Association of a tgf-b1-509c/t polymorphism with gastric cancer risk: a meta-analysis

The Influence of Family History on Stage and Survival of Gastric Cancer According to the <i>TGFB1</i> C-509T Polymorphism in Korea

Background/Aims

The survival rate of gastric cancer (GC) is known to be higher in patients with a family history (FH) of GC. There is an association between a polymorphism in the transforming growth factor-β1 (TGFB1) gene and the risk of GC in patients with first-degree relatives with GC. This study was performed to investigate whether a FH affects GC outcomes according to the TGFB1 C-509T polymorphism.

Methods

TGFB1 was genotyped by the polymerase chain reaction-restriction fragment length polymorphism method in 1,143 GC patients, including 216 patients (18.9%) with first-degree relatives with GC.

Results

The proportion of stage I–II GCs was significantly higher in patients with a FH than in those without a FH of GC (83.8 vs 74.9%, p=0.005). The association between a FH of GC and stage I–II GC was not significant in subgroups divided based on the TGFB1 C-509T polymorphism and sex. A FH did not affect the overall survival rate of GC in patient with all stages and each stage. The overall survival rates were not significantly different between patients with the CC and CT/TT genotypes of the TGFB1-509 polymorphism.

Conclusions

Patient with a FH of GC had lower cancer stage (I–II) at diagnosis than those without a FH of GC, but there was no significant difference in overall survival between the patients with and without a FH of GC. A FH did not influence the tumor stage or overall survival in patients stratified by the presence of the TGFB1 C-509T polymorphism.

Single nucleotide polymorphism of transforming growth factor-β1 and interleukin-6 as risk factors for ovarian cancer

INTRODUCTION

We investigated the association between common variants in TGF-β1, IL-6 and the risk of ovarian cancer (OC) in Tunisian patients and control women.

MATERIAL METHODS AND RESULTS

Study subjects comprised 71 OC cases and 74 control women. Genotyping of TGF-β1 and IL-6 SNPs was done by real-time PCR. No differences were noted in the minor allele frequencies of the three TGF-β1 SNPs between OC patients and controls. However, marked differences in the distribution of TGF-β1 rs1800469 genotypes were seen between OC cases and controls (p < 0.001), with TGF-β1 rs1800469 heterozygous (C/T) genotype being negatively associated with OC (OR [95% CI] = 0.24 [0.15-0.58]). The allelic and genotypic distributions at IL-6 polymorphisms showed a positive association between minor allele (G) at IL-6 rs1880242 variant (p = 0.0275; R [95% CI] = 1.88 [1.03-3.46]) and the occurrence of OC. In fact, the presence of T allele [G/T + T/T] decrease the risk of OC (p = 0.021; OR [95% CI] = 0.38 [0.17-0.88]). In addition, the Haploview analysis demonstrated high linkage disequilibrium (LD) between IL-6 SNPs and eight-locus haplotype analysis identified that GGAGGGGA and GGAGGGTA haplotypes are positively associated with OC risk. A negative association was shown between IL-6 haplotype (TGGGCCTA) and OC occurrence.

CONCLUSIONS

Our results suggest that TGF-β1 rs1800469, IL-6 rs1880242 variants and IL-6 haplotype (TGGGCCTA) have protective roles of OC risk. IL-6 haplotypes (GGAGGGGA and GGAGGGTA) increase OC susceptibility among Tunisian women.

TGFβ C-509T, TGFβ T869C, XRCC1 Arg194Trp, IKBα C642T, IL4 C-590T Genetic polymorphisms combined with socio-economic, lifestyle, diet factors and gastric cancer risk: A case control study in South Indian population

BACKGROUND

Gastric cancer is worldwide the third major cause of cancer related death. Risk factors for gastric cancer includes Helicobacter pylori infection, gastric ulcer, less hygienic condition, use of tobacco, alcohol consumption, use of salted, smoked food, genetic alterations etc. In order to identify the risk factors associated with gastric cancer in South Indian population a case-control study involving 200 proven gastric cancer cases and 400 controls was conducted.

