Vascular endothelial growth factor and basic fibroblast growth factor expression in esophageal adenocarcinoma and Barrett esophagus

Impact of Reduced Saliva Production on Intestinal Integrity and Microbiome Alterations: A Sialoadenectomy Mouse Model Study

This study investigates the effect of reduced saliva production on intestinal histological structure and microbiome composition using a sialoadenectomy murine model, evaluating differences in saliva secretion, body weight, intestinal histopathological changes, and microbiome alteration using 16S rRNA gene sequencing across three groups (control, sham, and sialoadenectomy). For statistical analysis, one-way analysis of variance and multiple comparisons using Bonferroni correction were performed. p-values < 0.05 were considered statistically significant. Microbiome analysis was performed using Qiime software. The results show that reduced saliva secretion leads to structural changes in the intestinal tract, including shorter and atrophic villi, deformed Paneth cells, decreased goblet cell density, and immunohistochemical changes in epidermal growth factor and poly(ADP-ribose) polymerase-1, especially at three months after surgery. They also showed significant alterations in the intestinal microbiome, including increased Lactobacillaceae and altered populations of Ruminococcaceae and Peptostreptococcaceae, suggesting potential inflammatory responses and decreased short-chain fatty acid production. However, by 12 months after surgery, these effects appeared to be normalized, indicating potential compensatory mechanisms. Interestingly, sham-operated mice displayed favorable profiles, possibly due to immune activation from minor surgical intervention. This study underscores saliva's essential role in intestinal condition, emphasizing the "oral-gut axis" and highlighting broader implications for the relationship between oral and systemic health.

Humanized disulfide-stabilized diabody against fibroblast growth factor-2 inhibits PD-L1 expression and epithelial-mesenchymal transition in hepatoma cells through STAT3

Fibroblast growth factor 2 (FGF2) plays an important role in tumor angiogenesis. Humanized disulfide-stable double-chain antibody against fibroblast growth factor-2 (anti-FGF2 ds-Diabody) is a small molecule antibody with good tissue permeability and low immunogenicity, which has potential in tumor-targeted therapy. This study intended to investigate the effect of anti-FGF2 ds-Diabody on the migration and expression of programmed death-ligand1 (PD-L1) in hepatocellular carcinoma (HCC) cells. The anti-FGF2 ds-Diabody was expressed under methanol induction and purified with Ni2+ -affinity chromatography. Anti-FGF2 ds-Diabody significantly inhibited cell viability and proliferation in SK-Hep1 and HepG2 cells as confirmed by CCK-8 assays and colony formation assays. Western blot assays indicated that the proliferation of SK-Hep1 and HepG2 cells was inhibited by anti-FGF2 ds-Diabody through inhibiting the phosphorylation activation of AKT and MAPK. The results of transwell and western blot assays showed that the migration and invasion of SK-Hep1 and HepG2 cells were suppressed by anti-FGF2 ds-Diabody by affecting the epithelial-mesenchymal transition (EMT) process. Meanwhile, anti-FGF2 ds-Diabody inhibited the expression of PD-L1, and STAT3 participated in this process. Analysis of RT-PCR and Western blot suggested that fibroblast growth factor receptor 4 inhibitor 1 (FGFR4-IN-1) suppressed the expression of PD-L1, while STAT3 overexpression reversed this inhibitory effect. In addition, overexpression of STAT3 promoted migration and invasion and restored the suppressive effect of anti-FGF2 ds-Diabody on EMT. In conclusion, anti-FGF2 ds-Diabody could inhibit the expression of PD-L1 and EMT of hepatoma cells through FGF2/FGFR4/STAT3 axis. These results suggested that anti-FGF2 ds-Diabody has potential clinical application in inhibiting metastasis and immune escape of hepatocellular carcinoma.

Role of Basic Fibroblast Growth Factor in Cancer: Biological Activity, Targeted Therapies, and Prognostic Value

Cancer is the leading cause of death worldwide; thus, it is necessary to find successful strategies. Several growth factors, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF, FGF2), and transforming growth factor beta (TGF-β), are involved in the main processes that fuel tumor growth, i.e., cell proliferation, angiogenesis, and metastasis, by activating important signaling pathways, including PLC-γ/PI3/Ca2+ signaling, leading to PKC activation. Here, we focused on bFGF, which, when secreted by tumor cells, mediates several signal transductions and plays an influential role in tumor cells and in the development of chemoresistance. The biological mechanism of bFGF is shown by its interaction with its four receptor subtypes: fibroblast growth factor receptor (FGFR) 1, FGFR2, FGFR3, and FGFR4. The bFGF–FGFR interaction stimulates tumor cell proliferation and invasion, resulting in an upregulation of pro-inflammatory and anti-apoptotic tumor cell proteins. Considering the involvement of the bFGF/FGFR axis in oncogenesis, preclinical and clinical studies have been conducted to develop new therapeutic strategies, alone and/or in combination, aimed at intervening on the bFGF/FGFR axis. Therefore, this review aimed to comprehensively examine the biological mechanisms underlying bFGF in the tumor microenvironment, the different anticancer therapies currently available that target the FGFRs, and the prognostic value of bFGF.

Current and emerging anti-angiogenic therapies in gastrointestinal and hepatobiliary cancers

Gastrointestinal tumours are a heterogeneous group of neoplasms that arise in the gastrointestinal tract and hepatobiliary system. Their incidence is rising globally and they currently represent the leading cause of cancer-related mortality worldwide. Anti-angiogenic agents have been incorporated into the treatment armamentarium of most of these malignancies and have improved survival outcomes, most notably in colorectal cancer and hepatocellular carcinoma. New treatment combinations with immunotherapies and other agents have led to unprecedented benefits and are revolutionising patient care. In this review, we detail the mechanisms of action of anti-angiogenic agents and the preclinical rationale underlying their combinations with immunotherapies. We review the clinical evidence supporting their use across all gastrointestinal tumours, with a particular emphasis on colorectal cancer and hepatocellular carcinoma. We discuss available biomarkers of response to these therapies and their utility in routine clinical practice. Finally, we summarise ongoing clinical trials in distinct settings and highlight the preclinical rationale supporting novel combinations.

Effect of the Rehabilitation Program, ReStOre, on Serum Biomarkers in a Randomized Control Trial of Esophagogastric Cancer Survivors

Background

The Rehabilitation Strategies Following Esophagogastric cancer (ReStOre) randomized control trial demonstrated a significant improvement in cardiorespiratory fitness of esophagogastric cancer survivors. This follow-up, exploratory study analyzed the biological effect of exercise intervention on levels of 55 serum proteins, encompassing mediators of angiogenesis, inflammation, and vascular injury, from participants on the ReStOre trial.

Methods

Patients >6 months disease free from esophagogastric cancer were randomized to usual care or the 12-week ReStOre program (exercise training, dietary counselling, and multidisciplinary education). Serum was collected at baseline (T0), post-intervention (T1), and at 3-month follow up (T2). Serum biomarkers were quantified by enzyme-linked immunosorbent assay (ELISA).

Results

Thirty-seven patients participated in this study; 17 in the control arm and 20 in the intervention arm. Exercise intervention resulted in significant alterations in the level of expression of serum IP-10 (mean difference (MD): 38.02 (95% CI: 0.69 to 75.35)), IL-27 (MD: 249.48 (95% CI: 22.43 to 476.53)), and the vascular injury biomarkers, ICAM-1 (MD: 1.05 (95% CI: 1.07 to 1.66)), and VCAM-1 (MD: 1.51 (95% CI: 1.04 to 2.14)) at T1. A significant increase in eotaxin-3 (MD: 2.59 (95% CI: 0.23 to 4.96)), IL-15 (MD: 0.27 (95% CI: 0 to 0.54)) and decrease in bFGF (MD: 1.62 (95% CI: -2.99 to 0.26)) expression was observed between control and intervention cohorts at T2 (p<0.05).

