Gastric cancers with a high frequency of microsatellite instability (MSI-H), which is the result of hMLH1 silencing by hypermethylation, exhibited less frequent lymph node metastasis (dos Santos et al, 1996; Wu et al, 2000), and several genes are simultaneously methylated together with hMLH1 (Kim H et al, 2003; Homma et al, 2005). The gene discussed is MLH1; the disease is gastric cancer.