Chromosomal numerical aberrations are frequent in oesophageal and gastric adenocarcinomas: a study using in-situ hybridization

Aims (i) To investigate and compare the numerical aberrations of chromosome s 7, 8, 11, 17 and Y in a series of 60 adenocarcinomas of the oesophagus, g astric cardia and gastric antrum; and (ii) to specify the sequence of chrom osomal aberrations occurring during the neoplastic progression of Barrett's oesophagus. Methods and results: Chromosomal in-situ hybridization was performed on dep araffinized tissue sections from 20 Barrett's adenocarcinomas, 20 adenocarc inomas of the cardia and 20 adenocarcinomas of the antrum, with centromeric alpha satellite DNA probes specific for chromosomes 7, 8, 11, 17 and Y, la belled with digoxigenin. Signals were detected by immunoperoxidase staining . The copy number for each chromosome was counted in 200 tumour cells nucle i and 100 lymphocytes as controls. In parallel, the DNA content of the nucl ear suspensions was measured by flow cytometry. Numerical abnormalities of the five chromosomes (loss of the Y chromosome, monosomy, trisomy, and tetr asomy) were frequently observed in the three groups of adenocarcinomas (fro m 40% to 65% of the cases). Sixty per cent to 75% of oesophagus and gastric adenocarcinomas were DNA-aneuploid. Chromosomal aberrations progressively increased with advancing degrees of dysplasia in Barrett's mucosa, with an increasing frequency of trisomy and loss of the Y chromosome from non-dyspl astic Barrett's mucosa to invasive adenocarcinoma, and with monosomy and te trasomy present only in invasive cancers. Conclusions: Our study confirms the high frequency of chromosomal numerical aberrations in oesophageal and gastric adenocarcinomas, without difference s between adenocarcinomas of the gastric cardia and antrum. We have shown t hat these alterations occur early during the neoplastic transformation of B arrett's mucosa.