CCND2 polymorphisms are associated with human cancer risk, thusly we hypothesized that CCND2 gene polymorphisms may contribute to childhood ALL susceptibility. We selected the polymorphism rs3217927 located in the 3′UTR region of CCND2 to assess its associations with childhood ALL risk in a case-control study. A significant difference was found in the genotype distributions of rs3217927 polymorphism between cases and controls (P = 0.019) and homozygous GG genotype may be an increased risk factor for childhood ALL . Furthermore, this increased risk was more pronounced with GG genotype among high-risk ALL , low-risk ALL , B-phenotype ALL patients  and T-phenotype ALL patients . Our results provide evidence that CCND2 polymorphism rs3217927 may be involved in the etiology of childhood ALL, and the GG genotype of rs3217927 may modulate the genetic susceptibility to childhood ALL in the Chinese population. Further functional studies and investigations in larger populations should be conducted to validate our findings.CyclinD proteins, the ultimate recipients of mitogenic and oncogenic signals, play a crucial role in cell-cycle regulation. CyclinD2, one of the cyclinD family, is overexpressed in T-acute lymphoblastic leukemia (ALL) and B-cell chronic lymphocytic leukemia and involved in the pathogenesis of leukemias. Recent reports indicated that  Pediatric cancer is now the second most common cause of death by disease in children in developed countries It is widely accepted that the interaction between genes and the environment contributes to the pathogenesis of ALL in children. Potential molecular mechanisms implicated include sequential alterations in tumor-suppress genes, proto-oncogenes, and microRNA genes of hematopoietic stem cells or their committed progenitors CCND1, CCND2 and CCND3. CCND2 is one of the direct transcriptional targets of Hedgehog signaling and PI3K-AKT signaling pathways CCND2 inherited genetic variations are associated with the risk of colorectal cancer in Europeans and Asians CCND2 gene polymorphisms on the risk of childhood ALL.D-type cyclins, the ultimate recipients of mitogenic and oncogenic signals, have been recently recognized as potentially suitable molecular targets for chemotherapy due to their specific over-expression in malignancies CCND2 polymorphisms on the risk of developing childhood ALL in a Chinese population, we selected a tagging single nucleotide polymorphism (tSNP) rs3217927 from the data for Chinese in the HapMap database (http://hapmap.ncbi.nlm.nih.gov/), which locates in the 3′ untranslated region (UTR) of CCND2. We then genotyped this SNP in 753 patients with childhood ALL and 1088 normal controls in this case control study.To detect the potential impact of The research protocol was approved by the Medical Ethics Committee of Nanjing Children's Hospital affiliated to Nanjing Medical University. Written informed consent was obtained from the parents or legal guardians of all study subjects. From January 2007 to January 2013, 857 subjects with newly diagnosed childhood ALL and 1151 cancer-free controls were recruited from the Nanjing Children's Hospital Affiliated Nanjing Medical University, Shanghai Children's Medical Center Affiliated to Shanghai Jiao Tong University and Soochow University Affiliated Children's Hospital. Parents or legal guardians of the all subjects were interviewed in person to collect demographic data and exposure information, including age, gender, parental alcohol use and tobacco-smoking and painting status of the home. Then the numbers of subjects were reduced into 753 cases and 1088 controls because of the missing of demographic data. The 753 cases included 291 females and 462 males, with a median age of 5 years. Subjects aged from 1 to 18 years and were genetically unrelated to ethnic Han Chinese. All subjects underwent bone marrow aspiration and the diagnosis of ALL was confirmed by morphology, immunohistochemistry, cytogenetics, and molecular biology. Risk stratification of the cases was determined uniformly according to the Suggestion of Diagnosis and Treatment of ALL in Childhood, published by the Society of Pediatrics, Chinese Medical Association in 2006. The control subjects had no history of malignant neoplasm or thrombotic disease and were age and gender matched to the cases.CCND2 rs3217927 was genotyped with 384-well ABI 7900HT Real-Time PCR System  using TaqMan SNP Genotyping assay. The reaction contained 5 ng genomic DNA, TaqMan Master Mix, forward and reverse primers and probes for the wild type and the mutant allele in a total volume of 5 ul. The primer sequences were 5′-CTGCGCAGGCAAGCACTAT-3′ and 5′-CCTGCCAATTCAGTGTGATTGA-3′, and the probes were 5′-FAM-CTCTGCTGAGCGGTA-MGB-3′ and 5′-HEX-CCTCTGCTAAGCGG-MGB-3′, which were devised and manufactured by Nanjing Steed Biotechnology . The location of the CCND2 primer sequence is shown in Genomic DNA was extracted by standard protocols (Qiagen) from isolated peripheral blood lymphocytes. The 5′-CAGCTCAGTCAGGGCATCAC-3′ for CCND2, and 5′-GCACCGTCAAGGCTGAGAAC-3′ and 5′-GGATCTCGCTCCTGGAAGATG-3′ for GAPDH. The PCR thermal cycling protocol consisted of 50°C for 2 min, then 95°C for 10 min followed by 45 cycles of 95°C for 15 s and 60°C for 1 min.We extracted total RNA from bone marrow in 57 ALL patients from total 753 cases randomly. The total RNA was reverse transcribed into complementary DNA using ReverTra Ace qPCR RT kit , and the complementary DNA was used for subsequent real-time PCR analysis (ABI 7300). Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was used as an internal quantitative control for each sample and each assay was done in triplicate. The primers used for amplification were 5′-TCATTGCTCTGTGTGCCACC-3′and t-test was used for analyzing the results of CCND2 mRNA expression. Two-sided P values were selected and P<0.05 was considered statistically significant. All the statistical analyses were performed using Statistics Analysis System software .Hardy–Weinberg equilibrium of the genotype distribution for each SNP among the control group was examined by a goodness-of-fit χ2test. Chi-square (χ2) test was used to evaluate the distribution differences of selected demographic characteristics as well as each allele and genotypes of rs3217927 between the cases and controls. Unconditional univariate and multivariate logistic regression analyses were performed to obtain crude and adjusted odds ratios (ORs) for estimating risk of childhood ALL and their 95% confidence intervals (CIs) with adjustment for diagnosis age, gender, parental alcohol use, tobacco-smoking and housing painting status. Independent-sample The frequency distributions of all subjects including selected demographic variables are summarized in CCND2 rs3217927 polymorphism in cases and controls and their associations with childhood ALL risk are presented in CCND2 rs3217927 polymorphism between the cases and controls (P = 0.011).The observed genotype distributions and allele frequencies for CCND2 rs3217927 polymorphisms , but not in the dominant model .Multivariate logistic regression analysis revealed that the homozygous GG genotype of rs3217927 was associated with an increased risk of childhood ALL compared with the homozygous AA genotype , while the heterozygous AG was not . We also observed an elevated risk in the recessive model of CCND2 rs3217927 polymorphism and some clinical variables of ALL. As shown in The further stratification analysis was developed to evaluate the risk of 57 ALL patients with three genotypes of CCND2  were performed here. As shown in CCND2 rs3217927 polymorphism in 753 newly diagnosed childhood ALL patients and 1088 cancer-free controls. We found that the G allele of CCND2 polymorphism rs3217927 has a significant association with childhood ALL in a Chinese population and may be a risk factor for the development of the disease. In the stratified analysis, strong evidence were found to prove a pronounced association between homozygous GG and high-risk ALL, low-risk ALL, T-phenotype and B-phenotype ALL sub-groups, thus putting the homozygous GG a potential risk factor for ALL. As shown in This ongoing study explored the association of CCND2 gene, located on chromosome 12p13.32 and spanning 31.6 kb, is a necessary member of the cyclinD gene family which promotes cell growth and proliferation et al. discovered deregulation of cyclinsD2 by translocational activation in T-cell acute lymphoblastic leukemia et al demonstrated cyclinsD2 was a therapeutic target of myeloma and leukemia in mouse models and believed decreased D-cyclins may be a biomarker of an anticancer effect CCND2 inherited genetic variations linked with the risk of colorectal cancer and ovarian cancer et al. reported no significant association had been found between CCND2 rs3217927 and non-small cell lung cancer in a Chinese