Association between -251A>T polymorphism in the interleukin-8 gene and oral cancer risk: A meta-analysis

Background

Emerging evidence showed that the most common functional polymorphism (-251A>T, rs4073) in the promoter region of the interleukin-8 (IL-8) gene is involved in the regulation of the activities of interleukin-8, thus increasing an individual's susceptibility to oral cancer; but individually published results are inconclusive. The aim of this meta-analysis was to investigate the associations between IL-8 -251A>T polymorphism and oral cancer risk.

Methods

The PubMed, Embase, Web of Science and CBM databases were searched for all articles published up to October 1st, 2012 that addressed IL-8 -251A>T polymorphism and oral cancer risk. Statistical analyses were performed using STATA 12.0 software. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

Six case–control studies were included with a total of 1324 oral cancer cases and 1879 healthy controls. When all available studies were pooled into the meta-analysis, the results showed that the AA and AT genotypes of IL-8 -251A>T polymorphism were associated with increased risk of oral cancer (OR = 1.23, 95% CI: 1.03–1.46, P = 0.025; OR = 1.25, 95% CI: 1.07–1.47, P = 0.006; respectively). In the subgroup analysis by ethnicity, significant associations were observed between the AA and AT genotypes of IL-8 -251A>T polymorphism and increased risk of oral cancer among Caucasian populations (OR = 1.40, 95% CI: 1.14–1.72, P = 0.001; OR = 1.29, 95% CI: 1.06–1.57, P = 0.011; respectively). However, no statistically significant associations were found between IL-8 -251A>T polymorphism and oral cancer risk among Asian populations.

Conclusions

Results from the current meta-analysis indicate that the AA and AT genotypes of IL-8 -251A>T polymorphism might increase the risk of oral cancer, especially among Caucasian populations.     

Genetic polymorphisms of xeroderma pigmentosum group D gene Asp312Asn and Lys751Gln and susceptibility to prostate cancer: A systematic review and meta-analysis

Many studies have reported the role of xeroderma pigmentosum group D (XPD) with prostate cancer risk, but the results remained controversial. To derive a more precise estimation of the relationship, a meta-analysis was performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association between XPD Asp312Asn and Lys751Gln polymorphisms and prostate cancer risk. A total of 8 studies including 2620 cases and 3225 controls described Asp312Asn genotypes, among which 10 articles involving 3230 cases and 3582 controls described Lys751Gln genotypes and were also involved in this meta-analysis. When all the eligible studies were pooled into this meta-analysis, a significant association between prostate cancer risk and XPD Asp312Asn polymorphism was found. For Asp312Asn polymorphism, in the stratified analysis by ethnicity and source of controls, prostate cancer risk was observed in co-dominant, dominant and recessive models, while no evidence of any associations of XPD Lys751Gln polymorphism with prostate cancer was found in the overall or subgroup analyses. Our meta-analysis supports that the XPD Asp312Asn polymorphism contributed to the risk of prostate cancer from currently available evidence. However, a study with a larger sample size is needed to further evaluate gene–environment interaction on XPD Asp312Asn and Lys751Gln polymorphisms and prostate cancer risk.     

EGF + 61A > G polymorphism and gastrointestinal cancer risk: A HuGE review and meta-analysis

Emerging evidences from preclinical and clinical studies have shown that epidermal growth factor (EGF) has some effectiveness against endogenously arising carcinogenesis. Functional + 61A > G polymorphism (rs4444903 A > G) in the promoter region of the EGF gene was observed to modulate EGF levels, thus affecting the susceptibility to gastrointestinal cancer; but individually published studies showed inconclusive results. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis was to derive a more precise estimation of the association between EGF + 61A > G polymorphism and gastrointestinal cancer risk. A literature search of Pubmed, Embase, Web of Science and Chinese BioMedical databases from inception through July 2012 was conducted. Twelve studies were assessed with a total of 2868 gastrointestinal cancer cases and 4278 healthy controls. When all the eligible studies were pooled into the meta-analysis, the results showed that the G allele and GG genotype of EGF + 61A > G polymorphism might increase the risk of gastrointestinal cancer. In the stratified analysis by cancer types, the G allele and GG genotype of EGF + 61A > G polymorphism showed displayed significant correlations with increased risk of esophageal cancer. We also found significant correlations between the G carrier (GG + AG) and GG genotype of EGF + 61A > G polymorphism and colorectal cancer risk. However, EGF + 61A > G polymorphism did not appear to have an influence on gastric cancer susceptibility. Results from the current meta-analysis indicate that EGF + 61A > G polymorphism might increase the risk of esophageal and colorectal cancers. Nevertheless, further studies are needed to determine whether genetic associations between EGF + 61A > G polymorphism and susceptibility to gastric cancer are significant.     

