Meta-analysis of the association between VEGF-634 G>C and risk of malignancy based on 23 case-control studies

Association of VEGFA polymorphisms with the risk of oesophageal cancer in Punjab, India: A case-control study

Background & objectives Vascular endothelial growth factor (VEGF) is one of the most important angiogenic factors which stimulates tumour progression induction of endothelial cell migration and division, inhibition of the apoptosis of endothelial cells, induction of serine protease activity and enhancement of vascular permeability. This study aimed to investigate the correlation of VEGF+405G/C,-7C/T and+936C/T polymorphisms with oesophageal cancer risk. Methods DNA samples of 464 subjects (231 sporadic oesophageal cancer affected individuals and 233 controls) were genotyped forVEGF+936C/T,+405G/C and-7C/T polymorphisms. VEGF+936C/T and +405G/C polymorphisms were genotyped by PCR-RFLP method whereas VEGF-7C/T polymorphism was genotyped using Amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). Results CT genotype of VEGF-7C/T polymorphism was significantly associated with reduced risk of oesophageal cancer. VEGF-7C/T polymorphism was significantly associated with reduced risk of oesophageal cancer underdominant, co-dominant, over dominant and log-additive genetic models in total patients and in the female group. C+936G+405T-7 haplotype was significantly associated with decreased risk (P=0.01)of oesophageal cancer in total patients and also in the male group (P=0.02). Interpretation & conclusions In future, replication of the findings of the present study in a larger sample from different ethnic groups, along with functional analysis, may be insightful for the role of VEGFA polymorphisms in the pathogenesis of oesophageal cancer. Identification of the correlation of VEGF variants with specific therapy in oesophageal cancer may help in better selection of patients and monitoring treatment response in VEGF-therapy.

The association of VEGF rs833061 and rs2010963 polymorphisms with susceptibility to colorectal cancer in an Iranian population

Vascular endothelial growth factor (VEGF) is one of the most important regulators of angiogenesis. Several single nucleotide polymorphisms (SNPs) are associated with the VEGF overexpression and tumor progression in several cancers. This study aimed to determine the association of VEGF rs833061 and rs2010963 polymorphism and their haplotypes with susceptibility to colorectal cancer (CRC) in the Iranian population. A total of 284 colorectal cancer patients (37.3% women, 62.7% men) were enrolled in this study. Healthy controls without evidence of cancer history or family cancer predispositions were frequency-matched to the cases by sex and age (± 5 years). Genotyping was performed by the Sequenom mass ARRAY method and the genotype distribution and risk estimate were analyzed by SPSS software. The correlation between the genotypes and clinicopathological parameters (Dukes stage, phenotype, location, differentiation, and tumor size) among colorectal cancer patients were investigated. We found a significant relationship, between rs833061T/C genotype and their TG haplotype with the age of diagnosis < 60; (p = 0.012, p = 0.014) and rs2010963G/C genotype with female gender and TG haplotype with third and fourth tumor stage and tumor location (p = 0.04and p = 0.047). This study showed that rs833061T/C genotype and TG haplotype increase the susceptibility to colon cancer in the Iranian population. This susceptibility has a significant relationship with the age of diagnosis and different stages of the tumor.

Difference of polymorphism VEGF-gene rs699947 in Indonesian chronic liver disease population

Background

The VEGF gene polymorphism rs699947 related to clinical pathology, mortality, and recurrence of HCC. Few studies mentioned an association between VEGF gene polymorphisms with illness progression in chronic liver disease. We aimed to explore differences of VEGF gene polymorphism rs699947 in chronic hepatitis, liver cirrhosis and hepatocellular carcinoma patients in Indonesian population.

Methods

A cross-sectional study with consecutive sampling and without matching was performed during a 3 years period (2011–2014) at Dr. Sardjito General Hospital Yogyakarta, Indonesia. Blood DNA was sequenced from 123 subjects with chronic liver diseases [39 chronic hepatitis (CH), 39 liver cirrhosis (LC), and 45 hepatocellular carcinoma (HCC)]. 59 healthy subjects also participated. Using isolated VEGF genes for specific primers for rs699947, blood samples were examined by targeting DNA sequences with Applied Bio systems. All data were analyzed using STATA version 11.0 with significance level at P<0.05.

