In addition, analyzing the relationship between the hypermethylation and hypomethylation groups and the prognostic survival of gastric cancer, we found that PTGS2 (P < .05), MMP9 (P < .05), MMP2 (P < .01), and CXCR4 (P < .05), which were of significance for prognostic analyses, showed that the survival rate of the hypomethylation group was higher (Fig. 9C). Here, PTGS2 is linked to gastric cancer.