Association between MTR A2756G and MTRR A66G polymorphisms and maternal risk for neural tube defects: A meta-analysis

Background

Methionine synthase (MTR) and methionine synthase reductase (MTRR) genes have been considered to be implicated in the development of neural tube defects (NTDs). However, the results are inconsistent. Accordingly, we conducted a meta-analysis to further investigate such an association.

Methods

Published literature from PubMed and Embase databases was retrieved. All studies evaluating the association between MTR A2756G or MTRR A66G polymorphism and maternal risk for NTDs were included. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using the fixed- or random-effects model.

Results

A total of 11 studies (1005 cases and 2098 controls) on MTR A2756G polymorphism and 10 studies (1211 cases and 2003 controls) on MTRR A66G polymorphism were included. Overall, this meta-analysis revealed no significant association between maternal MTR A2756G polymorphism and NTD susceptibility in either genetic model. A significant association between MTRR A66G polymorphism and maternal risk for NTDs was observed for GG vs. AA (OR = 1.31, 95% CI 1.03–1.67) among Caucasians.

Conclusion

The present meta-analysis indicated that MTRR A66G polymorphism, but not MTR A2756G, is significantly associated with maternal risk for NTDs in Caucasians.     

Association between complement factor H Val62Ile polymorphism and age-related macular degeneration susceptibility: A meta-analysis

Background

An increasing body of studies has assessed the contribution of Val62Ile polymorphism to age-related macular degeneration (AMD) risk, but the exact association still remains uncertain. This meta-analysis was undertaken in order to further characterize the potential association between Val62Ile polymorphism and AMD risk in four different ethnic populations.

Methods

A meta-analysis was performed using data available from 16 case–control studies evaluating correlation between the Val62Ile polymorphism and AMD in Caucasian, Chinese, Japanese and South Korean populations. Data extraction and study quality assessment were performed in duplicate. Summary odds ratios (ORs) and 95% confidence intervals (CIs) of allele contrast and genotype contrast were estimated using the random-effects model. The Q-statistic test was used to identify heterogeneity, and the funnel plot was adopted to evaluate publication bias.

Results

Sixteen studies involving a total of 11,400 subjects based on the search criteria were included in the meta-analysis. In overall populations, the Val62Ile polymorphism seemed to be associated with AMD (OR_{AA vs. GG} = 0.40, 95% CI = 0.28–0.59; OR_{AA + GA vs. GG} = 0.72, 95% CI = 0.64–0.80; OR_{AA vs. GC + GG} = 0.50, 95% CI = 0.36–0.70; OR_{A vs. G} = 0.68, 95% CI = 0.58–0.78; OR_{GA vs. GG} = 0.71, 95% CI = 0.65–0.77). Similarly, subgroup analysis also revealed that this polymorphism was related to AMD in all ethnicities.

Conclusions

This meta-analysis suggested that Val62Ile polymorphism was associated with susceptibility to AMD.     

Association of p53 Arg72Pro polymorphism with bladder cancer: A meta-analysis

Background

p53 tumor suppressor gene Arg72Pro polymorphism has been associated with bladder cancer. However, results were inconsistent. We performed this meta-analysis to estimate the association between p53 Arg72Pro polymorphism and bladder cancer.

Methods

Electronic search of PubMed was conducted to select studies. Studies containing available genotype frequencies of Arg72Pro were chosen, and pooled odds ratio (OR) with 95% confidence interval (CI) was used to assess the association.

Results

The final meta-analysis included 14 published studies with 2176 bladder cancer cases and 2798 controls. The results suggested that the variant genotype was associated with the bladder cancer risk (additive model: OR = 1.72, 95% CI: 1.036–1.325, P = 0.011; dominant model: OR = 1.268, 95% CI: 1.003–1.602, P = 0.047) in Asian subgroup. However, the association was not significant between this polymorphism and bladder cancer risk in Caucasian (additive model: OR = 0.773, 95% CI: 0.564–1.059, P = 0.109; dominant model: OR = 0.685, 95% CI: 0.418–1.124, P = 0.134).

Conclusion

This meta-analysis suggests that p53 Arg72Pro polymorphism is associated with increased risk of bladder cancer in Asians. To validate the association between this polymorphism and bladder cancer, further studies with larger participants worldwide are needed.     

