TNF and infection: We then analyzed mRNA expression levels of inflammatory cell markers, Cd14 (macrophage) and Ela2 (neutrophil), and inflammation‐related genes, Il1b, Nos2, and Tnf, which are known to be associated with aberrant DNA methylation induction.10, 21 Expression levels of inflammatory cell markers and inflammation‐related genes increased by H. pylori infection, but the levels were not increased according to the infection period (Fig. 2a,b).