population CCND2 and childhood ALL.The human CCND2 and childhood ALL risk was investigated. We found that the homozygous GG genotype of the CCND2 rs3217927 correlated with a significantly increased risk of childhood ALL. This increased risk was most pronounced in high-risk ALL, low-risk ALL, B-phenotype and T-phenotype ALL patients, but not medium risk group, which may due to the lower number of samples in medium risk group reducing statistical power. A combination between AA genotype and AG genotype is performed as reference to conduct a recessive model, and the homozygous GG genotype still showed a significantly increased risk of childhood ALL among low-risk, B-phenotype and T-phenotype ALL patients, which indicated the importance of the association between homozygous GG and the risk of childhood ALL. Furthermore, the high risk of more parental alcohol consumption and house painting exposure, as well as genetic susceptibilities in rs3217927GG genotype in the subgroup, were observed in our study. The result above indicated ALL formation might be subjected to a variety of environmental expose and genetic factors. However, according to recent GWAS, the association between CCND2 polymorphisms and childhood ALL risk was not observed, as a possible result of ethnic differences In this study, the relevance of tagSNP rs3217927 of CCND2 rs3217927 http://www.bioguo.org/miRNASNP/index.php), has-miR-922 and has-miR-4291 specifically binding the sequence surrounding the variant site came to our sights. Besides, we noticed that the Gibbs free energy was -19.30 kcal/mol for the rs3217927 A allele, and 0 kcal/mol for the G allele. These bioinformatics forecasts indicated that this SNP may change the conformation of the secondary structure of CCND2 itself and may affect the binding affinity between CCND2 mRNA and the miRNAs (has-miR-922 or has-miR-4291 or both), which may finally alter the expression of cyclinD2. But no obvious difference was found here indicates A to G mutation changed the expression level of CCND2 mRNA. The reason for this result may be that we only have 57 ALL patients with three genotypes of CCND2 to conduct PCR assay . There are not sufficient GG type samples to provide high certainty. A larger size of subjects is needed to repeat this part of experiment in the following research. Based on discussion above, it is proper to suspect that rs3217927 may influence miRNA biogenesis and function, and may contribute to susceptibility for childhood ALL. Of course, this is just one hypothesis of many unknown pathogenesis. Further functional evaluations in vitro and vivo with a larger size of samples are needed to confirm our conjecture.It has been reported that the binding affinity between miRNA and its target mRNA may be changed by the SNPs located in miRNA target sites. The difference of those SNPs may lead to degradation of the mRNA and inhibition of the mRNA translation into proteins Some limitations of this study should be addressed. Firstly, this study is hospital-based case-control designed, which may give rise to selection bias of subjects related with some particular genotypes. To minimize potential confounding bias, we adopt rigorous exclusion criteria about epidemiological design in recruitment of control subject which is frequency matched to cases by age, sex and ethnicity. The genotype frequencies of rs3217927 polymorphism among the controls in our study were consistent with the information provided by the HapMap Project. Secondly, when designing this experiment, we did notice that an independent validation cohort is necessary but our data was just over the minimum value of statistical power (709 cases and 709 controls), which was performed by Epicacl 2000 based on 1∶1 ratio of cases to controls, expected OR 1.35, proportion controls exposed 40.0%, thresholds set on 0.05 and 80% of the calculated degree of certainty. In order to have the most trustworthy relevance, we devoted all our samples into relevance verification. Although we hold the opinion that the current data in this manuscript is enough to analyze the risk of ALL, it will be ideal to carry on a two-stage model. And we are still gathering data. Besides, it is essential to validate our results in a larger size of subjects, which we believe should be at least 4044 subjects in total containing 2022 cases and 2022 controls. This assessment was performed using Epicacl 2000 based on 1∶1 ratio of cases to controls, expected OR 1.2, proportion controls exposed 35.0%, thresholds set on 0.05 and 80% of the calculated degree of certainty. Thirdly, the detailed epidemiologic data provided here is not adequate to evaluate gene-environment interaction. In order to provide more detailed interpretation of association between environmental toxic exposure and ALL, it would become an essential pre-work to acquire abundant epidemiologic exposure data and clinical information. Last but not least, our research about the gene susceptibility connected with childhood ALL is only limited on the statistics and epidemiology level and the further functional studies are warranted to validate our findings and reveal the underlying molecular mechanisms.CCND2 may be relevant to susceptibility of Childhood ALL in a Chinese population. Further validation in a larger sample size with diverse ethnic populations and functional evaluations in vitro and vivo are warranted.In conclusion, for the first time we found evidence that rs3217927 polymorphism in the cell cycle gene Figure S1The nucleotide localization of the CCND2 rs3217927 primer sequences.(DOCX)Click here for additional data file.Table S1Interaction analyses of CCND2 rs3217927 and parental drinking and house-painting.(DOC)Click here for additional data file.


Many studies have investigated the distributions of RANTES genotypes between HIV-1 infected patients and uninfected individuals. However, no definite results have been put forward about whether the RANTES −28C/G polymorphism can affect HIV-1 susceptibility.We performed a meta-analysis of 12 studies including 7473 subjects for whom the RANTES −28C/G polymorphism was genotyped. Odds ratios (ORs) with 95% confidence intervals (CIs) were employed to assess the association of the polymorphism with HIV-1 susceptibility. By dividing the controls into healthy controls and HIV-1 exposed but seronegative (HESN) controls, we explored the both allelic and dominant genetic models.By using the healthy controls, we found a marginally significant association between the −28C/G polymorphism and susceptibility to HIV-1 infection in the allelic model . But sensitivity analysis suggested that the association was driven by one study. We further performed stratified analysis according to ethnicity. The −28G allele decreased susceptibility to HIV-1 infection in the allelic model among Asians . By using the HESN controls, no association between the polymorphism −28C/G and the susceptibility to HIV-1 infection was revealed in either the allelic model  or the dominant model .Our findings suggested that the RANTES −28G allele might play a role in resistance to HIV-1 infection among Asians. Additional well-designed studies were required for the validation of this association. However, the susceptibility to infection after exposure and natural course of infection vary among individuals Human immunodeficiency virus-1(HIV-1)/acquired immunodeficiency syndrome (AIDS) remains one of the world's most significant public health challenges. Up to now, nearly 34 million people live with HIV/AIDS all over the world, particularly in low and middle-income countries, and an estimated 2.7 million people were newly infected with the virus in 2010 . The following key words were used: ‘HIV or AIDS or human immunodeficiency viruses’, ‘RANTES or CCL5’ and ‘polymorphism or variant’. The search was conducted with restriction on language in English and/or Chinese, also limited to human subjects. Reference lists of the identified articles were also examined and the literature retrieval was performed in duplicate by two independent reviewers (Gong and Tang).We searched PubMed, Embase, and China National Knowledge Infrastructure for all articles on the association between RANTES polymorphisms and HIV-1 infection  case-control studies, regardless of sample size, that were conducted to evaluate the association between RANTES −28C/G polymorphism and the risk of HIV-1 infection, (b) studies that provided data on the distributions of −28C/G polymorphism in the case-control population, (c) studies that were published in English or Chinese languages. The major reasons for exclusion of studies were (a) duplication of previous studies, (b) reviews, (c) not human studies, (d) no cases or controls.Two investigators (Gong and Tang) reviewed and extracted the information from all eligible publications independently according