Conclusions

Exercise intervention significantly altered the expression of a number of serum biomarkers in disease-free patients who had prior treatment for esophagogastric cancer.

Impact

Exercise rehabilitation causes a significant biological effect on serum biomarkers in esophagogastric cancer survivors.

Clinical Trial Registration

ClinicalTrials.gov (NCT03314311).

Targeting the Microenvironment in Esophageal Cancer

Esophageal cancer (EC) is the eighth most common type of cancer and the sixth leading cause of cancer-related deaths worldwide. At present, the clinical treatment for EC is based mainly on radical surgery, chemotherapy, and radiotherapy. However, due to the limited efficacy of conventional treatments and the serious adverse reactions, the outcome is still unsatisfactory (the 5-year survival rate for patients is less than 25%). Thus, it is extremely important and urgent to identify new therapeutic targets. The concept of tumor microenvironment (TME) has attracted increased attention since it was proposed. Recent studies have shown that TME is an important therapeutic target for EC. Microenvironment-targeting therapies such as immunotherapy and antiangiogenic therapy have played an indispensable role in prolonging survival and improving the prognosis of patients with EC. In addition, many new drugs and therapies that have been developed to target microenvironment may become treatment options in the future. We summarize the microenvironment of EC and the latest advances in microenvironment-targeting therapies in this review.

Spectral Endoscopy Enhances Contrast for Neoplasia in Surveillance of Barrett's Esophagus

Early detection of esophageal neoplasia enables curative endoscopic therapy, but the current diagnostic standard of care has low sensitivity because early neoplasia is often inconspicuous with conventional white-light endoscopy. Here, we hypothesized that spectral endoscopy could enhance contrast for neoplasia in surveillance of patients with Barrett's esophagus. A custom spectral endoscope was deployed in a pilot clinical study of 20 patients to capture 715 in vivo tissue spectra matched with gold standard diagnosis from histopathology. Spectral endoscopy was sensitive to changes in neovascularization during the progression of disease; both non-dysplastic and neoplastic Barrett's esophagus showed higher blood volume relative to healthy squamous tissue (P = 0.001 and 0.02, respectively), and vessel radius appeared larger in neoplasia relative to non-dysplastic Barrett's esophagus (P = 0.06). We further developed a deep learning algorithm capable of classifying spectra of neoplasia versus non-dysplastic Barrett's esophagus with high accuracy (84.8% accuracy, 83.7% sensitivity, 85.5% specificity, 78.3% positive predictive value, and 89.4% negative predictive value). Exploiting the newly acquired library of labeled spectra to model custom color filter sets identified a potential 12-fold enhancement in contrast between neoplasia and non-dysplastic Barrett's esophagus using application-specific color filters compared with standard-of-care white-light imaging (perceptible color difference = 32.4 and 2.7, respectively). This work demonstrates the potential of endoscopic spectral imaging to extract vascular properties in Barrett's esophagus, to classify disease stages using deep learning, and to enable high-contrast endoscopy. SIGNIFICANCE: The results of this pilot first-in-human clinical trial demonstrate the potential of spectral endoscopy to reveal disease-associated vascular changes and to provide high-contrast delineation of neoplasia in the esophagus. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/12/3415/F1.large.jpg.

From genetics to signaling pathways: molecular pathogenesis of esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) has one of the fastest rising incidence rates in the U.S. and many other Western countries. One of the unique risk factors for EAC is gastroesophageal reflux disease (GERD), a chronic digestive condition in which acidic contents from the stomach, frequently mixed with duodenal bile, enter the esophagus resulting in esophageal tissue injury. At the cellular level, progression to EAC is underlined by continuous DNA damage caused by reflux and chronic inflammatory factors that increase the mutation rate and promote genomic instability. Despite recent successes in cancer diagnostics and treatment, EAC remains a poorly treatable disease. Recent research has shed new light on molecular alterations underlying progression to EAC and revealed novel treatment options. This review focuses on the genetic and molecular studies of EAC. The molecular changes that occur during the transformation of normal Barrett's esophagus to esophageal adenocarcinoma are also discussed.

Antiangiogenic Therapy in Gastroesophageal Cancer

Antiangiogenesis therapy is one of only 2 biologically targeted approaches shown to improve overall survival over standard of care in advanced adenocarcinoma of the stomach or gastroesophageal junction (GEJ). Therapeutic targeting of vascular endothelial growth factor receptor 2 improves overall survival in patients with previously treated advanced gastric/GEJ adenocarcinoma. No antiangiogenesis therapy has demonstrated an overall survival benefit in patients with chemo-naïve or resectable esophagogastric cancer or in patients whose tumors arise from the esophagus. Promising ongoing clinical investigations include the combination of antiangiogenesis therapy with immune checkpoint inhibition and anti-human epidermal growth factor receptor 2 therapy.

Effect of Acid and Pepsin on Gene Expression in Laryngeal Fibroblasts

The aim of this study was to determine changes that momentary low pH with or without pepsin causes in gene expression in laryngeal fibroblasts. Cell cultures were established from human false vocal fold (FVF) and postcricoidal (PC) mucosae. Using a real-time polymerase chain reaction, we analyzed messenger RNA gene expression of growth factors (transforming growth factor β1, vascular endothelial growth factor, fibroblast growth factor 2), matrix metalloproteinases (MMP-1, MMP-2), and decorin in normal media, pH 4 media, and pH 5 media with and without pepsin. The FVF fibroblast gene expression differed substantially from the PC fibroblast gene expression. No significant interaction effects for acid and pepsin were found in the FVF culture, but in PC cultures we found a significant overexpression interaction effect for vascular endothelial growth factor, fibroblast growth factor 2, MMP-1, MMP-2, and decorin. These results imply that PC tissue is more sensitive than FVF tissue to the noxious effects of gastric contents. Furthermore, there appears to be a synergistic effect for acid and pepsin exposure in the posterior larynx.

The tumor microenvironment in esophageal cancer

Esophageal cancer is a deadly disease, ranking sixth among all cancers in mortality. Despite incremental advances in diagnostics and therapeutics, esophageal cancer still carries a poor prognosis, and thus there remains a need to elucidate the molecular mechanisms underlying this disease. There is accumulating evidence that a comprehensive understanding of the molecular composition of esophageal cancer requires attention to not only tumor cells but also the tumor microenvironment, which contains diverse cell populations, signaling factors, and structural molecules that interact with tumor cells and support all stages of tumorigenesis. In esophageal cancer, environmental exposures can trigger chronic inflammation, which leads to constitutive activation of pro-inflammatory signaling pathways that promote survival and proliferation. Anti-tumor immunity is attenuated by cell populations such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), as well as immune checkpoints like programmed death-1 (PD-1). Other immune cells such as tumor-associated macrophages can have other pro-tumorigenic functions, including the induction of angiogenesis and tumor cell invasion. Cancer-associated fibroblasts secrete growth factors and alter the extracellular matrix (ECM) to create a tumor niche and enhance tumor cell migration and metastasis. Further study of how these TME components relate to the different stages of tumor progression in each esophageal cancer subtype will lead to development of novel and specific TME-targeting therapeutic strategies, which offer considerable potential especially in the setting of combination therapy.

Ischemic heart disease, factor predisposing to Barrett's adenocarcinoma: A case control study

AIM

To define the significance of ischemic heart disease (IHD) (stable angina to infarction) co-existance in Barrett esophagus (BE) patients and patients with esophageal adenocarcinoma (AdE).

