in node-negative (N0) oesophageal cancer. The prognostic significance of a number of histological variables following surgical resection of N0 oesophageal cancer was studied.

Methods

The case notes of 219 patients undergoing potentially curative oesophagectomy for N0 squamous cell carcinoma or adenocarcinoma of the oesophagus were reviewed. Details of the patient's sex, age at operation, histological type, longitudinal tumour length, tumour (T) stage, circumferential resection margin involvement, tumour grade, presence of vascular invasion, perineural invasion, Barrett's metaplasia, and survival were noted. Univariate and multivariate analyses were performed to identify prognostic factors.

Results

Univariate analysis revealed three factors that correlated with poor prognosis: T stage (P = 0·024), adenocarcinoma (P = 0·033) and degree of differentiation (P = 0·001). Multivariate analysis revealed that all three were significant independent adverse prognostic indicators.

Conclusion

Surgical resection of node-negative oesophageal cancer is associated with diverse long-term outcomes. This diversity of outcome is not reflected in the tumour node metastasis (TNM)-based staging system. The utility of the TNM system in predicting prognosis after surgical resection is open to question.

Targeting the HER-kinase axis in cancer

The human epidermal growth factor receptor (HER) family of receptor tyrosine kinases controls critical pathways involved in the differentiation, growth, division, and motility of normal epithelial cells. Most human solid tumors are of epithelial origin. The process of malignant transformation and progression in many cancers may depend on activation of ligands and receptors that function as part of the HER-kinase pathway. This signaling axis has earned increased attention because of the development of antibodies and small-molecule tyrosine kinase inhibitors that specifically target components of the HER-kinase axis for cancer therapy. This review focuses on the basic biology underlying HER-kinase pathway activation and the current state of development for agents that target this axis. In particular, the importance of pan-HER inhibitors is discussed.

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Investigation of the prognostic value of coexpressed erbB family members for the survival of colorectal cancer patients after curative surgery

Epidermal growth factor receptor (EGFR), erbB2, erbB3 and erbB4 are four transmembrane glycoproteins belonging to the subtype I tyrosine kinases. They share structure homologies and are believed to direct cellular growth through the ligand-stimulated tyrosine phosphorylation of intracellular substrate. The overexpression of these tyrosine kinases has been linked to various cancers. To examine the role of the erbB family in the neoplastic transformation of the human colon, we analysed the protein expression of these four members by immunohistochemistry in paraffin-embedded specimens from 125 resected colorectal cancers. Our data showed that for EGFR expression, 62 (50%) were scored as '+', and 2 (2%) as '++'. For erbB2 expression, 39 (31%) were classified as '+', and 5 (4%) as '++'. For erbB3 expression, 43 (34%) were scored as '+', and 3 (2%) as '++'. A significantly higher percentage of overexpressed erbB3 was observed in early stage carcinomas (Dukes' stage A or B) (50%) than in advanced stage cancers (Dukes' stage C or D) (15%) (P<0.0001). For erbB4 expression, 22 (18%) were scored as '+', and 5 (4%) as '++'. Early stage patients had a lower percentage of erbB4 overexpression than the late stage ones (18% versus 28%). Concomitant overexpression of erbB2 and erbB3 occurred in 21% (16/78) of the early stage carcinomas, whereas it occurred in only 2% (1/47) of the late stage ones (P=0.003). Conversely, simultaneous overexpression of erbB2 and erbB4 occurred in 17% (8/47) of the late stage carcinomas but in only 4% (3/78) of the early stage ones (P=0.02). Overexpression of EGFR, erbB2, erbB3 or erbB4 alone was not significantly associated with a shortened survival. However, patients with a simultaneous overexpression of erbB2 and erbB4 had a shorter overall survival time than others in the univariate analysis (P=0.01). This significance disappeared after adjustment for Dukes' staging in the Cox model. In conclusion, overexpressed erbB3 was common in early stage colorectal cancers, but its prevalence was significantly reduced in late stage ones. The percentage of its coexpression with erbB2 was significantly higher in early stage than in late-stage cancers. Heterodimerisation between erbB2 and erbB4 may play a role in the late stages of carcinogenesis.

Molecular and biologic basis of upper gastrointestinal malignancy--esophageal carcinoma

Esophageal cancer is one of the most deadly forms of gastrointestinal cancer. Even though the incidence of esophageal adenocarcinoma has been rising in Western populations over the past two decades, esophageal squamous cell carcinoma remains the predominant type of esophageal malignancy in the remainder of the world. With the recent advances in molecular biology, high-output genome wide screening has provided comprehensive profiles of molecular alterations in human esophageal carcinomas. The elucidation of the basic mechanisms of esophageal carcinogenesis brings with it the promise of developing treatment and preventive strategies that are based on the molecular biology of these tumors. The genetic alterations discussed in this article are not unique to the formation of esophageal carcinomas and represent only a fraction of the molecular changes found in these tumors. The goal of this article is to provide the clinician with a useful conceptual basis for evaluating studies on the molecular mechanisms underlying the development of esophageal carcinomas.