to the inclusion and exclusion criteria listed above. Disagreements were resolved by discussion between the two investigators. The following characteristics were collected from each study: first author, year of publication, country of studied population, ethnicity, number of HIV-1 patients, number of healthy controls, number of HIV-1 exposed but seronegative (HESN) controls, and the distributions of the RANTES −28C/G polymorphism in the cases and controls.2-based Q-test. If the P value for heterogeneity was >0.05, indicating an absence of heterogeneity between studies, we used the fixed-effect model (Mantel-Haenszel) to evaluate the summary ORs. In contrast, if the P value for heterogeneity was ≤0.05, indicating a high extent of heterogeneity between studies, we used the random-effect model (DerSimonian and Laird) to evaluate the summary ORs. The departure of frequencies of the RANTES polymorphism from expectation under Hardy-Weinberg equilibrium was assessed by the χ2 test in controls. Sensitivity analysis was performed by sequentially excluding individual studies to assess the stability of the results. Possible publication bias was tested by Begg's funnel plot and Egger's test.Crude odds ratios (ORs) with their 95% confidence intervals (CIs) were used to assess the strength of association between RANTES polymorphisms and susceptibility HIV-1 infections. Because the negligible frequency of genotype −28GG in the population, we didn't perform the homozygous model (GG vs. CC) and recessive model (GG vs. GC+CC) in this study. Both allelic model (G vs. C) and dominant model (GG+GC vs. CC) were conducted for the subgroup with both healthy controls and HIV-1 exposed but seronegative (HESN) controls. Analyses stratified by ethnicity were also performed. Heterogeneity assumption was assessed by χP value less than 0.05 was used to denote statistical significance.All statistical tests were conducted with Stata software package . A As shown in After pooling the data from the 12 studies for meta-analysis, the results were calculated according to the allelic and dominant models.P = 0.175 for heterogeneity test). No association was found in the dominant model. We further performed stratified analysis according to ethnicity. The −28G allele decreased the susceptibility to HIV-1 infection in the allelic model among Asians . The results were shown in By using the healthy controls, we only found a marginally significant association between the −28C/G polymorphism and susceptibility to HIV-1 infection in the allelic model  and dominant model .By using the HESN controls, as shown in P = 0.393 for heterogeneity test) by using the healthy controls. However, the results for the other models remained stable (Data were not shown).Sensitivity analysis was performed by deleting one study at one time to assess the stability of the pooled ORs. Sensitivity analysis was performed for various comparisons in the total population and all the subgroups. When one study among the Korean (Asian) population was deleted P = 1.00, Egger's test P = 0.82)    or in th = 0.69) .Many studies have investigated the associations between chemokine and chemokine-receptor gene polymorphisms and the susceptibility to HIV-1 infection. Recently a meta-analysis had demonstrated that the variable number tandem repeat (VNTR) allele polymorphism of Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin related (DC-SIGNR) might have a role in resistance to HIV infection, particularly in Asian populations + T lymphocyte depletion rates and slowed HIV-1 progression in affected individuals The RANTES-CCR5 pathway can influence immune responses in multiple ways during acute viral infections + T cells and increase RANTES expression in vivo.The results involved in 12 eligible studies had suggested that the RANTES -28C/G polymorphism demonstrated a marginal association with the susceptibility to HIV-1 infection among Asians in the allelic model. The most probable explanation is that RANTES −28G could reduce the depletion rate of CD4Further in sensitivity analysis, we found the data from one study It is now a consensus to define HESN individuals from several group of individuals who are at high risk of exposure which include : (1) commercial sex workers, (2) people with hemophilia, (3) discordant couples, (4) intravenous drug users, and (5) mother-to-child transmission Although meta-analysis is a powerful statistical method, some limitations still exist here. First, the data of one included study significantly deviated from others which caused the unstable results; thus we should make conclusion more cautiously. Second, we only included the studies written in English and Chinese, and the related reports in other languages were not included, which might bias our conclusion in this study. Third, publication bias could not be excluded though the test showed negative results. The studies reporting significant associations between certain genotypes and reduced susceptibility to HIV infection would be more readily published while the studies with no significant associations would be more difficult to publish. Fourth, gene-gene and gene-environment interactions may influence host susceptibility to HIV-1 infection. In fact, many genes have been proven to influence HIV-1 infection risk, but we did not have enough data to eliminate these interfering factors. The prevalence of HIV-1 infection and progression is always related to the social economic status. Finally, further stratified analyses of patients and HESN individuals by infection exposure routes  could not be performed because the data detailing the infection route for the HIV-1 patients were lacking.In conclusion, this meta-analysis involved in 12 case-control studies provided evidence that the RANTES −28G allele might play a role in resistance to HIV-1 infection among Asians. When the sensitivity analysis suggested that the results might be unstable sometimes, we should obtain this conclusion cautiously. Future studies in different ethnic populations and with clear infection routes should be performed to evaluate these associations.Table S1PRISMA 2009 Checklist.(DOC)Click here for additional data file.


Carrying the A allele for the TNFα-308 had 18%  increased risk, but this was not significant for developing graft rejection than the G allele. Conversely, carrying the minor alleles for both TGFβ1-c10 and c25 had nonsignificantly lower odds of graft rejection than major alleles, with the pooled ORs of 0.87  and 0.70 , respectively. There was no evidence of publication bias for all poolings. An updated meta-analysis is required when more studies are published to increase the power of detection for the association between these polymorphisms and allograft rejection.We performed a systematic review and meta-analysis with the aim of assessing the association between cytokine gene polymorphisms and graft rejection in heart transplantation. We identified relevant studies from Medline and Embase using PubMed and Ovid search engines, respectively. Allele frequencies and allele and genotypic effects were pooled. Heterogeneity and publication bias were explored. Four to 5 studies were included in pooling of 3 gene polymorphisms. The prevalences of the minor alleles for TNF Heart transplantation is a treatment of choice for the end-stage heart diseases with the goal to improve patient survival and the quality of life , 2. Acutβ1) and tumor necrosis factor alpha (TNFα) are among the key cytokines which have been reported in association with inflammation and rejection episodes after renal [β1 at codon 10 (position +869 (T → C)) and codon 25 (position +915 (G → C)) [α at position −308 (G → A) [β1 gene is located on chromosome 19q13.1 (MIM#190180), and the polymorphisms have variable effects on cytokine production. The TNFα gene is located on chromosome 6p21.3 (MIM#191160), and such polymorphisms have generated a high responder genotype associated with acute liver allograft rejection [ Cytokine gene polymorphisms are responsible for the regulation of inflammatory response and are known to play a role in mediating allograft rejection after transplantation. Transforming growth factor-beta 1  . The TGF These polymorphisms had been reported in association with poor clinical outcomes after heart transplantation. However, gene effects identified in these studies were controversial; that is, some studies found positive associations between polymorphisms and rejection episodes –8, 13–15Relevant studies were identified from MEDLINE and Embase since initiations to February 2013 using PubMed and Ovid search engines, respectively. The search strategies for PubMed were “(heart failure OR graft failure OR graft rejection) AND ((TGF beta OR TGF-beta OR transforming growth factor beta) OR ) AND  AND .” Searching was limited to English and human studies.