MICROSATELLITE INSTABILITY OCCURS FREQUENTLY IN HUMAN GASTRIC-CARCINOMA

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