Tumour-necrosis factor-A polymorphisms and gastric cancer risk: a meta-analysis

The Role of Tumor Necrosis Factor-α (TNF-α) Polymorphisms in Gastric Cancer: a Meta-Analysis

PURPOSE

Tumor necrosis factor alpha (TNF-α) is an inflammatory cytokine which may play a role in the development of gastric cancer (GC). This study aimed to investigate the association of five TNF-α polymorphisms including TNF-α-857, TNF-α-1031, TNF-α-863, TNF-α-308, and TNF-α-238 polymorphisms with GC risk.

METHODS

All eligible case-control studies were collected by searching PubMed, Scopus, and Web of Science. The association of the risk of GC with TNF-α polymorphisms was estimated using odds ratio (OR) and 95% confidence interval (CI). Heterogeneity was assessed via Cochrane's Q and I² analyses.

RESULTS

A total of 46 publications involving 16, 715 cases with GC and 27, 998 controls were recruited. The study revealed a significant association for TNF-α 308 (recessive model: OR = 0.646, P = 0.035), TNF-α-1031 (homozygote model: OR = 1.584, P = 0.027), and TNF-α-857 (homozygote model: OR = 1.760, P = 0.001) polymorphisms with the GC risk. The results of subgroup analysis based ethnicity found a significant association between GC risk and TNF-α-857 polymorphism in Caucasian subgroup (P = 0.005) and TNF-α-1031 polymorphism and GC risk in Asians (P = 0.018).

CONCLUSIONS

This study suggested that TNF-α-857 and TNF-α-1031 polymorphisms may be associated with the increased gastric cancer risk.

Association of polymorphisms in TP53 and the promoter region of IL10 with gastric cancer in a Kazakh population

The emerging evidence indicates that single nucleotide polymorphisms (SNPs) of the tumor necrosis factor (TNF), interleukin 10 (IL10), tumor protein p53 (TP53), and cluster of differentiation 14 (CD14) genes may determine individual susceptibility to gastric cancer (GC). We aimed to investigate the associations for polymorphisms of the TNF, IL10, TP53, and CD14 genes in a population of Kazakhs, to identify potential risk or protective associations of the SNPs with GC. A case group of 143 patients hospitalized for GC was enrolled. Controls were 355 volunteers with no history of any cancer and frequency matched with cases by age. Differences in proportions for categorical variables and the assessment of genotypic frequencies conforming to the Hardy-Weinberg equilibrium law were evaluated by the Chi-square test. Associations between genetic polymorphisms and the risk of GC were estimated by regression analysis. For genetic analysis, three genetic models (additive, dominant, and recessive) were used. Four significant associations were found. The SNPs rs1042522 of TP53 and rs1800896 of IL10 were risk factors for GC by the additive model. Two polymorphisms of IL10 were protective of GC, namely, rs1800872 by additive model and rs1800871 by recessive model. No significant associations were observed between the TNF and CD14 polymorphisms and GC. The polymorphisms TP53 rs1042522 and IL10 rs1800896 are associated with GC risk, while the polymorphisms IL10 rs1800872 and rs1800871 are protective of GC in the population of Kazakhs.

A meta-analysis of tumor necrosis factor-α-308 G>A polymorphism in gastric cancer

Background

Gastric cancer (GC) is the common cause of cancer-related deaths worldwide and inflammation represents the early phases in the GC.

Objective

To review the tumor necrosis factor (TNF)-α-308 G>A (GG, GA, and AA) in GC by meta-analysis studies for any differences in TNF-α-308 G>A gene polymorphisms.

Methods

Case–control studies published from 2003 to 2017 were identified by searching PubMed, EMASE, and the Internet with the English language. The analysis published on TNF-α-308 G>A polymorphism was analyzed and a limited number of articles were included in the present study. TNF-α-308 G>A from 4,157 patients and 5,185 healthy controls was evaluated. Studies were evaluated using Cochrane Q-test and publication bias was evaluated by constructing funnel plots.

Results

Overall, TNF-α-308 GA genotype showed significant association [P < 0.0001, odds ratio (OR), 95% confidence interval (CI) = 0.82 (0.74–0.91)]. However, meta-analysis of TNF-α-308 genotypes (GG, GA, AA, and GA + AA) between GC patients and controls showed nonsignificant association with GC [P > 0.05, recessive model: OR = 1.38, 95% CI: 1.15–1.66; dominant model: OR = 1.23, 95% CI: 1.09–1.39; (G/A) vs. (G/G): OR = 1.15, 95% CI: 1.02–1.28; (A/A) vs. (G/G): OR = 1.44, 95% CI: 1.19–1.73]. Analysis stratified by ethnicity showed same results in Asian and Caucasian populations.

Conclusions

Results revealed nonsignificant association of TNF-α-308 genotypes (GG, GA, AA, and GA + AA) and GC. TNF-α-308GA genotype showed significant association whereas homozygous genotype AA did not show association with GC risk.

TNF genetic polymorphism (rs1799964) may modify the effect of the dietary inflammatory index on gastric cancer in a case-control study

The inflammatory process is known to increase the risk of gastric carcinogenesis, and both genetic and dietary factors are associated with inflammation. In the present study of 1,125 participants (373 cases and 752 controls), we determined whether the dietary inflammatory index (DII) is associated with the risk of gastric cancer (GC) and investigated whether a TNF polymorphism (rs1799964) modifies this association. Semi-quantitative food frequency questionnaire derived data were used to calculate the DII scores. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using multivariable logistic models adjusted for confounders. When we stratified the data by sex, the association between GC and the DII was significant only among the women (OR, 2.27; 95% CI 1.25-4.19), and the DII effect on the risk of GC differed depending on the TNF genotype (OR, 2.30; 95% CI 1.27-4.24 in TT genotype; OR, 0.78; 95% CI 0.37-1.65 in CC + CT, p for interaction = 0.035). Furthermore, the association between the DII and GC was significant in the Helicobacter pylori-positive group; similarly, the effect differed based on the TNF genotype (OR, 1.76; 95% CI 1.13-2.73 in TT genotype; OR,0.98; 95% CI 0.54-1.77 in CT + CC, p for interaction = 0.034). In conclusion, rs1799964 may modify the effect of the DII on GC.

Effects of the IL6 -174G>C promoter polymorphism and IL-6 serum levels on the progression of cutaneous malignant melanoma

Cutaneous malignant melanoma (CMM) is one of the most immunogenic types of cancer, with a 6-fold higher rate of spontaneous regression than any other malignancy. In addition to responsiveness to different immunotherapies, the immunogenicity of CMM highlights the important role of the host immune system in the response to CMM. The present study aimed to explore the role of two functional promoter polymorphisms [IL6 -174G>C (rs1800785) and TNFA -308G>A (rs1800629)] in the regulation of the genes encoding the pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor-α, specifically in patients with CMM. A total of 76 patients with CMM and 200 control subjects were genotyped using PCR-restriction fragment length polymorphism. The genotype frequencies for both single nucleotide polymorphisms (SNPs) did not differ significantly between the patients and controls (P=0.358 and P=0.810 for IL6 and TNFA, respectively). However, compared with carriers of C-allele genotypes (CG+CC), patients with the IL6 -174GG genotype exhibited more advanced melanoma (Clark scale ≥3; P=0.037) and shorter survival times, particularly those who worked outdoors (in conditions with increased sunlight exposure; P=0.016). Furthermore, the serum IL-6 levels of patients with CMM were significantly higher than those of the control subjects, which were associated with unfavorable blood and serum characteristics and tumor progression (development of new distant metastases; P=0.004), and with a shorter overall survival time (P=0.042). Using a Cox proportional hazard model, the IL6 -174GG genotype was found to be an independent prognostic factor for reduced survival time (P=0.030), together with sex (being male; P=0.004) and occupations with higher exposure to sunlight (P=0.047). In conclusion, the results of the present study indicated that the promoter polymorphisms IL6 -174G>C and TNFA -308G>A are not predisposing factors for CMM. However, the IL6 -174G>C SNP and IL-6 serum concentrations are likely to influence the progression of the disease, and the GG genotype and higher IL-6 serum levels may indicate shorter survival.