METHODS

All BE/AdE patients in Blackpool-Wyre-Fylde area and Trikala prefecture identified from medical records. Patient clinical details were obtained from hospital and General Practitioner records. Additional information was gathered from validated questionnaire.

RESULTS

Forty (33%) AdE and 83 (19%) BE patients had IHD (P = 0.002). Eighteen (15%) AdE and 34 (8%) BE patients had suffered a myocardial infarction (P = 0.03). Three (3%) AdE and 7 (2%) BE patients had severe heart failure (P = 0.82). Thirty-nine (47%) BE with IHD and 8 (20%) AdE patients with IHD consumed aspirin daily (P = 0.004). Seventh-seven (93%) BE patients with IHD and 36 (90%) AdE patients with IHD were on statins (P = 0.86). Logistic regression analysis: AdE was more frequent in the elderly, with long term reflux, long BE and concurrent IHD (odds ratio: 2.086, P = 0.001) not consuming statins. Eighteen (22%) BE patients with IHD [16 (84%) with myocardial infarction] vs 33 (10%) without IHD died from non-neoplastic causes within 24 mo from BE diagnosis (P = 0.005).

CONCLUSION

IHD is more prevalent in AdE than BE patients. Increased prevalence of AdE is related with the presence of myocardial infarction but not severe heart failure, possibly because patients with BE and severe IHD have low life expectancy.

Pneumo-CT assessing response to neoadjuvant therapy in esophageal cancer: Imaging-pathological correlation

Pneumo-computed tomography (PnCT) is a technique primarily developed and used to study stenotic lesions of the esophagus, gastroesophageal junction and stomach for pre-surgical planning. It helps to define both upper and lower borders of neoplasms located in the aforementioned areas. It achieves maximum lumen distension with CO₂ highlighting thickened areas of the esophageal wall, thus allowing an accurate quantification of their extents. Although there are other alternatives for distension (oral contrast agents, water and effervescent granules), they may be suboptimal. Patients with locally advanced esophageal cancer have a dismal prognosis despite surgical resection. Therefore, neoadjuvant treatment strategies using radiation therapy and chemotherapy were developed to improve survival. Neoadjuvant therapy improves esophageal tumor prognosis in a substantial proportion of patients, and the use of imaging techniques is mandatory to detect their response. PnCT combined with virtual endoscopy and multiplanar reconstruction enhances morphologic details in esophageal cancer, and thus would allow an improved assessment of response to neoadjuvant treatment. Therefore, more information could be provided to assess the efficacy of pre-surgical treatment. We describe the potential use of PnCT to assess the response to neoadjuvant therapy in esophageal cancer with an imaging pathologic correlation.

Loss of CRNN expression is associated with advanced tumor stage and poor survival in patients with esophageal squamous cell carcinoma

OBJECTIVE

CRNN gene expression is downregulated in esophageal squamous cell carcinoma (ESCC), although its clinical implications in esophageal cancer remain unclear.

METHODS

We performed integrated microarray analysis and identified the CRNN gene as 1 of the major downregulated genes in ESCC. CRNN downregulation was validated at the nucleic acid level in 16 ESCC cases using complementary DNA microarray and at the protein level by immunohistochemical stains in an additional 220 ESCC cases. The clinicopathologic relevance and prognostic significance of CRNN expression in ESCC were explored.

RESULTS

Downregulated CRNN expression was noted at the messenger RNA and protein levels. Immunohistochemical staining revealed negative and positive CRNN expression in 171 (77.7%) and 49 (22.3%) patients with ESCC, respectively. Patients with negative CRNN protein expression had an advanced tumor invasion depth (P = .002), advanced nodal involvement (P = .014), and longer tumor length (P = .037). Patients with negative CRNN expression (median survival, 14.0 months; 5-year survival rate, 20.5%) had poorer overall survival than those with positive expression (30.0 months and 40.3%, respectively; P = .006). On multivariate analysis, negative CRNN expression, nodal involvement, and distant metastasis remained significant prognostic factors for poor overall survival (negative vs positive CRNN, hazard ratio, 1.464; P = .047).

CONCLUSIONS

Our analysis has highlighted the clinical implications of CRNN expression in ESCC. Loss of CRNN expression correlated with advanced tumor length, greater tumor invasion depth, lymph node metastasis, and poor survival in patients with ESCC.

Signaling pathways in the molecular pathogenesis of adenocarcinomas of the esophagus and gastroesophageal junction

Esophageal adenocarcinoma develops in response to severe gastroesophageal reflux disease through the precursor lesion Barrett esophagus, in which the normal squamous epithelium is replaced by a columnar lining. The incidence of esophageal adenocarcinoma in the United States has increased by over 600% in the past 40 years and the overall survival rate remains less than 20% in the community. This review highlights some of the signaling pathways for which there is some evidence of a role in the development of esophageal adenocarcinoma. An increasingly detailed understanding of the biology of this cancer has emerged recently, revealing that in addition to the well-recognized alterations in single genes such as p53, p16, APC, and telomerase, there are interactions between the components of the reflux fluid, the homeobox gene Cdx2, and the Wnt, Notch, and Hedgehog signaling pathways.

Warburg and Crabtree effects in premalignant Barrett's esophagus cell lines with active mitochondria

BACKGROUND

Increased glycolysis is a hallmark of cancer metabolism, yet relatively little is known about this phenotype at premalignant stages of progression. Periodic ischemia occurs in the premalignant condition Barrett's esophagus (BE) due to tissue damage from chronic acid-bile reflux and may select for early adaptations to hypoxia, including upregulation of glycolysis.

METHODOLOGY/PRINCIPAL FINDINGS

We compared rates of glycolysis and oxidative phosphorylation in four cell lines derived from patients with BE (CP-A, CP-B, CP-C and CP-D) in response to metabolic inhibitors and changes in glucose concentration. We report that cell lines derived from patients with more advanced genetically unstable BE have up to two-fold higher glycolysis compared to a cell line derived from a patient with early genetically stable BE; however, all cell lines preserve active mitochondria. In response to the glycolytic inhibitor 2-deoxyglucose, the most glycolytic cell lines (CP-C and CP-D) had the greatest suppression of extra-cellular acidification, but were able to compensate with upregulation of oxidative phosphorylation. In addition, these cell lines showed the lowest compensatory increases in glycolysis in response to mitochondrial uncoupling by 2,4-dinitrophenol. Finally, these cell lines also upregulated their oxidative phosphorylation in response to glucose via the Crabtree effect, and demonstrate a greater range of modulation of oxygen consumption.

CONCLUSIONS/SIGNIFICANCE

Our findings suggest that cells from premalignant Barrett's esophagus tissue may adapt to an ever-changing selective microenvironment through changes in energy metabolic pathways typically associated with cancer cells.

Evaluation of microvascular density in Barrett's associated neoplasia

Angiogenesis has an important role in the carcinogenesis of esophageal adenocarcinoma, however, the diagnostic and prognostic utility of microvascular density counts have not been clinically established. The aim of this study is to assess the correlation between microvascular density and disease progression of non-dysplastic Barrett's esophagus, low-grade dysplasia, high-grade dysplasia and invasive carcinoma in the superficial aspects of the tissue. Archival histological specimens from two referral centers for Barrett's esophagus and esophageal cancer were selected for review. A total of 160 regions marked according to histological grade were assessed with digitally interactive software to measure microvascular density. This was quantified in three levels: 0-50, 50-100 and 100-150 μm. In the areas of gastric cardia, Barrett's esophagus, low-grade dysplasia, high-grade dysplasia and cancer, microvascular density was significantly different (P<0.0001) among the five groups in the most superficial 150 μm of the mucosa. Furthermore, when examining the pairwise difference between the groups, there was a significant difference between cancer and each of the lower grades of histology (P<0.05) and between high-grade dysplasia and each of the lower grades of histology (P<0.05). These statistically significant differences were preserved in examining the depth at the most superficial 50 μm. We have used digital pathology to demonstrate a significant and stepwise increase in microvascular density, which supports the hypothesis that angiogenesis has a key role in Barrett's carcinogenesis. Furthermore, the differences in the most superficial mucosal layers are consistent with findings of increased vascularity by depth-restricted imaging modalities.