Null genotypes of GSTM1 and GSTT1 contribute to increased risk of diabetes mellitus: A meta-analysis

Diabetes mellitus (DM) is a common disease which results from various causes including genetic and environmental factors. Glutathione S-Transferase M1 (GSTM1) and Glutathione S-Transferase T1 (GSTT1) genes are polymorphic in human and the null genotypes lead to the absence of enzyme function. Many studies assessed the associations between GSTM1/GSTT1 null genotypes and DM risk but reported conflicting results. In order to get a more precise estimate of the associations of GSTM1/GSTT1 null genotypes with DM risk, we performed this meta-analysis. Published literature from PubMed, Embase and China Biology Medicine (CBM) databases was searched for eligible studies. Pooled odds ratios (OR) and corresponding 95% confidence intervals (95%CI) were calculated using a fixed- or random-effects model. 11 publications (a total of 2577 cases and 4572 controls) were finally included into this meta-analysis. Meta-analyses indicated that null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1–GSTT1 were all associated with increased risk of DM (GSTM1: OR _{random-effects} = 1.60, 95%CI 1.10–2.34, P_OR = 0.014; GSTT1: OR _{random-effects} = 1.47, 95%CI 1.12–1.92, P_OR = 0.005; GSTM1–GSTT1: OR _{fixed-effects} = 1.83, 95%CI 1.30–2.59, P_OR = 0.001). Subgroup by ethnicity suggested significant associations between null genotypes of GSTM1 and GSTT1 and DM risk among Asians (GSTM1: OR _{random-effects} = 1.77, 95%CI 1.24–2.53, P_OR = 0.002; GSTT1: OR _{random-effects} = 1.58, 95%CI 1.09–2.27, P_OR = 0.015). This meta-analysis suggests null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1–GSTT1 are all associated with increased risk of DM, and null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1–GSTT1 are potential biomarkers of DM.     

An updated meta-analysis of endothelial nitric oxide synthase gene: Three well-characterized polymorphisms with ischemic stroke

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene may influence the risk of ischemic stroke (IS), but the results are still debatable. A meta-analysis was performed to investigate the association between the eNOS gene polymorphisms in IS risk. Case–control studies on the association between the G894T, T-786C, and 4b/a polymorphisms and IS were searched up to July 2012, and the genotype frequencies in the control group were found to be consistent with the Hardy–Weinberg equilibrium (HWE). The effect summary odds ratio (OR) and 95% confidence intervals (CIs) were obtained. Meta-regression was used to explore the potential sources of heterogeneity. Funnel plots and Egger's test was used to estimate small study biases, and heterogeneity was assessed by chi-square-based Q-test and I² test. There were total 6537/6475 cases/controls for G894T, 3459/3951 cases/controls for 4b/a, and 2125/2673 cases/controls for T-786C polymorphism. For G894T and 4b/a, a significant association of 894 T allele and 4a allele with increased risk of IS was found in Asians (TT + GT vs. GG: p < 0.00001, OR = 1.60, 95% CI = 1.38–1.79, P_{heterogeneity} = 0.11; aa + ba vs. bb: P < 0.00001, OR = 1.60, 95% CI = 1.30–1.97, P_{heterogeneity} = 0.02), but not in Caucasians (TT + GT vs. GG: P = 0.60, OR = 0.94, 95% CI = 0.75–1.19, P_{heterogeneity} = 0.002; aa + ba vs. bb: P = 0.13, OR = 0.81, 95% CI = 0.62–1.06, P_{heterogeneity} = 0.63). For T-786C polymorphism, there were no significant differences in genotype distribution between IS and control in Asians (CC + TC vs. TT: P = 0.15, OR = 1.14, 95% CI = 0.95–1.37, P_{heterogeneity} = 0.94) and in Caucasians (CC + TC vs. TT: P = 0.72, OR = 0.96, 95% CI = 0.75–1.22, P_{heterogeneity} = 0.53). This analysis provides strong evidence that the eNOS T-786C gene polymorphism is not associated with IS, the G894T and 4b/a polymorphisms might be associated with IS, at least in Asians.     