Metastasis-associated protein (MTA)1 enhances migration, invasion, and anchorage-independent survival of immortalized human keratinocytes

The human metastasis-associated gene (MTA1), a member of the nucleosome remodeling complex with histone deacetylase activity, is frequently overexpressed in biologically aggressive epithelial neoplasms. Here, we extend this observation to squamous carcinoma cells, which express high levels of MTA1 relative to normal or immortalized keratinocytes. To address functional aspects of MTA1 expression, we established variants of human immortalized keratinocytes (HaCaT cells) by expressing MTA1 cDNA in both the sense and antisense orientations. We demonstrate that (1) forced MTA1 expression enhances migration and invasion of immortalized keratinocytes; (2) MTA1 expression is necessary but not sufficient for cell survival in the anchorage independent state; (3) MTA1 contributes to expression of the anti-apoptotic Bcl-2 family member Bcl-x(L); (4) MTA1 expression in immortalized keratinocytes depends, in part, on activation of the epidermal growth factor receptor (EGFR). These results establish that, in keratinocytes, MTA1 expression contributes to several aspects of the metastatic phenotype including survival in the anchorage independent state, migration, and invasion.

Significance of preoperative elevation of serum C-reactive protein as an indicator of prognosis in esophageal carcinoma

BACKGROUND

Preoperative elevation of serum C-reactive protein (CRP) has been reported to be a prognostic indicator in gastric carcinoma and colorectal carcinoma. The aim of this study was to establish the significance of preoperative elevation of serum CRP as an indicator of prognosis in patients with esophageal carcinoma.

METHODS

Two hundred sixty-two patients with esophageal carcinoma who had been treated by esophageal resection and reconstruction of digestive tracts were evaluated, excluding patients with neoplasms in other organs. Preoperative serum CRP was measured, and the relation between the elevation of serum CRP and the clinicopathological factors and prognosis of the patients was investigated.

RESULTS

The mean size of the tumors and the proportions of lymph node metastasis and lymphatic invasion were significantly larger in patients with preoperative elevation of serum CRP than in patients without preoperative elevation of serum CRP (5.8 +/- 2.5 cm versus 4.8 +/- 2.5 cm, P <0.01, 59.5% versus 35.4%, P <0.001, and 35.7% versus 23.6%, P <0.05, respectively). 1-, 3-, and 5-year survival rates in patients with preoperative elevation of serum CRP (60.6%, 18.4%, and 11.5%, respectively) were significantly lower than those in patients without preoperative elevation of serum CRP (88.7%, 70.9%, and 68.4%, respectively; P <0.0001). Multivariate analysis demonstrated that the preoperative elevation of serum CRP was an independent prognostic factor in esophageal carcinoma (P <0.0001).

CONCLUSIONS

The preoperative serum elevation of CRP can be a marker of the malignant potential of the tumor and an independent prognostic indicator in esophageal carcinoma.

Molecular markers predictive of response to chemotherapy in gastrointestinal tumors

Gastrointestinal cancers account for a large amount of human tumors. Surgery is the standard treatment for localized gastrointestinal cancer, but in a large number of patients, tumors are unresectable at time of diagnosis and even when resectable, survival is often poor. Current attempts to improve these results include the use of chemotherapy in the adjuvant setting, in the advanced disease, or as neoadjuvant treatment. However, less than half the patients respond to chemotherapeutic treatments, mostly reporting important side-effects. The identification of molecular markers, such as p53, thymidylate synthase, K-ras, and others, may provide an important tool for medical oncologists in defining subsets of patients with gastrointestinal cancers more suitable to benefit from chemotherapy or from experimental therapies. The relationship between the clinical outcome to anticancer drugs and molecular markers in gastrointestinal tumors has been reviewed. Available data are promising, but most of them arise from retrospective and small studies. Well designed, prospective trials are warranted to change the target approach from a general to an individual treatment strategy.