Results

The mean of age in HCC and LC subjects were older than in CH and healthy (P value <0.05); there were more males in LC, HCC and the healthy groups but not in CH (P>0.05). HBV was the dominant etiology in HCC, LC, and CH besides HCV and non HBV-HCV (P<0.05). There were significant differences in the SNP -2578 distributions of allele C compared to allele A in all subjects (healthy vs. LC, and HCC; LC vs. CH (P<0.05), but no significant difference A>C vs. C>C, and genotypes distribution. Proportion of SNP -2578 A>C vs. C>C CH 1.8:1; HCC 1.4:1; healthy 1.7:1; but its proportion in LC was inversed (1:1.2). Genotype A was low in all subjects (5%-11%). Significant difference of allele distribution was found in healthy vs. LC, and HCC; CH vs. LC. Based on HWE analyses, distribution of allele C was dominant. There were not significant differences in deletion, insertion-deletion at -2547 until -2526, and haplotype (Ht) CCGACCCC (P>0.05). The OR analyses of allele and SNP showed that allele A can be a predictor of disease progression in LC to HCC (OR 2.26) and healthy to LC (OR 1.65); and SNP A>C also can be a predictor in healthy to HCC (OR 1.41) and CH (OR 1.14).

Conclusion

The occurrence of allele A and SNP A>C VEGF gene (-2578) might predict illness progression from healthy to CH, LC or HCC and LC to HCC.

The role of vascular endothelial growth factor -634 G/C and its soluble receptor on chronic liver disease and hepatocellular carcinoma

BACKGROUND AND STUDY AIMS

The single nucleotide polymorphism (SNP) of the vascular endothelial growth factor (VEGF) gene -634 G/C (rs2010963) influences the progression of hepatocellular carcinoma (HCC). There have been no studies on the role of VEGF SNP -634 G/C in chronic liver disease (CLD). The aim of the present study was to analyse the correlation between VEGF SNP -634 and the clinical severity of CLD and HCC.

PATIENTS AND METHODS

A cross sectional study was conducted on 182 subjects (46 HCC, 39 liver cirrhotic/LC, 38 chronic hepatitis/CH; and 57 healthy subjects). The study was conducted from 2010 to 2014 at the Dr. Sardjito Hospital Yogyakarta, Indonesia. All subjects submitted blood serum for DNA sequencing examination using primer. The clinical data of CLD and HCC were assessed, and sVEGFR-2 was examined in 149 subjects. All data were analysed using STATA programme 11.0.

RESULTS

Significant differences were observed in genotypic frequency (GG/GC/CC) between HCC, LC, CH and healthy subjects (p=0.004), but though no significant differences were observed between the G>G and C>G genotypic frequencies (p=0.337). The frequency of genotype GG was significantly higher than genotype GC or CC in HCC and was associated with declining of clinical conditions (p<0.05). No significant difference in the distribution genotypes was observed with respect to the level of sVEGFR-2 in the serum. However, we observed a significant correlation between sVEGFR-2 and clinical characteristics in LC and CH (p<0.05).

CONCLUSION

Genotype GG of the VEGF SNP -634 is the dominant genotype in severe CLD and HCC. sVEGFR-2 correlates with the disease severity but is not directly associated with the SNP -634 genotype.

Systematic Review and Meta-Analysis of the Relationship between EPHX1 Polymorphisms and the Risk of Head and Neck Cancer

Aim

To evaluate the association between the EPHX1 Tyr113His and His139Arg polymorphisms in the EPHX1 gene and the risk of head and neck cancer.

Materials and Methods

Studies on the association of EPHX1 Tyr113His and His139Arg polymorphisms with HNC performed up until June 1st, 2014, were identified using a predefined search strategy. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the strength of these associations.

Results

In this meta-analysis, 10 case-control studies, which included 9 studies of Tyr113His (1890 cases and 1894 controls) and 10 studies of His139Arg polymorphisms (1982 cases and 2024 controls), were considered eligible for inclusion. Overall, the pooled results indicated that the EPHX1 Tyr113His polymorphism was significantly associated with increased HNC risk (Tyr/His vs. Tyr/Tyr, OR = 1.26, 95%1.02–1.57;His/His+ Tyr/His vs. Tyr/Tyr, OR = 1.29, 95% I = 1.03–1.61). However, no significant association was found between the His139Arg polymorphism and HNC risk. In the subgroup analysis, a statistically significant association between the EPHX1 Tyr113His polymorphism and HNC was observed in population-based case-control studies (PCC), which involved less than 500 participants and genotype frequencies in HWE. This association showed minimal heterogeneity after excluding studies that were determined to contribute to heterogeneity. After categorizing the studies by publication time, a sensitivity analysis and cumulative meta-analysis of the two associations were conducted, and the results of the two analyses were consistent.

Conclusion

Our meta-analysis suggests that EPHX1 Tyr113His polymorphism may be a risk factor for HNC, while the EPHX1 His139Arg polymorphism has no association with HNC risk.

Association of vascular endothelial growth factor--a gene polymorphisms and haplotypes with breast cancer metastases

BACKGROUND

Vascular endothelial growth factor (VEGF-A) is a key regulator of tumor-induced angiogenesis and essential for tumor growth and distant tumor spread. The aim of the present study was to evaluate the role of VEGF-A polymorphisms and haplotypes for metastatic progression in breast cancer patients.