Polimorfismos IL1B-511 y TNF-A-308 en una población infectada con Helicobacter pylori de una zona de bajo riesgo de cáncer gástrico en Nariño-Colombia

Objetivo: Estudiar los polimorfismos IL1B-511 y TNF-A-308 asociaciados a lesiones precursoras de cáncer gástrico (CG) en una población infectada con Helicobacter pylori (H. pylori) de bajo riesgo de CG de Nariño. Material y método: De 105 pacientes con síntomas de dispepsia se incluyeron 81 infectados por H. pylori, (n=63) con gastritis no atrófica y (n=18) con lesiones precursoras de CG de Tumaco: población de bajo riesgo de CG. Las lesiones gástricas se clasificaron por el sistema de Sydney y H. pylori por tinción de Giemsa. Los polimorfismos de IL1B-511 y TNF-A-308 se genotipificaron por PCR-RFLP’s. Los polimorfismos y su asociación con lesiones gastricas se evaluaron por análisis bivariado y regresión logística binomial. Resultados: Los pacientes portadores del alelo mutante T (IL-1B-511) no se encontraron a riesgo de lesiones precursoras de malignidad (OR=0,7). No se calculó el OR para TNF-A-308, por fijación del alelo normal G. Ser hombre y estar infectado por H. pylori incrementa 4,3 veces el riesgo de presentar lesiones precursoras de CG y no estar vinculado al régimen de salud aumenta 6,7 veces el riesgo de atrofia gástrica, (OR=4,27 y OR=6,72), respectivamente. Conclusión: El alelo mutante T (IL-1B-511) es un biomarcador de resistencia de los pobladores de Tumaco, de bajo riesgo de CG e infectados con H. pylori a padecer lesiones precursoras de CG.

The Mexican consensus on the detection and treatment of early gastric cancer

Gastric cancer is one of the most frequent neoplasias in the digestive tract and is the result of premalignant lesion progression in the majority of cases. Opportune detection of those lesions is relevant, given that timely treatment offers the possibility of cure. There is no consensus in Mexico on the early detection of gastric cancer, and therefore, the Asociación Mexicana de Gastroenterología brought together a group of experts and produced the "Mexican consensus on the detection and treatment of early gastric cancer" to establish useful recommendations for the medical community. The Delphi methodology was employed, and 38 recommendations related to early gastric cancer were formulated. The consensus defines early gastric cancer as that which at diagnosis is limited to the mucosa and submucosa, irrespective of lymph node metástasis. In Mexico, as in other parts of the world, factors associated with early gastric cancer include Helicobacter pylori infection, a family history of the disease, smoking, and diet. Chromoendoscopy, magnification endoscopy, and equipment-based image-enhanced endoscopy are recommended for making the diagnosis, and accurate histopathologic diagnosis is invaluable for making therapeutic decisions. The endoscopic treatment of early gastric cancer, whether dissection or resection of the mucosa, should be preferred to surgical management, when similar oncologic cure results can be obtained. Endoscopic surveillance should be individualized.

Tumor necrosis factor-alpha-308 gene promoter polymorphism associates with survival of cancer patients: A meta-analysis

BACKGROUND

Tumor necrosis factor-alpha (TNF-α) is involved in cancer pathogenesis, and TNF-α-308G>A, a single-nucleotide polymorphism, is associated with cancer prognosis; however, different studies have reported inconsistent results. This meta-analysis aimed to determine the correlation between TNF-α-308G>A polymorphism and the survival of cancer patients.

METHODS

PubMed, Web of Science, Embase, Wanfang database, VIP database, and China National Knowledge Infrastructure database were used to obtain articles on association between TNF-α-308G>A polymorphism and cancer survival, published until April 2018. A meta-analysis was carried out using Stata 12.0 software to determine the pooled hazard ratio (HR) and 95% confidence intervals (95% CI). Furthermore, publication bias was assessed, and sensitivity analysis was performed to validate the analysis.

RESULTS

In total, 13 retrospective cohort studies including 2559 cancer patients were reviewed to estimate the association between TNF-α-308G>A polymorphism and overall survival (OS) of cancer patients. The pooled results suggested that within TNF-α-308G>A polymorphism, genotypes GA+AA/GG (HR = 1.39, 95% CI: 0.90-2.14, P < .001, I = 78.1%), GA/GG (HR = 1.06, 95% CI: 0.83-1.36, P = .072, I = 53.5%), and AA/AG+GG (HR = 3.28, 95% CI: 0.92-11.72, P = .001, I = 85.9%) were not associated with the OS of cancer patients. However, interestingly, the HR was greater for patients with the AA genotype than for those with the GG genotype, suggesting an association between TNF-α-308G>A polymorphism and OS among cancer patients (AA/GG, HR = 2.16, 95% CI: 1.36-3.43, P = .281, I = 21.5%).

CONCLUSION

TNF-α-308G>A polymorphism affects the OS of cancer patients and is a potential therapeutic target for cancer.

Role of polymorphisms in genes that encode cytokines and Helicobacter pylori virulence factors in gastric carcinogenesis

The Helicobacter pylori (H. pylori) infection is a determinant factor in gastric cancer (GC) development. However, the infection outcomes are variable and depend on both host and bacterial characteristics. Some host cytokines such as interleukin (IL)-1β, IL-1Ra, IL-8, IL-10 and tumor necrosis factor-α play important roles in the host immune system response to the pathogen, in the development of gastric mucosal lesions and in cell malignant transformation. Therefore, these host factors are crucial in neoplastic processes. Certain polymorphisms in genes that encode these cytokines have been associated with an increased risk of GC. On the other hand, various virulence factors found in distinct H. pylori bacterial strains, including cytotoxin-associated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and blood group antigen binding adhesin, have been associated with the pathogenesis of different gastric diseases. The virulent factors mentioned above allow the successful infection by the bacterium and play crucial roles in gastric mucosa lesions, including malignant transformation. Moreover, the role of host polymorphisms and bacterial virulence factors in gastric carcinogenesis seems to vary among different countries and populations. The identification of host and bacterium factors that are associated with an increased risk of GC development may be useful in determining the prognosis of infection in patients, what could help in clinical decision-making and in providing of an optimized clinical approach.

Helicobacter pylori associated factors in the development of gastric cancer with special reference to the early-onset subtype

Nowadays, gastric cancer is one of the most common neoplasms and the fourth cause of cancer-related death on the world. Regarding the age at the diagnosis it is divided into early-onset gastric carcinoma (45 years or younger) and conventional gastric cancer (older than 45). Gastric carcinomas are rarely observed in young population and rely mostly on genetic factors, therefore provide the unique model to study genetic and environmental alternations. The latest research on early-onset gastric cancer are trying to explain molecular and genetic basis, because young patients are less exposed to environmental factors predisposing to cancer. In the general population, Helicobacter pylori, has been particularly associated with intestinal subtype of gastric cancers. The significant association of Helicobacter pylori infection in young patients with gastric cancers suggests that the bacterium has an etiologic role in both diffuse and intestinal subtypes of early-onset gastric cancers. In this paper we would like to ascertain the possible role of Helicobacter pylori infection in the development of gastric carcinoma in young patients. The review summarizes recent literature on early-onset gastric cancers with special reference to Helicobacter pylori infection.

Association of tumor necrosis factor alpha gene polymorphisms with Helicobacter pylori infection in dyspeptic patients in Sri Lanka

Single nucleotide polymorphisms present on the promoter sequence of the TNF-α gene may affect production of TNF-α, a pro-inflammatory cytokine, during immune responses. The presence of TNF-α polymorphisms is also reportedly associated with more severe manifestations of Helicobacter pylori infection. However, the frequency of TNF-α polymorphisms and the associated disease severity vary between different patient groups. In this study, gastric biopsies and blood specimens were collected from 138 patients with dyspepsia undergoing routine upper gastrointestinal endoscopy. Our institution's Ethics Review Committee approved the study and written informed consent was obtained from all participants. The presence of H. pylori was confirmed histologically in all patients. The frequency of TNF-α polymorphisms in the study cohort was investigated using PCR-restriction fragment length polymorphism and expression of serum TNF-α quantitated using a commercial ELISA assay. The proportions of selected TNF-α polymorphisms (TNF-α -238, -308 and -863) were similar in H. pylori-positive and -negative patients. Homozygous mutations of TNF-α polymorphisms were rarely detected in the study group. There was a significant difference in TNF-α concentrations between patients with mild chronic gastritis and TNF-α -308 GG genotype and patients with moderate to severe chronic gastritis (P = 0.008). It was not possible to identify an association between these genotypes and disease severity because of the low frequency of heterozygous and homozygous mutated genes in Sri Lankan patients with dyspepsia.

Function of tumor necrosis factor alpha before and after mutation in gastric cancer

Purpose

To explore the cause of functional changes of tumor necrosis factor alpha (TNF-α) in development of gastric cancer through the structural changes of each site in TNF-α before and after mutation.

Methods

Three typical mutant sites (TNF-α-308G/A, 857C/T and 863C/A of TNF-α) were chosen and methods like ab initio modeling was adopted for 3D modeling of TNF-α before and after mutation, besides, the structural changes were also analyzed.