Biology of Barrett's esophagus and esophageal adenocarcinoma

The past few years have brought new advances in our understanding of the molecular mechanisms underlying the development of Barrett's esophagus and esophageal adenocarcinoma. Although knowledge of the genetic basis for these conditions has not yet translated into clinically useful biomarkers, the current pace of biomedical discovery holds endless possibilities for molecular medicine to improve the diagnosis and management of patients with these conditions. This article provides a useful conceptual basis for understanding the molecular events involved in the making of Barrett metaplasia and in its neoplastic progression, and provides a rationale for evaluating studies on the application of molecular medicine to the diagnosis and management of patients with Barrett's esophagus and esophageal adenocarcinoma.

Vascular endothelial growth factor polymorphisms and esophageal cancer prognosis

PURPOSE

Vascular endothelial growth factor (VEGF) promotes angiogenesis and vascular permeability. The VEGF gene is polymorphic. We investigated the prognostic significance of three VEGF single nucleotide polymorphisms (SNP) in esophageal cancer.

EXPERIMENTAL DESIGN

Three hundred sixty-one patients were genotyped for three VEGF SNPs (-460T/C, 405G/C, and 936C/T) using DNA extracted from prospectively collected blood samples. The association of each individual SNP, and haplotypes of the three SNPs, on overall survival (OS) was investigated.

RESULTS

The variant allele of 936C/T was associated with improved OS compared with the wild-type genotype (log-rank P < 0.001). This association remained significant for OS after adjustments for age, gender, performance status, and disease stage [VEGF 936C/T: adjusted hazard ratio (AHR), 0.70; 95% confidence interval (95% CI), 0.49-0.99; P = 0.04; VEGF 936T/T: AHR, 0.11; 95% CI, 0.02-0.82; P = 0.03]. No independent associations were found for VEGF -460T/C and VEGF 405G/C. The CGC haplotype of the three VEGF SNPs (-460T/C, 405G/C, and 936C/T) combined was associated with reduced OS compared with all other patients (CGC/CGC: AHR, 1.51; 95% CI, 1.00-2.30; P = 0.05).

CONCLUSIONS

VEGF 936C/T, and a haplotype of 460T/C, 405G/C, and 936C/T combined, has potential prognostic significance in esophageal cancer.

Correlations between selected tumor markers and fluorodeoxyglucose maximal standardized uptake values in esophageal cancer

OBJECTIVE

Esophageal cancer tumor biology is best assessed clinically by 2-[18F]fluoro-2-deoxy-d-glucose (FDG)-PET. Both FDG-PET maximal positron emission tomography (PET) standardized uptake values (SUVmax) and selected tumor markers have been shown to correlate with stage, nodal disease, and survival in esophageal cancer. Interestingly, there is limited data examining the relationship between FDG-PET SUVmax and expression of these tumor markers in esophageal cancer. The purpose of this study was to determine the correlation of tumor markers with FDG-PET SUVmax in esophageal cancer.

METHODS

FDG-PET SUVmax was calculated in 67 patients with esophageal cancer of which 59 (88%) had adenocarcinoma. Neoadjuvant radiotherapy and/or chemotherapy were administered to 42% (28/67) of patients. Esophageal tumor tissue and surrounding normal tissue was obtained and tissue microarrays were created. Immunohistochemical analysis was performed for five known esophageal cancer tumor markers (GLUT-1, p53, cyclin D1, epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF)). Assessment of each tumor marker was made by two independent, blinded pathologists using common grading criteria of intensity and percentage of cells stained. A p value <0.05 was considered significant.

RESULTS

There were 55 men (82%) and 12 women (18%) with a median age of 63 years (range 40-83). Pathologic staging included stage I (n=29, 43%), stage II (n=19, 28%), stage III disease (n=18, 27%), and stage IV disease (n=1, 2%). PET SUVmax correlated with T stage (p=0.001). In patients undergoing surgery without induction therapy, increasing SUVmax values correlated with increased expression of GLUT-1 transporter (p=0.01). There was no correlation between SUVmax and EGFR, cyclin D1, VEGF, or p53 expression in primary tumor.

CONCLUSIONS

FDG-PET SUVmax correlates with an increased expression of GLUT-1 transporter in esophageal cancer specimens not subjected to induction therapy. No significant difference in tumor marker expression was noted between patients undergoing induction therapy or surgery alone except p53 expression decreased in primary tumors following induction therapy. Failure of SUVmax values to correlate with known prognostic esophageal cancer tumor markers suggests that FDG-PET may have limited clinical utility in assessing response to therapies targeting these markers.

What is the clinical significance of stromal angiogenesis in Barrett's esophagus?

BACKGROUND

Enriched blood vessels occur in the stroma of Barrett's esophagus and are related to the ease of tumor invasion in the early stage of the cancer. Hypoxia-inducible factor (HIF) is closely related with angiogenesis through expression of vascular endothelial growth factor. The aim of the present study was to determine the predictors for angiogenesis in Barrett's esophagus and evaluate their clinical significance.

METHODS

Between December 2003 and May 2004, 209 patients with endoscopically and histologically proven Barrett's esophagus were enrolled. Before endoscopic examination, all participants answered structured questionnaires for gastroesophageal reflux symptoms and drug usage. HIF-1alpha and COX-2 protein expressions, cellular proliferation, and apoptosis were investigated immunohistochemically in biopsy samples taken from the esophagus of each patient. The degree of angiogenesis was determined by CD34 immunostaining analysis. Predictors for angiogenesis were evaluated with multivariate logistic regression analysis.

RESULTS

Sixty (28.7%) of the 209 enrolled patients with Barrett's esophagus had a high CD34 score. Factors proven as positive predictors for a high CD34 score were presence of gastroesophageal reflux symptoms, reflux esophagitis, COX-2 protein expression, and the proliferating cell nuclear antigen (PCNA) index. Administration of proton-pump inhibitors and HIF-1alpha protein expression were not predictors.

CONCLUSIONS

Reflux esophagitis and gastroesophageal reflux symptoms were positive predictors for enriched angiogenesis in the stromal portion of Barrett's esophagus, which has malignant potential because the epithelial cells express COX-2 and have accelerated cellular proliferation.