MATERIAL AND METHODS

We performed a prospective study including 801 breast cancer patients. Occurrence of metastases was examined in regular follow-up investigations. Seven VEGF-A polymorphisms were selected and determined by 5'-nuclease assays (TaqMan). The selection of VEGF-A variants was based upon their location (promoter or UTR) as well as a minor allele frequency of at least 0.10. Haplotypes and linkage disequilibrium were determined using the Haploview program.

RESULTS

Within a median follow-up time of 84 months, 165 (21%) patients developed distant metastases. In univariate analysis, carriers of the CCCCC haplotype formed by five polymorphisms upstream the coding region were at decreased risk of distant metastases [hazard ratio (HR)=0.743; 95% CI 0.579-0.953; p=0.019]. Univariate analysis also revealed a decreased risk of distant metastases for postmenopausal patients carrying the -634G>C polymorphism (HR 0.704; 95% CI 0.514-0.965; p=0.029) and the CCCCC haplotype (HR=0.645; 95% CI 0.464-0.898; p=0.009). After adjustment for other co-variates, the HR for distant metastases was 0.651 (95% CI 0.447-0.948) for postmenopausal carriers of the -634G>C polymorphism (p=0.025; corrected p-value=0.262), and 0.586 (95% CI 0.393-0.873) for postmenopausal patients with the CCCCC haplotype (p=0.009, corrected p-value=0.189).

CONCLUSION

The results from univariate and multivariate analyses suggest an influence of VEGF-A gene variants on the development of distant metastases in breast cancer patients. However, none of the observed associations reached statistical significance after correction for the effects of multiple testing. Additional prospective and sufficiently powered studies are essential before firm conclusions about the role of VEGF-A gene variants for distant progression in breast cancer can be drawn.

Prognostic and predictive role of vascular endothelial growth factor polymorphisms in breast cancer

Current evidence indicates that angiogenesis plays an important role in the pathogenesis of several malignancies, including breast cancer. The vascular endothelial growth factor (VEGF) pathway has been investigated extensively, due to its important role in angiogenesis. The major mediator of tumor angiogenesis is VEGF-A, frequently referred to as VEGF, which activates the VEGF receptor-2. The VEGF gene is located on chromosome 6 and constitutes a highly polymorphic gene. Numerous SNPs in the promoter, 5′- and 3′-untranslated regions (UTR) of VEGF gene have been recognized. This genetic variability possibly influences the production and function of VEGF. Subsequently, the VEGF SNPs may have an impact on breast cancer risk and disease outcome. Moreover, these SNPs may be of predictive value in patients receiving agents targeting the VEGF pathway. This review presents an update on the potential role of VEGF SNPs as prognostic and/or predictive markers in patients with breast cancer.

Ethnic background and genetic variation in the evaluation of cancer risk: a systematic review

The clinical use of genetic variation in the evaluation of cancer risk is expanding, and thus understanding how determinants of cancer susceptibility identified in one population can be applied to another is of growing importance. However there is considerable debate on the relevance of ethnic background in clinical genetics, reflecting both the significance and complexity of genetic heritage. We address this via a systematic review of reported associations with cancer risk for 82 markers in 68 studies across six different cancer types, comparing association results between ethnic groups and examining linkage disequilibrium between risk alleles and nearby genetic loci. We find that the relevance of ethnic background depends on the question. If asked whether the association of variants with disease risk is conserved across ethnic boundaries, we find that the answer is yes, the majority of markers show insignificant variability in association with cancer risk across ethnic groups. However if the question is whether a significant association between a variant and cancer risk is likely to reproduce, the answer is no, most markers do not validate in an ethnic group other than the discovery cohort's ancestry. This lack of reproducibility is not attributable to studies being inadequately populated due to low allele frequency in other ethnic groups. Instead, differences in local genomic structure between ethnic groups are associated with the strength of association with cancer risk and therefore confound interpretation of the implied physiologic association tracked by the disease allele. This suggest that a biological association for cancer risk alleles may be broadly consistent across ethnic boundaries, but reproduction of a clinical study in another ethnic group is uncommon, in part due to confounding genomic architecture. As clinical studies are increasingly performed globally this has important implications for how cancer risk stratifiers should be studied and employed.