β1 at codon 10 or codon 25, or TNFα-308, and had acute or chronic graft rejection as the outcome of interest. Studies with insufficient data for pooling, that is, no frequencies of genotypes or alleles for each polymorphism and outcomes, were excluded.Identified studies were independently selected by two reviewers (Sasitorn Yongcharoen and Sasivimol Rattanasiri) based on previously designed inclusion and exclusion criteria. Studies were selected regardless of ethnicity if they met the following criteria: pediatric or adult patients with heart transplantation, assessment of at least one of the following gene effects: TGFThe outcome of interest was acute or chronic graft rejection, which was defined according to original studies. Briefly, a severe graft rejection was defined as histopathological finding for rejection scores of grade 3A or higher according to already established criteria by the International Society of Heart and Lung Transplantation classification .The quality of studies was also independently assessed by the same 2 reviewers (Sasitorn Yongcharoen and Sasivimol Rattanasiri) based on a risk of bias score for genetic association studies . The scoQ test and the degree of heterogeneity was quantified by I2. If heterogeneity was present , the OR was pooled using the DerSimonian and Laird method; otherwise the inverse-variance method was used.We used data in the control group to estimate a pooled allelic prevalence. Hardy-Weinberg equilibrium (HWE) was assessed , and onl1 (minor homozygous versus major homozygous genotypes) and OR2 (heterozygous versus major homozygous genotypes) using the same methods as per-allele analysis. A mixed logistic regression was applied by fitting graft rejection on genotypic variables, treating study as a random effect and genotype as a fixed effect [P value less than 0.05 was considered statistically significant, except for the heterogeneity test in which P-value < 0.10 was used. For genotype analysis, heterogeneity was assessed for ORd effect –24. A liThe flow of identification and selection of studies in the meta-analysis is described in The results of bias assessment of the 7 studies have been presented in α-308 polymorphism and graft rejection (n = 659). The G and A allele frequencies were described according to studies and have been presented in supplement Table 1 see Supplementary Material available online at http://dx.doi.org/10.1155/2013/387184. All except one study [Q = 11.10, d.f. = 3, P = 0.011, and I2 = 73.0%) across the studies. The pooled ORs with DerSimonian and Laid method were 1.18 , suggesting that individuals carrying A allele had 18% increased risk for developing graft rejection than those carrying G allele. However, this risk was not statistically significant. The Egger test did not suggest any evidence of publication bias . Five studies –12 repor1 for AA versus GG was homogenous  whereas the OR2 for GA versus GG was highly heterogeneous ; see Figures 1 and OR2 of 1.98  and 1.11 , respectively, which suggested that individuals carrying AA and GA genotypes had 98% and 11% higher odds of graft rejections than those carrying GG genotype but these were not statistically significant. The Egger test did not suggest any asymmetry for both ORs . The estimated lambda was 0.42 , suggesting that an additive mode was most likely. Genotype frequency and estimated OR for each study have been presented in β1-c10 and graft rejection (n = 399). Allele frequencies across outcomes were described and all studies observed HWE and have been presented in supplement Table 2. The minor C allele prevalence was 0.382  in rejection and 0.413  in nonrejection groups, respectively. The allelic effects for C versus T alleles were homogenous across the studies  with the pooled OR of 0.87 , which suggested that individuals carrying C alleles were at 13% lower odds than those carrying T allele. Publication bias was assessed by graphing a funnel plot, which indicated little asymmetry . Five studies –10 asses1 for CC versus TT and OR2 for TC versus TT were mildly heterogeneous across the studies . The pooled OR1 and OR2 were 0.76  and 0.84 , respectively  and OR2 .  Genotype frequency and estimated ORs for each study have been presented in β1-c25 and graft rejection (n = 387). The G/C allele frequencies and estimated OR have been presented in supplement Table 3. The pooled prevalence of C alleles was 0.056  and 0.082  in the rejection and the nonrejection groups, respectively. The allelic effects for C versus G alleles were homogeneous across the studies  with the pooled OR of 0.70 . This suggested that individuals carrying C alleles had 30% lower risk (but this was not significant) to develop graft rejection than those carrying G alleles. The Egger test did not suggest asymmetry of funnel . Five studies –10 assesQ = 2.21, d.f. = 4, P = 0.697, and I2 = 0.0%) with the pooled OR of 0.63 , shown in  Genotype frequencies and estimated ORs for each study have been presented in α-308, TGFβ1-c10, and TGFβ1-c25) and graft rejection in heart transplantation. Four to 5 studies were included in pooling of 3 polymorphisms with a total sample size of 337 to 399 subjects. We observed no significant polymorphism in association with graft rejection. Nonetheless, our results indicated a signal of association between TNFα-308 A allele and graft rejection. It was found that individuals carrying A allele would approximately had 18% increased risk of graft rejection relative to those carrying G allele. Conversely for TGFβ1 at c10 and c25, carry C alleles for both polymorphisms were respectively 13% and 30% lower risk of graft rejection than carry T and G allele.We had performed a systematic review and meta-analysis assessing associations between 3 cytokine polymorphisms , this estimation was still uncertain with 95% CI of 0.02 to 0.96. We however could not assess a mode of gene effect for TGFβ1 at codon 25 polymorphism since there was no CC genotype in non-rejection group for all studies. As for previous report, this polymorphism was in linkage disequilibrium with TGFβ1 at codon 10 (r = 0.30) [β1 at codon 25 would go with the minor C allele in TGFβ1 at codon 10. As a result, the mode of gene effect of TGFβ1 at codon 25 might be similar to the effect of TGFβ1 at codon 10 polymorphism. However, our finding was in disagreement with the previous finding in renal transplant patients [ For TGFα-308 and we needed a sample size of 454 to detect this association. Further updated meta-analysis is required if there are more studies published in the literatures. We pooled gene effects on graft rejection based on summary data which were provided from individual studies. Although most studies had considered acute graft rejection, few studies had mixed acute and chronic graft rejections. Among the acute graft rejection, the severity of graft rejection might also be varied; for instance, 6 out of 8 patients died within 3 months after transplant in the study by Azzawi et al. [ The strength of our study is multifold. First, we identified all relevant studies which had assessed the association between these polymorphisms and allograft outcomes in heart transplantation. Second, the review was performed based on rigorous analytical methods and thus biases were due to the selection of studies and less likely due to data extraction. Third, data were pooled using both allele and genotype approaches. The allele approach is better than the genotype approach if a minor genotype is very rare in most included studies. The sample size of the allele pooling is doubled and thus increased the power of detection of the gene effect . Howeveri et al. . Recategα-308 polymorphism might have more risk of developing graft rejection, whereas individuals carrying minor allele C alleles for TGFβ1-c10 and TGFβ1-c25 polymorphisms might have less susceptibility to develop graft rejections in heart transplantation. Further studies with larger sample sizes are needed to update and confirm the role of these polymorphisms in association with allograft rejection in heart transplantation.In summary, this meta-analysis has demonstrated that individuals carrying a minor A allele of TNFSupplementary Table 1: This table described major and minor allele frequencies of TNFa-308 polymorphism between rejection and controls groups. Prevalence of the major and minor alleles were estimated and pooled across studies. HWE was checked and OR of allele effect was estimated for each study.Supplementary Table 2: Numbers of major and minor alleles for TGFb1-c10 between groups were described for each study. Prevalence of allele, HWE, and allele effect were reported.Supplementary Table 3: Numbers of major and minor alleles for TGFb1-c25 between groups were described for each study. Prevalence of allele, HWE, and allele effect were reported.Click here for additional data file.