METHODS

A structured questionnaire was used to interview all the subjects who participated in our study. Genotyping assay was performed using Taqman allelic discrimination assay for 5 Single Nucleotide Polymorphisms (SNPs)-TGFβ C-509T, TGFβ T869C, XRCC1 Arg194Trp, IkBα C642T and IL4C-590T.

RESULTS

Odds Ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression. Statistical analysis on socio-economic factors, lifestyle factors had showed that subjects from low socio economic status, use of tobacco and consumption of non-vegetarian food had increased risk of developing gastric cancer. Multi-factorial analysis for the SNPs adjusting for the risk factors obtained in this study showed that TGFΒ C-509T TT genotypes had four fold increased risk of gastric cancer (OR = 4.11, CI = 1.02-16.56) and TGFβ T869C CC genotype had a decreased risk of gastric cancer (OR = 0.21, CI = 0.05-0.85).

CONCLUSION

Economic status, tobacco use and food habits play a significant role in gastric cancer development. TT genotype for TGFβ C-509T had an increased risk and CC genotype for TGFβ T869C had a decreased risk of gastric cancer in south Indian population after adjusting for socio-economic factors and lifestyle factors.

Familial Clustering of Gastric Cancer: A Retrospective Study Based on the Number of First-Degree Relatives

This comprehensive cross-sectional study aimed to identify factors contributing to familial aggregation of gastric cancer (GC). A total of 1058 GC patients and 1268 controls were analyzed separately according to the presence or absence of a first-degree relative of GC (GC-relative). Logistic regression analysis adjusted for age, gender, residence during childhood, smoking, alcohol intake, monthly income, spicy food ingestion, Helicobacter pylori status and host cytokine polymorphisms was performed. Cytotoxin-associated gene A (cagA) positivity was a distinctive risk factor for GC in the family history (FH)-positive group (odds ratio [OR], 2.39; 95% confidence interval [CI], 1.42-4.00), while current/ex-smoker, moderate to strong spicy food ingestion, and non-B blood types were more closely associated with GC in the FH-negative group. Among the FH-positive group, alcohol consumption showed a synergistic carcinogenic effect in the at least 2 GC-relatives group compared to the 1 GC-relative group (1.71 vs. 9.58, P for interaction = 0.026), and this was dose-dependent. In the subjects with ≥2 GC-relatives, TGFB1-509T/T was a risk factor for GC (OR 23.74; 95% CI 1.37-410.91), as were rural residency in childhood, alcohol consumption, spicy food ingestion, and cagA positivity. These results suggest that subjects with FH may be a heterogeneous group in terms of gastric cancer susceptibility. Especially, subjects with ≥2 GC-relatives should undergo risk stratification including TGFB1-509T/T and alcohol consumption.

Association Between IL-4 and IL-6 Expression Variants and Gastric Cancer Among Portuguese Population

Introduction

Multiple studies have reported strong associations between Helicobacter pylori (Hp) inflammation and gastric cancer (GC) development. Altered expressions of pro/anti-inflammatory cytokines have a crucial role in Hp and GC proliferation. Although there are many studies related to cytokines polymorphisms involvement in GC risk, the role of Interleukin-4 (IL-4) and Interleukin-6 (IL-6) in gastric inflammation process is not yet clarified.

Aim

This study aimed to investigate the impact of common IL-4 and IL-6 polymorphisms in GC development risk among Portuguese population.

Methods

A total of 100 GC biopsies (50 with intestinal type, IGC, 50 with diffuse type, DGC) and 50 chronic gastritis cases, used as control group, were included in this case-control study. IL-4 and IL-6 common polymorphisms were genotyped by PCR-SSP, using commercially available kits.

