Neoplastic risk assessment in Barrett’s esophagus: how far have we come?

CD80 expression promotes immune surveillance in Barrett's metaplasia

Esophageal adenocarcinoma (EAC) is the final step of a pathway starting with esophageal reflux disease, Barrett's metaplasia and Barrett's dysplasia. Positive costimulatory ligands such as CD80 have been suggested to contribute to anti-tumor T-cell efficacy. Here we report for the first time the role of CD80 in the inflammatory esophageal carcinogenesis and characterize the immune environment of EAC. Mucosa samples from cancer were obtained during esophagectomy from patients affected by EAC. Fresh biopsies were obtained from patients who underwent endoscopy for screening or follow-up. A rodent model of reflux induced esophageal carcinogenesis was created with an esophago-gastro-jejunostomy. CD80 expression was increased in epithelial cells during metaplasia in the inflammatory esophageal carcinogenesis cascade. Cd80 null mice as well as WT mice that received antiCD80 antibodies showed a higher rate of dysplasia and KI-67+ cells. These results suggest that CD80 mediates an active immune surveillance process in early inflammation-driven esophageal carcinogenesis.

Investigation of genomic instability in paediatric Barrett's oesophagus using laser microdissection on paraffin-embedded endoscopic biopsies

OBJECTIVES

To investigate the occurrence of microsatellite instability (MSI) in paediatric Barrett's oesophagus (BE) with the aim of identifying a potential marker for patients at risk for developing dysplasia or adenocarcinoma at a later stage.

PATIENTS AND METHODS

Endoscopic oesophageal biopsies from 6 pediatric patients harbouring BE and 6 age-matched controls were retrospectively investigated. After all of the samples were made anonymous, a 5-microm section was cut and stained with toluidine blue. A precise cell was selected and captured using a laser microdissection microscope. Microsatellite analysis was performed on the DNA extracted from the captured cells. Genomic DNA was amplified by polymerase chain reaction using primers for 5 mononucleotide repeats and analysed by GeneMapper software on an ABI 3730. DNA extracted from a formalin-fixed colonic adenocarcinoma known to have MSI was used as a positive control.

RESULTS

The median age of the patients with BE was 9 years. The relevant complaint was long-standing vomiting in 4 cases and history of dysphagia in 3 cases (1 case had both symptoms). All of the cases had a history of reflux oesophagitis with histological confirmation of oesophagitis. Reflux was associated with a hiatus hernia, obesity, and cerebral palsy in each of 3 cases, and with asthma in 2 patients. Histologically, all of the cases showed the presence of specialized intestinal metaplasia containing goblet cells replacing the squamous oesophageal epithelium. None of the cases tested showed any evidence of MSI.

CONCLUSIONS

A single molecular marker that would allow recognition of those patients at risk for Barrett's adenocarcinoma has not yet been identified. The absence of MSI in our cases could be due to the need for a longer period of BE before genomic instability develops, or MSI may only arise in a proportion of patients. This does not exclude other genetic alterations, however rare they may be.

Molecular biology of Barrett's cancer

Oesophageal adenocarcinoma (OA) remains one of the more deadly forms of gastro-intestinal cancer with a mortality rate exceeding 90%. The incidence of OA remains unabated and has a reported fivefold increase since 1970 [Pera M, Cameron AJ, Trastek VF, Carpenter HA & Zinsmeister AR. Increasing incidence of adenocarcinoma of the esophagus and esophagogastric junction. Gastroenterology 1993; 104(2): 510-513]. Gastro-oesophageal reflux disease and its sequelae, Barrett's oesophagus, is one of the principle risk factors in the development of OA, with a 30-fold increased risk in Barrett's patients compared with the general population [Tytgat GNJ. Does endoscopic surveillance in esophageal columnar metaplasia (Barrett's-Esophagus) have any real value. Endoscopy 1995; 27(1): 19-26]. OA is thought to be a microcosm of evolution, developing sequentially along the metaplasia-dysplasia-adenocarcinoma sequence. Progression is attributed to a series of genetic and epigenetic events that ultimately allow for clonal selection of Barrett's cells via subversion of intrinsic control mechanisms regulating cellular proliferation and/or apoptosis. This review will describe the current suppositions of the mechanisms behind the selection and subsequent expansion of Barrett's clones, and focus on some of the principle hallmarks associated with this transition.