Association of the interleukin-10 − 592A/C, − 1082G/A and − 819T/C gene polymorphisms with type 2 diabetes: A meta-analysis

There is more evidence that interleukin-10 (IL-10), as a multifunctional regulatory cytokine of inflammatory responses, may have an important role in type 2 diabetes (T2D). However, genetic association studies that evaluated the relationship between IL-10 gene variants and T2D have produced conflicting results. The aim of this study was to determine whether the IL-10 gene polymorphisms (− 592A/C, − 1082G/A, − 819T/C) conferred susceptibility to T2D through a meta-analysis. A comprehensive search was conducted to examine all the eligible studies. A total of 9 studies involving 2838 T2D patients and 2773 controls were considered in the meta-analysis. Overall, there was no significant association between IL-10 − 592A/C and T2D (A vs C: OR = 0.93, P = 0.625; AA + AC vs CC: OR = 0.89, P = 0.511; AA vs AC + CC: OR = 0.93, P = 0.821). We failed to find the association between the IL-10 − 1082G allele and T2D (OR = 1.04, P = 0.430), but the genotypes of the IL-10 − 1082G/A polymorphism conferred a risk for the development of T2D (GA vs AA: OR = 1.21, P = 0.027; GG + GA vs AA: OR = 1.17, P = 0.048). Analysis of the − 819T/C polymorphism revealed no significant association with T2D (T vs C: OR = 1.04, P = 0.853; TT + TC vs CC: OR = 1.07, P = 0.834; TT vs TC + CC: OR = 1.08, P = 0.824). In conclusion, the present meta-analysis suggests association between the IL-10 − 1082G/A polymorphism and T2D. However, additional well-designed and larger scale primary studies are required to further evaluate the IL-10 gene polymorphisms and T2D.     

Secretoglobin 1A member 1 (SCGB1A1) + 38A/G polymorphism is associated with asthma risk: A meta-analysis

Background

Epidemiological studies have evaluated the association between Secretoglobin 1A member 1 (SCGB1A1) + 38A/G polymorphism and asthma, but the results remain inconclusive. The aim of this study was to perform a meta-analysis to investigate a more authentic association between SCGB1A1 + 38A/G polymorphism and asthma.

Methods

Published literature from PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Embase databases were searched for eligible publications. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random or fixed-effect model according the between-study heterogeneity.

Results

A total of 19 case-control studies in 18 articles were included in the meta-analysis, including 3191 cases and 5182 controls. We found that SCGB1A1 + 38A/G polymorphism was associated with a significantly increased risk of asthma risk when all studies were pooled in a dominant model (OR = 1.29; 95% CI 1.08–1.54; P = 0.005). The cumulative meta-analysis and sensitivity analysis further strengthened the stability of the result. Furthermore, publication bias was not detected.

Conclusions

This study suggested that SCGB1A1 + 38A/G polymorphism was a risk factor for asthma. Further large and well-designed studies are needed to confirm this association.     

Association of the macrophage migration inhibitory factor gene − 173G/C polymorphism with inflammatory bowel disease: A meta-analysis of 4296 subjects

A variety of epidemiologic studies have focused on the association between macrophage migration inhibitory factor (MIF) gene − 173G/C polymorphism and inflammatory bowel disease (IBD). However, results in different studies have been inconsistent. In order to derive a more precise estimation of the associations, we performed this meta-analysis and systematic searches of electronic databases PubMed and Web of Science (up to April 30, 2013). Based on our search criteria, a total of seven eligible studies concerning the MIF − 173G/C polymorphism and IBD risk were included in the final meta-analysis, comprising 2162 IBD cases and 2134 controls. Significant association was found between MIF − 173G/C polymorphism and the risk of IBD when all studies were pooled into the meta-analysis (for C allele vs. G allele: OR = 1.25, 95% CI = 1.12–1.41, p = 0.000; for C/C vs. G/G: OR = 1.71, 95% CI = 1.23–2.39, p = 0.002; for C/C + G/C vs. G/G: OR = 1.24, 95% CI = 1.09–1.42, p = 0.002; for C/C vs. G/C + G/G: OR = 1.67, 95% CI = 1.20–2.33, p = 0.002). Heterogeneity and publication bias did not exist in the overall comparisons. The present meta-analysis suggests an association between the MIF − 173G/C polymorphism and IBD risk. However, due to few studies and the selection bias existed in some studies, the results should be interpreted with caution.     

