LOSS OF HETEROZYGOSITY DURING THE DEVELOPMENT AND PROGRESSION OF DIFFERENTIATED ADENOCARCINOMA OF THE STOMACH

In a recent allelotypic analysis of differentiated adenocarcinoma of t he stomach, loss of heterozygosity (LOH) was found frequently on chrom osomes 2q, 4p, 5q, 6p, 7q, 11q, 14q, 17p, 18q, and 21q. To clarify the sequence of these chromosomal losses during gastric carcinogenesis, m icrosatellite analysis of the chromosome arms described above was perf ormed in 25 early and 29 advanced differentiated adenocarcinomas of th e stomach. LOH on these chromosome arms fell within a range of 20-50 p er cent. On 4p, 7q, 14q, 17p, and 21q, LOH was detected at a similar f requency in both early and advanced carcinomas, while LOH on 2q, 5q, 6 p, 11q, and 18q was observed more than twice as frequently in advanced than in early lesions. Mean fractional allelic losses (FAIs) were 0.2 21 in early and 0.413 in advanced carcinomas, representing a significa nt difference P<0.05). These results suggest that LOH on 4p, 7q, 14q, 17p, and 21q is a relatively early event, while LOH on 2q, 5q, 6p, 11q , and 18q typically accumulates during the progression of gastric carc inogenesis. (C) 1998 John Wiley & Sons, Ltd.