The associations between Rad51 gene polymorphisms (G135C and G172T) and risk of cancer have been investigated, but the results were inconclusive. To get a comprehensive evaluation of the association above, we performed a meta-analysis of published studies.A computerized search of PubMed, Embase and Web of Knowledge databases for all relevant studies was performed and the data were analyzed in a meta-analysis. The overall odds ratio (OR) with the 95% confidence interval (95% CI) was calculated to assess the strength of the association between Rad51 polymorphisms and cancer risk. Data were analyzed using fixed- or random-effects model when appropriate. Sensitivity analysis and publication bias test were also estimated.Overall, a total of 54 case-control studies were included in the current meta-analysis, among which 42 studies with 19,142 cases and 20,363 controls for RAD51 G135C polymorphism and 12 studies with 6,646 cases and 6,783 controls for G172T polymorphism. For G135C polymorphism, the pooled results indicated that significantly increased risk was found in overall cancers , especially in breast cancer . For G172T polymorphism, a decreased cancer risk was observed in head and neck cancer .Our results suggested that the Rad51 G135C polymorphism is a candidate for susceptibility to overall cancers, especially to breast cancer, and that the Rad51 G172T might play a protective role in the development of head and neck cancer. Human cancer is still one of the leading causes of death worldwide, resulting in one of the most challenging global health issues confronted by mankind today. According to etiological studies, carcinogenesis of cancer is a complex, multistep and multifactor process, in which many genetic and environmental factors are involved. In recent years, it has become clear that individual variation in genetic backgrounds can lead to various consequences following the environmental exposure and may ultimately contribute to the cancer pathogenesis and progression DNA repair pathways are responsible for maintaining the genomic stability and integrity and play a pivotal role in protecting against genetic mutations Human RAD51, one of the key proteins for homologous recombination, is essential to meiotic and mitotic recombination and plays a crucial role in homologous recombination repair of DNA double-strand breaks In the past decade, a number of molecular epidemiological studies have been done to evaluate the association between RAD51 gene polymorphisms (G135C and G172T) and cancer risk in diverse populations, but the results remained controversial. Therefore, to derive a more precise estimation of the association between RAD51 G135C and G172T polymorphisms and cancer risk, a meta-analysis was performed. To the best of our knowledge, this is the most comprehensive meta-analysis regarding the RAD51 polymorphisms and cancer risk.All studies investigating the association between the RAD51 gene polymorphisms (G135C and G172T) and risk of cancer were identified by comprehensive computer-based searches of PubMed, Embase and Web of Knowledge databases . The search was performed using various combinations of keywords like (“RAD51 gene” OR “RAD51 recombinase gene”) AND (“polymorphism” OR “variant” OR “variants”). The exact search is available on request from the authors. Additional studies were also identified by a hand search of all the references of retrieved articles. Our search was restricted to studies published in the English language.Studies included in the current meta-analysis had to meet all the following criteria: (1) studies to investigate the associations between the polymorphisms of G135C or G172T in RAD51gene and risk of cancer; (2) an unrelated case-control or cohort design (3) sufficient data (genotype distributions for cases and controls) to calculate an odds ratio (OR) with its 95%CI; (4) studies published in English; (5) genotype distribution of control population consistent with Hardy-Weinberg Equilibrium (HWE). We did not consider abstracts or unpublished reports. Case reports, editorials, review articles, and letters were excluded. Articles were also excluded if they did not include a control population and did not determine genotype frequency. If studies with the same or overlapping data were published by the same authors, the study with the larger sample size was selected. The supporting PRISMA checklist is available as supporting information; see Two authors extracted information from all eligible publications independently according to the inclusion criteria listed above. Disagreement was resolved by the evaluation of a third reviewer and discussion until a consensus was reached. The following characteristics were collected from each study: the first author, year of publication, country, patient ethnicity, cancer type, source of control groups ), and genotype frequencies in case and control groups. Meanwhile, we did not define any minimum number of cases or controls to be included in our meta-analysis.We first analyzed HWE in the controls for each study using goodness-of-fit test (chi-square or Fisher's exact test) and violation of HWE was determined by P<0.05. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association between the RAD51 gene polymorphisms and cancer susceptibility. The pooled ORs for RAD51 G135C polymorphism were performed under dominant model (CC+GC vs. GG), recessive model (CC vs. GG+GC), homozygote model (CC vs. GG) and allelic genetic model (C vs. G). C and G represent the minor and the major allele respectively. The same methods were applied to the analysis of the RAD51 G172T polymorphism. Stratified analyses were conducted with respect to ethnicity, cancer type and source of controls.2-based Q-test was performed to test the heterogeneity across the eligible comparisons, which is considered to be significant if P<0.05. The variation caused by heterogeneity was estimated by calculating the inconsistency index I2, with I2<25%, 25-75% and >75% representing low, moderate or high degrees of inconsistency, respectively A χAll statistical analyses were performed using the STATA software . Two-sided P values less than 0.05 were considered significant.The initial literature search through PubMed, Embase and Web of Knowledge databases yielded 203 published articles after duplicates were removed. When reviewed by titles or abstracts, 115 records did not fulfill the inclusion criteria, leaving 88 potentially relevant studies that were reviewed in full-text. Among the remaining 88 articles, 10 were not concerned with G135C or G172T polymorphisms in RAD51gene, 7 were not human studies, 4 was not published in English, 6 were not case-control studies, 5 were no usable reported data, 2 were meeting abstracts, 4 were meta-analysis, and 11 were not in HWE; these publications were also excluded. Finally, a total of 54 case-control studies in 37 articles were identified in the current meta-analysis The pooled results of meta-analysis for the association between RAD51 polymorphisms (G135C and G172T) and cancer susceptibility are shown in As for G135C polymorphism, a total of 42 case-control studies in 37 publications with 19,142 cases and 20,363 controls were identified. Overall, significantly elevated cancer risk was found in all genetic models  were performed to provide the most comprehensive assessment of the relationship between RAD51 polymorphisms and cancer risk. For Rad51 G135C polymorphism, the C allele of G135C polymorphism had significant association with the cancer susceptibility for the homozygote model, allelic genetic model, and recessive genetic model in overall populations. Nevertheless, the results suggested that Rad51 G172T polymorphism was not associated with overall cancer risk when all studies were accumulated together. Considering the possible role of ethnic differences in genetic backgrounds, we performed subgroup analysis based on ethnicity. Consequently, significant association was found in both Caucasians and Asians for Rad51 G135C polymorphism but not for G172T polymorphism. When stratified by the source of controls, our results found evidence of an association between cancer risk and G135C polymorphism in both population-based and hospital-based controls, while no significant association was indicated in either population-based or hospital-based controls for G172T polymorphism. In the stratified analysis by cancer type, our results strongly indicated that Rad51 G135C polymorphism was associated with increased breast cancer risk while G172T polymorphism with decreased head and neck cancer risk.Previous meta-analyses were carried out to assess the effect of Rad51 G135C polymorphism on either the risk of breast cancer or acute leukemia Heterogeneity between studies should be noted because it may affect the strengths of the meta-analysis. In the current meta-analysis, significance heterogeneity was observed for both Rad51 G135C and G172T polymorphisms. Thus, random-effect models were used if significant heterogeneity was identified. Meanwhile, to diminish the heterogeneity, we carried out subgroup analysis based on ethnicity, cancer types and source of controls. The results indicated that heterogeneity reduced or disappeared in subgroups. We also performed sensitivity analysis to ascertain the primary origin of the heterogeneity. The analysis showed that no single study materially altered the pooled ORs, suggesting that the results of this meta-analysis were statistically stable and reliable. The publication bias for the association between these two polymorphism and cancer risk was not observed.Some limitations of the present meta-analysis should be taken into consideration when interpreting the results. First of all, only published studies and papers written in English were searched in this meta-analysis, some unpublished studies or studies written in other language that might also meet the inclusion criteria were overlooked. Second, in some studies, detailed information such as age and sex in case and control of different genotypes were not available, which limited further estimates to a certain extent. Third, the current meta-analysis did not consider gene-gene and gene-environment interactions due to the lack of sufficient data. Further studies are needed to evaluate the possible gene-gene and gene-environment interactions in the association between Rad51 gene polymorphism and susceptibility to cancer. Fourth, most of the patients in our study were Caucasians, which may limit the general application of our results. In spite of these, our present meta-analysis also had some advantages. First, analyzing two Rad51 gene polymorphisms with a total of 54 case-control studies has a much greater statistical power compared with any single study. Second, we excluded the studies in which genotype frequencies in controls were not in accordance with HWE, providing sufficient evidence for drawing safe conclusions about the association between the Rad51 polymorphisms and cancer risk. Third, the stability and credibility of the present meta-analysis was confirmed by the sensitivity analyses and publication biases analyses. Last, the findings highlight the association between Rad51 gene polymorphisms and cancer development and will provide directions for future research on molecular mechanism of cancer.Our investigations suggested that the Rad51 G135C polymorphism is a candidate for susceptibility to overall cancers, especially to breast cancer, and that the G172T polymorphism is significantly associated with decreased risk of head and neck cancers. Further studies are needed with large sample size and deeper evaluation about the effect of gene-gene and gene-environment interactions on the Rad51 polymorphisms and cancer risk.Figure S1Sensitivity analysis of the summary OR of the association between Rad51 G135C polymorphism and cancer susceptibility in homozygote model.(TIF)Click here for additional data file.Figure S2Sensitivity analysis of the summary OR of the association between Rad51 G172T polymorphism and cancer susceptibility in homozygote model.(TIF)Click here for additional data file.Checklist S1PRISMA Checklist.(DOCX)Click here for additional data file.