Results

Mutation of TNF-α-308G/A led to the production of multiple helical structures and that of 863C/A caused the production of one helical structure in its adjacent region. Mutation of 857C/T, however, did not cause the change in the basic structure of TNF-α.

Conclusions

Structural changes of TNF-α may have a significant effect on development of gastric cancer.

The relationship between tumor necrosis factor-α polymorphisms and gastric cancer risk: An updated meta-analysis

The aim of the present study was to evaluate the relationship between tumor necrosis factor-α (TNF-α) and the development of gastric cancer, and to investigate whether it can be used as a biological marker for gastric cancer. In the current study, a new meta-analysis was performed to assess the association between TNF-α gene polymorphisms and gastric cancer susceptibility. Subgroup analyses based on ethnicity, control population source and non-cardia cancers were also conducted. Summary odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model. TNF-α 308 polymorphisms indicated a significant relationship with gastric cancer risk among a normal population [GA/AA vs. GG; 1.17 (1.10–1.23)]. In analysis stratified by ethnicity, TNF-α 238 displayed an association with gastric cancer risk in eastern populations [GA/AA vs. GG: 1.24 (1.02–1.50)], but not in western populations [GA/AA vs. GG: 0.96 (0.79–1.18)]. The overall ORs (95% CIs) for TNF-α 857, TNF-α 1031 and TNF-α 863 were 1.13 (1.04–1.24), 0.94 (0.85–1.05) and 0.89 (0.78–1.02), respectively, under dominant genetic model comparison. Among the above three SNPs, only TNF-α 857 was robustly associated with gastric cancer inclination, and this association remained consistently robust when limited to non-cardia gastric cancers [GA/AA vs. GG: 1.16 (1.03–1.31)]. TNF-α 308 and TNF-α 857 genotypes were potential risk factors of statistical significance in gastric cancer, and TNF-α 238 indicated to be significantly associated with gastric cancer risk only in eastern populations. TNF-α 1031 and TNF-α 863 were not significantly associated with gastric cancer risk.

Association of the IL-1RN variable number of tandem repeat polymorphism and Helicobacter pylori infection: A meta-analysis

The aim of this study was to clarify the association of IL-1RN variable number of tandem repeat (VNTR) polymorphism and H. pylori infection. We performed a meta-analysis of studies retrieved by systematic searches of Pubmed, Embase and the Cochrane Library. Data were analyzed with STATA 13.1 using pooled odds ratios (ORs) with 95% confidence intervals (CIs). A total of 18 studies were included in our meta-analysis, and IL-1RN VNTR was found to be significantly associated with H. pylori infection in the comparisons of 22+2L vs. LL (OR = 1.17, 95% CI = 1.02-1.33) and 2 allele vs. L allele (OR = 1.18, 95% CI = 1.00-1.40). Stratified analyses on study designs and ethnicities were also conducted. IL-1RN VNTR was positively correlated with H. pylori infection in Asian subgroup and Hospital-Based subgroup (i.e., study samples obtained from hospital inpatients). In conclusion, our study demonstrated that IL-1RN VNTR polymorphism might increase the risk of H. pylori infection, especially in Asians.

TNF-α-308/-238 polymorphisms are associated with gastric cancer: A case-control family study in China

BACKGROUND

Associations of TNF-α-308 (rs1800629) and -238 (rs361525) with gastric cancer had the inconsistent indication among different populations.

METHODS

In this case-control family study, 47 families were determined with the probands diagnosed with gastric cancer (case family, n=296), accordingly 47 families without gastric cancer were matched with the case families by multivariate distribution of age, sex, social class, and pedigree size (control family, n=319). Polymerase chain reaction-restriction fragment length polymorphism (RFLP-PCR) was used to identify the TNF genotype. Chi-square test was used to compare the groups regarding genotype and the allele frequencies, HWE test for Hardy-Weinberg equilibrium.

RESULTS

The frequencies of TNF-α-308 GA and AA genotypes were significantly higher in case family than that in control family. The risk of gastric cancer was increased in GA and AA carriers in the first degree (OR=2.06, 95% CI=1.20-3.51 and OR=4.89, 95% CI=2.74-8.74), however the similar result was not found in the second degree. Helicobacter pylori infection status were significantly associated with risk of gastric cancer in first-degree relatives (OR=1.96, 95% CI=1.26-3.05) while no statistical significance was noted in the second-degree relatives. Haplotypes of TNF-α-308/-238 alleles, GA/GG, AA/GG and AA/GA indicated the susceptibilities to gastric cancer with OR and 95% confident intervals resulting 2.07 (1.34-3.21), 4.49 (2.74-7.33) and 4.98 (1.76-14.01) respectively.

CONCLUSIONS

TNF-α-G308A (rs1800629) polymorphisms are associated with gastric cancer in Chinese population. Haplotypes of TNF-α-308/-238 GA/GG, AA/GG and AA/GA increase the susceptibilities to gastric cancer. The first-degree relatives are more likely to develop into gastric cancer with TNF-α-G308 polymorphisms and H. pylori positive than the second-degree are.

Soluble IL-1 decoy receptor is associated with gastric adenocarcinoma

Background:

In recent years, studies on gastric cancer include changes in cancer associated immune system activation and the levels of immune system markers. It has been demonstrated that TNF-α (tumor necrosis factor-alpha) and IL-6 (interleukin-6) play a role in inflammatory associated carcinogenesis.

Objective:

Our aim was to investigate serum soluble IL-1 decoy receptor (sIL- 1RII), TNF-α and IL-6 levels in gastric adenocarcinoma patients.

Materials and methods:

Male gastric adenocarcinoma patients and dyspeptic participants, in total 55 cases were included. Serum sIL-1RII, TNF-α and IL-6 concentrations were measured.

Results:

The median sIL-1RII levels of the patients were statistically significantly lower than the median of the control group (3111 ng/mL; 3601 ng/mL, respectively) (p=0.003). But the median TNF-α and IL-6 levels (58.17 ng/mL; 10.22 ng/mL, respectively) were both numerically higher than those of control group levels (16.62 ng/mL; 5.74 ng/mL, respectively). Also, patients’ median TNF-α levels were found statistically significantly higher (p=0.034).

Conclusion:

This study showed the increase of TNF-α, IL-6 levels and for the first time the decrease of sIL-1RII in gastric cancer patients. We propose that negative regulation of gastric cancer using sIL-1RII could be a new anti-cancer strategy.

General significance:

Our study provides target pathways for further studies in the pathophysiology of gastric cancer.

Association between TNF-α rs1799964 and RAF1 rs1051208 MicroRNA binding site SNP and gastric cancer susceptibility in an Iranian population

AIM

The aim of this study was to find the relationship between rs1799964 in TNF-α gene as well as rs1051208 of RAF1 gene SNPs on GC in an Iranian population.

BACKGROUND

Gastric cancer (GC) is the second leading cause of cancer-related death worldwide after lung cancer. Tumor necrosis factor (TNF) is one of the most important factors in the pathogenesis of this cancer. Single nucleotide polymorphisms have a principle role in gene expression of TNF-α and miRNAs which may lead to gastric cancer.

METHODS

In a case-control study, we investigated the risk of GC in 198 Iranians. For this purpose, 5 mL of peripheral blood was collected in EDTA -containing tube and genomic DNA was isolated. Genotyping of SNPs was also performed by PCR-RFLP; to approve the outcome, 10% of genotyping results with RFLP were sequenced.

RESULTS

The comparison between case and control groups revealed a significant association between the rs1051208 C allele of RAF1 gene and GC (P = 0.04). We did not observe any remarkable association between TNF-α -1031 in gastric cancer patients and the healthy control group.

CONCLUSION

The results indicated that C allele in RAF1 gene plays a role in susceptibility to gastric cancer. Therefore, SNPs are among notable biomarkers for predicting susceptibility to dreadful diseases, especially cancers.

Gastric cancer and family history

Gastric cancer is associated with high morbidity and mortality rates worldwide. Identifying individuals at high risk is important for surveillance and prevention of gastric cancer. Having first-degree relatives diagnosed with gastric cancer is a strong and consistent risk factor for gastric cancer, but the pathogenic mechanisms behind this familial aggregation are unclear. Against this background, we reviewed the risk factors for gastric cancer in those with a first-degree relative with gastric cancer, and the possible causes for familial clustering of gastric cancer including bacterial factors, inherited genetic susceptibility, environmental factors or a combination thereof. Among individuals with a family history, current or past Helicobacter pylori infection, having two or more first-degree affected relatives or female gender was associated with an increased risk of developing gastric cancer. To date, no specific single nucleotide polymorphism has been shown to be associated with familial clustering of gastric cancer. H. pylori eradication is the most important strategy for preventing gastric cancer in first-degree relatives of gastric cancer patients, particularly those in their 20s and 30s. Early H. pylori eradication could prevent the progression to intestinal metaplasia and reduce the synergistic effect on gastric carcinogenesis in individuals with both H. pylori infection and a family history. Endoscopic surveillance is also expected to benefit individuals with a family history. Further large-scale, prospective studies are warranted to evaluate the cost-effectiveness and optimal time point for endoscopy in this population. Moreover, genome-wide association studies that incorporate environmental and dietary factors on a 'big data' basis will increase our understanding of the pathogenesis of gastric cancer.

