Multiple promoter CpG islands would be methylated by H. pylori infection, and an increased number of methylated CpG sites correlate with histological and serological severity of chronic gastritis.

Background/Aim: We investigated the relationship of gastric cancer (GC) and CpG island hypermethylation (CIHM) in tumor suppressor genes of non-neoplastic gastric mucosa. Methods: Gastric mucosa samples were obtained from 125 GC and 180 non-GC subjects. CIHM of p14, p16, DAP-kinase and CDH1 genes were determined by methylation-specific polymerase chain reaction. High CIHM was defined as three or all methylated CpG islands. Results: Rates of CIHM of p14, CDH1, DAP-kinase, and high CIHM were significantly higher in all GC samples than non-GC samples (p14: 32.2 vs. 50.4%; OR = 1.70, 95% CI = 1.03–2.80, p = 0.04, CDH1: 36.1 vs. 84.0%; OR = 8.65, 95% CI = 14.74–15.77, p < 0.0001, DAP-kinase: 42.2 vs. 83.2%; OR = 5.98, 95% CI = 3.37–10.62, p < 0.0001, and high CIHM: 44.4 vs. 80.8%; OR = 4.40, 95% CI = 2.51–7.72, p < 0.0001). CIHM in CDH1 and DAP-kinase were associated with a greater risk of GC including all of its different subtypes. An increased number of CIHM was associated with an increased risk of all GC (1 CIHM; OR = 2.33, 95% CI = 0.82–6.64, p = 0.11, 2 CIHM; OR = 4.89, 95% CI = 1.79–13.37, p = 0.002, 3 CIHM; OR = 9.43, 95% CI = 3.20–27.78, p < 0.0001, and all CIHM OR = 24.71, 95% CI = 6.70–91.18, p < 0.0001). Three and all CIHM were closely associated with a higher risk of intestinal-type GC, Helicobacter pylori-positive infection status, male gender, and middle and older GC while 3 CIHM was closely associated with a higher risk of diffuse-type GC, H. pylori-negative infection status and younger GC. Conclusions: CIHM of CDH1 and DAP-kinase in non-neoplastic gastric mucosa corresponded to a risk of GC regardless of histological subtype, H. pylori infection status, gender and generation. An increased number of CIHM correlates with a higher GC risk including its various clinico-pathological subtypes.

So far, a number of association studies have focused on the effect of polymorphisms in IL-1β and TNF-α genes on the susceptibility to gastric cancer (GC). Here, we evaluate the possible association between common polymorphisms in the IL-1β and TNF-α genes with various clinicopathological characteristics, including overall survival of GC patients. Restriction fragment length polymorphism analysis was performed for IL-1β-31(T > C) and IL-1β-511(C > T) and TNF-α-857 (C > T) polymorphisms in 130 GC patients. IL-1β-31CC and IL-1β-511TT genotypes held a significantly lower risk of lymphatic invasion (IL-1β-31CC vs. others: adjusted OR = 0.39, 95% CI = 0.15-0.96, P = 0.04, IL-1β-511TT vs. others: adjusted OR = 0.23, 95% CI = 0.08-0.67, P = 0.007). The IL-1β-31CC and IL-1β-511TT genotypes were weakly associated with reduced risk of venous invasion (IL-1β-31CC vs. others: adjusted OR = 0.35, 95% CI = 0.12-1.05, P = 0.06, IL-1β-511TT vs. others: adjusted OR = 0.32, 95% CI = 0.08-1.20, P = 0.09). The IL-1β-511TT genotype was also weakly associated with reduced risk of lymph node metastasis (IL-1β-511TT vs. others: adjusted OR = 0.42, 95% CI = 0.17-1.04, P = 0.06). When the TNF-α-857CT and TNF-α-857-TT genotypes were considered as T carrier, the patients with TNF-α-857T carrier showed significantly better overall survival than patients with CC genotype (P = 0.011). GC patients who have both IL-1β-31 CC and IL-1β-511 TT genotypes and have at least one of protective genotypes (IL-1β-31 CC, IL-1β-511 TT, TNF-α-857 T carrier) were also associated with better prognostic factors, such as lymphatic and venous invasion better survival. IL-1β-31CC, IL-1β-511TT genotype, and TNF-α-857T carrier may have protective effect against GC progression.