Vascular and lymphatic properties of the superficial and deep lamina propria in Barrett esophagus

A well-known type of mesenchymal/epithelial interaction occurs in Barrett esophagus (BE) characterized by the formation of a new, superficially located, muscularis mucosae (MM), which results in the division of the lamina propria (LP) into a superficial and deep compartment. The vascular and lymphatic properties of these 2 regions of LP are unknown. The risk of metastases of carcinomas that infiltrate these 2 anatomic areas also remains unclear. The aim of this study was to evaluate the density of blood vessels and lymphatic spaces within the superficial and deep LP and submucosa in patients with BE, and to compare the results to normal squamous-lined esophagus. Thirty esophago-gastrectomy specimens were stained immunohistochemically with CD31 (stains blood vessel and lymphatic endothelium) and D2-40 (stains lymphatic endothelium only). The density of CD31+ blood and lymphatic vessels (per 20 x field) in BE (superficial LP=37 and deep LP=38) was significantly lower compared with the LP of squamous-lined esophagus (68; P<0.001). However, the total number of blood and lymphatic vessels in the superficial and deep LP in BE was statistically similar to the LP of squamous-lined esophagus. The density of CD31+ blood and lymphatic vessels (per 20x field) in the submucosa of BE (21) was not significantly different from the submucosa of squamous-lined esophagus (23; P>0.05). We conclude that in BE, the "native" LP in squamous-lined esophagus is separated into 2 LP compartments (superficial and deep) by the formation of a new MM. These findings suggest that carcinomas that invade through the superficial MM into the deep LP should be considered "intramucosal" rather than "submucosal." Further outcome studies are needed to evaluate the risk of vascular/lymphatic metastasis in BE patients with different levels of LP invasion.

Genetic polymorphisms of VEGF, interactions with cigarette smoking exposure and esophageal adenocarcinoma risk

Vascular endothelial growth factor (VEGF) is a major regulator of angiogenesis in the process of tumor growth and metastasis in esophageal adenocarcinoma (EA). Polymorphisms in the VEGF gene have been associated with altered VEGF expression and plasma VEGF levels. We hypothesized that polymorphisms of VEGF may contribute to EA risk. Functional polymorphisms in the VEGF gene (-460C/T, +405C/G and +936C/T) were determined in 308 patients with EA and 546 healthy controls. Logistic regression analysis was employed to assess the associations between genotypes, haplotypes of VEGF and EA risk, adjusting for multiple confounding factors. Compared with the +936CC genotype, the combined +936CT+TT genotypes were significantly associated with increased risk of developing EA, with adjusted odds ratio (OR) = 1.49 [95% confidence interval (CI), 1.05-2.12; P = 0.027]. The -460CT+CC were associated with increased risk of EA in smokers (adjusted OR = 1.57; 95% CI, 1.07-2.30; P = 0.021), whereas the -460CT/CC were associated with decreased risk of EA (adjusted OR = 0.47; 95% CI, 0.25-0.91; P = 0.025) in non-smokers. Compared with non-smokers with the +460TT, smokers with the +460CT+CC had significantly higher risk of EA (adjusted OR = 3.32; 95% CI, 1.56-7.10; P = 0.002). No overall or interacting association with EA risk was found for the +405C/G polymorphism. Haplotype CGT (-460C/+405G/+936T) was significantly associated with higher risk of EA (adjusted OR = 1.70; 95% CI, 1.04-2.73; P = 0.034). These results suggested that cigarette smoking modifies the association between VEGF polymorphisms and EA risk among Caucasians.

The evaluation of esophageal adenocarcinoma using dynamic contrast-enhanced magnetic resonance imaging

Although neoadjuvant chemoradiation eradicates esophageal adenocarcinoma in a substantial proportion of patients, conventional imaging techniques cannot accurately detect this response. Dynamic contrast-enhanced magnetic resonance imaging is an emerging approach that may be well suited to fill this role. This pilot study evaluates the ability of this method to discriminate adenocarcinoma from normal esophageal tissue. Patients with esophageal adenocarcinoma and control subjects underwent scanning. Patients treated with neoadjuvant therapy underwent pre- and postchemoradiation scans. Parameters were extracted for each pixel were Ktrans (equilibrium rate for transfer of contrast reagent across the vascular wall), ve (volume fraction of interstitial space), and taui (mean intracellular water lifetime). Five esophageal adenocarcinoma patients and two tumor-free control subjects underwent scanning. The mean Ktrans value was 5.7 times greater in esophageal adenocarcinoma, and taui is 2.0 times smaller, than in the control subjects. Ktrans decreased by 11.4-fold after chemoradiation. Parametric maps qualitatively demonstrate a difference in Ktrans. DCE MRI of the esophagus is feasible. Ktrans, a parameter that has demonstrated discriminative ability in other malignancies, also shows promise in differentiating esophageal adenocarcinoma from benign tissue. The determination of Ktrans represents an in vivo assay for endothelial permeability and thus may serve as a quantitative measure of response to induction chemoradiation.

Selective cyclooxygenase-2 inhibition suppresses basic fibroblast growth factor expression in human esophageal adenocarcinoma

Inhibition of cyclooxygenase (COX)-2 is reported to suppress growth and induce apoptosis in human esophageal adenocarcinoma (EADC) cells, although the precise biologic mechanism is unclear. In this study we tested the hypothesis that the antitumor activity of COX-2 inhibitors may involve modulation of basic fibroblast growth factor (FGF-2), which is overexpressed in EADC. We evaluated the effects of NS-398, a selective COX-2 inhibitor, on FGF-2 expression and proliferation of EADC cell lines that express COX-2 and those that do not. We also correlated COX-2 and FGF-2 expression with clinico-pathologic findings and outcome in a well-characterized series of surgically resected EADC tissues. Seg-1 cells robustly expressed COX-2 and FGF-2, whereas Bic-1 cells expressed neither transcript. FGF-2 was reduced to undetectable levels in Seg-1 cells following NS-398 treatment, but increased within 4 h of drug removal. NS-398 significantly inhibited the growth of Seg-1 cells, and this effect was ameliorated by addition of exogenous FGF-2. In contrast, NS-398 had no effect on Bic-1 cell proliferation and FGF-2 alone had no effect on proliferation of either cell line. NS-398, or a neutralizing anti-FGF-2 antibody, induced apoptosis in Seg-1 cells, and these effects were inhibited by addition of exogenous FGF-2. COX-2 protein was strongly expressed in 46% (10/22) of EADCs, and was associated with a trend towards reduced disease-free survival. These findings indicate that the antitumor effects of COX-2 inhibition in EADC cells may be mediated via suppression of FGF-2, and that COX-2 may be a clinically relevant molecular marker in the management of human EADC.

An in vivo platform for translational drug development in pancreatic cancer

Effective development of targeted anticancer agents includes the definition of the optimal biological dose and biomarkers of drug activity. Currently available preclinical models are not optimal to this end. We aimed at generating a model for translational drug development using pancreatic cancer as a prototype. Resected pancreatic cancers from 14 patients were xenografted and expanded in successive groups of nude mice to develop cohorts of tumor-bearing mice suitable for drug therapy in simulated early clinical trials. The xenografted tumors maintain their fundamental genotypic features despite serial passages and recapitulate the genetic heterogeneity of pancreatic cancer. The in vivo platform is useful for integrating drug screening with biomarker discovery. Passages of tumors in successive cohorts of mice do not change their susceptibility to anticancer agents and represent a perpetual live bank, facilitating the application of new technologies that will result in the creation of an integrated stable database of tumor-drug response data and biomarkers.

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.

Transforming growth factor-beta binding receptor endoglin (CD105) expression in esophageal cancer and in adjacent nontumorous esophagus as prognostic predictor of recurrence

BACKGROUND

We hypothesized that the potent neovascularization marker endoglin (CD105), by differentially highlighting a subset of microvessels (MV) in esophageal cancer (EC), could provide better prognostic/therapeutic information than the panendothelial marker CD34, which also highlights MV.

METHODS

Endoglin messenger ribonucleic acid (mRNA) expression in normal, malignant, and adjacent nontumorous esophagus tissue was quantified by real-time reverse-transcription polymerase chain reaction (RT-PCR). Sections of formalin-fixed, paraffin-embedded tissues were analyzed immunohistochemically for CD105 and CD34. MV density was counted following a standard protocol. Circulating soluble endoglin levels were determined in patient and control sera, and compared with clinical outcome.