Vascular endothelial growth factor gene polymorphism (-634G/C) and breast cancer risk

The aim of this meta-analysis was to assess if the -634G/C polymorphism represents a predisposition factor for the risk of breast cancer. We included eight published case-control studies, in which a total of 6,175 cancer cases and 6,421 cancer-free controls were included. Pooled ORs and 95 % CIs were calculated by the fixed effects model to evaluate the association of the -634G/C polymorphism and breast cancer risk. When all studies were pooled, we did not find statistical evidence of any significant association with overall breast cancer risk (ORBB vs. bb = 1.00, 95 % CI = 0.93-1.07, P = 0.999; ORBB + Bb vs. bb = 1.00, 95 % CI = 0.95-1.05, P = 0.999; ORBB vs. Bb + bb = 1.03, 95 % CI = 0.96-1.09, P = 0.984; ORallele B vs. allele b = 1.01, 95 % CI = 0.97-1.05, P = 0.998; ORBb vs. bb = 0.99, 95 % CI = 0.92-1.06, P = 0.992). In further stratified analyses by ethnicity and control source, no significant association was revealed. This study suggests that the -634G/C polymorphism does not appear to represent a risk factor for breast cancer.

The association of IL1α and IL1β polymorphisms with susceptibility to systemic lupus erythematosus: a meta-analysis

Many epidemiological studies have investigated IL1α and IL1β polymorphisms with SLE risk, but no conclusions are available because of conflicting results. This meta-analysis was performed to more precisely estimate the relationships. The databases of PubMed updated to September 1st, 2012 were retrieved. Odds ratio (OR) and corresponding 95% confidence interval (95% CI) as effect size were calculated by a fixed- or random-effect model. In total, six case-control studies for IL1β-511C/T, four studies for IL1β+3953C/T, three studies for IL1α-889C/T and three studies for IL1α+4845G/T were involved in this analysis. The results indicated that for IL1α-889C/T polymorphism T allele was associated with decreased risk of SLE (OR (95% CI)) (T vs. C: 0.802 (0.679-0.949); TT+CT vs. CC: 0.615 (0.380-0.995); TT vs. CC: 0.679 (0.466-0.989)). However, when analysis for TT vs. CT+CC was conducted, the result indicated that IL1α-889C/T polymorphism was not associated with SLE (OR (95% CI): 0.847 (0.595-1.205)). Combined analysis indicated that IL1β-511C/T polymorphism was not overall associated with risk of SLE (OR (95% CI)) (T vs. C: 1.113 (0.954-1.298); TT vs. CT+CC: 1.146 (0.889-1.447); TT+CT vs. CC: 1.145 (0.903-1.452); TT vs. CC: 1.255 (0.928-1.698)). When subgroup analysis for Asian ethnicity was conducted, the results indicated that IL1β-511C/T polymorphism was associated with SLE only for TT vs. CT+CC (OR (95% CI): 1.468 (1.001-2.152)), but was not associated for T vs. C (OR (95% CI): 1.214 (0.955-1.544)), TT+CT vs. CC (OR (95% CI): 1.112 (0.765-1.615)) and TT vs.CC (OR (95% CI): 1.411 (0.896-2.222)). In addition, overall analyses indicated that IL1β+3953C/T and IL1α+4845G/C polymorphisms were also not associated with risk of SLE (OR (95% CI)) (for IL1β+3953C/T T vs. C: 0.996 (0.610-1.626), TT vs. CT+CC: 0.658 (0.318-1.358), TT+CT vs. CC: 1.021 (0.618-1.687), TT vs. CC: 0.640 (0.309-1.325); for IL1α+4845G/T T vs. G: 1.067 (0.791-1.440), TT+GT vs. GG: 0.934 (0.646-1.351)).This study inferred that IL1α-889C/T polymorphism might be moderately associated with SLE, but no sufficient evidence was available to support any associations between IL1β+3953C/T or IL1α+4845G/C polymorphisms and SLE. We could not draw a definite conclusion between IL1β-511C/T polymorphism and risk of SLE owing to the limited data. Further large sample-sized studies should be required.

Angiotensin-converting enzyme insertion/deletion polymorphism and risk of myocardial infarction in an updated meta-analysis based on 34993 participants

The association between angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism and risk of myocardial infarction (MI) has been extensively studied. However, the results were in controversy. This study aimed to explore the association between ACE I/D polymorphism and risk of MI by using a meta-analysis. We retrieved the following databases to indentify eligible studies: Medline, Embase, ISI, VIP, CBM and Wan Fang database. The latest update was 10th May, 2012. Odds ratio and 95% confidence interval (95% CI) were used to present the strength of the association. A total of 40 case-control studies with 34993 participants were included. Overall, D allele of ACE I/D polymorphism was significantly associated with an increased risk of MI in genetic comparison models (OR (95% CI): 1.41 (1.22-1.64) for DD vs. II; 1.11 (1.01-1.21) for ID vs. II; 1.23 (1.10-1.37) for D carriers vs. II; 1.28 (1.15-1.43) for DD vs. I carriers and 1.06 (1.02-1.10) for D carriers vs. I carriers). Subgroup analyses, according to ethnicities and countries of participants also indicated that D allele was significantly associated with an increased risk of MI in Asians (especially for Chinese) and Caucasians (especially for English, French, Germans and Italians) (OR (95% CI) of DD vs. ID+II: 2.11 (1.65-2.70) for Asians and 1.15 (1.05-1.27) for Caucasians). In conclusion, this meta-analysis indicated that D allele of ACE I/D polymorphism was a possible risk factor for MI incidence for both Asians and Caucasians.