Lack of association between EGF + 61A>G polymorphism and melanoma susceptibility in Caucasians: A HuGE review and meta-analysis

Emerging evidence showed that the common polymorphism (+ 61A>G, rs4444903) in the promoter region of epidermal growth factor (EGF) gene might be associated with melanoma susceptibility in humans. But individually published results are inconclusive. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis is to derive a more precise estimation of the association between EGF + 61A>G polymorphism and melanoma risk. The PubMed, Embase, Web of Science and CBM databases were searched for all articles published up to July 1st, 2012. Seven case–control studies were included with a total of 2367 melanoma cases and 4184 healthy controls. Meta-analysis results showed that there was no significant relationship between EGF + 61A>G polymorphism and the risk of melanoma (G vs A: odds ratio [OR] = 1.08, 95% confidence interval [CI]: 0.91–1.28, P = 0.386; GG + AG vs AA: OR = 1.05, 95%CI: 0.88–1.26, P = 0.580; GG vs AA + AG: OR = 1.10, 95%CI: 0.81–1.49, P = 0.552; GG vs AA: OR = 1.06, 95%CI: 0.80–1.41, P = 0.700; GG vs AG: OR = 1.12, 95%CI: 0.81–1.56, P = 0.494). Further subgroup analyses based on source of controls, country, detection samples, genotype methods, and Breslow thickness of tumor, we also found no significant association between EGF + 61A>G polymorphism and melanoma risk. In conclusion, this meta-analysis indicates that EGF + 61A>G polymorphism might not be a primary determinant in melanoma development and progression; EGF gene might be expected to interact with other genes in different signaling pathways to initiate and promote the carcinogenic process.     

Association between interleukin-6 gene − 174 G/C polymorphism and the risk of coronary heart disease: A meta-analysis of 20 studies including 9619 cases and 10,919 controls

Interleukin-6 (IL-6) gene − 174 G/C polymorphism has been reported to be associated with coronary heart disease (CHD), but the results remain inconclusive. The present meta-analysis was therefore designed to clarify these controversies. This meta-analysis was performed by searching PubMed, Embase and Web of Science databases. A total of 20 studies including 9619 CHD cases and 10,919 controls were combined showing no evidence of association between IL-6 gene − 174 G/C polymorphism and CHD risk (for C/C + C/G vs. G/G: OR = 1.10, 95% CI = 0.99–1.22, p = 0.07; for C/C vs. C/G + G/G: OR = 1.08, 95% CI = 0.93–1.24, p = 0.33; for C/C vs. G/G: OR = 1.16, 95% CI = 0.97–1.39, p = 0.11; for C allele vs. G allele: OR = 1.10, 95% CI = 1.00–1.21, p = 0.06). Moreover, we also did not find significant association between IL-6 gene − 174 G/C polymorphism and myocardial infarction (MI) risk. However, in the subgroup analysis by ethnicity, significant association was found among Asians (for C/C + C/G vs. G/G: OR = 1.35, 95% CI = 1.05–1.63, p = 0.02). In summary, the present meta-analysis suggests that IL-6 gene − 174 G/C polymorphism is associated with increased CHD risk among Asians. However, due to the small subjects included in the subgroup analysis of Asians, the results should be interpreted with caution.     

Epigenetic modulation of RFC1, MHC2TA and HLA-DR in systemic lupus erythematosus: Association with serological markers and six functional polymorphisms of one-carbon metabolic pathway