RESULTS

CD105 mRNA was upregulated by a median factor of 2.89 in ECs versus controls. In 28% of patients, CD105 mRNA was upregulated by a median factor of 2.65 in adjacent non-tumorous versus normal tissue. In tumor tissues, CD105 was stained negatively or positively only in a subset of MV. CD34 always showed positive extensive MV staining. In adjacent nontumorous esophagus, CD105 rarely showed diffuse MV staining, while CD34 stained blood-vessel endothelial cells in all non-neoplastic tissue. CD105 expression was high in residual highly dysplastic Barrett's-type mucosa associated with some adenocarcinomas. No statistically significant difference in endoglin serum levels appeared between patients and normal subjects. Correlation with clinicopathological data showed higher intra-tumor MV-CD105+ scores at more-advanced clinical stages. High-scoring MV-CD105+ patients had significantly shorter disease-free and overall survival; MV-CD34+ density was not survival related. Diffuse CD105 expression in adjacent nontumorous esophagus predicted poorer disease-free and overall survival.

CONCLUSIONS

Our findings could help identify EC patients who may benefit from targeted anti-angiogenic therapies.

Increasing expression of hypoxia-inducible proteins in the Barrett's metaplasia-dysplasia-adenocarcinoma sequence

Hypoxia-associated markers are involved in the progression of several malignancies, but are relatively unstudied in Barrett's carcinogenesis. Our aim was to assess the immunohistochemical expression of hypoxia-inducible factor (HIF)-1α, HIF-2α, erythropoietin (Epo), Epo receptor (Epo-R), Glut-1 and vascular endothelial growth factor (VEGF) along with Ki67/MIB-1 in the Barrett's metaplasia–dysplasia–adenocarcinoma sequence. Endoscopic biopsies of normal squamous epithelium (NSE) (n=20), columnar-lined oesophagus (CLO) (n=15), CLO with intestinal metaplasia (n=20), dysplasia (n=17) and Barrett's type adenocarcinoma (n=20) were obtained. Immunohistochemistry was performed on the paraffin-embedded tissue. A score was calculated for each marker (range 0−300) by multiplying intensity (none 0, weak 1, moderate 2, strong 3) by percentage of expression (range 0–100). Significant increases in the expression of HIF-2α (P=0.014), VEGF (P<0.0001), Epo-R (P<0.0001) and Ki67 (P<0.0001) were found as tissue progressed from NSE to adenocarcinoma. HIF-2α was expressed late in the sequence and was only seen in dysplasia and adenocarcinoma. High HIF-2α expression was seen in 12 out of 20 Barrett's type adenocarcinoma. The late expression of HIF-2α in the Barrett's carcinogenesis sequence and its high expression in adenocarcinoma suggest that it is worth further investigation as a marker of disease progression and therapeutic target.

Cytogenetic characterization and gene expression profiling in the rat reflux-induced esophageal tumor model

OBJECTIVES

The reasons for the increasing incidence of esophageal adenocarcinoma are not clear. A causal relation between gastroesophageal reflux disease and esophageal adenocarcinoma has been suggested. Support for this comes from the development of esophageal adenocarcinoma in the rat reflux model. However, to date, no systematic characterization of the tumors derived from this model has been reported.

METHODS

We induced biliary reflux by creating esophagojejunal anastomoses in 12 Sprague-Dawley rats. The experiment was terminated at 9 months, and rat esophagi were harvested for histopathologic documentation of reflux-associated changes and evidence of tumor formation. Three cell lines were established from 2 of the reflux-associated tumors. We tested the ability of these cells to grow in vitro in tissue culture and in vivo as xenografts in an orthotopic location at the gastroesophageal junction. Furthermore, we performed a cytogenetic analysis and determined the array-based gene expression profiles of these 3 rodent carcinoma lines compared with normal esophageal mucosa.

RESULTS

At 9 months, 12 of 12 rodents had histologic features of metaplastic columnar epithelium in the esophagus, with 7 having invasive carcinomas with glandular differentiation (either adenocarcinomas or adenosquamous carcinomas). The 3 cell lines established from 2 reflux-associated tumors were capable of sustained in vitro propagation and grew successfully as xenografts in both subcutaneous and orthotopic locations, confirming the tumorigenic nature of these lines. Despite their establishment from primary tumors with glandular features, the histology of the xenografts was that of well-differentiated squamous carcinomas. Karyotype analyses demonstrated cytogenetic heterogeneity and aneuploidy; furthermore, translocation (7:11) was present in all 3 lines. Array-based gene expression profiling confirmed upregulation of several cancer-related genes important in human esophageal cancer. Quantitative reverse transcription-polymerase chain reaction was used to confirm the differential expression of selected transcripts (vascular endothelial growth factor [VEGF], polo-like kinases [PLK], cyclin dependent kinase 4 [CDK4], hypoxia-inducible factor 1alpha [HIF1alpha], and insulin-like growth factor 1 [IGF-1]) in comparison with nonneoplastic esophageal mucosal scrapings.

CONCLUSIONS

The rodent reflux model is capable of inducing metaplastic epithelial changes simulating Barrett esophagus, as well as subsequent neoplastic transformation, at a high frequency. Cell lines have been established from these tumors that are capable of in vitro and in vivo passaging. The rodent reflux model should be a valuable model for studying therapy and chemoprevention efforts for Barrett esophagus, whereas the established cell lines provide a useful resource for drug discovery and other high-throughput studies.

Targeted agents and esophageal cancer--the next step?

Esophageal cancer (EC) is an aggressive cancer and is a leading cause of cancer-related death worldwide. In the United States and Western Europe, there has been a decline in the incidence of squamous cell carcinomas coupled with a rapid rise in incidence of adenocarcinoma of the esophagus and gastroesophageal junction. Although the 5-year survival rates have slowly increased over time from 4% to 14%, the outcomes are still dismal. The lack of adequate preventative strategies, inadequate screening techniques, early lymphatic and hematogenous spread, and lack of truly effective therapeutic agents all contribute to the poor outcome. This review will highlight the current status of targeted therapies in EC. This will include a review of agents targeting the vascular endothelial growth factor and epidermal growth factor receptor pathways and trials planned or ongoing to incorporate these and other agents into therapy for advanced disease and into combined modality therapy for early-stage tumors. Further work is required regarding the rational integration of these targeted agents and the optimal selection of patients who will most likely benefit.

Relationship between time of exposure of laryngopharyngeal reflux and gene expression in laryngeal fibroblasts

OBJECTIVES

Acid reflux is damaging to the laryngeal mucosa; however, the significance of the duration of reflux episodes has not been evaluated. The purpose of this study was to determine whether varying the exposure times at low pH with or without pepsin alters gene expression in laryngeal fibroblasts.

METHODS

Human false vocal fold and postcricoidal cultures were exposed to pH 4 or pH 5 media with and without pepsin for 10, 30, 60, and 240 seconds. Using a real-time polymerase chain reaction, we determined the messenger RNA expression of TGFbeta-1, VEGF, FGF-2, EGR-1, ATF-3, CTGF, MMP-1, MMP-2, and decorin.

RESULTS

Molecular responses were initiated at pH 5. Postcricoidal fibroblasts were more sensitive than false vocal fold fibroblasts to the presence of pepsin. Changes in transcript levels were dependent on acid exposure time, and the most significant changes were measured during the first 60 seconds after exposure.

CONCLUSIONS

Time of exposure to acid and pepsin needs to be taken into consideration when determining limit of pathology in pharyngeal reflux. Genes are identified that are induced by low pH and that may be of potential importance in the pathogenesis of reflux laryngitis.

