Systematic review: the application of molecular pathogenesis to prevention and treatment of oesophageal adenocarcinoma

The severity of duodeno-esophageal reflux influences the development of different histological types of esophageal cancer in a rat model

The mechanism through which each histological type of carcinoma arises from the esophageal mucosa remains unknown. This study was designed to investigate whether there is an association between the severity of duodeno-esophageal reflux and the histological type of esophageal cancer. A series of 120 male Fischer rats, weighing ∼180 g, were randomized to receive one of the following procedures: duodeno-forestomach reflux (DFR) with reduced exposure to duodenal contents, duodeno-esophageal reflux (DER) with increased exposure to duodenal contents and three control operations (DFR, DER control and sham). The reflux of bile was estimated with (99m)Tc-PMT scintigraphy. All animals were fed a standard diet without carcinogen. The esophageal mucosa was assessed 50 weeks after surgery for carcinoma. The median scanned fraction rate of duodeno-esophageal reflux was significantly lower for the rodents in the DFR group than those in the DER group. Five of 28 rodents in the DFR group and 17 of the 22 rodents in the DER group developed esophageal carcinoma. None of the controls developed carcinoma. The five rodents in the DFR group developed SCC. Of 22 esophageal carcinomas for the DER group, nine were SCC, 12 ADC and one was adenosquamous carcinoma. The fraction of esophageal SCC for the DFR group was significantly higher than that for the DER group, while the fraction of esophageal ADC for the DFR group was significantly lower than that for the DER group. These observations suggest that the severity of duodeno-esophageal reflux in rodents is related to the development of different histological types of esophageal carcinoma.

Identification of the up-regulation of TP-alpha, collagen alpha-1(VI) chain, and S100A9 in esophageal squamous cell carcinoma by a proteomic method

Esophageal squamous cell carcinoma (ESCC) is one of the most common primary malignant tumor of digestive tract. However, the early diagnosis and molecular mechanisms that underlie tumor formation and progression have been progressed less. To identify new biomarkers for ESCC, we performed a comparative proteomic research. Isobaric tags for relative and absolute quantitation-based proteomic method was used to screen biomarkers between ESCC and normal. 802 non-redundant proteins were identified, 39 of which were differentially expressed with 1.5-fold difference (29 up-regulated and 10 down-regulated). Through Swiss-Prot and GO database, the location and function of differential proteins were analyzed, which are related to the biological processes of binding, cell structure, signal transduction, cell adhesion, etc. Among the differentially expressed proteins, TP-alpha, collagen alpha-1(VI) chain and S100A9 were verified to be upregulated in 77.19%, 75.44% and 59.65% of ESCC by immunohistochemistry and western-blot. Diagnostic value of these three proteins was validated. These results provide new insights into ESCC biology and potential diagnostic and therapeutic biomarkers, which suggest that TP-alpha, collagen alpha-1(VI) chain and S100A9 are potential biomarkers of ESCC, and may play an important role in tumorigenesis and development of ESCC.

Chemoprevention in Barrett's oesophagus

Barrett's oesophagus normally affects the distal oesophagus when metaplastic columnar lined epithelium replaces stratified squamous epithelium which predisposes to cancer development. This develops as a consequence of chronic gastroesophageal reflux (GORD). Those with Barrett's have a 40 fold increased risk of oesophageal adenocarcinoma [1]. There are is still a lack of understanding of the natural history of the cell of origin. This does hamper research into this area. We accept that there is a limitation in testing of the pathogenesis of Barrett's oesophagus due to a lack of a universally accepted animal model. The major questions surrounding Barrett's oesophagus include validity of surveillance strategies, the optimal treatment and more importantly an agent that can prevent progression to cancer without unacceptable side effects. The main chemopreventative agents that show promise are aspirin and proton pump inhibitors (PPIs). There are other agents such as green tea, berries and antioxidants and diet that have been suggested; we discuss the evidence available for these strategies. We hope for continued improvement in the clinical trial infrastructure to facilitate testing of new pharmacological and endoscopic interventions for Barrett's oesophagus.

