LTA 252GG and GA genotypes are associated with diffuse-type noncardia gastric cancer risk in the Japanese population

Modifying Effect of Chronic Atrophic Gastritis on Radiation Risk for Noncardia Gastric Cancer According to Histological Type

The findings from previously published studies have suggested that radiation exposure is associated with increased mortality and incidence of gastric cancer. However, few cohort studies have incorporated risk factors such as Helicobacter pylori (H. pylori) infection or chronic atrophic gastritis (CAG). The current study is aimed at evaluating the modifying effect of CAG on radiation risk of noncardia gastric cancer by histological type, by reanalyzing data from a nested case-control study conducted within the longitudinal clinical cohort of atomic bomb survivors. The analysis was restricted to 297 intestinal- or diffuse-type noncardia cases and 873 controls rematched to the cases on gender, age, city, and time and type of serum storage, and countermatched on radiation dose. Multivariable-adjusted relative risks [95% confidence interval (CI)] of noncardia gastric cancer were 3.9 (2.1-7.2) for H. pylori IgG seropositivity with cytotoxin-associated gene A (CagA) IgG low titer, 2.6 (1.9-3.6) for CAG, 1.9 (1.3-2.8) for current smoking, and 1.4 (1.1-1.9) for 1 Gy irradiation. Among subjects without CAG, the relative risk (95% CI) of noncardia gastric cancer at 1 Gy was 2.3 (1.4-3.7), whereas relative risk (95% CI) at 1 Gy was 1.1 (0.8-1.5) among subjects with CAG (for the overall interaction, P = 0.012). By histological type, the risk at 1 Gy was high for diffuse type without CAG, with adjusted relative risk (95% CI) of 3.8 (2.0-7.6), but was not high for diffuse type with CAG or for intestinal-type irrespective of CAG status. The results indicate that radiation exposure is associated with increased risk of diffuse-type noncardia gastric cancer without CAG, and this association exists despite adjustment for H. pylori infection and smoking habit.

Positive association between lymphotoxin-alpha variation rs909253 and cancer risk: a meta-analysis based on 36 case-control studies

Lymphotoxin-alpha (LTA) polymorphism rs909253 has been reported to be a risk factor for cancers, but some results are inconsistent. To establish a more conclusive association, we performed a meta-analysis of this variant with cancers. A systematic search was performed for informative case-control studies of rs909253 with cancers among literature databases, including PubMed, Web of Science, Embase, China National Knowledge Infrastructure (CNKI), and Wanfang Chinese Periodical Database. After a comprehensive filtration procedure, 36 publications involved with 35,677 participants were selected for the current meta-analysis. Stratified factors, such as cancer type, populations, and source of control, were used for a better interpretation of this variant. Minimal heterogeneity was shown in the current meta-analysis (I (2) = 0.0%, P = 0.48). Our results show a significant association of rs909253 and cancer risk (odds ratio (OR) = 1.12, P (z) < 0.001). In the subgroup analysis, significant association of rs909253 was found in adenocarcinoma (OR = 1.16, P (z) < 0.001) and hematological malignancy (OR = 1.10, P (z) < 0.001). Our meta-analyses established a significant association of rs909253 with cancer risk among multiple populations including North Americans, Asians, and Europeans.

Association between tumor necrosis factor β 252 A/G polymorphism and risk of gastric cancer: a meta-analysis

Tumor necrosis factor β (TNF-β) 252 A/G polymorphism has been implicated to be associated with risk of gastric cancer, but previous studies showed inconsistent and inconclusive results. Therefore, we performed a meta-analysis to assess the association between TNF-β 252 A/G polymorphism and gastric cancer risk. Relevant studies were searched from PubMed database. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated to evaluate the strength of the associations between TNF-β 252 A/G polymorphism and gastric cancer risk. Overall, 11 individual case-control studies with 2,270 cases and 4,404 controls were included in the final meta-analysis. Meta-analysis of total 11 studies showed that TNF-β 252 A/G polymorphism was associated with the risk of gastric cancer (G vs. A: OR = 1.10, 95% CI 1.02-1.19, P = 0.015; GG/AG vs. AA: OR = 1.21, 95% CI 1.00-1.47, P = 0.049). Subgroup analysis by ethnicity showed that TNF-β 252 A/G polymorphism was only associated with the risk of gastric cancer in Asians, but not Caucasians. The findings from the current meta-analysis suggest that TNF-β 252 A/G polymorphism is associated with the risk of gastric cancer, especially in Asians.

TNF-β +252 A>G polymorphism and susceptibility to cancer

OBJECTIVE

Tumor necrosis factor-β (TNF-β) plays important roles in mediating cancer development. Many studies have argued possible associations of TNF-β +252 A>G polymorphism with different cancers. However, association between this most frequently studied polymorphism and susceptibility to cancer still remains controversial and ambiguous. The aim of this study is to determine the relationship of TNF-β +252 A>G polymorphism with cancer through meta-analysis.

METHODS

Electronic searches of several databases were conducted for all publications on the associations between this variant and cancer through October 2011. Odds ratios (ORs) with 95 % confidence intervals (95 % CIs) were used to access the strength of this association in random-effect model.

RESULTS

Thirty-three studies with 14,435 cancer patients and 10,583 healthy controls were included. In this meta-analysis, we detected statistically significant connections between this polymorphism and cancer risks [GG + GA vs. AA: OR = 1.24, 95 % CI = 1.02-1.51; GG vs. AA: OR = 1.43, 95 % CI = 1.05-1.95; G vs. A: OR = 1.28, 95 % CI = 1.28 (1.09-1.50)] in the overall ethnic population. Meanwhile, we detected significant associations in Asian population (GG + GA vs. AA), other population (GG vs. GA + AA), and Caucasian population (GG vs. AA, G vs. A) with the OR values being 1.21 (1.04-1.40), 1.64 (1.35-1.99), 1.65 (1.02, 2.65), and 1.39 (1.09-1.75), respectively.