Positive association of the vascular endothelial growth factor-A +405 GG genotype and poor survival in stage I-II gastric cancer in the Northern Chinese population

The vascular endothelial growth factor-A (VEGF-A) plays an important role in the angiogenesis and prognosis for gastric cancer. In addition, several single-nucleotide polymorphisms (SNPs) in VEGF-A have been shown to affect gene expression and process of angiogenesis. The present study evaluated the correlations between SNPs in VEGF-A and gastric cancer survival. Formalin-fixed paraffin-embedded tissues of 404 gastric cancer patients and blood samples from 404 controls were included in the study. The SNPs -460T/C (rs833061), +405G/C (rs2101963), -7C/T (rs25648) and +936C/T (rs3025039) were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. We showed patients carrying the +405GG genotype had significantly worse survival in the N0 (lymph-node negative), N0L0 (lymph-node negative and lymphovascular-invasion negative) and TNM stage I-II subgroups (P = 0.021, P = 0.007 and P = 0.017, respectively). In addition, haplotype -460T/+405G/-7C and -460C/+405G/-7C carriers showed poor survival in the N0, N0L0 and TNM stage I-II subgroups (P = 0.004, P = 0.030 and P = 0.009 for TGC; P = 0.033, P = 0.049 and P = 0.011 for CGC). Overall, the +405 GG genotype or TGC and CGC haplotypes were correlated with poor survival in TNM stage I-II gastric cancer patients. The +405G/C polymorphism of VEGF-A could be used as a biomarker for molecular staging in stage I-II gastric cancer in Northern China.

The role of vascular endothelial growth factor a polymorphisms in breast cancer

Breast cancer is the most common cancer in females and the leading cause of cancer death in women worldwide. Angiogenesis, the formation of new blood vessels, plays an important role in the development and progression of breast cancer. Vascular endothelial growth factor A (VEGFA), the key modulator of angiogenesis, is highly expressed in cancer tissue and correlates with its more aggressive features. Polymorphisms of VEGFA alter the levels of expression and subsequently influence the susceptibility and aggressiveness of breast cancer. Assessment of VEGFA polymorphisms may be used for the identification of patients suitable for anti-VEGFA therapy.

Adiponectin (ADIPOQ) rs2241766 G/T polymorphism is associated with risk of cancer: evidence from a meta-analysis

Associations between adiponectin (ADIPOQ) genetic polymorphisms (rs2241766 G/T and rs266729 G/C) and cancer risk have been extensively studied in the past decade, while conflicting results were reported. Therefore, this study would explore the associations by using a meta-analysis. The databases of Medline, Embase, and Wangfang were retrieved, and the latest updated time was 1 August 2012. Effect sizes of odds ratio and 95 % confidence interval (OR and 95 % CI) were calculated by using a fixed- or random-effect model. A total of 12 studies with 10,368 participants were identified for association between ADIPOQ rs2241766 G/T and risk of cancer, and ten studies with 12,665 participants were for association between ADIPOQ rs266729 G/C and risk of cancer. Overall combined analyses indicated that neither ADIPOQ rs2241766 G/T nor rs266729 G/C was associated with risk of cancer incidence (OR (95 % CI), 0.89 (0.61-1.30) for GG vs. TT and 0.94 (0.83-1.06) for G carriers vs. T carriers for rs2241766 G/T; 0.99 (0.85-1.16) for GG vs. CC and 0.96 (0.87-1.06) for G carriers vs. C carriers for rs266729 G/C). When stratified analyses were conducted according to the participants' ethnicity, sources of controls, types of cancer, and sample size, we found that G allele of ADIPOQ rs2241766 G/T was significantly associated with decreased risk of cancer based on population-based case-control studies (OR (95 % CI), 0.65 (0.50-0.85) for GG vs. TT and 0.88 (0.79-0.98) for G carriers vs. T carriers). In contrast, there was no association between rs266729 G/C polymorphism and risk of cancer when subgroup analyses were conducted. In summary, this meta-analysis indicated that ADIPOQ rs2241766 G/T rather than rs266729 G/C polymorphism was closely associated with risk of cancer development.