Expression of the putative stem cell marker Musashi-1 in Barrett's esophagus and esophageal adenocarcinoma

The cancer stem cell theory states that cancers contain tumor-forming cells that have the ability to self-renew as well as give rise to cells that differentiate. Cancer stem cells have been identified in several solid tumors, but stem cells in normal human esophagus or in Barrett's esophagus or adenocarcinoma have not been reported. Musashi-1 is expressed by the crypt base columnar cells identified as intestinal stem cells. In other diseases of the gastrointestinal tract, local inflammation of the tunica mucosa may be an initiating factor of alteration of focal tissue 'niches,' where dormant stem cells locate. The present study investigated whether Musashi-1 is expressed in the esophagus and its relation to immune inflammation of the mucosa in Barrett's esophagus and esophageal adenocarcinoma. A total of 41 esophageal tissue specimens from 41 patients were studied. Of these, 15 were esophageal adenocarcinoma, 17 were Barrett's esophagus (10 intestinal metaplasia and 7 dysplasia), and 9 were normal squamous esophagus tissue specimens from patients without esophageal pathology. Immunohistochemistry was performed using antibodies to Musashi-1 and to a set of cell type-specific markers. A multiplexed tandem polymerase chain reaction method was used to measure the relative mRNA expression levels of Musashi-1 and the specific dendritic cell marker dendritic cell-specific intercellular molecule-3 (ICAM-3)-grabbing nonintegrin. Immunohistochemistry demonstrated the presence of small numbers of Musashi-1+ cells scattered in the connective tissue stroma and within the epithelium in cardiac-type glands in biopsies from patients without Barrett's esophagus. Musashi-1 expression was present in Barrett's intestinal metaplasia and in dysplastic Barrett's in which the majority of epithelial cells in individual glands expressed this antigen. Expression of Musashi-1 was highest in esophageal adenocarcinoma, where it was most intense in glands that displayed features of early stages of adenocarcinoma formation. In contrast, Musashi-1 staining level was weaker in glands that displayed features of advanced adenocarcinoma. Double immunostaining with proliferating cell nuclear antigen showed low proliferation in the vast majority of Musashi-1+ cells. Musashi-1 mRNA expression levels were significantly higher in esophageal adenocarcinoma than in normal esophagus or Barrett's esophagus tissues. Dendritic cell-specific intercellular molecule-3 (ICAM-3)-grabbing nonintegrin (DC-SIGN) mRNA expression levels were significantly increased in both Barrett's tissues and adenocarcinoma tissues. Expression of the putative stem cell marker Musashi-1 is absent in normal squamous epithelium, weak in esophageal cardiac-type glands and Barrett's esophagus, and markedly increased in adenocarcinoma, especially in glands displaying features of early cancer development. Musashi-1 expressing cells may be significant in the etiology of Barrett's esophagus and adenocarcinoma, and perhaps even a cell of origin for this disease. We speculate that immune inflammation occurring in Barrett's esophagus alters the mucosal microenvironment in a manner which is favorable to the activation of dormant stem cells.

Pilot translational study of dietary vitamin C supplementation in Barrett's esophagus

The transcription factor Nuclear factor kappa B (NF-kappaB) is central to the regulation of genes encoding for mediators of inflammation and carcinogenesis. In the esophagus, NF-kappaB is progressively activated from inflammation to Barrett's metaplasia and adenocarcinoma. Vitamin C, an antioxidant, can inhibit NF-kappaB in in vitro models, and the aim of this study was to prospectively assess the effect of supplemental vitamin C on NF-kappaB and associated cytokines in patients with Barrett's esophagus. Twenty-five patients with long-segment Barrett's and specialized intestinal metaplasia received dietary vitamin C (1000 mg/day) orally for four weeks, and had pre- and post-vitamin C endoscopic biopsies. NF-kappaB activity (activated p50 and p65 subunits) of nuclear extracts was assessed using the Active Motif NF-kappaB assay, and cytokines and growth factors were measured using the Evidence Investigator biochip array. NF-kappaB and related pro-inflammatory cytokines and growth factors (IL-8, VEGF, IL-10) were activated in all Barrett's tissue pre-treatment. Down-regulation in activated NF-kappaB and cytokines was observed in 8/25 (35%) patients. Dietary vitamin C supplementation may down-regulate pro-inflammatory markers in a subset of Barrett's patients. Further studies with larger numbers of endpoints will be needed to further evaluate this effect.

