BACKGROUND. Genetic factors are probably important in the development
of gastric carcinoma in young patients (younger than 40 years). The au
thors investigated early onset primary gastric adenocarcinomas for the
presence of microsatellite instability, which is a phenotypic marker
fur the hereditary nonpolyposis colon carcinoma syndrome. METHODS. DNA
was extracted from archival microdissected carcinoma and correspondin
g normal tissue from 10 British gastric carcinoma patients age 19 to 3
9 years at tile time of diagnosis. A panel of 12 microsatellite loci w
ere amplified by fluorescent polymerase chain reaction and analyzed us
ing an automated DNA sequencer. RESULTS. There was no evidence of micr
osatellite instability. In contrast, allelic imbalance was recorded at
D3S966, D3S1076, D10S197, D11S904, P53, NM23, and DCC microsatellite
loci. CONCLUSIONS. The authors reported ten cases of early onset gastr
ic carcinoma that demonstrated allelic imbalance but no evidence of in
stability at microsatellite loci. It is unlikely that defective DNA mi
smatch repair is important in this group of young patients. (C) 1997 A
merican Cancer Society.