Systematic review and meta-analysis of the relationship between EPHX1 polymorphisms and colorectal cancer risk

BACKGROUND

Microsomal epoxide hydrolase (EPHX1) plays an important role in both the activation and detoxification of PAHs, which are carcinogens found in cooked meat and tobacco smoking. Polymorphisms at exons 3 and 4 of the EPHX1 gene have been reported to be associated with variations in EPHX1 activity. The aim of this study is to quantitatively summarize the relationship between EPHX1 polymorphisms and colorectal cancer (CRC) risk.

METHODS

Two investigators independently searched the Medline, Embase, CNKI, and Chinese Biomedicine Databases for studies published before June 2012. Summary odds ratios (ORs) and 95% confidence intervals (CIs) for EPHX1 Tyr113His (rs1051740) and His139Arg (rs2234922) polymorphisms and CRC were calculated in a fixed-effects model and a random-effects model when appropriate.

RESULTS

This meta-analysis yielded 14 case-control studies, which included 13 studies for Tyr113His (6395 cases and 7893 controls) and 13 studies for His139Arg polymorphisms (5375 cases and 6962 controls). Overall, the pooled results indicated that EPHX1 Tyr113His polymorphism was not associated with CRC risk; while the His139Arg polymorphism was significantly associated with decreased CRC risk (Arg/His vs. His/His, OR = 0.90, 95%CI = 0.83-0.98; dominant model, OR = 0.92, 95%CI = 0.85-0.99). The statistically significant association between EPHX1 His139Arg polymorphism and CRC was observed among Caucasians and population-based case-control studies. This association showed little heterogeneity and remained consistently strong when analyses were limited to studies in which genotype frequencies were in Hardy-Weinberg equilibrium, or limited to studies with matched controls. When cumulative meta-analyses of the two associations were conducted by studies' publication time, the results were persistent and robust.

CONCLUSION

This meta-analysis suggests that EPHX1 Tyr113His polymorphism may be not associated with CRC development; while the EPHX1 His139Arg polymorphism may have a potential protective effect on CRC.

Correlation between TGF-β1-509 C>T polymorphism and risk of digestive tract cancer in a meta-analysis for 21,196 participants

The association between transforming growth factor β1 (TGF-β1)-509 C>T and risk of digestive tract cancer (DTC) remained uncertain as previous studies reported conflicting results. The aim of this study was to assess the association by using a meta-analysis. The databases of MEDLINE, EMBASE and WANGFANG (Chinese database) were retrieved, and latest update was on 2nd February, 2012. Pooled odds ratio and 95% confidence interval (OR and 95% CI) were calculated by using a fixed- or random-effect model. Ultimately, twenty nine case-control studies with 8664 cases and 12,532 controls were included in this meta-analysis. Overall, there was no association between TGF-β1-509 C>T and risk of DTC in all genetic comparison models (OR and 95% CI: 0.96 and 0.81-1.15 for TT vs. CC, 0.98 and 0.91-1.05 for T carriers vs. C carriers). When subgroup analyses were conducted according to ethnicity, types of cancer and sample size, T allele was significantly associated with decreased risk of DTC for Caucasians and for large sample-sized studies, and was associated with decreased risk of colorectal cancer (OR and 95% CI for TT vs. CC: 0.82 and 0.70-0.97 for Caucasians, 0.80 and 0.68-0.98 for large sample-sized studies, 0.78 and 0.62-0.97 for colorectal cancer). This study indicated that TGF-β1-509 C>T polymorphism was probably associated with risk of DTC, especially for Caucasians. Because of modest limitation, our findings should be confirmed by future studies.

Helicobacter pylori infection contributes to high risk of ischemic stroke: evidence from a meta-analysis

Chronic infection of Helicobacter pylori (H. pylori) in ischemic stroke (IS) incidence has been previously studied in several publications; however, conflicting results have been reported. A meta-analysis was used to assess whether chronic infection of H. pylori was associated with risk of IS, and which of the following was more effective for predication of IS risk, antibody IgG of H. pylori (anti-H. pylori IgG), antibody IgG of cytotoxin-associated gene-A (anti-Cag A IgG) or the (13)C-urea breath test. We searched the databases of Medline and Embase, and latest update was January 1, 2012. Case-control studies were considered to be eligible. The odds ratio (OR) and 95 % confidence interval (95 % CI) were calculated using the random-effect model. A total of 13 studies including 4,041 participants were included in this meta-analysis. Of these studies, ten, four and four studies were for anti-H. pylori IgG, anti-Cag A IgG and the (13)C-urea breath test, respectively. Combined analysis indicated that positive anti-H. pylori IgG, anti-Cag A IgG and (13)C-urea breath test were significantly associated with increased risk of IS, respectively, and positive anti-Cag A IgG was more effective for predication of IS risk [OR (95 % CI) = 1.60 (1.21-2.11), P (heterogeneity) = 0.001 for positive versus negative anti-H. pylori IgG; 2.33 (1.76-3.09), P (heterogeneity) = 0.71 for positive versus negative anti-Cag A IgG and 1.65 (1.11-2.47), P (heterogeneity) = 0.17 for positive versus negative (13)C-urea breath test]. In addition, we found that positive anti-H. pylori IgG was closely associated with risk of IS caused by atherosclerosis and small artery disease, but not for cardioembolic IS. This meta-analysis indicated that chronic H. pylori infection was significantly associated with an increased risk of IS, especially for non-cardioembolic IS. Compared with anti-H. pylori IgG and the (13)C-urea breath test, anti-Cag A IgG seemed more effective for prediction of risk of IS.

