While GSTP1 and PTEN promoters remained unmethylated in both neoplastic and non-neoplastic gastric epithelia (Sato et al, 2002; Tamura, 2004), TSLC1 promoter hypermethylation is highly cancer specific, but is observed at only a low frequency in gastric cancer (Honda et al, 2002). This evidence concerns the gene PTEN and gastric cancer.