Basic fibroblast growth factor (FGF-2) overexpression is a risk factor for esophageal cancer recurrence and reduced survival, which is ameliorated by coexpression of the FGF-2 antisense gene

PURPOSE

The basic fibroblast growth factor (FGF-2) gene is bidirectionally transcribed to generate overlapping sense and antisense (FGF-AS) mRNAs. FGF-AS has been implicated in the post-transcriptional regulation of FGF-2 expression. The aim of this study was to characterize FGF-2 and FGF-AS in esophageal cancer and to correlate their expression with clinicopathologic findings and outcome.

EXPERIMENTAL DESIGN

Reverse transcription-PCR was used to study FGF-2 and FGF-AS mRNA expression (normalized to glyceraldehyde-3-phosphate dehydrogenase) in 48 esophageal cancers relative to matched histologically normal esophageal epithelia (internal control). We used Cox proportional hazards analysis to calculate hazard ratios for recurrence and survival of patients with underexpression relative to the overexpression of FGF-2 and/or FGF-AS.

RESULTS

Overexpression of FGF-2 mRNA, by comparison with tumors underexpressing FGF-2, was associated with significantly increased risk for tumor recurrence (hazard ratio, 3.80; 95% confidence interval, 1.64-8.76) and reduced overall survival (hazard ratio, 2.11; 95% confidence interval, 1.0-4.58). When the effects of FGF-2 and FGF-AS were considered simultaneously, the association of FGF-2 mRNA overexpression with recurrence and mortality was even more pronounced, whereas FGF-AS mRNA overexpression was associated with reduced risk for recurrence and improved survival.

CONCLUSIONS

Overexpression of FGF-2 mRNA is associated with tumor recurrence and reduced survival after surgical resection of esophageal cancer and that these risks are reduced in tumors coexpressing the FGF-AS mRNA. These data support the hypothesis that FGF-AS is a novel tumor suppressor that modulates the effect of FGF-2 expression and may have potential clinical application to the development of novel therapeutic strategies.

Targeted therapies for esophageal cancer

Esophageal cancer is a highly aggressive neoplasm. In 2005, 14,520 Americans will be diagnosed with esophageal cancer, and more than 90% will die of their disease. On a global basis, cancer of the esophagus is the sixth leading cause of cancer death worldwide. In fact, gastric and esophageal cancers together accounted for nearly 1.3 million new cases and 980,000 deaths worldwide in 2000-more than lung, breast, or colorectal cancer. Although esophageal squamous cell carcinoma cases have steadily declined, the incidence of gastroesophageal junction adenocarcinoma has increased 4%-10% per year among U.S. men since 1976, more rapidly than for any other cancer type, and parallels rises in population trends in obesity and reflux disease. With advances in surgical techniques and treatment, the prognosis of esophageal cancer has slowly improved over the past three decades. However, the 5-year overall survival rate (14%) remains poor, even in comparison with the dismal survival rates (4%) from the 1970s. The underlying reasons for this disappointingly low survival rate are multifold: (a) ineffective screening tools and guidelines; (b) cancer detection at an advanced stage, with over 50% of patients with unresectable disease or distant metastasis at presentation; (c) high risk for recurrent disease after esophagectomy or definitive chemoradiotherapy; (d) unreliable noninvasive tools to measure complete response to chemoradiotherapy; and (e) limited survival achieved with palliative chemotherapy alone for patients with metastatic or unresectable disease. Clearly, additional strategies are needed to detect esophageal cancer earlier and to improve our systemic treatment options. Over the past decade, the field of drug development has been transformed with the identification of and ability to direct treatment at specific molecular targets. This review focuses on novel targeted treatments in development for esophageal squamous cell carcinoma and distal esophageal and gastroesophageal junction adenocarcinoma.

Lymphatic vessel density in the neoplastic progression of Barrett's oesophagus to adenocarcinoma

BACKGROUND

Oesophageal adenocarcinoma is an aggressive neoplasm with poor prognosis as a result of early lymph node metastasis.

AIMS

To measure lymphatic vessel density (LVD) in the neoplastic progression from Barrett's metaplasia to adenocarcinoma and determine whether LVD can predict the risk of cancer. In addition, to correlate LVD with lymph node metastasis and assess whether LVD could be used as a prognostic indicator for outcome or survival.

METHODS

LVD and microvascular density (MVD) were assessed after immunohistochemical staining of vessels in Barrett's metaplasia, dysplasia, and adenocarcinoma tissues and were correlated with clinicopathological features.

RESULTS

LVD was significantly reduced in adenocarcinoma, being half that seen in normal stomach/oesophagus or metaplasia/dysplasia. LVD did not correlate with tumour grade, stage, or clinical outcome; however, patients who had either lymph node metastasis or invasion of tumour cells into peritumorous lymphatic vessels had a significantly worse overall survival. MVD was also assessed as a prognostic marker; its increase appeared to be linked more with the development of Barrett's metaplasia than adenocarcinoma.

CONCLUSIONS

The reduction in lymphatic vessel numbers was not useful for determining disease outcome in the patient group studied. It is the entry of tumour cells into pre-existing peritumorous lymphatic vessels that confers a significantly worse overall survival.

Anti-angiogenic treatment of gastrointestinal malignancies

The scientific rationale to block angiogenesis as a treatment strategy for human cancer has been developed over the last 30 years, but is only now entering the clinical arena. Preclinical studies have demonstrated the importance of the vascular endothelial growth factor (VEGF) pathways in both physiologic and pathologic angiogenesis, and have led to the development of approaches to block its role in tumor angiogenesis. Bevacizumab is an antibody to VEGF and has been shown to prolong survival when given with chemotherapy in the treatment of metastatic colorectal cancer (CRC). Although this is the first anti-angiogenic treatment to be approved for the treatment of human epithelial malignancy, a number of other approaches currently are in development. Soluble chimeric receptors to sequester serum VEGF and monoclonal antibodies against VEGF receptors have both shown considerable promise in the laboratory and are being brought into clinical investigation. A number of small-molecule tyrosine kinase inhibitors that have activity against VEGF receptors also are in clinical trials. Although these novel treatments are being pioneered in CRC, anti-angiogenic approaches also are being tested in the treatment of other gastrointestinal malignancies. Anti-VEGF therapy has shown promise in such traditionally resistant tumors as pancreatic cancer and hepatocellular carcinoma. This review will examine the preclinical foundation and then focus on the clinical studies of anti-VEGF therapy in gastrointestinal cancers.

Anti-angiogenic strategies in gastrointestinal malignancies

Advances in our understanding of the mechanisms underlying tumor progression suggest that angiogenesis plays a key role in gastrointestinal malignancies. Vascular endothelial growth factor (VEGF) has emerged as an important therapeutic target, and a variety of strategies to inhibit VEGF are under investigation. The approval of bevacizumab for use in patients with previously untreated metastatic colorectal cancer was based on clinical data suggesting that VEGF is a valid therapeutic target in this disease. As the data mature from ongoing trials, the role of angiogenesis inhibitors in the treatment of colon cancer and other gastrointestinal malignancies will be more clearly defined. Additional information is needed to identify the diseases and stages most likely to benefit from anti-angiogenic agents and the optimal sequences and therapeutic combinations that should be studied.