Expression of syndecan-1 is common in human lung cancers independent of expression of epidermal growth factor receptor

In order to determine syndecan-1 expression in lung cancer, we examined 115 lung cancer specimens and 17 lung cancer cell lines. Syndecan-1 was immunohistochemically stained with a polyclonal antibody in 115 paraffin-embedded specimens; 84 cases out of 97 non-small cell lung cancer (NSCLC) and eight cases out of 18 small cell lung cancer (SCLC) were positively stained. Simultaneously, epidermal growth-factor receptor (EGFR) was stained; 47 cases out of 97 NSCLC and one case of 18 SCLC were positively stained. No significant correlation was shown between EGFR and syndecan-1 expression (P=0.68). Syndecan-1 mRNA was detectable in 16 of 17 lung cancer cell lines and EGFR mRNA in nine of 17. Eight cell lines had syndecan-1 mRNA as well as EGFR mRNA. PR-39 (1 microM) and 80 pM transforming growth factor-beta(1) (TGF-beta(1)), did not increase expressions of syndecan-1 mRNA and EGFR in five lung cancer cell lines. We concluded that lung cancer had detectable syndecan-1; however, expression of syndecan-1 protein did not correlate with survival time of lung cancer patients.

Receptor tyrosine kinase inhibition suppresses growth of pediatric renal tumor cells in vitro

PURPOSE

Children who undergo standard therapy for renal tumors are at an increased risk for treatment sequelae such as congestive heart failure, abnormal trunk development, and secondary malignancies. Therefore, research on the use of novel chemotherapeutic agents with fewer side effects is justified. Recent experimental evidence suggests that growth factor receptors such as epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor (PDGFR) play an important role in growth and development of pediatric renal tumors especially that of Wilms' tumor. In this study we investigated the effects of genistein, AG1478, and AG1295, from the class of growth factor receptor tyrosine kinase (GFR-TK) inhibitors, on proliferation and colonigenic growth of 2 pediatric renal tumor cell lines.

METHODS

The authors studied the effect of genistein (broad-spectrum GFR-TK inhibitor), AG1478 (EGFR-specific GFR-TK inhibitor), and AG1295 (PDGFR-specific GFR-TK inhibitor) on proliferation and colonigenic growth of rhabdoid tumor of the kidney and Wilms' tumor cell lines: G-401 and SK-NEP-1, respectively. The effect of genistein at concentrations of 0 to 200 micromol/L, and AG1478 and AG1295 at 0 to 10,000 nmol/L were tested on proliferation by using a growth inhibition assay. Viable cell counts at each concentration were obtained by hemocytometer and trypan blue exclusion, and percent growth inhibition was calculated based on control cultures at the same time-point. As a measure of colonigenic survival, the percent inhibition of colony formation in drug-treated dishes was calculated based on the number of colonies (>50 cells) in control dishes.

RESULTS

Genistein at concentrations of 25 and 50 micromol/L inhibited the colonigenic growth of G-401 by 37% and 79% (P = .01 and 5E-06, 2-tailed t test, respectively) and that of SK-NEP-1 by 44% and 74% (P = .0001 and 9.9E-07). The mean percent growth inhibition at the above doses was 57% +/- 7.9% and 96% +/- 0.2% for G-401, and 47% +/- 11.2% and 60% +/- 2.7% for SK-NEP-1. AG1478 at concentrations of 1,000 and 5,000 nmol/L inhibited the colonigenic growth of G401 by 75% and 78% (P = .0005 and 7.38E-06, respectively) and that of SK-NEP-1 by 19% and 40% (P = .02 and .0001). The percent growth inhibition at the mentioned concentrations for G-401 were 53% +/- 9.3% and 63% +/- 6.3%, and for SK-NEP-1 were 55% +/- 14.5% and 65% +/- 20.1%, respectively. AG1295 did not appear to be as effective as AG1478.

CONCLUSIONS

This is the first experimental study on the use of GFR-TK inhibitors as a potential treatment for pediatric renal tumors. GFR-TK inhibitors such as genistein occur naturally in soybean foods and have been shown to reach therapeutic levels in blood after consuming a soybean-based diet. Considering the significance of growth factor receptor activity in Wilms' tumor development, inhibition of GFR-TKs should be investigated as effective and potentially nontoxic adjunctive treatment for this childhood tumor. Furthermore, GFR-TK inhibitors may offer an effective alternative to the treatment of commonly fatal rhabdoid tumor of the kidney in children.

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.

Expression, regulation and clinical significance of bone morphogenetic protein 6 in esophageal squamous-cell carcinoma

