To determine the methylation status at the TET1 3′-shore during gastric carcinogenesis, we performed MethyLight analysis of 179 formalin-fixed paraffin-embedded (FFPE) samples of various types of gastric lesions, including chronic gastritis (CG, without IM), IM, gastric adenoma (GA), and GC. Here, TET1 is linked to chronic gastritis.