Our objectives were to analyze four NHANES datasets using consistent Regression models were adjusted for creatinine, age, gender, race/ethnicity, education, income, smoking, heavy drinking, BMI, waist circumference, calorie intake, family history of heart attack, hypertension, sedentary time, and total cholesterol. Urinary BPA was not significantly associated with adverse health outcomes for any of the NHANES surveys, with ORs (95% CIs) ranging from 0.996 (0.951–1.04) to 1.03 (0.978–1.09) for CHD, 0.987 (0.941–1.04) to 1.04 (0.996–1.09) for heart attack, and 0.957 (0.899–1.02) to 1.01 (0.980–1.05) for diabetes.Using scientifically and clinically supportable exclusion criteria and outcome definitions, we consistently found no associations between urinary BPA and heart disease or diabetes. These results do not support associations and causal inferences reported in previous studies that used different criteria and definitions. We are not drawing conclusions regarding whether BPA is a risk factor for these diseases. We are stating the opposite–that using cross-sectional datasets like NHANES to draw such conclusions about short-lived environmental chemicals and chronic complex diseases is inappropriate. We need to expend resources on appropriately designed epidemiologic studies and toxicological explorations to understand whether these types of chemicals play a causal role in chronic diseases. The Centers for Disease Control and Prevention’s (CDC) National Biomonitoring Program – part of the National Health and Nutrition Examination Survey (NHANES) - measures over 450 chemicals in people in the US. The scientific literature is replete with publications reporting associations between US population levels of chemicals in blood and/or urine and a health outcome or biochemical indicator using NHANES data Three studies These studies varied in their methods with respect to subject inclusion criteria, case definitions and modeling strategies. Utilization of different methodologies is not inherently inappropriate; however, even in the absence of consistent methods, a robust association should yield consistent findings.a priori chosen methods to 1) reassess the evidence for associations between urinary BPA and health outcomes, 2) determine whether use of a consistent scientifically and clinically supportable methodology yields coherent results across datasets, and 3) compare our methodology and results with previous studies that examined individual NHANES surveys. Most importantly, we address a larger question: Is NHANES an appropriate source of data for investigating associations between chemicals with short physiologic half-lives such as BPA and chronic diseases with multi-factorial etiologies such as diabetes or heart disease?In this paper, we analyze data from four NHANES surveys  with consistent http://www.cdc.gov/nchs/nhanes.htm. Urinary BPA data are from a subsample (Laboratory 24) of the total NHANES population. Total BPA, after hydrolysis of conjugated metabolites, was measured in urine . The method limit of detection (LOD) is given as 0.36 ng/ml for the 2003–2004 survey and 0.4 ng/ml for the other three surveys. CDC assigns a value of the LOD/√2 for measures below the detection limit The CDC National Center for Health Statistics data files for NHANES are available at Outcomes of interest are CHD, heart attack, and diabetes because these were the focus of several previous studies. For CHD and heart attack, we use physician diagnosis to define cases (variables MCQ160C for CHD and MCQ160E for heart attack). Information on these outcomes was available in all four surveys for participants ≥20 years of age.Participants were categorized as having type 2 diabetes if they met at least one of the following criteria physician-diagnosed diabetes , orfasting glucose >126 mg/dl , ortwo-hour glucose tolerance test >200 mg/dl .To limit the health outcome to type 2 diabetes, we excluded participants who started insulin at the time of diagnosis (if current age in years (variable RIDAGEMN divided by 12) minus age of diagnosis (DID040Q) was ≤ the number of years of reported insulin use (variable DID060Q)).a priori selected potential confounders including, but not limited to, those used in the previous studies All multivariable analyses were controlled for Analyses of the association between urinary BPA and each health outcome were conducted separately for each of the four NHANES surveys. All analyses used multivariable logistic regression models with results expressed as adjusted odds ratios (ORs) with corresponding 95% confidence intervals (CI) and P-values. The ORs for continuous variables in these models, including urinary BPA, reflect the change in odds of outcome per unit change of exposure.a priori selected covariates.In addition to assessing the results across survey years, we conducted pooled analyses of all four NHANES datasets. To assess the impact of covariates on study results, the pooled analyses used six models, each involving progressively more covariates. The baseline model (Model 0) included only BPA and survey year. Model 1 also controlled for creatinine, age, gender, ethnicity, education and income. Model 2 used previously included covariates plus smoking and drinking. Model 3 added BMI and waist circumference and Model 4 further added hypertension and total cholesterol. The final model (Model 5) included all of the above plus family history, and thus controlled for all CDC’s weighting factors were incorporated in the analysis. Missing data were handled by including only those individuals for whom all covariates were available. Analyses were carried out using SAS 9.3 statistical software .Age and gender were statistically significantly associated with CHD in all four surveys . The assFor heart attack , the onlIn the analyses of diabetes , adjusteWhen the data from four surveys were pooled, the ORs (95% CIs) for the full model that included all covariates were 1.004 (0.998–1.009) for CHD, 1.002 (0.998–1.007) for heart attack, and 0.995 (0.982–1.007) for diabetes. As shown in A comparison of our methods and results to those of previous studies evaluating the relation between urinary BPA and diabetes, CHD and heart attack is presented in For CHD and heart attack, Lang et al. In this paper, we used four NHANES datasets to assess inter-survey agreement with respect to associations between BPA and diabetes, CHD, and heart attack. We also compared our results with previous studies that addressed the same research questions based on the same NHANES surveys, but using slightly different methods of data selection, characterization and analysis. Finally, we used this research to address a larger question: Is NHANES an appropriate source of data for investigating the associations between chemicals with short physiologic half-lives such as BPA and chronic diseases with multi-factorial etiologies such as diabetes or heart disease?In order to adequately compare our findings to those of Lang et al. In assessing inter-survey agreement we expected, based on previous reports, that the 2003–2004 NHANES analyses would demonstrate a stronger association between BPA and outcomes of interest compared to more recent surveys. Our findings, however, were highly consistent across all four surveys, unexpectedly showing no associations for any of the outcomes.Past analyses of the 2003–2004 and 2005–006 NHANES surveys produced different results from ours, leading to markedly different conclusions An exploration of these methodological differences yielded important insights. First, we observed our adjustment for additional covariates that are known risk factors had no qualitative effect on the results (data not shown). This observation may be interpreted as either an indication that confounding by these covariates is not a source of bias in these data, or alternatively, evidence that information available in NHANES does not permit adequate control for confounders. Regardless of the interpretation, clearly inclusion of different covariates in the models did not explain the discrepancy between the two sets of results. We also found that the discrepancy between our findings on diabetes and those reported by Lang et al. There were no differences in case definitions for CHD and heart attacks, yet our findings were in disagreement with those of Lang et al. http://www.cdc.gov/nchs/nhanes/about_nhanes.htm). According to CDC http://www.cdc.gov/exposurereport/faq.html). In this research, we showed how small, scientifically-supported changes in methodology can have critical consequences, resulting in inconsistent BPA-health outcomes associations. Rather than ascertaining which methodology and results are “superior,” these inconsistencies are used to highlight the larger question regarding whether use of NHANES data for studies of this type is appropriate, i.e., are observed associations, or lack thereof, meaningful?NHANES serves as an important source of data for determining the burden of chronic diseases and prevalence of risk factors in the US (The main limitation of cross-sectional studies such as NHANES is the inability to determine the temporal sequence of exposure and outcome, the main property of a cause-and-effect relation This issue is illustrated by our results pertaining to cholesterol levels. In all of our analyses, cholesterol levels were statistically significantly inversely associated with heart attack and CHD. Given the well-documented positive association between cholesterol and heart disease from prospective studies This lack of temporal information impacts assessments of chemicals with short physiologic half-lives. BPA, with a half-life in the body of only a few hours, is just one of many short-lived chemicals that have been examined using NHANES databases for associations with chronic disease. Problems associated with the validity of NHANES BPA exposure measures for this type of evaluation were raised by Wolff With scientifically and clinically supportable exclusion criteria and outcome definitions, we consistently found no associations between urinary BPA and heart disease or diabetes across four NHANES datasets. These results do not support associations and causal inferences reported in previous studies that used different criteria and definitions. To be clear, we are not drawing conclusions as to whether BPA is a risk factor for any of the chronic diseases discussed in this paper. In fact, we are stating the opposite - that using the NHANES surveys to draw such conclusions about short-lived environmental chemicals and chronic complex diseases is inappropriate. We need to expend resources on more appropriately designed epidemiologic studies and toxicological explorations to understand whether these types of chemicals play a causal role in chronic diseases.


