Microsatellite instability is reportedly present in 15–33% of solitary gastric cancers, although mutations of the MLH1 or MSH2 genes are rare in sporadic gastric cancers (Chong et al, 1994; Mironov et al, 1994; Strickler et al, 1994; Tamura et al, 1996). This evidence concerns the gene MLH1 and gastric cancer.