Clonal analysis of a case of multifocal oesophageal (Barrett's) adenocarcinoma by comparative genomic hybridization

Oesophageal adenocarcinomas arising in Barrett's epithelium occasionally pr esent as multiple lesions. This could be due to either a multifocal present ation of the same tumour, or different neoplasms arising simultaneously in a dysplastic Barrett's oesophagus ('field cancerization'). This is a report of the genetic analysis of multiple neoplastic sites in a Barrett's oesoph agus with an extensive area of dysplasia. In addition, the dysplastic Barre tt's epithelium was evaluated. For the genetic screening, comparative genom ic hybridization (CGH) allowed evaluation of the whole genome of each speci men. Five cancerous regions were selected and subsequently dissected from p araffin-embedded tissue blocks. The use of archival materials enabled a tar geted collection of representative tumour locations. Multiple genetic aberr ations were detected by CGH in all cancer sites. Losses on 3p, 4, 7q, 18q, and Y, as well as gains on 8q, 9q, 12p, 13q, 17q, 20p and X, were found in each specimen. In four out of the five lesions, simultaneous losses on 9p, 15q, and 16q, with concomitant gains on 5p, 7q, and 10p, were disclosed by CGH. Adjacent high-grade dysplastic Barrett's mucosa shared the losses on 3 p, 4, 7q, 9p, 18, and Y, as well as the gains on 5p, 7q, 13q, 17q, and X, t hereby confirming its precursor status. Within this single and rare case of multifocal Barrett's adenocarcinoma, a monoclonal genotype was present. Th is must have been caused by an extensive outgrowth of a single tumour. Copy right (C) 1999 John Wiley & Sons, Ltd.