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.     

GSTP1 Ile105Val polymorphism and colorectal cancer risk: An updated analysis

Background

Many studies have investigated the association between the Glutathione S transferase-P1 (GSTP1) Ile105Val polymorphism and colorectal cancer (CRC) susceptibility, but the results were conflicting. The aim of this study is to quantitatively summarize the relationship between this polymorphism and CRC risk.

Methods

Two investigators independently searched the Medline, Embase, China National Knowledge Infrastructure (CNKI) and Chinese Biomedicine databases for studies published before December 2012. Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) for GSTP1 polymorphism and CRC were calculated in a fixed-effects model (the Mantel–Haenszel method) and a random-effects model (the DerSimonian and Laird method) when appropriate.

Results

This meta-analysis included 29 case–control studies, which included 8160 CRC cases and 10,450 controls. Overall, the variant genotypes (ValVal and IleVal) of the Ile105Val were not associated with CRC risk when compared with the wild-type IleIle homozygote. Similarly, no associations were found in the dominant and recessive models. When stratifying for ethnicity, source of controls, study sample size and genotyping methods, no evidence of significant association was observed in any subgroup, except among those studies taking others as genotyping methods (recessive model, OR = 0.71, 95%CI = 0.52–0.96). Limiting the analysis to the studies within Hardy–Weinberg equilibrium, the results were persistent and robust. No publication bias was found in the present study.

Conclusion

This updated meta-analysis suggests that the GSTP1 Ile105Val polymorphism may not be associated with CRC risk, while the observed decrease in risk of CRC may be due to small-study bias.     

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.     

Calpain-10 genetic polymorphisms and polycystic ovary syndrome risk: A meta-analysis and meta-regression

Recent evidences suggest that common functional polymorphisms in the promoter region of the Calpain-10 gene may have an impact on an individual's susceptibility to polycystic ovary syndrome (PCOS), but individually published results are inconclusive. Our meta-analysis is aimed to provide a more precise estimation of the relationships between Calpain-10 genetic polymorphisms and PCOS risk. An extensive literature search for relevant studies was conducted on PubMed, Embase, Web of Science, Cochrane Library, and CBM databases from inception through April 1st, 2013. This meta-analysis was performed using the STATA 12.0 software. The crude odds ratio (OR) with 95% confidence interval (CI) was calculated. Fourteen case–control studies were included with a total of 2123 PCOS patients and 3612 healthy controls. Nine common SNPs in the Calpain-10 gene were addressed. Our meta-analysis indicated that UCSNP-19, UCSNP-63 and UCSNP-45 polymorphisms in the Calpain-10 gene might be associated with increased PCOS risk. However, no statistically significant association was observed in UCSNP-43, UCSNP-22, UCSNP-43, UCSNP-45, UCSNP-56, UCSNP-58, and UCSNP-110 polymorphisms. Further subgroup analysis by ethnicity revealed that UCSNP-19, UCSNP-63 and UCSNP-45 polymorphisms might decrease the risk of PCOS among Asian populations, but not among Caucasian populations. The current meta-analysis indicates that UCSNP-19, UCSNP-63 and UCSNP-45 polymorphisms in the Calpain-10 gene may be risk factors for PCOS, especially among Asian populations.     

Meta-analyses of HFE variants in coronary heart disease

Aim

HFE gene variants can cause hereditary hemochromatosis (HH) that often comes along with an increased risk of coronary heart disease (CHD). The goal of our study is to assess the contribution of four HFE gene variants to the risk of CHD.