CONCLUSIONS

TNF-β +252 A>G polymorphism is positively associated with susceptibility to cancer. However, this study also suggests that more studies should be conducted to further confirm the associations between this variant and specific types of cancers.

Profiles of gene polymorphisms in cytokines and Toll-like receptors with higher risk for gastric cancer

BACKGROUND

Chronic inflammation and gastric carcinogenesis show a close association, so gene polymorphisms that modify the intensity of the inflammatory response may contribute to variations in gastric cancer risk.

AIMS

The purpose of this study was to investigate the combined effect of the pro- and anti-inflammatory cytokines and toll-like receptors polymorphisms on the chronic gastritis and gastric cancer risk in a Brazilian population sample.

METHODS

We evaluated 669 DNA samples (200 of gastric cancer [GC], 229 of chronic gastritis [CG], and 240 of healthy individuals [C]). Ten polymorphisms were genotyped: IL-1RN and TLR2 -196 to -174 del using the allele-specific PCR method and TNF-A (rs1800629; rs1799724), TNF-B (rs909253), IL-8 (rs4073; rs2227532), IL-10 (rs1800872) and TLR4 (rs4986790; rs4986791) using PCR-RFLP.

RESULTS

Polymorphisms TNF-A-308G/A, IL-8-251A/T, TNF-B + 252A/G and TLR4 + 1196C/T were not associated with risk of any gastric lesion. However, an association with increased risk for GC was observed for polymorphisms IL-1RNL/2 (p < 0.001), TNF-A-857C/T (p = 0.022), IL-8-845T/C (p < 0.001), IL-10-592C/A (p < 0.001), TLR2ins/del (p < 0.001), and TLR4 + 896A/G (p = 0.033). In CG, an association was observed only with polymorphisms IL-1RNL/2 and IL-10-592A/C (p < 0.001 for both). A combined analysis of these six polymorphisms associated with GC revealed a profile with two to four combined genotypes which confer a higher risk of gastric carcinogenesis, with an OR increased 2.95-fold to 50.4-fold, highlighting the combinations IL-1RN2/TNF-A-857T/IL-8-845C, IL-1RN2/IL-8-845C/TLR2del, IL-1RN2/IL-10-592A/TLR4 + 896G, IL-10-592A/TLR2del/TLR4 + 896G, and IL-1RN2/TNFA-857T/IL8-845C/TLR2del.

CONCLUSIONS

Our findings evidenced that the combined effect of polymorphisms in genes involved in the inflammatory process may potentiate the risk of gastric cancer, thus emphasizing the importance of evaluating multiple polymorphisms together.

IL-1ra anti-inflammatory cytokine polymorphism is associated with risk of gastric cancer and chronic gastritis in a Brazilian population, but the TNF-β pro-inflammatory cytokine is not

Genetic polymorphisms in genes that codify inflammatory cytokines have been associated with gastric carcinogenesis. This study evaluated polymorphisms IL-1RN VNTR and TNFB+252A/G in a population from Southeast Brazil with regard to the risk of chronic gastritis and gastric cancer and the presence of an association of gastric lesions with risk factors such as gender, age, smoking, drinking and Helicobacter pylori infection. In this case-control study, polymorphism at IL-1RN VNTR was investigated using the allele-specific polymerase chain reaction method, while the polymerase chain reaction-restriction fragment length polymorphism technique was used to identify the TNFB+252A/G genotype in 675 Brazilian individuals [229 with chronic gastritis (CG), 200 with gastric cancer (GC) and 246 healthy individuals as controls (C)]. Multiple logistic regression analysis (log-additive, dominant, and recessive models) have not showed association of the genotype frequencies for the SNP TNFB + 252A/G with risk of CG or GC. However, as for IL-1RN VNTR it was observed significant differences in all three analysis models, with higher values of OR in recessive model, both in the GC group (OR = 3.04, 95% CI = 1.41-6.56, p < 0.01) and CG (OR = 2.32, 95% CI = 1.10-4.90, p = 0.02) compared to the C group. In addition, the multiple logistic regression showed also an association with risk factors such as male gender, older age and alcohol intake regarded GC group. So, our results indicated that the IL-1RN*2 allele may increase the risk of gastric cancer and precancerous lesions in the Southeast Brazilian population, reinforcing the importance of host genetic factors in the susceptibility to gastric cancer and the participation of cytokines in both the inflammation and the carcinogenic process.

Increased risk for gastric cancer in carriers of the lymphotoxin-α+252G variant infected by Helicobacter pylori

The objective of this study is to determine whether polymorphisms in the lymphotoxin-α (LTA) and interleukin-10 (IL-10) genes were associated with gastric cancer (GC) in a Chinese population. One hundred ninety-six patients with GC and 248 healthy individuals were enrolled in this case-control study. The LTA 252G was associated with an increased risk of GC, with an adjusted odds ratio (OR) of 1.74 (95% confidence interval [CI]: 1.12-2.69) for the LTA 252G heterozygotes and 2.42 (95% CI: 1.28-4.58) for the LTA 252G homozygotes as compared with noncarriers. In contrast, such association is not found in polymorphisms in IL-10; however, a potential interaction between LTA +252 G allele and IL-10-1082 G/A was found to be associated with the occurrence of GC (adjusted OR: 1.91; 95% CI: 1.01-3.64). This study indicates that the LTA +252G allele is associated with increased risk for the presence of GC in a Helicobacter pylori infection positive subgroup and potential interaction between IL-10 and LTA may contribute to the risk of GC.