The current study was conducted to elucidate the effect of genetic variations in one-carbon metabolism on the epigenetic regulation of major histocompatibility complex II transactivator (MHC2TA), reduced folate carrier 1 (RFC1/SLC19A1) and human leukocyte antigen (HLA)-DR in systemic lupus erythematosus (SLE). PCR-RFLP/AFLP, bisulfite-sequencing and real-time PCR approaches were used for genetic, epigenetic and expression analysis respectively. SLE cases exhibited elevated plasma homocysteine levels compared to healthy controls (24.93 ± 1.3 vs. 11.67 ± 0.48 μmol/l), while plasma folate levels showed no association (7.10 ± 2.49 vs. 7.64 ± 2.09 ng/ml). The RFC1 80G>A polymorphism showed 1.32-fold risk (95% CI: 1.02–1.72) for SLE, while glutamate carboxypeptidase II (GCPII) 1561C>T showed reduced risk (OR: 0.47, 95% CI: 0.24–0.90). The expression of RFC1 (0.37 ± 0.09 vs. 0.60 ± 0.17) and HLA-DR (0.68 ± 0.17 vs. 0.98 ± 0.02) was down regulated in the SLE cases. The hypermethylation of RFC1 as observed in the current study may contribute for its down regulation. Plasma folate and thymidylate synthase (TYMS) 5′-UTR 28 bp tandem repeat showed an inverse association with methylation of RFC1 and MHC2TA. SLE cases with hypocomplementemia showed hypermethylation of RFC1, hypomethylation/up regulation of MHC2TA and down regulation of HLA-DR. The hypermethylation of MHC2TA and down regulation of RFC1, MHC2TA and HLA-DR were observed in anti-cardiolipin antibody positive SLE cases. The up regulation of RFC1 and HLA-DR was observed in anti-dsDNA antibody positive SLE cases. The hypomethylation/upregulation of RFC1 and MHC2TA was observed in anti-RNP antibody positive cases. To conclude, one-carbon genetic variants influence epigenetic of MHC2TA and RFC1, thus contributing to phenotypic heterogeneity of SLE.     

Current evidence on the relationship between five polymorphisms in the matrix metalloproteinases (MMP) gene and lung cancer risk: A meta-analysis

Purpose

Matrix metalloproteinase (MMP) 1, MMP2, MMP3 and MMP9 are important members of the MMP family. Recently, many studies have been carried out on the association between polymorphisms of MMP1-1607 1G/2G, MMP2-735 C/T, MMP2-1306 C/T, MMP3-1171 5A/6A and MMP9-1562 C/T and lung cancer risk. However the results of these studies remained inconclusive due to conflicting results from different case–control studies. To clarify these associations, we conducted a meta-analysis.

Methods

We conducted a comprehensive search in Medline, EMBASE, OVID and Chinese Biomedical Literature Database (date from Jan 2000 to Aug 2012). Overall and subgroup analysis by the ethnicity of study population was carried out. Odds ratio (OR) with 95% confidence interval (95%CI) was used to assess the strength of the association.

Results

There were 17 studies involving five polymorphic sites in four MMP genes. For MMP1-1607,increased lung cancer risk was found under dominant model (MMP1-1607 1G/2G: OR = 1.14, 95%CI = 1.03–1.26, P = 0.01), but not in the Caucasian population. For MMP2-1306 C/T, T polymorphism decreased lung cancer risk under dominant and recessive models (dominant, OR = 0.63, 95%CI = 0.46–0.88, P = 0.0006; recessive, OR = 0.61, 95%CI = 0.38–0.99, P = 0.04). For MMP9-1562 C/T, TT genotype decreased this risk under the recessive model (OR = 0.38, 95%CI = 0.19–0.75, P = 0.005), but not in the Asian population. For MMP2-735 C/T and MMP3-1171 5A/6A, there was no association between this polymorphism and lung cancer risk under the dominant and recessive models.

Conclusions

MMP1-1607 1G/2G polymorphism increased lung cancer risk in Asians. It was also found thatMMP2-1306 C/T polymorphism decreased lung cancer risk in Asians, while MMP9-1562 C/T polymorphism decreased lung cancer risk in Caucasians. No significant difference was found in any genotype of MMP2-735 C/T and MMP3-1171 5A/6A. Further studies with larger sample sizes should be carried out.     

Genetic association of interleukin-10 promoter polymorphisms and susceptibility to diffuse large B-cell lymphoma: A meta-analysis