The ERCC1-4533/8092, TNF-α 238/308 polymorphisms and the risk of hepatocellular carcinoma in Guangxi Zhuang populations of China: Case-control study

OBJECTIVE

To investigate the relationship between excision repair cross-complementing group 1 (ERCC1)-4533/8092, tumor necrosis factor-alpha (TNF-α)-238/308 polymorphisms, and the risk of hepatocellular carcinoma (HCC) in Guangxi Zhuang population of China.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism method was used to detect the ERCC1-4533/8092 and TNF-α-238/308 polymorphisms in 88 cases with HCC and 82 cases of normal control.

RESULTS

There were no differences in the frequency distribution of ERCC1-4533 and TNF-α-238 polymorphisms in the HCC group and the control group (P > 0.05). The genotype frequency distributions of the ERCC1-8092 and TNF-α-308 in the HCC group and the control group were different (P < 0.05). Compared with ERCC1-8092 CC genotype, ERCC1-C8092 CA/AA genotype had higher risk of HCC (CA/AA vs CC; odds ratio 3.51, 95% confidence interval 1.03-12.016). Compared with TNF-α-308 GG genotype, TNF-α-308 GA/AA genotype was significantly associated with an increased risk of HCC (GA/AA vs GG; odds ratio 3.84, 95% confidence interval 1.011-14.57).

CONCLUSION

The genetic polymorphisms of ERCC1-8092 and TNF-α-308 are associated with the risk of HCC in Guangxi Zhuang population of China.

Tumor necrosis factor-α (TNF-α)-308G/A promoter polymorphism in colorectal cancer in ethnic Kashmiri population - A case control study in a detailed perspective

Background

Inflammation constitutes one of the important components of colorectal cancer (CRC) pathogenesis. Tumor necrosis factor-α (TNF-α), a cytokine and an important inflammatory mediator plays a pivotal role in the malignant cellular proliferation, angiogenesis, tissue invasion and metastasis in CRC. The studies on association of various polymorphisms in human TNF-α gene including TNF-α-308G/A single nucleotide polymorphism (SNP) are limited, mixed and inconclusive.

Materials and methods

The aim of this study was to analyze the association of TNF-α-308G/A promoter SNP with colorectal cancer (CRC) susceptibility and development risk and also to evaluate the modifying effects of possible TNF-α-308G/A genotypes on different risk factors of CRC in ethnic population of Kashmir, India through a case–control setup. The genotype frequencies of TNF-α-308G/A promoter SNP were compared between 142 CRC patients and 184 individually matched healthy controls by using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. The associations between the TNF-α-308G/A SNP and CRC risk were examined through conditional logistic regression models adjusted for multiple possible confounding (third) variables. Further, the associations between this SNP and various clinico-pathological parameters, demographic variables and environmental factors within the case group subjects with regard to CRC risk were also evaluated.

Results

The association between the TNF-α-308G/A SNP and the modulation of risk of CRC was not found to be significant (p value = 0.156). The effect of less common TNF-α-308A allele on the risk of colorectal cancer was also not found to be significant (p value = 0.175). The variant genotype (AA) was nonexistent in the study population. Further, we found no significant effect modulation of CRC risk by wild and heterozygous TNF-α-308G/A SNP genotypes in presence of different possible risk factors (p > 0.05). We also found no significant association of TNF-α-308G/A SNP with the subsets of various characteristics of the case group subjects under study (p > 0.05).

Conclusions

This study indicates that there is no significant association between the TNF-α-308G/A promoter SNP and the risk of developing CRC in ethnic Kashmiri population. However, in order to substantiate our findings, this study needs to be replicated with bigger sample size and should involve other ethnically defined populations with high CRC risk.

Molecular alterations in gastric cancer with special reference to the early-onset subtype

Currently, gastric cancer (GC) is one of the most frequently diagnosed neoplasms, with a global burden of 723000 deaths in 2012. It is the third leading cause of cancer-related death worldwide. There are numerous possible factors that stimulate the pro-carcinogenic activity of important genes. These factors include genetic susceptibility expressed in a single-nucleotide polymorphism, various acquired mutations (chromosomal instability, microsatellite instability, somatic gene mutations, epigenetic alterations) and environmental circumstances (e.g., Helicobcter pylori infection, EBV infection, diet, and smoking). Most of the aforementioned pathways overlap, and authors agree that a clear-cut pathway for GC may not exist. Thus, the categorization of carcinogenic events is complicated. Lately, it has been claimed that research on early-onset gastric carcinoma (EOGC) and hereditary GC may contribute towards unravelling some part of the mystery of the GC molecular pattern because young patients are less exposed to environmental carcinogens and because carcinogenesis in this setting may be more dependent on genetic factors. The comparison of various aspects that differ and coexist in EOGCs and conventional GCs might enable scientists to: distinguish which features in the pathway of gastric carcinogenesis are modifiable, discover specific GC markers and identify a specific target. This review provides a summary of the data published thus far concerning the molecular characteristics of GC and highlights the outstanding features of EOGC.

Helicobacter pylori infection and gastric carcinoma: Not all the strains and patients are alike

Gastric carcinoma (GC) develops in only 1%-3% of Helicobacter pylori (H. pylori) infected people. The role in GC formation of the bacterial genotypes, gene polymorphisms and host's factors may therefore be important. The risk of GC is enhanced when individuals are infected by strains expressing the oncoprotein CagA, in particular if CagA has a high number of repeats containing the EPIYA sequence in its C'-terminal variable region or particular amino acid sequences flank the EPIYA motifs. H. pylori infection triggers an inflammatory response characterised by an increased secretion of some chemokines by immunocytes and colonised gastric epithelial cells; these molecules are especially constituted by proteins composing the interleukin-1beta (IL-1β) group and tumour necrosis factor-alpha (TNF-α). Polymorphisms in the promoter regions of genes encoding these molecules, could account for high concentrations of IL-1β and TNF-α in the gastric mucosa, which may cause hypochlorhydria and eventually GC. Inconsistent results have been attained with other haplotypes of inflammatory and anti-inflammatory cytokines. Genomic mechanisms of GC development are mainly based on chromosomal or microsatellite instability (MSI) and deregulation of signalling transduction pathways. H. pylori infection may induce DNA instability and breaks of double-strand DNA in gastric mucocytes. Different H. pylori strains seem to differently increase the risk of cancer development run by the host. Certain H. pylori genotypes (such as the cagA positive) induce high degrees of chronic inflammation and determine an increase of mutagenesis rate, oxidative-stress, mismatch repair mechanisms, down-regulation of base excision and genetic instability, as well as generation of reactive oxygen species that modulate apoptosis; these phenomena may end to trigger or concur to GC development.

Association between hepatocellular carcinoma and tumor necrosis factor alpha polymorphisms in South Korea

AIM: To investigate associations between the tumor necrosis factor alpha (TNF-α) -1031 T>C, -863 C>A, -857 C>T, -308 G>A, and -238 G>A polymorphisms and HCC in Korea.

METHODS: Hepatocellular carcinoma (HCC) cases were diagnosed at CHA Bundang Medical Center from June 1996 to August 2008. The association between TNF-α polymorphisms and HCC was analyzed in 157 HCC patients and 201 controls using a polymerase chain reaction-restriction fragment length polymorphism assay. We investigated five TNF-α polymorphisms, which are TNF-α -1031 T>C, -863 C>A, -857 C>T, -308 G>A, and -238 G>A. The TNF-α genotype frequencies, genotype combinations and haplotypes were analyzed to disclose the association with HCC.