Meta-analyses of the associations between four common TGF-β1 genetic polymorphisms and risk of colorectal tumor

The associations between four common genetic polymorphisms of transforming growth factor-β1 (TGF-β1 -509 C > T, +869 T > C, +915 G > C, and -800 G > A) and risk of colorectal tumor (including adenoma and cancer) have been widely studied. To date, no conclusions could be available because of controversial results reported. Thus, we conducted a meta-analysis to further assess the associations. We searched the databases of Medline, Embase, and Wangfang to identify eligible studies, and latest update was on January 1, 2012. Odds ratio (OR) and 95% confidence interval (95%CI) were calculated to present the associations. Our meta-analysis indicated that TGF-β1 -509 C > T, +869 T > C, +915 G > C, and -800 G > A were not associated with risk of colorectal adenoma (OR = 0.89 for C carriers vs. TT for -509 C > T, 1.03 for C carriers vs. TT for +869 T > C, 1.09 for C carriers vs. GG for +915 G > C, and 1.19 for A carriers vs. GG for 800 G > A). However, C allele of TGF-β1 -509 C > T and A allele of -800 G > A were associated with increased risk of colorectal cancer (CRC), and OR (95%CI) was 1.23 (0.99-1.52) for CC vs. TT for -509 C > T and 6.64 (3.46-12.72) for A carriers vs. GG. The positive association between -509 C allele and risk of CRC was more obvious when subgroup analyses were conducted for population-based and large sample-sized studies as well as Caucasians. In contrast, we did not observed any associations between TGF-β1 +869 T > C, +915 G > C, and risk of CRC. This study indicated that C allele of TGF-β1-509 C > T and A allele of -800 G > A might contribute to the increased risk of CRC, and could be used as two of genetic marks for screening individuals at high risk of CRC. Because of modest limitation, large sample-sized studies were required to confirm the findings.

Polymorphisms of interleukin-1 and interleukin-6 genes on the risk of ischemic stroke in a meta-analysis

Many epidemiological studies have investigated the associations between polymorphisms of interleukin-1 (IL1) and interleukin-6 (IL6) genes and risk of ischemic stroke (IS), but no conclusions are available because of conflicting results. The aim of this study was to assess the relationships by meta-analysis. The databases of Pubmed, Embase and Wangfang, updated to August 1st, 2011, were retrieved. Odds ratio (OR) and corresponding 95% confidence interval (95% CI) as effect size were calculated by a fixed- or random-effect model. In total, three case-control studies for IL1α-889C/T, eight studies for IL1β-511C/T, eight studies for IL1-Ra and seven studies for IL6-147G/C were included in this meta-analysis. Combined analysis indicated that IL1β-511C/T polymorphism was not overall associated with risk of IS [OR (95% CI)=1.22 (0.85-1.87) for TT vs. CC]. However, when subgroup analyses for countries were conducted, the results indicated that T allele was associated with increased risk of IS for Polish and associated with a trend of increased risk of IS for Chinese although it did not reach statistical significance [TT vs. CC: OR (95% CI)=1.97 (1.22-3.17) for Polish and 1.40 (0.99-1.99) for Chinese]. In addition, overall and subgroup analyses indicated that IL1α-889C/T, IL1-Ra and IL6-147G/C polymorphisms were also not associated with risk of IS [OR (95% CI)=1.21 (0.86-1.70) for TT vs. CC of IL1α-889C/T, 1.22 (0.85-1.75) for RN2/RN2 vs. RN1/RN1 for IL1-Ra and 1.09 (0.84-1.40) for G carriers vs. C carriers for IL6-147G/C]. This study inferred that IL1β-511C/T polymorphism might be moderately associated with increased risk of IS, but no sufficient evidence was available to support any associations between IL1-Ra and IL6-147G/C polymorphisms and IS. We could not draw a conclusion between IL1α-889C/T polymorphism and risk of IS based on the limited data, and further large sample-sized studies were required.

