Prognostic implications of microsatellite genotypes in gastric carcinoma

Microsatellite alterations such as loss of heterozygosity (LOH) and microsatellite instability (MSI) are observed in most (70% to 80%) gastric carcinomas. To determine whether the microsatellite genotypes are correlated with clinicopathological features, 118 patients with gastric carcinomas were examined by using polymorphic microsatellite markers for LOH on 5 gastric cancer‐associated chromosome arms and non‐polymorphic BAT markers for MSI. Microsatellite genotypes were categorized as high‐frequency MSI (MSI‐H), high‐level LOH (LOH‐H), low‐level LOH (LOH‐L) and LOH non‐detectable (LOH‐N). A significant fraction of the MSI‐H, LOH‐H and LOH‐L types was observed in intestinal‐type gastric carcinomas, whereas the LOH‐N type was highly associated with diffuse‐type tumors (p = 0.00162). There was a close relationship between microsatellite genotype and TNM (tumor‐node‐metastasis) stage (p = 0.001). Univariate analysis showed that patients of LOH‐H or LOH‐N types and those of MSI‐H or LOH‐L types correlated with poor and favorable survival, respectively, not only in all tumor stages (p = 0.0001) but also in stages II and III (p = 0.0271). It is likely that the major genotypes of gastric carcinomas can be placed into at least 4 microsatellite categories, thus allowing the construction of a comprehensive genetic classification useful for the prediction of diverse clinical courses. Int. J. Cancer 89:378–383, 2000. © 2000 Wiley‐Liss, Inc.