RESULTS: None of the TNF-α polymorphisms was significantly associated with HCC. However, nine genotype combinations had associations with increased likelihood of HCC. Among them, TNF-α -1031/-857/-238 TT/CC/GA (AOR = 18.849, 95%CI: 2.203-161.246, P = 0.007), TNF-α -1031/-308/-238 TT/GG/GA (AOR = 26.956, 95%CI: 3.071-236.584, P = 0.003), and TNF-α -1031/-238 TT/GA (AOR = 21.576, 95%CI: 2.581-180.394, P = 0.005) showed marked association with HCC. There were five haplotypes of TNF-α polymorphisms which were significantly associated with HCC. They are TNF-α -1031/-863/-857/-308/-238 T-C-C-G-A (OR = 25.824, 95%CI: 1.491-447.223, P = 0.0005), TNF-α -1031/-857/-308/-238 T-C-G-A (OR = 12.059, 95%CI: 2.747-52.950, P < 0.0001), TNF-α -1031/-857/-238 T-C-A (OR = 10.696, 95%CI: 2.428-47.110, P = 0.0001), TNF-α -1031/-308/-238 T-G-A (OR = 7.556, 95%CI: 2.173-26.280, P = 0.0002) and TNF-α -1031/-238 T-A (OR = 10.865, 95%CI: 2.473-47.740, P = 0.0001). Moreover, HCC Okuda stage III cases with the TNF-α -1031 CC genotype had better survival than those with the TT genotype (AOR = 5.795, 95%CI: 1.145-29.323).

CONCLUSION: Although no single TNF-α polymorphism is associated with HCC in this study, some TNF-α genotype combinations and haplotypes are associated with HCC. In addition, HCC Okuda stage III cases with the TNF-α -1031 TT genotype may have a better prognosis than those with the CC genotype.

Polymorphisms of Tumor Necrosis Factor Alpha in Moroccan Patients with Gastric Pathology: New Single-Nucleotide Polymorphisms in TNF-α(-193) (G/A)

Polymorphisms in tumor necrosis factor alpha (TNF-α) gene are emerging as key determinants of gastric diseases. The TNF-α⁻³⁰⁸ (G/A) and TNF-α⁻²³⁸ (G/A) single-nucleotide polymorphisms SNPs are the most extensively studied. However, all these studies are conducted in Caucasian and Asian populations. Thus, for the first time in Africa, we sought to investigate whether polymorphisms in TNF-α gene were associated with the development of gastric pathology in Morocco. Two SNPs located in the promoter region (positions −308 and −238) in TNF-α gene were genotyped in 244 individuals (170 patients and 74 healthy controls). Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using logistic regression analysis. The TNF-α⁻²³⁸ (G/A) genotype was significantly associated with a high risk of gastritis and gastric cancer (GC) (P = 0.001 and P = 0.002, resp.). Furthermore, a new polymorphism located in the promoter region at position −193 in TNF-α gene was identified. The distribution of this SNP was markedly different in patients suffering from ulcers. The association between TNF-α⁻¹⁹³ (G/A) genotype and high risk of ulcer was significant (P = 0.03). These results suggest that the TNF-α⁻¹⁹³ (G/A) allele has a protective function against gastric cancer by developing ulcer.

Tumor necrosis factor, tumor necrosis factor inhibition, and cancer risk

OBJECTIVE

Tumor necrosis factor (TNF) is a highly pleiotropic cytokine with multiple activities other than its originally discovered role of tumor necrosis in rodents. TNF is now understood to play a contextual role in driving either tumor elimination or promotion. Using both animal and human data, this review examines the role of TNF in cancer development and the effect of TNF and TNF inhibitors (TNFis) on malignancy risk.

RESEARCH DESIGN

A literature review was performed using relevant search terms for TNF and malignancy.

RESULTS

Although administration of TNF can cause tumor regression in specific rodent tumor models, human expression polymorphisms suggest that TNF can be a tumor-promoting cytokine, whereas blocking the TNF pathway in a variety of tumor models inhibits tumor growth. In addition to direct effects of TNF on tumors, TNF can variously affect immunity and the tumor microenvironment. Whereas TNF can promote immune surveillance designed to eliminate tumors, it can also drive chronic inflammation, autoimmunity, angiogenesis, and other processes that promote tumor initiation, growth, and spread. Key players in TNF signaling that shape this response include NF-κB and JNK, and malignant-inflammatory cell interactions, each of which may have different responses to TNF signaling. Focusing on rheumatoid arthritis (RA) patients, where clinical experience is most extensive, a review of the clinical literature shows no increased risk of overall malignancy or solid tumors such as breast and lung cancers with exposure to TNFis. Lymphoma rates are not increased with use of TNFis. Conflicting data exist regarding the risks of melanoma and nonmelanoma skin cancer. Data regarding the risk of recurrent malignancy are limited.

CONCLUSIONS

Overall, the available data indicate that elevated TNF is a risk factor for cancer, whereas its inhibition in RA patients is not generally associated with an increased cancer risk. In particular, TNF inhibition is not associated with cancers linked to immune suppression. A better understanding of the tumor microenvironment, molecular events underlying specific tumors, and epidemiologic studies of malignancies within specific disease indications should enable more focused pharmacovigilance studies and a better understanding of the potential risks of TNFis.

The association between the polymorphisms of TNF-α and non-Hodgkin lymphoma: a meta-analysis

Many genetic variations in the promoter region of tumor necrosis factor alpha (TNF-α) may confer host susceptibility to cancer by influencing TNF-α expression. Nevertheless, the results remain inconclusive. The current meta-analysis was performed to investigate the association between three common TNF-α promoter polymorphisms and the risk of non-Hodgkin lymphoma (NHL). A literature search was conducted mainly from PubMed for all eligible studies. The pooled odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) were used to assess the association of TNF-α polymorphisms with the risk of NHL. TNF-α -308 A allele showed a statistically significant increased risk for NHL under the homozygous (AA vs. GG, OR = 1.51, 95 % CI = 1.26-1.80) and recessive (OR = 1.47, 95 % CI = 1.23-1.75) models, respectively. The stratified analyses showed an increased risk of NHL with the presence of TNF-α -308 A allele among Africans and Caucasians, but a decreased risk among Asians. No association was observed between -238 G/A polymorphism and NHL risk either in the overall analysis or in the stratified analysis. Similarly, pooled analysis did not reveal an altered risk of NHL with -857 C/T polymorphism. Nonetheless, a statistically significant association was observed among Asians when stratified by ethnicity. Among the three genetic variations of interest, TNF-α -308 G/A polymorphism was significantly associated with the risk of NHL; neither -238 G/A nor -857 C/T polymorphism was shown to alter the overall NHL risk; however, stratified analysis by ethnicity observed a statistically significant association between -857 C/T polymorphism and the risk of NHL among Asians.

Review article: the epidemiology and prevention of gastric cancer

BACKGROUND

Gastric cancer can be divided into cardia and noncardia gastric adenocarcinoma (NCGA). Non cardia gastric cancer is a disease that has declined in global incidence but has remained as an extremely lethal cancer.

AIM

To review recent advances in epidemiology and strategies in prevention of non cardia gastric cancer.

METHODS

A rapid literature search strategy was developed for all English language literature published before March 2013. The search was conducted using the electronic databases PubMed and EMBASE. The search strategy included the keywords 'stomach neoplasms', 'gastric cancer', 'epidemiology', 'risk factor', 'early detection of cancer', 'mass screening', 'cancer burden', 'prevention' and 'cost-effectiveness'. The search strategy was adjusted according to different requirements for each database. The specific search was also performed in cancer-related websites for country-specific information. The search was limited to past 10 years.

RESULTS

Gastric cancer is the fifth most common cancer but the third leading cause of cancer death. The case fatality rate is 75%. Screening by radiological or endoscopic methods has limited success in prevention of gastric cancer. Helicobacter pylori has been identified as a carcinogen, accounting for 60-70% of gastric cancer globally and eradication is a potential preventive measure. A meta-analysis in 2009 demonstrated that individuals treated with H. pylori eradication therapy can reduce gastric cancer risk. The extended Shandong Intervention trial that lasted 14.3 years showed that H. pylori eradication therapy significantly reduced gastric cancer incidence by 39%. Consensus groups from Asia, Europe and Japan have recommended H. pylori eradication as primary prevention in high-risk areas. Following eradication therapy, endoscopic surveillance of pre-malignant lesions using enhanced imaging appears to be another promising preventive strategy.

CONCLUSIONS

Gastric cancer remains a major diagnostic and therapeutic challenge. There is emerging evidence that H. pylori eradication in high gastric cancer regions can lead to a decline in the incidence of this highly lethal disease.