Multimodality therapy for adenocarcinoma of the esophagus, gastric cardia, and upper gastric third

There is considerable controversy over the level of recommendations from randomized trials underpinning management decisions for patients presenting with localized adenocarcinoma of the esophagus and esophagogastric junction. Despite a paucity of Level 1 recommendations compared with other gastrointestinal sites, in particular rectal cancer, there is an emerging consensus in practice to consider multimodal approaches in all cases that present with T3 or node-positive disease. There is also an optimism that new approaches, including response prediction based on sequential 18FDG-PET scanning following induction chemotherapy, and novel drugs targeted at EGF, EGFR, VEGF, and tyrosine kinase inhibition may improve treatment pathways and outcomes. In this review, we assess the level of recommendations from the major published trials and -discuss new trials and approaches.

Cost-effectiveness of endoscopic screening followed by surveillance for Barrett's esophagus: a review

Screening interventions for Barrett's esophagus (BE) are appealing, but there is little supporting evidence. We reviewed health economics studies about BE endoscopic screening followed by, as required, endoscopic surveillance ("screening and surveillance" hereafter) to help inform the design and conduct of future research. Health economics studies about BE screening and surveillance were identified using electronic database searches and personal contact with authors of identified studies. No studies examined general population screening. Five US studies published between 2003 and 2007 examined the cost effectiveness of screening and surveillance (against no intervention) in patients with chronic gastroesophageal reflux disease (GERD). There was no randomized trial evidence to inform model construction. Assumptions about prevalence and transition probabilities between BE histologic subtypes and about surveillance and treatment protocols varied substantially between studies. Parameters such as potential BE diagnosis-related reduction in quality of life or increase in health care use, diagnostic accuracy, and infrastructural costs (for quality assurance) were considered either "optimistically" or not at all. Only 2 studies considered endoscopic treatments. No study considered the recently introduced radiofrequency ablation technique, or the potential for biomarker-based risk stratification of surveillance interval or duration. Current health economics evidence is likely to have provided optimistic cost-effectiveness estimates and is not sufficient to support introduction of endoscopic BE screening programs among GERD patients. The evidence does not adequately incorporate novel (endoscopic) treatments and the potential for (clinical, endoscopic, or biomarker-based) risk stratification of surveillance. Future research should aim to encompass both these factors.

Pharmacokinetics and pharmacogenomics in esophageal cancer chemoradiotherapy

Esophageal cancer is one of the most lethal malignancies. Surgical resection of the tumor from the primary site has been the standard treatment, especially for localized squamous cell carcinoma, but considerable clinical efforts during the last decade have resulted in novel courses of treatment. These options include chemoradiotherapy, consisting of a continuous infusion of 5-fluorouracil (5-FU), cisplatin (CDDP), and concurrent radiation. Given the substantial inter- and/or intra-individual variation in clinical outcome, future improvements will likely require the incorporation of a novel anticancer drug, pharmacokinetically guided administration of CDDP or 5-FU, and identification of potential responders by patient genetic profiling prior to treatment. In this review, the latest information on incidence, risk factors, biomarkers, therapeutic strategies, and the pharmacokinetically guided or genotype-guided administration of CDDP and 5-FU is summarized for future individualization of esophageal cancer treatment.

Esophageal cancer: epidemiology, pathogenesis and prevention

Esophageal cancer is highly aggressive and is a common cancer both worldwide and in the US. In the past two decades, the incidence and mortality of esophageal cancer in the US have both increased, where as the incidence and mortality of other cancers have decreased. Although esophageal squamous cell carcinoma and esophageal adenocarcinoma differ in their histology and epidemiologic distribution, some of their risk factors (e.g. dietary deficiencies and tobacco) and underlying mechanisms of carcinogenesis are the same. Intensive research into risk factors combined with the ability to identify precursor lesions (e.g.squamous dysplasia in esophageal squamous cell carcinoma and Barrett's esophagus in esophageal adenocarcinoma) has paved the way for studies of chemoprevention for esophageal cancer, some of which have shown promising results.

Treatment options for esophageal cancer

There is considerable controversy over the level of evidence from randomized trials underpinning management decisions for patients presenting with localized cancer of the esophagus and esophago-gastric junction. There is also an optimism that new drugs and new approaches, including response prediction based on sequential (18)FDG-PET scanning following induction chemotherapy, may improve treatments pathways and outcomes. In this review we assess the level of evidence from the major published trials, and discuss new trials and approaches.