Clinical review: Healing in gastrointestinal anastomoses, Part II

Complications arising from gastrointestinal anastomosis failures are a major source of morbidity and mortality. This review examines the effects of local blood flow on anastomotic healing, and discusses strategies for improving perfusion. Disruption of blood supply plays a significant role in the development of anastomotic leakage. Several methods have been suggested to improve perfusion. Omental pedicles have been employed as buttresses to promote angiogenesis, but efficacy in preventing anastomotic dehiscence has not been established. The administration of exogenous pharmacologic agents (such as vascular endothelial growth factor) is another potential strategy, although the oncological safety of this approach has been questioned. Two techniques which show promise in reducing anastomotic leakage rates include the vascular augmentation of grafts at risk for ischemia (supercharging) and ischemic conditioning (utilizing the delay phenomenon). Further studies of these strategies are needed to establish their efficacy and safety for routine use in gastrointestinal anastomoses.

The molecular signature of normal squamous esophageal epithelium identifies the presence of a field effect and can discriminate between patients with Barrett's esophagus and patients with Barrett's-associated adenocarcinoma

BACKGROUND AND AIM

Genetic alterations in the normal tissues surrounding various cancers have been described, but a comprehensive analysis of this carcinogenic field effect in Barrett's-associated adenocarcinoma of the esophagus disease has not been reported. The aim of this study was to analyze the gene expression profile of a panel of highly selected genes in the normal squamous esophagus epihelium of patients with Barrett's esophagus, patients with Barrett's-associated adenocarcinoma, and a healthy control group to define the existence of a carcinogenic field effect, and to investigate the clinical importance of such a field effect in the management of Barrett's disease.

METHODS

Forty-nine histologic normal squamous esophageal epithelia collected from 19 patients with Barrett's esophagus, 20 patients with Barrett's-associated esophageal adenocarcinoma, and a healthy control group of 10 patients were studied. A quantitative real-time reverse transcription-PCR method (TaqMan) was used to measure the expression of a panel of genes with known associations with gastrointestinal carcinogenesis.

RESULTS

A widespread carcinogenic field effect was detected for more than 50% of the genes analyzed including Bax, BFT, CDX2, COX2, DAPK, DNMT1, GSTP1, RARalpha, RARgamma, RXRalpha, RXRbeta, SPARC, TSPAN, and VEGF. Based on the expression signature of the normal appearing squamous esophagus, a linear discriminant analysis was able to distinguish between the three groups of patients with an error rate of 0%.

CONCLUSION

This study provides the first comprehensive investigation of a carcinogenic field effect in Barrett's esophagus disease. Based on the gene expression signature of the normal esophagus, patients could be correctly characterized according to their pathologic classification by applying a linear discriminant analysis. Our results provide evidence that a molecular classification might have clinical importance for the diagnosis and treatment of patients with Barrett's esophagus disease.

Molecular targets for treatment of Barrett's esophagus

SUMMARY. Esophageal cancer is one of the most deadly forms of gastrointestinal cancer with a mortality rate exceeding 90%. The major risk factors for esophageal adenocarcinoma are gastroesophageal reflux disease (GERD) and its sequela, Barrett's esophagus. GERD commonly leads to esophagitis. In a minority of patients however, ongoing GERD leads to replacement of esophageal squamous mucosa with metaplastic, intestinal-type Barrett's mucosa. In the setting of continued peptic injury, Barrett's mucosa can give rise to esophageal adenocarcinoma. Despite the widespread use of potent acid suppressive therapies for patients with GERD, the incidence of esophageal adenocarcinoma, among white men in the USA, the UK and Europe has continued to rise. Cancers in Barrett's esophagus arise through a sequence of genetic events that endow the cells with six essential physiologic hallmarks of cancer as described by Hanahan and Weinberg in 2000. These cancer hallmarks include the ability to proliferate without exogenous stimulation, to resist growth-inhibitory signals, to avoid triggering the programmed death mechanism (apoptosis), to resist cell senescence, to develop new vascular supplies (angiogenesis), and to invade and metastasize. While the acquisition of these essential attributes is not specific to the neoplastic progression of Barrett's esophagus, this review will focus on the genetic alterations that occur in Barrett's cells that contribute to the acquisition of each of the hallmarks. Moreover, potential diagnostic and therapeutic strategies for Barrett's patients aimed at each of these cancer hallmarks will be reviewed.

Clinical significance of VEGF-A, -C and -D expression in esophageal malignancies

Vascular endothelial growth factors (VEGF)-A, -C and -D are members of the proangiogenic VEGF family of glycoproteins. VEGF-A is known to be the most important angiogenic factor under physiological and pathological conditions, while VEGF-C and VEGF-D are implicated in the development and sprouting of lymphatic vessels, so called lymphangiogenesis. Local tumor progression, lymph node metastases and hematogenous tumor spread are important prognostic factors for esophageal carcinoma (EC), one of the most lethal malignancies throughout the world. We found solid evidence in the literature that VEGF expression contributes to tumor angiogenesis, tumor progression and lymph node metastasis in esophageal squamous cell carcinoma (SCC), and many authors could show a prognostic value for VEGF-assessment. In adenocarcinoma (AC) of the esophagus angiogenic properties are acquired in early stages, particularly in precancerous lesions like Barrett's dysplasia. However, VEGF expression fails to give prognostic information in AC of the esophagus. VEGF-C and -D were detected in SCC and dysplastic lesions, but not in normal mucosa of the esophagus. VEGF-C expression might be associated with lymphatic tumor invasion, lymph node metastases and advanced disease in esophageal SCC and AC. Therapeutic interference with VEGF signaling may prove to be a promising way of anti-angiogenic co-treatment in esophageal carcinoma. However, concrete clinical data are still pending.

The molecular biology of esophageal adenocarcinoma

BACKGROUND

Barrett's esophagus is an acquired metaplastic change that occurs in the distal esophagus secondary to chronic gastroesophageal reflux. This premalignant condition forms the most important risk factor for developing esophageal adenocarcinoma, which is an extremely aggressive tumor with a 5-year survival rate of less than 25%. Carcinomas that arise in the setting of Barrett's esophagus are thought to develop as part of the metaplasia-dysplasia-carcinoma sequence.

OBJECTIVE

To review the current knowledge on the genomic alterations involved in the development of Barrett's esophagus and its progression to dysplasia and/or cancer.

RESULTS

Several changes in gene structure, gene expression, and protein structure are associated with the progression of Barrett's esophagus to adenocarcinoma. Accumulation of these changes seems to be essential, rather than the exact sequence of these changes. Multiple molecular pathways are involved and interact with each other. Alterations in tumor suppressor genes, amongst which p53 and p16, are early events in the metaplasia-dysplasia-adenocarcinoma sequence, followed by loss of cell cycle checkpoints. Ongoing genomic instability leads to cumulative genetic errors and thereby the generation of multiple clones of transformed cells.

CONCLUSIONS

Within the multistep process of esophageal adenocarcinogenesis, to date no single molecular marker came forward able to predict who will and who will not develop cancer in the setting of Barrett's esophagus. Instead, panels of markers need to be developed in the future allowing to indicate disease progression. Identification of crucial molecular pathways involved in esophageal adenocarcinogenesis would ultimately improve therapy and facilitate development of new treatment strategies.

Molecular alterations during development of esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma has risen significantly over the last decades. During esophageal carcinogenesis many molecular alterations occur that disrupt essential cellular processes, directing the cell to a rapidly proliferating, immortal state. The chronic inflammation that is present in Barrett's esophagus creates an environment in which such molecular alterations are both induced and tolerated. Here, the novel insights in the molecular mechanisms that underlie the development of esophageal adenocarcinoma are reviewed, focusing on the role of inflammation, angiogenesis, apoptosis inhibition, loss of cell cycle control, and loss of cell-cell adhesion. These novel developments will open new perspectives for diagnosis, treatment, and prevention of esophageal adenocarcinoma.