MTHFR) C677T and A1298C polymorphisms with hypertension (H) or hypertension in pregnancy (HIP). However, the results were controversial. We therefore performed a comprehensive meta-analysis to provide empirical evidences on the associations.Several epidemiological studies have investigated the associations of methylenetetrahydrofolate reductase  and 95% confidence intervals (CIs) were calculated to evaluate the strength of the associations. Meta-regression, subgroup analysis, sensitivity analysis, cumulative meta-analysis and assessment of publication bias were performed in our study.A total of 114 studies with 15411 cases and 21970 controls were included, 111 studies with 15094 cases and 21633 controls for the C677T polymorphism and 21 with 2533 cases and 2976 controls for the A1298C polymorphism. Overall, the C677T polymorphism was significantly associated with H and HIP . Stratified analysis by ethnicity revealed a significant association among East Asians and Caucasians, but not among Latinos, Black Africans, and Indians and Sri Lankans. In the stratified analyses according to source of controls, genotyping method, sample size and study quality, significant associations were observed in all the subgroups, with the exception of population based subgroup in H studies and large sample size and “others” genotyping method subgroups in HIP studies. For the A1298C polymorphism, no significant association was observed either in overall or subgroup analysis under all genetic models.MTHFR C677T rather than A1298C polymorphism may be associated with H & HIP, especially among East Asians and Caucasians.This meta-analysis suggests that the  MTHFR) gene have been assessed as potential candidates.Hypertension (H), whose prevalence has dramatically increased in recent years, is a major risk factor for many disorders including stroke, cardiovascular diseases and renal failure and ultimately increases mortality worldwide MTHFR is an enzyme that catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methytetrahydrofolate, the carbon donor for the remethylation of homocysteine (Hcy) to methionine MTHFR gene is localized on chromosome 1 at 1p36.6 MTHFR C677T and A1298C polymorphisms as common genetic causes for HHcy are expected to be associated with hypertension and hypertension in pregnancy (H & HIP).MTHFR C677T and A1298C polymorphisms and H & HIP. However, the results were conflicting or inconclusive, presumably due to small sample size in each published study, various genetic backgrounds and possible selection bias. Meta-analysis is a widely used statistical method in medical research, especially for a topic being extensively studied while controversial results are being reported. Two meta-analyses, one by Qian et al. MTHFR C677T and A1298C polymorphisms with H and/or HIP in different populations and provide new evidences that were not included in these previous meta-analyses. Moreover, both meta-analyses did not address the associations of the A1298C polymorphism with H and/or HIP. To provide a more comprehensive assessment of the associations of the MTHFR C677T and A1298C polymorphisms with H & HIP in worldwide populations, we carried out a meta-analysis of all eligible studies.Numerous epidemiological studies were conducted in recent years to evaluate the associations between the MTHFR C677T and A1298C polymorphisms with H or HIP published before December 10, 2013 were identified by computerized searches in databases including Pubmed, Embase, ISI Web of Science, China Biological Medicine Database (CBM), Wanfang, China National Knowledge Infrastructure (CNKI), and Chongqing VIP Chinese Science and Technology Periodical Database (VIP). The search strategies were based on combinations of the following key words: (“methylenetetrahydrofolate reductase” or “MTHFR”) and  and . The reference lists of retrieved articles were also hand searched for additional articles.All studies reporting the relationships of the MTHFR C677T and/or A1298C polymorphisms and H or HIP; (2) hypertensive patients were diagnosed according to the criteria of SBP≥140 mmHg or DBP≥90 mmHg and the controls were healthy individuals; (3) case-control or cohort study, regardless of sample size, using a hospital based or a population based design; (4) sufficient published data for estimating the Odds Ratio (OR) and 95% confidence interval (CI); (5) for duplicate publication, the most recent or largest study was selected.Qualified studies had to meet the following criteria: (1) evaluation of the Two reviewers (Boyi Yang and Shujun Fan) independently extracted the following information from each included study: the first author’s name, publication year, sample size, source of controls, ethnicity, genotyping method, matching variables of controls with cases, H type (H vs. HIP), age, gender proportion, and counts of alleles and genotypes in both cases and controls.www.ohri. ca/programs/clinical_epidemiology/oxford.asp). This scale consists of three parts relating to selection, comparability and ascertainment of exposure. A maximum nine scores could be given to the highest quality studies. A score of five or more was regarded as “high quality”; otherwise, the study was regarded as “low quality”.Two authors (Boyi Yang and Xueyuan Zhi) independently assessed the quality of the included studies according to Newcastle Ottawa Scale (NOS) . Hardy-Weinberg equilibrium (HWE) in controls was calculated again in our meta-analysis. The chi-square goodness of fit was used to test deviation from HWE.All statistic tests performed in this study were two tailed and MTHFR C677T and A1298C polymorphisms with H and/or HIP. The significance of the pooled OR was determined by the Z test. Pooled frequency analysis was carried out using the method suggested by Thakkinstian 1 (AA vs. aa), OR2 (Aa vs. aa) and OR3 (AA vs. Aa) were explored with A as the risk allele. The above pairwise differences were used to determine the most appropriate genetic model. If OR1 = OR3 ≠ 1 and OR2 = 1, then a recessive model is selected. If OR1 = OR2 ≠ 1 and OR3 = 1, then a dominant model is selected. If OR2 = 1/OR3 ≠ 1 and OR1 = 1, then a complete overdominant model is selected. If OR1> OR2>1 and OR1> OR3>1 (or OR1< OR2<1 and OR1< OR3<1), then a codominant model is selected Crude ORs with corresponding 95% CIs were calculated to estimate the strength of the associations of the I2 statistic  P<0.10 for Q-test or I2>50%), the Dersimonian and Laird random effects model was used; otherwise, the Mantel Haenszel method fixed effects model was applied Between-study heterogeneity was calculated by Cochran’s Chi-square based Q-test The combined search yielded 1884 articles. After the removal of overlapping articles and those did not meet our inclusion criteria, a total of 112 articles MTHFR C677T polymorphism. MTHFR C677T polymorphism and H & HIP. For the dominant model, the pooled OR using random effects model was 1.26 (95% CI = 1.17–1.34) (P = 0.043), while the H type (P = 0.829), year of publication (P = 0.293), source of controls (P = 0.400), genotyping method (P = 0.439) and sample size (P = 0.579) had no statistical significance.We firstly pooled all the studies (111 studies with 15094 cases and 21633 controls) involving both H and HIP to estimate the associations between the diseases and the 17–1.34) . Subgrou17–1.34) . SignifiMTHFR A1298C polymorphism and H & HIP under all genetic models (P = 0.155), year of publication (P = 0.351), ethnicity (P = 0.411), source of controls (P = 0.906), genotyping method (P = 0.197) and sample size (P = 0.850) were not the sources of heterogeneity.Twenty one studies with 2533 cases and 2976 controls on the relationship between the A1298C polymorphism and H & HIP were included in the meta-analysis. The dominant model was determined according to the principle of genetic model selection c models –S10. Forc models . Similarc models . SignifiMTHFR C677T polymorphism and H were included in our meta-analysis. The results of overall pooled analyses under five genetic models are listed in P = 0.191), ethnicity (P = 0.953), source of controls (P = 0.066), genotyping method (P = 0.734) and sample size (P = 0.551) were not the sources of heterogeneity.Thirty six studies with 6584 cases and 6760 controls reporting the relationship between the We identified eight studies with 1196 cases and 1213 controls investigating the relationship of the polymorphism with H. The results of overall pooled analyses under five genetic models are listed in MTHFR C677T polymorphism and HIP were included in the meta-analysis. The results of overall pooled analyses under five genetic models are presented in P = 0.004) while the year of publication (P = 0.240), source of controls (P = 0.290), genotyping method (P = 0.476) and sample size (P = 0.713) had no statistical significance.Seventy five studies with 8510 cases and 14873 controls on the relationship between the MTHFR A1298C polymorphism with HIP were included in the meta-analysis. The summary results of overall pooled analysis under five genetic models are showed in Thirteen studies with 1337 cases and 1763 controls on the relationship of the MTHFR C677T and A1298C polymorphisms. Regarding to C677T, a trend of a more significant association was consistently observed with a narrowing of the 95% CI as information accumulated by year , indicating the stability of our results. Additionally, we excluded the studies that genotype distribution in the controls deviating from HWE, and the corresponding pooled ORs were not significantly changed .Funnel plot and Egger’s linear regression were performed to assess the publication bias of the included studies. The shapes of the funnel plots did not reveal any evidence of obvious asymmetry . The