At the bedside: Helicobacter pylori, dysregulated host responses, DNA damage, and gastric cancer

Clinical trials performed in populations at high GC risk have demonstrated that eradication of Helicobacter pylori from the stomach with a course of combination antimicrobials helps prevent gastric carcinogenesis when they are administered before precancerous lesions have yet developed. In this review, we consider the insights into H. pylori-associated gastric carcinogenesis that have been gained from these and many other clinical studies in the field to highlight priority areas for basic research and clinical investigation. Among these are defining the magnitude of the risk reduction that may be achieved in clinical practice and at a population level by H. pylori eradication and investigating when, during the slow multistep progression to GC, intervention will be of the most benefit. Additional strategies to prevent GC induced by H. pylori, including chemoprevention, dietary modification, and close endoscopic surveillance, may also have value in augmenting the risk reduction. Why only a small subpopulation of those infected by H. pylori go on to develop GC may be partially explained by genetic susceptibility related to SNPs in several genes regulating the intensity of the gastric inflammatory response to H. pylori. Investigation of the basic mechanisms underlying the promotion of GC by H. pylori and the associated inflammatory response will likely continue to improve clinical strategies for the prevention of one of the most common causes of cancer death globally. See related review, At the Bench: H. pylori, dysregulated host responses, DNA damage, and gastric cancer.

IFRD1 polymorphisms and gastric cancer risk in a Chinese population

The association between gene polymorphisms of IFRD1 and gastric cancer is not clear. The aim of this study was to investigate the association between IFRD1 polymorphisms and gastric cancer in Chinese population. Fifty-three consecutive patients with the diagnosis of gastric cancer were defined as the case group, and another 50 healthy donors were denoted as the control group. About 4 ml of peripheral blood was collected from each donor for extracting DNA. Finally, IFRD1 rs7818, rs3807213, and rs6968084 SNPs were detected with polymerase chain reaction. C/C genotype distribution frequencies of rs6968084 and rs7817 in gastric cancer patients were similar with the controls (OR 0.192, 95 % CI 0.513-2.769, P = 0.683 and OR 2.075, 95 % CI 0.744-5.792, P = 0.16, respectively). Patients with gastric cancer had a significantly higher frequency of rs3807213 C allele and rs3807213 C/C genotype than controls. (OR 4.028, 95 % CI 1.513-10.72, P = 0.004) (OR 3.759, 95 % CI 1.521-9.294, P = 0.003). This study suggests that the SNPs of IFRD1 rs7818 and rs6968084 have nothing to do with the gastric cancer susceptibility. The allele gene C and genotype C/C of rs3807213 SNP are involved in susceptibility to gastric cancer, but there were no relations when subgroup stratified all the three SNPs according to pathological stages.

Pattern-recognition receptors and gastric cancer

Chronic inflammation has been associated with an increased risk of several human malignancies, a classic example being gastric adenocarcinoma (GC). Development of GC is known to result from infection of the gastric mucosa by Helicobacter pylori, which initially induces acute inflammation and, in a subset of patients, progresses over time to chronic inflammation, gastric atrophy, intestinal metaplasia, dysplasia, and finally intestinal-type GC. Germ-line encoded receptors known as pattern-recognition receptors (PRRs) are critical for generating mature pro-inflammatory cytokines that are crucial for both Th1 and Th2 responses. Given that H. pylori is initially targeted by PRRs, it is conceivable that dysfunction within genes of this arm of the immune system could modulate the host response against H. pylori infection, and subsequently influence the emergence of GC. Current evidence suggests that Toll-like receptors (TLRs) (TLR2, TLR3, TLR4, TLR5, and TLR9), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) (NOD1, NOD2, and NLRP3), a C-type lectin receptor (DC-SIGN), and retinoic acid-inducible gene (RIG)-I-like receptors (RIG-I and MDA-5), are involved in both the recognition of H. pylori and gastric carcinogenesis. In addition, polymorphisms in genes involved in the TLR (TLR1, TLR2, TLR4, TLR5, TLR9, and CD14) and NLR (NOD1, NOD2, NLRP3, NLRP12, NLRX1, CASP1, ASC, and CARD8) signaling pathways have been shown to modulate the risk of H. pylori infection, gastric precancerous lesions, and/or GC. Further, the modulation of PRRs has been suggested to suppress H. pylori-induced inflammation and enhance GC cell apoptosis, highlighting their potential relevance in GC therapeutics. In this review, we present current advances in our understanding of the role of the TLR and NLR signaling pathways in the pathogenesis of GC, address the involvement of other recently identified PRRs in GC, and discuss the potential implications of PRRs in GC immunotherapy.

Genetic susceptibility and gastric cancer risk: the importance of meta-analyses as a statistical tool

Gastric cancer (GC) is a complex disease and a worldwide health burden due to its high prevalence and poor prognosis. A deeper knowledge of the factors involved in the development and progression of GC could help to identify subpopulations at risk that therefore require surveillance or early treatment strategies. Current research is based on the study of genetic variants that confer a higher risk of GC and their interactions with environmental exposure. Recently, meta-analysis has emerged as an important statistical method involving pooling of data from individual association studies to increase statistical power and obtain more conclusive results. Given the importance of chronic inflammation in the process of gastric carcinogenesis, the present article reviews the most recent meta-analyses of the contribution of cytokine gene polymorphisms to GC risk.

Tumor necrosis factor-a polymorphisms and colorectal cancer risk: a meta-analysis

BACKGROUND AND OBJECTIVES

Tumor necrosis factor-alpha (TNF-a) was related to inflammation and involved in the development of colorectal cancer. Polymorphisms located in TNF-a promoter region, such as 308G/A and 238G/A, could affect the risk of various types of cancer by regulating TNF-a production. In this study, a meta-analysis was performed to investigate the association between common polymorphisms of TNF-a promoter region and colorectal cancer susceptibility.

METHODS

Searching of several databases was performed for all publications on the association between TNF-a polymorphisms and colorectal cancer. Summary odds ratios (ORs) with their 95% confidence intervals (95% CIs) were calculated using random-effects models. Stratified analyses based on ethnicity and control population source were also conducted.

RESULTS

Overall, TNF-a 308A polymorphism showed a significant association with increased risk of colorectal cancer in worldwide populations under homozygote comparison [AA vs. GG, OR (95% CI) = 1.46 (1.07-1.97)] other than heterozygote comparison [AG vs. GG, OR (95% CI) = 1.05 (0.93-1.19)]. TNF-a 238A was not associated with colorectal cancer risk under homozygote or heterozygote comparisons. In stratified analysis, significant association was observed only in Western populations [AA vs. GG, OR (95% CI) = 1.39 (1.01-1.91)] other than in Eastern populations under homozygote comparison. No significant difference was observed between population-based subgroup and hospital-based subgroup.

CONCLUSIONS

TNF-a 308A was moderately associated with an increased risk of colorectal cancer in Western populations, and TNF-a 238A polymorphism was not significantly associated with colorectal cancer risk.

The role of inflammation in gastric cancer

Gastric cancer, despite its declining incidence rate, is still the second cause of cancer-related death worldwide, killing 750,000 people each year and remaining the second common type of cancer. The best examples of inflammation-associated cancer in human beings may be gastric cancer. Understanding the molecular mechanism of the inflammation in gastric carcinogenesis is important for developing new strategies against gastric cancer.

Population differences concerning TNF-α gene polymorphisms in gastric carcinogenesis based on meta-analysis

BACKGROUND

Recent meta-analyses have studied population differences concerning interleukin (IL)-1 gene polymorphisms in gastric carcinogenesis. In addition to the IL-1 gene cluster, candidate genes include those encoding the pro-inflammatory cytokine tumor necrosis factor (TNF)-α. The aim of the study was to systematically review the role of TNF-α-238 and TNF-α-308 gene polymorphisms (genotypes G/G, G/A, A/A) in gastric carcinogenesis by meta-analyzing all relevant studies to look for any differences concerning TNF-α gene polymorphisms in gastric carcinogenesis.

METHODS

Extensive English language medical literature searches for human studies were performed up to the end of May 2013, using suitable keywords. Pooled estimates [odds ratio (OR) with 95% confidence intervals (CI)] were obtained using the random-effects model. Heterogeneity between studies was evaluated with the Cochran Q test whereas the likelihood of publication bias was assessed by constructing funnel plots. Their symmetry was estimated by the adjusted rank correlation test.

RESULTS

In seventeen studies, from various countries, the TNF-α-308 and TNF-α-238 frequencies of genotypes G/G, G/A, A/A were examined in gastric cancer patients and controls. For TNF-α-308 frequency overall, the pooled ORs with 95%CI for genotype G/G, A/A and G/A were 0.837 (0.712-0.982), 1.430 (1.064-1.923) and 1.145 (0.973-1.348) with respective P values 0.029, 0.018 and 0.104. Subgroup analyses showed significant results for genotype G/G only in Asians [OR=0.774 (0.610-0.983), P=0.036].

CONCLUSION

In this meta-analysis there was an overall statistically significant increased cancer risk associated with TNF-α-308 G/G and A/A genotypes. Subgroup analyses showed significant results for genotype G/G in Asians, whereas no such significant results were found for Caucasians and Hispanics.