Results

IL-4 low producer genotypes, IL-4-590TT (OR = 6.7; 95% CI 1.4–32.4) and IL-4-1098GG (OR = 4.4; 95% CI 1.7–16.9) were found associated with IGC and DGC, respectively. We also verified that IL-4 TTT haplotype was linked with both IGC (OR = 5.8; 95% CI 2.3–14.4) and DGC (OR = 2.3; 95% CI 1.0–5.5) groups. Concerning IL-6 results, IL-6-174CG genotype showed a higher prevalence among IGC cases (OR = 7.3; 95% CI 2.7–20.3), and IL-6-174CC (OR = 3.8; 95% CI 1.7–8.7) showed upper prevalence within DGC subjects. Finally, IL-6-174/nt565CG haplotype showed a significant association with both IGC (OR = 7.3; 95% CI 2.7–20.3) and DGC (OR = 7.9; 95% CI 4.2–14.9).

Conclusion

IL-6 and IL-4 expression variants seem to have an important role in GC risk mechanisms. This study provides preliminary evidence that IL-4 and IL-6 polymorphisms, although not directly linked to the disease, may be useful tools in the study of this multifactorial disease.

Influence of TGFB1 C-509T polymorphism on gastric cancer risk associated with TGF-β1 expression in the gastric mucosa

BACKGROUND

Transforming growth factor-β1 (TGF-β1) has dual roles inhibiting and promoting carcinogenesis. Although many researchers have conducted association studies between TGFB1 C-509T polymorphism and the risk of developing gastric cancer, the results are not uniform.

METHODS

We genotyped 1028 gastric cancer patients and 958 controls by the polymerase chain reaction-restriction fragment length polymorphism method. Immunohistochemistry was performed to assess the expression of TGF-β1 in the cancer and noncancerous tissues of 120 gastric cancer patients. mRNA expression was also measured in noncancerous gastric mucosa by qRT-PCR in the 282 subjects.

RESULTS

The CT genotype in the TGFB1 C-509T polymorphism was associated with an increased risk of gastric cancer development (adjusted OR 1.35, 95 % CI 1.07-1.71, P = 0.013), especially for intestinal-type cancer (adjusted OR 1.43, 95 % CI 1.08-1.90, P = 0.014). More frequent TGF-β1 expression was found in the center of cancer tissue in the TGFB1-509T carrier group than in the others (90.5 % vs. 72.2 %, P = 0.010). T-carriers also presented higher expression level of gastric TGF-β1 mRNA than non T-carriers (median 1.29 vs. 0.80, P = 0.004) when they were infected by H. pylori. Cancer patients showed elevated gastric TGFB1gene expression compared to the control group (median 1.22 vs. 0.89, P = 0.009).

CONCLUSIONS

The carcinogenic effect of TGF-β1 might be associated with increased gastric TGF-β1 expression in subjects with the T allele of TGFB1-509.

Association of transforming growth factor-β1 T869C, G915C, and C509T gene polymorphisms with rheumatoid arthritis risk

The association of transforming growth factor-β1 (TGFβ1) is an important signaling pathway factor involving extracellular matrix regulation, and its gene polymorphisms with the risk of rheumatoid arthritis (RA) is currently still fiercely debated. Therefore, this meta-analysis was performed to determine if TGFβ1 T869C, G915C, and C509T gene polymorphisms correlate with the risk of developing RA. Association reports were identified from PubMed, Cochrane Library and CBM-disc (China Biological Medicine Database) on 1 May 2013, and eligible studies were recruited and synthesized to identifying patterns among study results. T869C TT genotype in the overall population was associated with increased RA risk (OR = 1.28, 95% CI: 1.02-1.60, p = 0.03). In the sub-group analysis, T869C TT genotype was shown to be a risk factor for RA, and T869C C allele or CC genotype a protective factor against RA disease in Asians, but these associations were not found in Caucasians. Furthermore, TGFβ1 C509T TT genotype was distinctly associated with RA susceptibility, but the T allele and CC genotype were not. TGFβ1 G915C gene polymorphism was not associated with RA susceptibility. In conclusion, the TT genotype of TGFβ1 T869C was associated with RA risk in the overall population and Asians. Furthermore, CC genotype or C allele was determined to be protective factors with respect to the RA risk in the overall population and Asians. Nonetheless, additional studies are required to firmly establish a correlation between the aforementioned polymorphisms and RA risk.

