Prognostic value and clinicopathological profile of microsatellite instability in gastric cancer.

In this study, microsatellite instability (MI) was investigated in 126 gastric carcinomas and correlated with clinicopathological features and prognosis; at least 5-10 microsatellite loci were analyzed. MI was identified in 56 (44.5%) of all investigated carcinomas, one locus being affected in 40 (31.7%) carcinomas, two loci being affected in 6 (4.8%) carcinomas, and more than two loci being affected in 10 (8.0%) carcinomas. MI was correlated with neither age and sex of the patients nor with depth of invasion, lymph node metastasis, tumor differentiation, or histological type according to WHO and Laurén classification. The frequency of MI was the same in early gastric carcinomas as it was in advanced gastric carcinomas, suggesting that MI arises early during the tumorigenesis of gastric cancer. No significant differences in survival could be demonstrated between patients with MI-negative and MI-positive gastric carcinomas.