CDKN2A and gastric cancer: On the analysis of four CpG-island genes located within a 3-kb distance to the nearest retroelements (CDH1, ARRDC4, PPARG and CDKN2A) (Figure 5A), the frequency of overmethylated genes was significantly low in the gastric cancers (LOH-B, 33%, P < 0.0001; LOH-L, 33%, P < 0.0001; LOH-H, 20%, P < 0.0001) when compared with the H. pylori-positive gastric mucosa (78%).