GPA: a statistical approach to prioritizing GWAS results by integrating pleiotropy and annotation

Results from Genome-Wide Association Studies (GWAS) have shown that complex diseases are often affected by many genetic variants with small or moderate effects. Identifications of these risk variants remain a very challenging problem. There is a need to develop more powerful statistical methods to leverage available information to improve upon traditional approaches that focus on a single GWAS dataset without incorporating additional data. In this paper, we propose a novel statistical approach, GPA (Genetic analysis incorporating Pleiotropy and Annotation), to increase statistical power to identify risk variants through joint analysis of multiple GWAS data sets and annotation information because: (1) accumulating evidence suggests that different complex diseases share common risk bases, i.e., pleiotropy; and (2) functionally annotated variants have been consistently demonstrated to be enriched among GWAS hits. GPA can integrate multiple GWAS datasets and functional annotations to seek association signals, and it can also perform hypothesis testing to test the presence of pleiotropy and enrichment of functional annotation. Statistical inference of the model parameters and SNP ranking is achieved through an EM algorithm that can handle genome-wide markers efficiently. When we applied GPA to jointly analyze five psychiatric disorders with annotation information, not only did GPA identify many weak signals missed by the traditional single phenotype analysis, but it also revealed relationships in the genetic architecture of these disorders. Using our hypothesis testing framework, statistically significant pleiotropic effects were detected among these psychiatric disorders, and the markers annotated in the central nervous system genes and eQTLs from the Genotype-Tissue Expression (GTEx) database were significantly enriched. We also applied GPA to a bladder cancer GWAS data set with the ENCODE DNase-seq data from 125 cell lines. GPA was able to detect cell lines that are biologically more relevant to bladder cancer. The R implementation of GPA is currently available at http://dongjunchung.github.io/GPA/.

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.

Gastric cancer susceptibility genes

Genetic susceptibility results from genetic factors or some genetic defects, and endows the offspring with some physiological and metabolic features prone to certain diseases. At present, gastric cancer susceptibility genes have become a hot research topic in China, and the identification and characterization of gastric cancer susceptibility genes can help develop methods for exploring gastric cancer etiology and provide a scientific basis for the prevention and control of this malignancy. In this paper, we will review the current progress in research of gastric cancer susceptibility genes.

An updated meta-analysis of transforming growth factor-β1 gene: three polymorphisms with gastric cancer

To derive a more precise estimation of the relationship between TGF-β1 polymorphisms and gastric cancer (GC) risk, we conducted a meta-analysis of all available case-control studies relating the C-509 T, T869C, and G 915C polymorphisms of the TGF-β1 gene to the risk of developing GC. The effect summary odds ratio (OR) and 95% confidence intervals (CIs) were obtained. Funnel plots and Egger's test were used to estimate publication bias. Finally, 11 studies were included in the final meta-analysis. With respect to C-509 T polymorphism, it was found that significantly increased GC risk was associated with the TT genotype in the recessive genetic model in overall analysis (TT vs. CC + CT: OR = 1.23, 95% CI 1.09-1.38, P(heterogeneity) = 0.13) and in Asian population (TT vs. CC + CT: OR = 1.24, 95% CI 1.10-1.39, P(heterogeneity) = 0.18). With respect to T869C and G915C polymorphisms, no significant association with GC risk was demonstrated in overall analysis and subgroup analyses according to ethnicity for all genetic models. This meta-analysis suggested that the T allele of TGF-β1 509C/T polymorphism is probably the susceptibility factor for GC.