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

Therapeutic Upper Gastrointestinal Endoscopy in Pediatric Gastroenterology

This paper seeks to give a broad overview of pediatric upper gastrointestinal (GI) pathologies that we are now able to treat endoscopically, acquired or congenital, and we hope this delivers the reader an impression of what is increasingly available to pediatric endoscopists and their patients.

Endoscopic findings of esophagogastric junction in children

Esophagogastric landmarks are recognizable in the same way both in children and in adults, and palisade-shaped vessels can be observed at the distal position of esophageal mucosa, even in infants. Few studies have been done in respect to Barrett's esophagus (BE) in children. Incidence of endoscopically suspected BE among all children undergoing esophagogastroduodenoscopy (EGD) is approximately 0.25-1.4%, but can be up to 9.7% in patients with gastroesophageal reflux disease (GERD). Some data suggest that BE is an acquired disorder and point to the possibility of a congenital component in combination with severe mucosal injury. Recent reports noted that multilayered epithelium (ME), which shows morphological and immunocytochemical characteristics of both squamous and columnar epithelium, is associated with goblet cell metaplasia in adult patients with columnar-lined esophagus. The role of ME in the development of intestinal metaplasia in children is uncertain. Furthermore, detailed mechanisms about how short-segment BE (SSBE) changes to long-segment BE (LSBE) are not yet well understood. Further studies are required to understand the pathological esophagogastric junction (EGJ) and BE in children based on reliable epidemiological data and analysis especially in children who have reflux symptoms. Better understanding of the pediatric EGJ and BE may allow improved diagnosis, monitoring, therapy and, therefore, prognosis of GERD-related disorders in adulthood.

Clinical implications of molecular changes in pediatric Barrett's esophagus

Barrett's esophagus (BE) is a preneoplastic condition that predisposes to esophageal adenocarcinoma. Although data on the occurrence of BE in children are limited, recent studies have suggested an increase in the pediatric population. BE is thought to be a complex disease in which individual genetic predisposition interacts with environmental stimuli. Early premalignant clones produce biological and genetic heterogeneity, resulting in stepwise changes in differentiation, proliferation, and apoptosis, allowing disease progression under selective pressure. The value of endoscopic surveillance biopsy for dysplasia and carcinoma in patients with BE is controversial. Thus, the recognition of early and objective alternative risk markers, less susceptible of sampling error, will be of relevance in the management of BE patients. The possibility of performing molecular genetics on paraffin-embedded biopsies will expand our understanding of the natural history of BE and may lead to the use of biomarkers to inform treatment strategies.

Molecular abnormalities in pediatric barrett esophagus: can we test for potential of neoplastic progression?

Barrett esophagus (BE) is a preneoplastic condition that predisposes to esophageal adenocarcinoma and is a consequence of prolonged gastroesophageal reflux disease. The condition is mainly seen in adults and is thought to be a complex disease in which individual genetic predisposition interacts with environmental stimuli. The aim of our study was to investigate whether genetic biomarkers of potential disease progression are the same in the rare situation of pediatric BE, as described in adults. We performed fluorescence in situ hybridization with probes from Abbott Vysis Corporation on 4-micron sections taken from 48 paraffin-embedded sequential biopsies of 10 cases of BE. The 4 probe sets were specific for HER2 at 17q12/17 centromere/4 centromere, p16 at 9p21/9 centromere, TP53 at 17p13/17 centromere/6 centromere, and CCND1 at 11q13/11 centromere. The probe sets were validated on 10 cases of adult Barrett adenocarcinoma. Of the 10 cases, 6 biopsies in 5 cases were informative. Two had gain of HER2 detected in 1 biopsy each (1 also had gain of chromosome 17) and 4 separate cases showed p16 deletion in 1 biopsy of each (1 also had gain of chromosome 9). The genetic markers informative in 50% of our cases were also identified in adult patients with Barrett adenocarcinoma. The importance of this study is that even at the pediatric level, BE can show genetic changes associated with neoplastic progression.