Contribution of NAD(P)H quinone oxidoreductase 1 (NQO1) Pro187Ser polymorphism and risk of colorectal adenoma and colorectal cancer in Caucasians: a meta-analysis

BACKGROUND AND AIMS

The effects of polymorphism of NAD(P)H quinone oxidoreductase 1 (NQO1 Pro187Ser, rs1800566) on the risks of colorectal adenoma and cancer have been widely studied and results remain controversial. Therefore, the aim of this meta-analysis was to quantitatively assess the relationships.

METHODS

Databases of Medline, Embase and Wanfang were retrieved until May 15, 2011. Pooled odds ratio (OR) and 95% confidence interval (95% CI) as effect sizes were calculated by using fixed- or random-effect model. Cochrane Q-test was used to explore between-study heterogeneity; p <0.10 indicated statistical significance.

RESULTS

A total of 12 case-control studies with 11,700 individuals (including 5528 cases and 6172 controls) were included in this meta-analysis. Of these studies, four studies conducted in Caucasian populations were for colorectal adenoma, and eight studies were for colorectal cancer. NQO1 187Ser allele was significantly associated with increased risk of colorectal adenoma in co-dominant and dominant comparison models (OR = 1.07, 95% CI = 1.04-1.32 for ProSer vs. ProPro and OR = 1.19, 95% CI = 1.06-1.33 for Ser carries vs. ProPro), without between-study heterogeneity. Overall, NQO1 Pro187Ser was not associated with risk of colorectal cancer, without between-study heterogeneity. Subgroup analyses indicated that Ser allele was significantly associated with increased risk of colorectal cancer for Caucasians (OR = 1.14, 95% CI = 1.00-1.30 for ProSer vs. ProPro and OR = 1.16, 95% CI = 1.02-1.31 for Ser carries vs. ProPro).

CONCLUSIONS

This meta-analysis suggested that Ser allele of NQO1 Pro187Ser significantly contributed to the increased risks of colorectal adenoma and cancer in Caucasians.

System review and metaanalysis of the relationships between five metabolic gene polymorphisms and colorectal adenoma risk

The relationships between some metabolic (including EPHX1, GSTs and NQO1) gene polymorphisms and colorectal adenoma (CRA) risk have been commonly studied, and no conclusions are available up to now. Therefore, we quantitatively studied the relationships by a metaanalysis. The databases of Medline and Embase were retrieved updated to June 15th, 2011. Crude or adjusted odds ratio (crude OR or adjusted OR) and 95% confidence interval (95%CI) were calculated to present the strength of the associations. Overall, nine case-control studies for EPHX1 Tyr113His and His139Arg, five case-control studies for GSTM1, four studies for GSTP1 Ile105Val, two studies for GSTP1 Ala114Val, six studies for GSTT1 and four studies for NQO1 Pro187Ser were included in this metaanalysis. The results of combined analyses indicated that EPHX1 Tyr113His and His139Arg, GSTT1, GSTM1, GSTP1 Ile105Val and Ala114Val were not associated with CRA risk [crude OR (95%CI): 0.98 (0.90-1.07) and P ( z-test) = 0.65 for EPHX1 His carriers vs. Tyr/Tyr; 1.05 (0.97-1.15) and P ( z-test) = 0.21 for EPHX1 Arg carriers vs. His/His; 1.05 (0.92-1.20) and P ( z-test) = 0.47 for GSTT1 Null vs. Present; 1.01 (0.90-1.13) and P ( z-test) = 0.90 for GSTM1 Null vs. Present; 1.04 (0.92-1.17) and P ( z-test) = 0.56 for G carriers vs. AA for GSTP1 Ile105Val; 0.88 (0.70-1.11) and P ( z-test) = 0.28 for T carriers vs. CC for GSTP1 Ala114Val]. In contrast, Ser allele of NQO1 Ser187Pro might be a modest risk factor for CRA development [1.19 (1.06-1.33) and P ( z-test) = 0.003 for Ser carriers vs. Pro/Pro]. To get more precise evidences, adjusted ORs (95%CI) for EPHX1 Tyr113His, His139Arg, GSTP1 Ile105Val and NQO1 Ser187Pro were also calculated based on adjusted ORs (95%CIs) reported in primary studies. The results still indicated that EPHX1 Tyr113His, His139Arg and GSTP1 Ile105Val were not associated with CRA risk except for NQO1 Ser187Pro. When subgroup analyses were performed for population-based case-control studies or studies in HWE for EPHX1 Tyr113His and His139Arg, and NQO1 Ser187Pro polymorphisms, the results were persistent. Although with modest limitations and biases, this metaanalysis suggests that EPHX1 Tyr113His and His139Arg, GSTT1, GSTM1, GSTP1 Ile105Val and Ala114Val polymorphisms may be not risk factors for CRA development, while Ser allele of NQO1 Ser187 Pro may be a modest risk factor for CRA development, and may be used with other genetic markers for screening CRA in the future.