Published data on the association between interleukin-10 (IL-10) gene polymorphisms and diffuse large B-cell lymphoma (DLBCL) risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed, focusing on four major IL-10 gene variants in the promoter region: –3575T/A, –1082A/G, –819C/T and –592C/A. We applied the false discovery rate (FDR) method to adjust for multiple testing. A significant association between IL-10 –3575T/A polymorphism and the risk of DLBCL was observed in the pooled 10 case–control studies (A vs. T: OR = 1.16, 95% CI = 1.08–1.25, P < 0.0001; AA + TA vs. TT: OR = 1.20, 95% CI = 1.08–1.33, P = 0.0009; AA vs. TA + TT: OR = 1.25, 95% CI = 1.09–1.44, P = 0.001). The results indicated that carriers of –1082G allele (–1082GG/GA genotypes) had a nearly 30% increased risk of DLBCL, as compared with carriers of –1082AA genotype (GG + GA vs. AA: OR = 1.30, 95% CI = 1.08–1.57, P = 0.005). When P-values were not adjusted for multiple testing, the risk was significantly decreased among people with –592AA genotype (AA vs. AC + CC: OR = 0.63, 95% CI = 0.43–0.94, P = 0.02), while carriers with –819TT genotype also modestly weakened the DLBCL susceptibility at a marginal level of significance (TT vs. CT + CC: OR = 0.59, 95% CI = 0.35–0.99, P = 0.05). However, these associations were not significant after correction for multiple testing. This meta-analysis suggests that IL-10 –3575A allele confers a greater risk to DLBCL susceptibility, while –1082A/G polymorphism also has significant association with DLBCL risk. These results may help to further clarify the malignancy-risk gene signature of DLBCL, and thus have prognostic and predictive value especially for early-stage DLBCL.     

Association study of TRAF1/C5 polymorphism (rs10818488) with susceptibility to rheumatoid arthritis and systemic lupus erythematosus: A meta-analysis

To determine whether the tumor necrosis factor (TNF)-receptor associated factor 1/complement component 5 (TRAF1/C5) polymorphism (rs10818488) confers susceptibility to rheumatoid arthritis (RA) and systemic lupus erythematous (SLE), a meta-analysis was performed. A total of 11 studies with 17 comparisons (11 for RA, 6 for SLE) were available for this meta-analysis, which consisted of 13,456 patients, 12,259 controls for RA and 1,894 patients, 6,729 controls for SLE. A significant association of the A allele of TRAF1/C5 polymorphism (rs10818488) with RA susceptibility was detected in the North Africa population (OR = 1.557, 95% CI: 1.225–1.977). Furthermore, the association between this allelic variant and SLE risk was additionally found in population of European (OR = 1.247, 95% CI: 1.060–1.466). Analysis also showed the A/G allelic frequency of TRAF1/C5 variant (rs10818488), in different healthy populations, had a different distribution (χ² = 269.41, P < 0.001). Taken together, our study demonstrates that the TRAF1/C5 polymorphism (rs10818488) may confer susceptibility to RA in North Africa population, and in European population, it might be a contributory factor towards SLE.     

Influence of interleukin-6 gene − 174G>C polymorphism on development of atherosclerosis: A meta-analysis of 50 studies involving 33,514 subjects

Increasing epidemiological studies have focused on the associations between interleukin-6 (IL-6) gene − 174G>C polymorphism and atherosclerotic diseases, but the results are still controversial. This meta-analysis was designed to identify whether this association exists. PubMed, Embase, Web of Science, Cochrane database, Clinicaltrials.gov and Current Controlled Trials, Chinese Clinical Trial Registry, CBMdisc, CNKI and Google Scholar were searched to get the genetic association studies. The crude odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were used to estimate the association between the IL-6 gene − 174G>C polymorphism and atherosclerosis ( AS ) risk. The subgroup analyses were made on the following: ethnicity, atherosclerotic diseases and source of controls. Finally, 50 studies (15,029 cases and 18,485 controls) were included in this meta-analysis. Overall, no significant association was found between the IL-6 gene − 174G>C polymorphism and AS risk (for C allele vs. G allele: OR = 1.02, 95% CI = 0.94–1.11, p = 0.64; for C/C vs. G/G: OR = 1.01, 95% CI = 0.85–1.21, p = 0.88; for C/C vs. C/G + G/G: OR = 0.97, 95% CI = 0.84–1.12, p = 0.68; for C/C + C/G vs. G/G: OR = 1.07, 95% CI = 0.97–1.17, p = 0.18). In the subgroup analyses, significant associations were found between the IL-6 gene − 174G>C polymorphism and AS in non-Caucasian group (for CC + CG vs. GG: OR = 1.22, 95% CI = 1.06–1.41, p = 0.005), other atherosclerotic diseases group (for C allele vs. G allele: OR = 0.75, 95% CI = 0.61–0.93, p = 0.008; for C/C vs. G/G: OR = 0.56, 95% CI = 0.38–0.81, p = 0.002; for C/C vs. C/G + G/G: OR = 0.60, 95% CI = 0.45–0.79, p = 0.0004) and population-based group (for C allele vs. G allele: OR = 1.09, 95% CI = 1.00–1.18, p = 0.04; for CC + CG vs. GG: OR = 1.15, 95% CI = 1.04–1.27, p = 0.005). In summary, the present meta-analysis suggests that the IL-6 gene − 174G C polymorphism is associated with the susceptibility to AS. However, due to the high heterogeneity in the meta-analysis, the results should be interpreted with caution.     