Biomarkers of Helicobacter pylori-associated gastric cancer

Helicobacter pylori-associated gastric cancer is a major cause of morbidity and mortality worldwide, and is predicted to become even more common in developing countries as the population ages. Since gastric cancer develops slowly over years to decades, and typically progresses though a series of well-defined histologic stages, cancer biomarkers have potential to identify asymptomatic individuals in whom surgery might be curative, or even those for whom antibiotics to eradicate H. pylori could prevent neoplastic transformation. Here we describe some of the challenges of biomarker discovery, summarize current approaches to biomarkers of gastric cancer, and explore some recent novel strategies.

Tumor necrosis factor-α 238 G/A polymorphism and gastric cancer risk: a meta-analysis

Though many studies were performed to assess the association between tumor necrosis factor-α (TNF-α) 238 G/A polymorphism and gastric cancer risk, there were no conclusive findings. A meta-analysis of previous published studies was performed to get a comprehensive assessment of the association between TNF-α 238 G/A polymorphisms and gastric cancer. The pooled odds ratios (ORs) and 95% confidence intervals (95 % CIs) were calculated to assess the association. Fifteen studies with a total of 7,795 participants were finally included into this meta-analysis. Overall, there was an obvious association between TNF-α 238 G/A polymorphism and increased risk of gastric cancer (A vs. G: OR = 1.32, 95% CI 1.02-1.72, P = 0.036; GA vs. GG: OR = 1.32, 95% CI 1.01-1.72, P = 0.042; and AA/GA vs. GG: OR = 1.34, 95% CI 1.02-1.76, P = 0.036). Subgroup analysis by ethnicity showed the statistically significant association between TNF-α 238 G/A polymorphism and gastric cancer was limited to Asian populations (A vs. G: OR = 1.59, 95% CI 1.29-1.97, P < 0.001; GA vs. GG: OR = 1.63, 95% CI 1.29-2.04, P < 0.001; and AA/GA vs. GG: OR = 1.64, 95%CI 1.31-2.05, P < 0.001), and there was no obvious association in Caucasians. In conclusion, TNF-α 238 G/A polymorphism is significantly associated with increased risk of gastric cancer, especially in Asians.

TNF-α gene promoter polymorphisms and risk of venous thromboembolism in gastrointestinal cancer patients undergoing chemotherapy

BACKGROUND

TNF-α has been proposed as a predictive factor for venous thromboembolism (VTE). Genetic polymorphisms could regulate TNF-α production. However, the relationship between TNFA gene variants and VTE is not clarified. This study aims to investigate the predictive role of five different TNFA gene promoter SNPs, or their haplotype combination(s), for a first VTE episode in gastrointestinal cancer out-patients treated with chemotherapy.

PATIENTS AND METHODS

Serum TNF-α levels and TNFA -863C/A, -857C/T, -376G/A, -308G/A and -238G/A gene promoter polymorphisms were retrospectively evaluated in 314 subjects, including 157 controls and 157 Caucasian patients with histologically diagnosed GI cancers beginning chemotherapy delivery (5-fluorouracil either as monotherapy or in combination with platinum compounds or irinotecan).

RESULTS

Haplotype analysis showed that a five-loci haplotype (CTGGG haplotype) has higher frequency in GI cancer patients who developed VTE (n = 15) during chemotherapy [odds ratio = 2.7, 95% confidence interval (CI) 1.04-7.11, P = 0.04]. GI patients who remained VTE-free did not differ in CTGGG haplotype frequency from controls. No association was observed between serum TNF-α levels and TNFA haplotype, but both were independent predictors of VTE. Approximately 20% of GI cancer patients carrying the CTGGG haplotype developed VTE compared with 4% of the remaining 101 patients (hazard ratio = 5.6, 95% CI 1.8-17.6, P = 0.003).

CONCLUSION

These results suggest that TNFA might represent a candidate gene contributing to VTE pathogenesis in GI cancer patients and suggest that VTE risk during chemotherapy might be genetically identified. Validation studies are needed for translation into clinical practice.

Association between tumor necrosis factor-alpha 857C/T polymorphism and gastric cancer: a meta-analysis

Tumor necrosis factor-alpha (TNF-α) is an inflammatory cytokine which may play an important role on the immune response may control the progression of gastric cancer. Previous studies on the association between TNF-α 857C/T polymorphism and gastric cancer risk reported conflicting results. We performed a meta-analysis to comprehensively assess the association between TNF-α 857C/T polymorphism and gastric cancer risk. Literature search was performed for all publications on the association between TNF-α 857C/T polymorphism and gastric cancer risk through March 6, 2013. The pooled odds ratios (ORs) with their 95% confidence interval (95%CIs) were calculated to assess the association between TNF-α 857C/T polymorphism and gastric cancer risk. Nine individual case-control studies with a total of 5,054 subjects (1,835 cases and 3,219 controls) were finally included into the meta-analysis. Meta-analysis of total nine studies showed that TNF-α 857C/T polymorphism was significantly associated with increased risk of gastric cancer under four genetic models (for T vs. C: OR = 1.19, 95%CI 1.07-1.33, P = 0.002; for TT vs. CC: OR = 1.44, 95%CI 1.03-2.02, P = 0.032; for CT vs. CC: OR = 1.19, 95%CI 1.05-1.36, P = 0.008; and for TT/CT vs. CC: OR = 1.21, 95%CI 1.07-1.38, P = 0.003). Subgroup analysis by ethnicity further showed that there was a significant association between TNF-α 857C/T polymorphism and increased risk of gastric cancer in Asians but not in Caucasians. The meta-analysis suggests that TNF-α 857C/T polymorphism is significantly associated with increased risk of gastric cancer, especially in Asians.

A systemic assessment of the association between tumor necrosis factor alpha 308 G/A polymorphism and risk of cervical cancer

Tumor necrosis factor alpha (TNF-α) is a multifunctional cytokine which plays an important role in the human immune response against various pathogens, and there may be a relationship between TNF-α 308 G/A polymorphism and cervical cancer risk. We performed a meta-analysis to get a systemic assessment of the association between TNF-α 308 G/A polymorphism and cervical cancer risk. Electronic searches of PubMed, Embase, and Web of Science were performed for all publications on the association between TNF-α 308 G/A polymorphism and cervical cancer risk through October 26, 2012. The pooled odds ratios (ORs) with their 95 % confidence interval (95 % CIs) were calculated to assess the association. Fifteen studies with a total of 3,743 cervical cancer cases and 4,096 controls were finally included into the meta-analysis. Overall, TNF-α 308 G/A polymorphism was significantly associated with increased risk of cervical cancer under three main genetic comparison models (A vs. G, OR 1.20, 95 % CI 1.02-1.42, P=0.03; AA vs. GG, OR 1.31, 95 % CI 1.00-1.72, P=0.048; AA vs. GG/GA, OR 1.30, 95 % CI 1.00-1.71, P=0.05). Subgroup analysis by ethnicity further showed that there was a significant association between TNF-α 308 G/A polymorphism and increased risk of cervical cancer in Asians (AA vs. GG, OR 1.83, 95 % CI 1.05-3.20, P=0.034; AA vs. GG/GA, OR 1.84, 95 % CI 1.05-3.22, P=0.032). The meta-analysis suggests that TNF-α 308 G/A polymorphism is associated with increased risk of cervical cancer, and TNF-α 308 G/A mutant allele A is a risk factor of cervical cancer.

Risk factors for gastric cancer in Latin America: a meta-analysis

BACKGROUND

Latin America has among the highest gastric cancer incidence rates in the world, for reasons that are still unknown. In order to identify region-specific risk factors for gastric cancer, we conducted a meta-analysis summarizing published literature.

METHODS

Searches of PubMed and regional databases for relevant studies published up to December 2011 yielded a total of 29 independent case-control studies. We calculated summary odds ratios (OR) for risk factors reported in at least five studies, including socioeconomic status (education), lifestyle habits (smoking and alcohol use), dietary factors (consumption of fruits, total vegetables, green vegetables, chili pepper, total meat, processed meat, red meat, fish, and salt), and host genetic variants (IL1B-511T, IL1B-31C, IL1RN*2, TNFA-308A, TP53 codon 72 Arg, and GSTM1 null). Study-specific ORs were extracted and summarized using random-effects models.

RESULTS

Chili pepper was the only region-specific factor reported in at least five studies. Consistent with multifactorial pathogenesis, smoking, alcohol use, high consumption of red meat or processed meat, excessive salt intake, and carriage of IL1RN*2 were each associated with a moderate increase in gastric cancer risk. Conversely, higher levels of education, fruit consumption, and total vegetable consumption were each associated with a moderately decreased risk. The other exposures were not significantly associated. No prospective study data were identified.