Methods and results

We conducted four meta-analyses of the studies examining the association between four HFE gene variants and the risk of CHD. A systematic search was conducted using MEDLINE, EMBASE, Web of Science and China National Knowledge Infrastructure (CNKI), Wanfang Chinese Periodical.

Results

Meta-analyses showed that HFE rs1799945-G allele was associated with a 6% increased risk of CHD (P = 0.02, odds ratio (OR) = 1.06, 95% confidence interval (CI) = 1.01–1.11). However, no association between the other three HFE gene variants (rs1800562, rs1800730, and rs9366637) and CHD risk was observed by the meta-analyses (all P values > 0.05). In addition, the results of our case–control study indicated that rs1800562 and rs1800730 were monomorphic, and that rs1799945 and rs9366637 were not associated with CHD in Han Chinese.

Conclusions

Our meta-analysis suggested that a significant association existed between rs1799945 mutation and CHD, although this mutation was rare in Han Chinese.     

The interleukin-4 − 589C/T polymorphism and the risk of asthma: A meta-analysis including 7345 cases and 7819 controls

Background

A number of studies assessed the association of − 589C/T polymorphism in the promoter region of interleukin-4 (IL-4) with asthma in different populations. However, the results were contradictory. A meta-analysis was conducted to investigate the association between polymorphism in the IL-4 and asthma susceptibility.

Methods

Databases including Pubmed, EMBASE, Wanfang Database, China National Knowledge Infrastructure (CNKI) and Weipu Database were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

Thirty-four studies involving 7345 cases and 7819 controls were included. Overall, significant association between − 589C/T polymorphism and asthma was observed for TT + CT vs. CC (OR = 1.26; 95% CI 1.12–1.42; P = 0.0001; I² = 26%). In the subgroup analysis by ethnicity, significant associations were found among Asians (OR = 1.36; 95% CI 1.07–1.73; P = 0.01; I² = 0%) and Caucasians (OR = 1.30; 95% CI 1.09–1.54; P = 0.004; I² = 53%) but not among African Americans (OR = 1.20; 95% CI 0.72–2.00; P = 0.48; I² = 48%). In the subgroup analysis by atopic status, no significant association was found among atopic asthma patients (OR = 1.20; 95% CI 0.92–1.34; P = 0.27; I² = 6%) and non-atopic asthma patients (OR = 0.97; 95% CI 0.73–1.28; P = 0.81; I² = 0%).

Conclusions

This meta-analysis suggested that the IL-4 − 589C/T polymorphism was a risk factor of asthma.     

Promoter polymorphisms in trefoil factor 2 and trefoil factor 3 genes and susceptibility to gastric cancer and atrophic gastritis among Chinese population

The polymorphisms in trefoil factor (TFF) gene family that protect gastrointestinal epithelium might influence individual vulnerability to gastric cancer (GC) and atrophic gastritis. We used the Sequenom MassARRAY platform to identify the genotypes of TFF2 rs3814896 and TFF3 rs9981660 polymorphisms in 478 GC patients, 652 atrophic gastritis patients, and 724 controls. For the TFF2 rs3814896 polymorphism, in the subgroup aged ≤ 50 years, we found that AG + GG genotypes were associated with a 0.746-fold decreased risk of atrophic gastritis [p = 0.023, 95% confidence interval (CI) = 0.580–0.960], a 0.626-fold decreased risk of GC (p = 0.005, 95% CI = 0.451–0.868), and a 0.663-fold decreased risk of diffuse-type GC (p = 0.034, 95% CI = 0.452–0.970) compared with the common AA genotype. For the TFF3 rs9981660 polymorphism, in the male subgroup, individuals with variant AG + AA genotype were associated with a 0.761-fold decreased risk of diffuse-type GC compared with the common GG genotype (p = 0.043, 95% CI = 0.584–0.992). Additionally, we found that in subjects aged ≤ 50 years compared with common AA genotype, TFF2 rs3814896 AG + GG genotypes were associated with increased TFF2 mRNA levels in the total gastric cancer specimens and in the diffuse-type gastric cancer specimens; and in males aged ≤ 50 years compared with common GG genotype, TFF3 rs9981660 AA + AG genotypes were associated with TFF3 mRNA levels in diffuse-type gastric cancer tissues and their corresponding non-cancerous tissues. To our knowledge, this is the first report of an association between the TFF2 rs3814896 AG + GG genotypes and decreased risks of GC, diffuse-type GC, and atrophic gastritis in younger people aged ≤ 50 years, and an association between TFF3 rs9981660 AG + AA genotype and decreased risk of diffuse-type GC in men. Moreover, we found that TFF2 rs3814896 AG + GG genotypes in people aged ≤ 50 years and TFF3 rs9981660 AG + AA genotypes in younger males with diffuse-type GC were associated with higher levels of TFF2 and TFF3 mRNA respectively.     