Association between cytotoxic T lymphocyte antigen-4 polymorphism and type 1 diabetes: A meta-analysis

Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) is an important mediators of T-cell activation in autoimmune diseases. The association of polymorphisms of CTLA gene with type 1 diabetes (T1D) has widely been reported; however, the results are inconsistent. To obtain further insight into this topic, we performed a meta-analysis of 52 studies involving a total of 11,017 cases and 14,191 controls for 49A/G (rs231775) polymorphism of the CTLA-4 gene to evaluate the effect of CTLA-4 on genetic susceptibility for T1D. An overall random effects odds ratio of 1.41 (95% CI: 1.31–1.53, p < 10^− 5) was found for G allele versus A allele. Significant results were also observed for heterozygous (OR = 1.29, 95% CI: 1.16–1.45, p < 10^− 5) and homozygous (OR = 1.96, 95% CI: 1.66–2.31, p < 10^− 5). When stratified by ethnicity, sample size, diagnostic criterion, HWE status, genotyping method, and onset types, significantly increased risks were found for the polymorphism in almost all genetic models. Subgroup analysis and meta-regression was used to identify potential source of heterogeneity. There was strong evidence of heterogeneity, which largely disappeared after stratification by ethnicity. This meta-analysis demonstrated that the G allele of rs231775 of CTLA-4 is a risk factor associated with increased T1D susceptibility.     

Assessment of clinical outcomes in breast cancer patients treated with taxanes: multi-analytical approach

Polymorphisms in genes encoding CYPs (Phase I) and ABCB1 (Phase III) enzymes may attribute to variability of efficacy of taxanes. The present study aims to find the influence of CYP and ABCB1 gene polymorphisms on taxanes based clinical outcomes. 132 breast cancer patients treated with taxanes based chemotherapy were genotyped for CYP3A4*1B, CYP3A5*3, CYP1B1*3, CYP2C8*3, ABCB1 1236C>T, 2677G>T/A and 3435C>T polymorphisms using PCR-RFLP. Associations of genetic variants with clinical outcomes in terms of response in 58 patients receiving neo-adjuvant chemotherapy (NACT), and chemo-toxicity in 132 patients were studied. Multifactor dimensionality reduction (MDR) analysis was performed to evaluate higher order gene–gene interactions with clinical outcomes. Pathological response to taxane based NACT was associated with GA genotype as well as A allele of CYP3A5*3 polymorphism (P_corr = 0.0465, P_corr = 0.0465). Similarly, association was found in dominant model of CYP3A5*3 polymorphism with responders (P_corr = 0.0465). Haplotype analysis further revealed A_CYP3A4–A_CYP3A5 haplotype to be significantly associated with responders (P_corr = 0.048). In assessing toxicity, significant association of variant (TT) genotype and T allele of ABCB1 2677G>T/A polymorphism, was found with ‘grade 1 or no leucopenia’ (P_corr = 0.0465, P_corr = 0.048). On evaluating higher order gene–gene interaction models by MDR analysis, CYP3A5*3; ABCB11236C>T and ABCB1 2677G>T/A; ABCB1 3435C>T and CYP1B1*3 showed significant association with treatment response, grade 2–4 anemia and dose delay/reduction due to neutropenia (P = 0.024, P = 0.004, P = 0.026), respectively. Multi-analytical approaches may provide a better assessment of pharmacogenetic based treatment outcomes in breast cancer patients treated with taxanes.     

Association between IL13 gene polymorphisms and susceptibility to cancer: A meta-analysis

Background/aims

Interleukin-13 (IL13) is an immunoregulatory cytokine which plays an important role in carcinogenesis through affecting tumor immunosurveillance. Many studies had reported the influence of IL13 rs1800925 and rs20541 polymorphisms on cancer risk, however, with inconclusive results. The aim of the present study was to conduct a meta-analysis to clarify the relationship.

