Microsatellite instability occurs frequently in human gastric carcinoma.

Microsatellites are short repeated oligonucleotide sequences found throughout the human genome. Microsatellite instability has been reported in hereditary and sporadic colorectal carcinomas. Since gastric carcinoma shares numerous molecular abnormalities with colon cancer, we evaluated 52 gastric adenocarcinomas and adjacent dysplastic tissues for microsatellite instability at five chromosomal loci. Instability at one or more loci was observed in 16 (31%) of the 52 tumors, but in only two dysplastic tissues adjacent to their respective tumors. These results demonstrate that microsatellite instability is not limited to colorectal carcinoma, but also occurs frequently in another cancer, that of the stomach. It is probably a late event, developing only rarely in premalignant dysplastic lesions.