DNMT1 and Atrophy: The methylation status of Hace1 promoter region was examined by MSP to confirm that reduced Hace1 mRNA expression in gastric mucosae is caused by hypermethylation of Hace1. Interestingly, Hace1 hypermethylation was observed only in the gastric mucosae with H. pylori infection, atrophy, and/or intestinal metaplasia (Fig. 7J), suggesting that NF-kB-induced DNMT1 expression caused by NKX6.3 inactivation may reduce Hace1 expression by hypermethylating the promoter region of Hace1 in the gastric mucosa.