MICROSATELLITE INSTABILITY IN THE PROGRESSION OF GASTRIC-CARCINOMA

Seventy-six gastric carcinomas were analyzed with regard to whether or how microsatellite instability was associated with the development of the carcinoma. Microsatellite instability occurred as a late genetic alteration, with an incidence significantly higher in the advanced sta ge (17 of 51) than in the early stage (3 of 25; P < 0.05). Chromosomal losses on 5q and 17p, detected by polymerase chain reaction-restricti on fragment length polymorphism, more frequently accompanied microsate llite instability (9 of 15 and 8 of 11, respectively), compared with c arcinomas which lacked instability (5 of 28 and 9 of 30, respectively; P < 0.01 and P < 0.05, respectively). Epstein-Barr virus was observed in only 8 of 76 carcinomas, none of which was associated with microsa tellite instability. No significant correlation,vas found between inst ability and the familial tendency to develop gastric carcinomas. Our r esults suggest that microsatellite instability might play a role in th e progression of gastric carcinomas but not in Epstein-Barr virus-asso ciated gastric carcinomas.