CONCLUSION

Risk factor associations for gastric cancer in Latin America are based on case-control comparisons that have uncertain reliability, particularly with regard to diet; the specific factors identified and their magnitudes of association are largely similar to those globally recognized. Future studies should emphasize prospective data collection and focus on region-specific exposures that may explain high gastric cancer risk.

Functional promoter -308G>A variant in tumor necrosis factor α gene is associated with risk and progression of gastric cancer in a Chinese population

BACKGROUND

Tumor necrosis factor-α (TNF-α) plays a crucial role in the development and progression of gastric cancer. A functional polymorphism, -308 G>A (rs1800629), which is located in the promoter of TNFA gene, has been suggested to alter the production of TNF-α and influence cancer risk. In the present study, we sought to investigate whether this polymorphism has effects on the risk and progression of gastric cancer in a Chinese population.

METHODS

We genotyped the TNFA -308 G>A polymorphism using the TaqMan method in a two-stage case-control study comprising a total of 1686 gastric cancer patients and 1895 cancer-free subjects. The logistic regression was used to assess the genetic associations with occurrence and progression of gastric cancer.

RESULTS

We found a significant association between the variant genotypes and increased risk of gastric cancer [P = 0.034, odds ratio (OR) = 1.39, 95% confidence interval (CI) = 1.01-1.67, GA/AA vs. GG]. Similar results were observed in the follow-up replication study. When combined the data from the two studies, we found a more significant association (P = 0.001, OR = 1.34, 95%CI = 1.13-1.59), especially for older subjects (>65 years). Furthermore, the patients carrying the variant genotypes had a significantly greater prevalence of T4 stage of disease (P = 0.001, OR = 2.19, 95%CI = 1.39-3.47) and distant metastasis (P = 0.013, OR = 1.61, 95%CI = 1.10-2.35).

CONCLUSIONS

Our results suggest that the functional promoter -308 G>A polymorphism in TNFA influence the susceptibility and progression of gastric cancer in the Chinese population.

Genetics of inflammation in the gastrointestinal tract and how it can cause cancer

Genetic epidemiology is an important discipline that is helping to unravel the aetiology and pathogenesis of complex human diseases. In the context of gastrointestinal malignancy, the paradigm model of host genetic influence on disease outcome is H. pylori-associated gastric adenocarcinoma. This cancer represents a classic example of an inflammation-induced malignancy and highlights the importance of host genetics in disease development. This chapter gives an insight into how genetic epidemiology can play an important role in the development of gastric cancer. Increasing our understanding of host genetics in cancer development may allow particularly susceptible individuals to be targeted for screening or treatment to reduce risk of future malignant transformation.

Detouring the Undesired Route of Helicobacter pylori-Induced Gastric Carcinogenesis

Epidemiological and experimental evidence has emerged that a dysregulated inflammation is associated with most of the tumors, and many studies have begun to unravel the molecular pathways linking inflammation and cancer. As a typical example linking these associations, Helicobacter pylori (H. pylori) infection-associated atrophic gastritis has been recognized as precursor lesion of gastric cancer. The identification of transcription factors such as NF-κB and STAT3, and their gene products such as IL-8, COX-2, iNOS, cytokines, chemokines and their receptors, etc have laid the molecular foundation for our understanding of the decisive role of inflammation in carcinogenesis. In addition to the role as the initiator of cancer, inflammation contributes to survival and proliferation of malignant cells, tumor angiogenesis, and even metastasis. In this review, the fundamental mechanisms of H. pylori-induced carcinogenesis as well as the possibility of cancer prevention through suppressing H. pylori-induced inflammation are introduced. We infer that targeting inflammatory pathways have a potential role to detour the unpleasant journey to H. pylori-associated gastric carcinogenesis.

Survival of metastatic gastric cancer: Significance of age, sex and race/ethnicity

BACKGROUND

Despite the success of modern chemotherapy in the treatment of large bowel cancers, patients with metastatic gastric cancer continue to have a dismal outcome. Identifying predictive and prognostic markers is an important step to improving current treatment approaches and extending survival.

METHODS

Extracting data from the US NCI's Surveillance, Epidemiology, and End Results (SEER) registries, we compared overall survival for patients with metastatic gastric cancer by gender, age, and ethnicity using Cox proportional hazards models. 13,840 patients (≥ 18 years) were identified from 1988-2004. Males and females were categorized by age grouping and ethnicity.

RESULTS

19% of Hispanic patients were diagnosed < 45 years of age as compared to 5.5% of Caucasians. Caucasian patients and men were more likely to be diagnosed with tumors in the gastric cardia (P<0.001). In our survival analysis, we found that women had a lower risk of dying as compared to men (P<0.001). Overall survival diminished with age (P<0.001). The median overall survival was 6 months in patients of ≤ 44 years old as compared to 3 months in patients 75 years and older. Gender differences in overall survival significantly varied by race and tumor grade/differentiation (P for interaction = 0.003 and 0.005, respectively).

CONCLUSION

This is the largest study of metastatic gastric cancer patients from the SEER registry to show that age, gender, and tumor location are significant independent prognostic factors for overall survival in patients with metastatic gastric cancer.

Tumour necrosis factor alpha -308G/A polymorphism and risk of the four most frequent cancers: a meta-analysis

The latest data show that breast, prostate, lung and colorectal cancer are the four most frequent cancers in both sexes worldwide. A number of molecular epidemiological studies have been conducted to examine the association between TNF alpha -308G/A and the risk of those cancers. However the results have been inconclusive or inconsistent. We then performed a meta-analysis to derive a precise estimation of this association. We carried out a comprehensive search in Medline, EMBASE, OVID and Chinese Biomedical Literature Database for studies using related keywords. The inclusion criteria were (i) in English or Chinese; (ii) case-control study on this association; (iii) provide usable genotype frequencies; and (iv) sufficient published data for estimating an odds ratio (OR) with 95% confidence interval (CI). ORs and 95% CIs were calculated to assess the strength of this association under homozygote comparison (AA vs GG), heterozygote comparison (GA vs GG), dominant (AA/GA vs GG) and recessive (AA vs GA/GG) genetic model comparison. Thirty case-control studies with a total number of 16,507 cases and 19,749 controls were selected for analysis. Overall, no significant association was found between this polymorphism and the risk of total four cancers (GA vs GG: OR=1.02, 95% CI=0.91-1.14, P=0.78). However, there was a significant association between this polymorphism and breast cancer risk in western populations (GA vs GG: OR=0.91, 95% CI=0.85-0.96, P=0.002). This meta-analysis also revealed that this polymorphism was not associated with susceptibility to the other three cancers.

Prevalence, pathophysiology, screening and management of osteoporosis in gastric cancer patients

Osteoporosis in gastric cancer patients is often overlooked or even neglected despite its high prevalence in these patients. Considering that old age, malnutrition, chronic disease, chemotherapy, decreased body mass index and gastrectomy are independent risk factors for osteoporosis, it is reasonable that the prevalence of osteoporosis in gastric cancer patients would be high. Many surviving patients suffer from back pain and pathological fractures, which are related to osteoporosis. Fractures have obvious associated morbidities, negative impact on quality of life, and impose both direct and indirect costs. In the era of a >55.6% 5-year survival rate of gastric cancer and increased longevity in gastric cancer patients, it is very important to eliminate common sequelae such as osteoporosis. Fortunately, the diagnosis of osteoporosis is well established and many therapeutic agents have been shown to be effective and safe not only in postmenopausal females but also in elderly males. Recently, effective treatments of gastric cancer patients with osteoporosis using bisphosphonates, which are commonly used in postmenopausal woman, were reported.

Tumor necrosis factor alpha 308 G/A polymorphism and hepatocellular carcinoma risk in a Chinese population

BACKGROUND

The genetic basis of susceptibility to hepatocellular carcinoma (HCC) is poorly understood. Tumor necrosis factor alpha (TNF-α) is a cytokine that may act as an endogenous tumor promoter. The association between TNF-α 308 G/A polymorphism and HCC risk remains unclear.

AIM

The aim of this study was to investigate the association between TNF-α 308 G/A polymorphism and HCC risk in a Chinese population.

METHODS

The study population consisted of 88 patients with documented HCC and 88 healthy controls. The gene polymorphism of TNF-α was analyzed by polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

HCC patients had a significantly lower frequency GG (odds ratio=0.36; 95% confidence interval=0.13, 0.94; p=0.04) and G allele (odds ratio=0.58; 95% confidence interval=0.37, 0.90; p=0.01) than healthy controls. When stratifying for tumor size and cirrhosis, no statistically significant results were found.

CONCLUSION

This study suggested that TNF-α -308GG and G allele were associated with a modest decrease in the risk of HCC in Chinese population.