Similarity of aberrant DNA methylation in Barrett's esophagus and esophageal adenocarcinoma

Background

Barrett's esophagus (BE) is the metaplastic replacement of squamous with columnar epithelium in the esophagus, as a result of reflux. It is the major risk factor for the development of esophageal adenocarcinoma (EAC). Methylation of CpG dinucleotides of normally unmethylated genes is associated with silencing of their expression, and is common in EAC. This study was designed to determine at what stage, in the progression from BE to EAC, methylation of key genes occurs.

Results

We examined nine genes (APC, CDKN2A, ID4, MGMT, RBP1, RUNX3, SFRP1, TIMP3, and TMEFF2), frequently methylated in multiple cancer types, in a panel of squamous (19 biopsies from patients without BE or EAC, 16 from patients with BE, 21 from patients with EAC), BE (40 metaplastic, seven high grade dysplastic) and 37 EAC tissues. The methylation frequency, the percentage of samples that had any extent of methylation, for each of the nine genes in the EAC (95%, 59%, 76%, 57%, 70%, 73%, 95%, 74% and 83% respectively) was significantly higher than in any of the squamous groups. The methylation frequency for each of the nine genes in the metaplastic BE (95%, 28%, 78%, 48%, 58%, 48%, 93%, 88% and 75% respectively) was significantly higher than in the squamous samples except for CDKN2A and RBP1. The methylation frequency did not differ between BE and EAC samples, except for CDKN2A and RUNX3 which were significantly higher in EAC. The methylation extent was an estimate of both the number of methylated alleles and the density of methylation on these alleles. This was significantly greater in EAC than in metaplastic BE for all genes except APC, MGMT and TIMP3. There was no significant difference in methylation extent for any gene between high grade dysplastic BE and EAC.

Conclusion

We found significant methylation in metaplastic BE, which for seven of the nine genes studied did not differ in frequency from that found in EAC. This is also the first report of gene silencing by methylation of ID4 in BE or EAC. This study suggests that metaplastic BE is a highly abnormal tissue, more similar to cancer tissue than to normal epithelium.

Barrett's esophagus: can biomarkers predict progression to malignancy?

Barrett's esophagus (BE) is one of the most common premalignant lesions and can progress to esophageal adenocarcinoma. It is characterized histologically by a specialized intestinal metaplasia that replaces the squamous epithelium of the distal esophagus, and is associated with chronic gastroesophageal reflux disease and obesity. Similar to the adenoma-carcinoma sequence of colorectal carcinomas, esophageal adenocarcinoma develops through progression from BE to low- and high-grade dysplasia, then to adenocarcinoma with accumulation of genetic and epigenetic abnormalities. The exact malignancy potential of BE is uncertain. Dysplasia is the most predictive marker for risk of esophageal adenocarcinoma, whereas endoscopic and histological diagnoses are still the gold standard for surveillance of patients with BE. However, both are limited, either by sampling errors in biopsies or by differences in histological interpretation. Several studies have identified candidate biomarkers that may have predictive value and may serve as additional factors for the risk assessment of esophageal adenocarcinoma. This review discusses the role of biomarkers in the progression from BE to adenocarcinoma, focusing on clinical and molecular markers.

Statins in esophageal cancer cell lines: promising lead?

Barrett's-associated esophageal adenocarcinoma (BEAC) is an important health concern in many western populations owing to its increasing incidence and the paucity of effective treatments. Statins have recently been suggested to induce anticancer effects against a variety of cancers in several, but not all, in vitro, in vivo, and epidemiologic studies. In the accompanying article by Ogunwobi and Beales, three statins were shown to inhibit proliferation and stimulate apoptosis in two EAC cell lines. These effects were achieved by reducing Ras, extracellular signal-regulated kinase (ERK), and protein kinase B (Akt)-related cellular signaling. Although these results are promising, they are clearly preliminary, and much additional work is needed to confirm or refute the potential anticancer effects of statins in human BEAC. In addition, the work of Ogunwobi and Beales highlights the importance of developing better, more predictive in vitro and in vivo models of BEAC, and of taking promising, low-risk agents, such as statins, into early-phase therapeutic and preventive clinical trials involving cancer patients and patients with Barrett's metaplasia/dysplasia, respectively.