Bone morphogenetic proteins (BMPs) are multifunctional cytokines. BMP-6 is involved in early steps of keratinogenesis. Esophageal squamous-cell carcinoma often shows abnormal keratinization. The aim of this study was to examine the expression and regulation of BMP-6 in esophageal carcinoma and to determine the relationship of its expression with tumor characteristics and survival. Avidin-biotin-peroxidase staining was performed using paraffin-wax-embedded tumor specimens collected from 172 patients with esophageal squamous-cell carcinoma, who underwent potentially curative surgery. Expression of BMP-6 and EGF-receptor in the esophageal-squamous-cell-carcinoma cell line COLO-680N and the hypopharyngeal-squamous-cell-carcinoma cell line FaDu was assayed with specific RT-PCR. In standard cell-cultivation conditions, COLO-680N and FaDu cells showed distinct expression of BMP-6, whereas in serum-free conditions BMP-6 expression was hardly detectable. The addition of EGF or EGF-related growth factors could elevate BMP-6 mRNA content. Immunohistochemically, all 172 tumors exhibited cytoplasmic immunoreactivity for BMP-6. The content of BMP-6 protein was inversely correlated with tumor differentiation (p < 0.01). Univariate survival analysis revealed that 74 patients with tumors of low immunoreactivity had higher 2-year and 5-year survival rates (50.0%/27.7%) than 75 patients with tumors of high immunoreactive scores (33.3%/21.6%). (p < 0.05). We conclude that BMP-6 is expressed in esophageal squamous-cell carcinoma. EGF-receptor activation is crucial for regulation of BMP-6 expression. BMP-6 protein content is correlated with the grade of tumor-cell differentiation and may add to indications of poor prognosis.

Prognostic factors of oesophageal squamous cell carcinoma from the perspective of molecular biology

Recent developments in molecular biology have revealed that several oncogenes, suppressor genes and adhesion molecules are involved in the development of oesophageal cancer; however, the role of these genes is still unknown. To evaluate which molecular biological factors are related to patients' prognosis and recurrence, we checked p53, p16, p21/Waf1, cyclin D1, Ki-67, epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), Mdm2, Bcl2, E-cadherin and MRP1/CD9 by means of immunohistochemical analysis in 116 cases of oesophageal cancer (R0). We also checked the regrowth capability of the primary cultures of the resected tumours and the effect of post-operative treatment. Although univariate analysis revealed that pN (pTNM), pT (pTNM), sex, cyclin D1, Ki-67, VEGF, E-cadherin and cell regrowth capability were prognostic factors, multivariate analysis revealed that pN (risk ratio (RR) 3.17), sex (RR 8.13), cell regrowth capability (RR 3.03) and E-cadherin (RR 0.30) were prognostic factors. Interestingly, step-wise analysis revealed that the following five factors were prognostic factors: pN (RR 5.74), sex (RR 3.14), cyclin D1 (RR 2.29), E-cadherin (RR 0.26) and cell regrowth capability (RR 1.94). Logistic regression analysis revealed that the risk factors of haematogenous recurrence were pN (odds ratio (OR) 8.97), cyclin D1 (OR 4.52) and EGFR (OR 0.18). On the other hand, the risk factor of lymph node recurrence was pN (OR 5.16). With regard to the effect of postoperative treatment, post-operative radiotherapy was a favourable risk factor (RR 0.43) and reduced the haematogenous recurrence (OR 0.18). Our data indicate that combination analysis using pN, sex, cyclin D1, E-cadherin, EGFR and cell regrowth capability may be useful for the prediction of patient survival and recurrence.

Suppression of extracellular signals and cell proliferation by the black tea polyphenol, theaflavin-3,3'-digallate

Previous studies in our laboratory have shown that the major green tea polyphenol, (-)-epigallocatechin-3-gallate (EGCG), suppressed autophosphorylation of epidermal growth factor (EGF) receptor induced by EGF in human A431 epidermoid carcinoma cells. In this study, we examined the inhibitory effects of black tea polyphenols, including theaflavin (TF-1), a mixture (TF-2) of theaflavin-3-gallate (TF-2a) and theaflavin-3'-gallate (TF-2b), theaflavin-3,3'-digallate (TF-3) and the thearubigin fraction on the autophosphorylation of the EGF and PDGF receptors in A431 cells and mouse NIH3T3 fibroblast cells, respectively. First, we examined the effects of these polyphenols on the proliferation of A431 and NIH3T3 cells. Both EGCG and TF-3 strongly inhibited the proliferation of A431 and NIH3T3 cells more than the other theaflavins did. In cultured cells with pre-treatment of tea polyphenol, TF-3 was stronger than EGCG on the reduction of EGF receptor and PDGF receptor autophosphorylation induced by EGF and PDGF, respectively. Other theaflavins slightly reduced the autophosphorylation of the EGF and PDGF receptors; furthermore, TF-3 could reduce autophosphorylation of the EGF receptor (or PDGF receptor) even with co-treatment with EGF (or PDGF) and TF-3, but EGCG was inactive under these conditions. In addition, TF-3 was stronger than EGCG in blocking EGF binding to its receptor. These results suggest that not only the green tea polyphenol, EGCG, but also the black tea polyphenol, TF-3, have an antiproliferative activity on tumor cells, and the molecular mechanisms of antiproliferation may block the growth factor binding to its receptor and thus suppress mitogenic signal transduction.

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

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