Methods

Twenty studies including a total of 6713 cancer cases and 8693 controls for IL13 rs20541 polymorphism and 4081 cancer cases and 6202 controls for IL13 rs1800925 polymorphism were included in the meta-analysis. Data were extracted from these studies and odds ratios with corresponding 95% confidence intervals were computed to estimate the strength of the association.

Results

Overall, the IL13 rs20541 polymorphism were associated with significantly decreased cancer risk in all genetic models (AA vs. GG: OR = 0.82, 95%CI = 0.71–0.95; GA vs. GG: OR = 0.92, 95%CI = 0.85–0.99; GA/AA vs. GG: OR = 0.90, 95%CI = 0.85–0.97; AA vs. GG/GA: OR = 0.85, 95CI% = 0.74–0.98). In the stratified analyses, significant effects were found among European populations, studies with population-based controls and studies of glioma. No influence of the IL13 rs1800925 polymorphism on the overall cancer risk was observed. However, in the stratified analyses, we found the IL13 rs1800925 polymorphism was significantly associated with decreased risk for glioma (CT vs. TT: OR = 0.72, 95%CI = 0.55–0.93; CT/TT vs. TT: OR = 0.76, 95%CI = 0.62–0.89).

Conclusion

Our meta-analysis suggests that the IL13 rs20541 polymorphism contributes to susceptibility to cancer, especially for glioma; and the IL13 rs1800925 polymorphism may be associated with glioma risk.     

Association between the ghrelin Leu72Met polymorphism and type 2 diabetes risk: A meta-analysis

Aims

Data on the association between the ghrelin Leu72Met polymorphism and type 2 diabetes are conflicting. A meta-analysis was performed on this topic.

Methods

We searched for case–control studies using electronic databases (Medline and PubMed) and reference lists of studies. Odds ratios (OR) and 95% confidence intervals (CI) assuming dominant, recessive and homozygote comparison genetic models were calculated.

Results

Six case–control studies involving a total of 3417 cases and 3081 controls were included in this meta-analysis. No association was found between the ghrelin Leu72Met polymorphism and type 2 diabetes risk in the overall population in dominant, recessive and homozygote comparison models. However, in subgroup analyses stratified by ethnicity, we found that the risk for type 2 diabetes was decreased in subjects with Met72 + genotypes in Caucasians (OR = 0.79, 95% CI: 0.64–0.98, P_z = 0.030).

Conclusion

The ghrelin Leu72Met polymorphism was protective against type 2 diabetes in Caucasians. Future studies performed in larger sample size are needed to allow a more definitive conclusion.     

Myeloperoxidase G-463A polymorphism and susceptibility to coronary artery disease: A meta-analysis

Published data on the association between the myeloperoxidase (MPO) G-463A polymorphism and coronary artery disease (CAD) are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis on this topic was performed. PubMed, EMBASE and Chinese national knowledge infrastructure were searched for studies regarding the association between the MPO G-463A polymorphism and CAD. A logistic regression analysis was used to estimate the genetic effect and the possible genetic model of action. Summary odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were calculated. There was strong evidence for an association between the MPO G-463A polymorphism and CAD. The genetic model of action was most likely to be co-dominant. Overall, the data showed that AA and GA genotypes were significantly associated with reduced risk of CAD (AA vs. GG: OR = 0.37, 95% CI = 0.17–0.78; GA vs. GG: OR = 0.73, 95% CI = 0.57–0.92). In subgroup analyses by study population and sources of controls, statistically significant results were observed in the Chinese population (AA vs. GG: OR = 0.21, 95% CI = 0.10–0.43; GA vs. GG: OR = 0.57, 95% CI =0.44–0.74) and in hospital-based control studies (AA vs. GG: OR = 0.20, 95% CI = 0.10–0.39; GA vs. GG: OR = 0.61, 95% CI = 0.48–0.77). This meta-analysis suggests that the MPO G-463A variant genotypes may be associated with decreased risk of CAD. However, given the limited number of studies and the potential biases, the influence of this polymorphism on CAD risk needs further investigation.