SCN1A rs3812718 polymorphism and susceptibility to epilepsy with febrile seizures: A meta-analysis

Background

Evidence showed that the SCN1A IVS5N+5G>A polymorphism might be associated with susceptibility to epilepsy with febrile seizures (EFS), however, the published data were inconclusive. Therefore, a meta-analysis was performed to estimate the overall EFS risk with the polymorphism.

Methods

The PubMed and Medline were searched up to March, 2013 for studies on the association between SCN1A IVS5N+5G>A polymorphism and EFS risk. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by means of a genetic model free approach. The heterogeneity and sensitivity of each report and the publication bias were also performed. All the statistical analyses were done using the STATA 11.0 software.

Result

A total of 6 studies with 2719 cases and 2317 controls met the selection criteria. We found significant association between SCN1A polymorphism and EFS (A vs. G: OR = 1.498, 95%CI = 1.138–1.972; AA vs. GG: OR = 2.292, 95%CI = 1.620–3.243; AG vs. GG: OR = 1.414, 95%CI = 1.010–1.978; recessive model: OR = 1.747, 95%CI = 1.119–2.728 and dominant model: OR = 1.730, 95%CI = 1.259–2.376). When compared with the epilepsy without febrile seizure (EWFS), the subgroup analysis stratified by ethnicity showed that the SNP was significantly associated with EFS in Caucasian (A vs. G: OR = 1.505, 95%CI = 1.218–1.861; AA vs. GG: OR = 2.081, 95%CI = 1.358–3.189; recessive model: OR = 1.715, 95%CI = 1.273–2.310 and dominant model: OR = 1.625, 95%CI = 1.096–2.410), but not in Indian and Chinese. When applying Bonferroni correction (significance was set at 0.05/20), the Caucasian still has robust association with EFS and epilepsy.

Conclusion

The present meta-analysis suggests that SCN1A IVS5N+5G>A polymorphism is a risk factor of EFS and epilepsy, especially in Caucasian.     

XRCC1 polymorphisms and differentiated thyroid carcinoma risk: A meta-analysis

The objective of this study is to quantitatively derive a more precise estimation of the association between X-ray repair cross-complementing group 1 (XRCC1) gene polymorphisms and differentiated thyroid carcinoma risk. A comprehensive literature search of three databases was conducted. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with fixed-effect models and random-effect models when appropriate. Overall, no association of the XRCC1 Arg399Gln, Arg280His, and Arg194Trp polymorphisms with differentiated thyroid carcinoma risk was found. In subgroup analyses, a decreased differentiated thyroid carcinoma risk was observed among Caucasians (Gln vs. Arg, OR = 0.86, 95% CI = 0.77–0.96, P = 0.343 for heterogeneity; Gln/Arg vs. Arg/Arg, OR = 0.84, 95% CI = 0.71–0.98, P = 0.229 for heterogeneity; Gln/Gln vs. Arg/Arg, OR = 0.77, 95% CI = 0.60–0.99, P = 0.477 for heterogeneity; dominant genetic model, OR = 0.82, 95% CI = 0.71–0.95, P = 0.272 for heterogeneity), not among Asians. No publication bias was observed. Our results suggest that XRCC1 Arg399Gln polymorphism is not associated with differentiated thyroid carcinoma risk, while a decreased risk is observed among Caucasian population.     

