MYC induced by H. pylori CagA in gastric cancer cells can suppress the expression of let-7a and let-7c through two epigenetic approaches: (1) MYC stimulates EZH2 expression by reducing its negative regulators, miR-26a and miR-101; (2) MYC interacts with DNMT3B and EZH2 on the let-7 promoter, and consequently the let-7 gene is silenced through both DNA and histone methylation. This evidence concerns the gene EZH2 and gastric cancer.