Prognostic implications of microsatellite genotypes in gastric carcinoma

Microsatellite alterations such as loss of heterozygosity (LOH) and microsa tellite instability (MSI) are observed in most (70% to 80%) gastric carcino mas. To determine whether the microsatellite genotypes are correlated with clinicopathological features, 118 patients with gastric carcinomas were exa mined by using polymorphic microsatellite markers for LOH on 5 gastric canc er-associated chromosome arms and non-polymorphic BAT markers for MSI. Micr osatellite genotypes were categorized as high-frequency MSI (MSI-H), high-l evel LOH (LOH-H), low-level LOH (LOH-L) and LOH non-detectable (LOH-N). A s ignificant fraction of the MSI-H, LOH-H and LOH-L types was observed in int estinal-type gastric carcinomas, whereas the LOH-N type was highly associat ed with diffuse-type tumors (p = 0.00162). There was a close relationship b etween 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 al lowing the construction of a comprehensive genetic classification useful fo r the prediction of diverse clinical courses. (C) 2000 Wiley-Liss, Inc.