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 XRCC1 Arg399Gln polymorphism with bladder cancer susceptibility: A meta-analysis

Genetic variations in DNA repair genes are thought to modify DNA repair capacity and may to be related to cancer susceptibility. However, epidemiological study results have been inconsistent. In this meta-analysis, we assessed 24 case–control studies of association between the X-ray repair cross complementing group 1 (XRCC1) Arg399Gln polymorphism and bladder cancer susceptibility in the general population and in Asian and non-Asian subgroups. A moderately significant association with bladder cancer risk was found for AG vs GG (OR = 1.110, 95% CI = 1.018–1.210). No significant associations with bladder cancer risk were found for AA vs GG (OR = 0.942, 95% CI = 0.823–1.077), the dominant model AA/AG vs GG (OR = 1.075, 95% CI = 0.990–1.167) and the recessive model AA vs AG/GG(OR = 0.890, 95% CI = 0.788–1.005). In subgroup analysis, a moderately significant association was also found for AG vs GG (OR = 1.091, 95% CI = 1.008–1.180) in non-Asian subgroup. The analysis suggests that the XRCC1 Arg399Gln polymorphism might be a moderate risk factor for bladder cancer, especially in non-Asian population.     

PSCA gene variants (rs2294008 and rs2978974) confer increased susceptibility of gallbladder carcinoma in females

Background and aim

PSCA is a tissue specific tumor suppressor or oncogene which has been found to be associated with several human tumors including gallbladder cancer. It is considered to be involved in the cell-proliferation inhibition and/or cell-death induction activity. Therefore, we aimed to investigate the role of PSCA gene polymorphisms in gallbladder cancer risk in North Indian population.

Methodology

A total of 405 gallbladder cancer patients and 247 healthy controls were included in the case–control study for risk prediction. We examined the association of two functional SNPs, rs2294008 and rs2978974 in PSCA gene by genotyping using Taqman allelic discrimination assays. Statistical analysis was done using SPSS software, version 17. Linkage disequilibrium and haplotype analysis was done with the help of SNPstats software. FDR test was used to correct for multiple comparisons.

Results

No significant associations of rs2294008 and rs2978974 genetic variants of the PSCA gene were found with GBC risk at allele, genotype or haplotype levels. Stratifying the subjects on the basis of gallstone also did not show any significant result. However, on gender stratification, we found a significant association of T_rs2294008-G_rs2978974 haplotype with higher risk of GBC in females (FDR Pcorr = 0.021, OR = 1.6). In contrary, T_rs2294008-A _rs2978974 haplotype conferred significant lower risk in males (FDR Pcorr = 0.013; OR = 0.25).

Conclusions

These findings suggest that PSCA genetic variants may have a significant effect on GBC susceptibility in a gender specific manner.     

Methylenetetrahydrofolate reductase 677TT genotype might be associated with an increased lung cancer risk in Asians

Background

The association between methylenetetrahydrofolate reductase (MTHFR) 677C > T polymorphism and lung cancer risk has been studied in various populations with conflicting results. The aim of this study was to assess the association strength by a meta-analysis of published studies.

Methods

We searched PubMed and Chinese Biomedical (CBM) databases for relevant literatures published by July 18, 2012. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the strength of the association.

Results

A total of 20 studies comprising 11,653 cases and 12,032 controls were included in the final meta-analysis. Using the random effect model, we found that MTHFR 677TT variant genotype was associated with an increased lung cancer risk (OR = 1.26, 95% CI = 1.05–1.50, P = 0.011 for TT vs. CC; OR = 1.19, 95% CI = 1.03–1.37, P < 0.001 for TT vs. CC + CT; OR = 1.11, 95% CI = 1.02–1.22, P = 0.017 for T allele vs. C allele). In the further stratified analyses, the increased lung cancer risk was found in Asian subjects (OR = 1.31, 95% CI = 1.01–1.71, P = 0.045 for TT vs. CC; OR = 1.17, 95% CI = 1.00–1.38, P = 0.048 for TT vs. CC + CT). There were no evidences for obvious publication bias in the overall meta-analysis and Asian subjects.

Conclusions

MTHFR 677TT genotype might increase the susceptibility of lung cancer, especially in Asians.     

The CXCL12 G801A polymorphism and cancer risk: Evidence from 17 case‐control studies

CXCL12 has been implicated in human carcinogenesis, but the association between the most-studied G801A polymorphism (rs1801157) and the risk of various cancers was reported with inconclusive results. The aim of this study was to assess the association between the CXCL12 G801A polymorphism and cancer risk. A meta-analysis of 17 studies with 3048 cancer patients and 4522 controls was conducted to evaluate the strength of the association using odds ratio (OR) with its 95% confidence interval (CI). The overall results showed that the variant genotypes were associated with a significantly increased risk of all cancer types (OR = 1.38, 95%CI = 1.18–1.61 for GA versus GG, and OR = 1.36, 95%CI = 1.17–1.59 for GA/AA versus GG). In the stratified analyses, there was a significantly increased risk for the studies of breast cancer (OR = 1.64, 95% CI = 1.16–2.33 for AA versus GG, OR = 1.42, 95%CI = 1.18–1.71 for GA versus GG, and OR = 1.44, 95%CI = 1.21–1.72 for GA/AA versus GG) and lung cancer (OR = 2.86, 95% CI = 1.75–4.69 for AA versus GG, OR = 1.62, 95% CI = 1.20–2.18 for GA vs. GG, OR = 1.80, 95% CI = 1.36–2.39 for GA/AA versus GG, and OR = 2.24, 95%CI = 1.41–3.57 for AA versus GA/GG), which remained for the studies of Asian populations and hospital-based control sources. Although some modest bias could not be eliminated, this meta-analysis indicates that the CXCL12 G801A polymorphism is a low-penetrance risk factor for cancer development.     

Interleukin-18 gene polymorphisms and rheumatoid arthritis: A meta-analysis

Interleukin-18 (IL-18) is a member of the IL-1 superfamily that enhances both innate and acquired immune responses. IL-18 is highly expressed in sera, synovial fluids and synovial tissues of patients with RA, and these IL-18 levels are correlated with RA disease activity, indicating an important role of IL-18 in the pathogenesis of RA. Several studies have examined the association of IL-18 gene polymorphisms with RA, but these studies have shown inconclusive and controversial results. To verify the association between IL-18 gene polymorphism and susceptibility to RA, we conducted a meta-analysis of all relevant reports cited in MEDLINE/PubMed before October 2012. A meta-analysis on the association between the IL-18 rs1946518 SNP and RA was performed for 2944 patients with RA and 2377 controls from 7 published studies and a meta-analysis on the association between the IL-18 rs187238 SNP and RA was performed for 1319 patients with RA and 1211 controls from 5 published studies. In addition, 2 studies involving 1873 RA patients and 1092 controls were considered in the meta-analysis of the association between the IL-18 rs360722 SNP and RA. No significant association was found between two IL-18 SNPs (rs1946518 and rs187238) and RA susceptibility in all subjects. In subgroup analysis stratified by ethnicity, there was still no significant association between these two IL-18 SNPs and RA susceptibility. However, the frequency of the T allele at rs360722 was found to be significantly lower in patients with RA compared with controls, although this finding was based on only 2 studies. The results of our meta-analysis suggest that IL-18 rs360722 SNP is only associated with RA susceptibility. However, due to only two studies included in our meta-analysis, large-scale well designed studies should be considered in future studies to confirm the exact role of IL-18 rs360722 SNP in RA susceptibility.     

Contribution of PTPN22, CD28, CTLA-4 and ZAP-70 variants to the risk of type 1 diabetes in Tunisians

Type 1 diabetes (T1D) is caused by an immune-mediated destruction of the insulin-producing β-cells. Several studies support the involvement of T cell activation molecules. In order to underline the role of the genes involved in this pathway, we investigated, using the Sequenom MassARRAY platform, polymorphisms of sixteen single-nucleotide polymorphisms (SNPs) belonging to PTPN22, CD28, CTLA-4, and ZAP-70 genes in 76 T1D patients and 162 unrelated healthy controls from Southern Tunisia.