resMTHFR C677T polymorphism was associated with both H and HIP . However, no association was detected between the MTHFR A1298C polymorphism and H & HIP . Sensitivity analysis and cumulative meta-analysis further strengthened the validity of these results.The present meta-analysis involved 111 studies with 15094 cases and 21633 controls that investigated the C677T polymorphism and 21 studies with 2533 cases and 2976 controls investigated the A1298C polymorphism. Overall, our meta-analytical results provided evidences that the MTHFR C677T polymorphism with H and/or HIP, and our findings were largely in line with these published meta-analyses In recent years several meta-analyses have been done to investigate the associations of the MTHFR C677T polymorphism was associated with H & HIP among East Asians and Caucasians, but not among Latinos, Black Africans, and Indians and Sri Lankans. Several factors may contribute to the phenomenon that the C677T polymorphism was associated with H & HIP in one population and the association was nil for another population. Above all, different genetic backgrounds may attribute to the discrepancy, since the 677T allele distributions vary among Latinos, East Asians, Caucasians, Black Africans, and Indians and Sri Lankans, with a prevalence of 41.1%, 32.5%, 30.6%, 12.3% and 6.7%, respectively. Another explanation may be that different populations live with multiple life styles and environmental factors, some of which may affect disease development MTHFR in this meta-analysis because of its relative simplicity. Although it is reported that other genotyping methods  may provide high sensitivity and accuracy in SNP genotyping under optimized condition After subgroup analysis according to ethnicity, the results indicated that the MTHFR A1298C polymorphism and H & HIP. Overall, our meta-analytical results indicated that the A1298C polymorphism was not associated with either H or HIP. In the stratified analyses according to ethnicity, source of controls, genotyping method, sample size and study quality, no evidence of any gene-association was obtained in almost all the subgroups. Although significant associations were found in Indians and Sri Lankans, “others” genotyping method and low quality subgroups for H association studies, these results should be interpreted with great caution because only one study was included in each of these subgroups. The overall lack of the correlation may be due to relatively small sample numbers of studies and participants. Detecting a very small effect may require much larger sample sizes. Another potential explanation may be that the effect of a single polymorphism might have a limited effect on H & HIP. This is consistent with the hypothesis that H & HIP are multi-factorial conditions that result from complicated interactions between environmental and genetic factors.To the best of our knowledge, this is the first comprehensive meta-analysis to date investigating the associations between the MTHFR C677T polymorphism. Although several potential sources of the heterogeneity were investigated including ethnicity, year of publication, source of controls, genotyping, sample size and study quality, none of them sufficiently explain the between-study heterogeneity. These results indicated that other unmeasured characteristics in various study populations and/or inherited limitations of the included studies might partially cause the detected heterogeneity. Secondly, the sample size of the MTHFR A1298C polymorphism involved is not large enough, especially for subgroup analysis. Thus they do not have adequate power to detect the possible association for this polymorphism and the observed significant associations in some subgroup analyses may be false. For the MTHFR C677T polymorphism, the results for East Asians and Black Africans should also be interpreted with caution due to the limited sample size. Thirdly, although funnel plot and Egger’s test showed that publication bias was not evident in the present study, selection bias might have occured because only studies in English and Chinese (expect one study in Persian) were included in our meta-analysis. Finally, gene-gene, gene-environment or even the different polymorphism loci of the MTHFR gene interactions were not estimated in our study because of the insufficient information. Despite these limitations, our meta-analysis has several clear advantages: (1) including a substantial number of cases and controls (15411 cases and 21970 controls) from different studies, thus guaranteeing the statistical power of our meta-analysis and obtaining more precise estimates; (2) the quality of the studies included in this meta-analysis was sufficient according to our well-designed selection criteria; (3) no evidence of publication bias was observed, and cumulative meta-analysis and sensitivity analysis indicated that our results were statistically robust.Several potential limitations of the present meta-analysis should be acknowledged. Firstly, significant heterogeneity was observed in overall and subgroup analyses, especially for the MTHFR C677T polymorphism is associated with H & HIP, especially among East Asians and Caucasians. However, the MTHFR A1298C polymorphism is not associated with H & HIP. Considering the limitations aforementioned, further large-scale and population based studies, especially among Black Africans and Indians and Sri Lankans, are warranted to validate the associations observed in our meta-analysis and to explore the potential gene-gene and gene-environment interactions between the polymorphisms and H & HIP.In conclusion, our meta-analysis provides evidences that the Figure S1Forest plot of the association between MTHFR C677T polymorphism and H & HIP in homozygous codominant model (TT vs. CC).(TIF)Click here for additional data file.Figure S2Forest plot of the association between MTHFR C677T polymorphism and H & HIP in heterozygous codominant model (CT vs. CC).(TIF)Click here for additional data file.Figure S3Forest plot of the association between MTHFR C677T polymorphism and H & HIP in dominant model (TT+CT vs. CC).(TIF)Click here for additional data file.Figure S4Forest plot of the association between MTHFR C677T polymorphism and H & HIP in recessive model (TT vs. CT+CC).(TIF)Click here for additional data file.Figure S5Forest plot of the association between MTHFR C677T polymorphism and H & HIP in allele contrast model (T vs. C).(TIF)Click here for additional data file.Figure S6Forest plot of the association between MTHFR A1298C polymorphism and H & HIP in homozygous codominant model (CC vs. AA).(TIF)Click here for additional data file.Figure S7Forest plot of the association between MTHFR A1298C polymorphism and H & HIP in heterozygous codominant model (AC vs. AA).(TIF)Click here for additional data file.Figure S8Forest plot of the association between MTHFR A1298C polymorphis and H & HIP in dominant model (CC+AC vs. AA).(TIF)Click here for additional data file.Figure S9Forest plot of the association between MTHFR A1298C polymorphism and H & HIP in recessive model (CC vs AC+AA).(TIF)Click here for additional data file.Figure S10Forest plot of the association between MTHFR A1298 polymorphism and H & HIP in allele contrast model (C vs A).(TIF)Click here for additional data file.Figure S11The cumulative forest plot of OR with 95% CI for MTHFR C677T polymorphism and H &HIP in dominant model.(TIF)Click here for additional data file.Figure S12The cumulative forest plot of OR with 95% CI for MTHFR A1298C polymorphism and H & HIP in dominant model.(TIF)Click here for additional data file.Table S1Baseline characteristics of qualified studies in this meta-analysis.(DOC)Click here for additional data file.Table S2Distribution of genotype and allele frequencies of the MTHFR C677T polymorphism.(DOC)Click here for additional data file.Table S3Distribution of genotype and allele frequencies of the MTHFR A1298C polymorphism.(DOC)Click here for additional data file.Check list S1PRISMA checklist.(DOC)Click here for additional data file.


PPARγ2) gene is reported to be associated with diabetes. However, the gene’s association with diabetic retinopathy (DR) in type 2 diabetes mellitus (T2DM) has been investigated in numerous epidemiologic studies with controversial results. This meta-analysis aimed to collectively assess the association of the Pro12Ala polymorphism with DR in T2DM.The Pro12Ala polymorphism of the peroxisome proliferator–activated receptor-γ2  versus Pro/Pro] was used to ensure adequate statistical power. Crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using the fixed effect model. Potential sources of heterogeneity and bias were explored.2=46%, Pheterogeneity=0.07). The sensitivity analysis showed a robust association of the Pro12Ala polymorphism with DR in T2DM after a study involving Caucasians that presented a big effect on heterogeneity  was excluded. Possible ethnic differences in the association of the Pro12Ala single nucleotide polymorphism and DR were demonstrated; a significant association was illustrated in the Caucasian subgroup  but was not found in the Asian subgroup . No publication bias was observed.This meta-analysis included genotype data from 2,720 cases with DR and 2,450 controls free of DR from eight eligible publications. The results showed the Ala allele had a protective effect on DR in T2DM . There was no significant evidence against homogeneity (IThis meta-analysis suggested a significant association exists between the Pro12Ala polymorphism and DR in T2DM with ethnic differences. The Ala allele had a significant protective effect against DR in T2DM. Diabetic retinopathy (DR) is the fifth most common cause of irreversible vision loss in working-age adults in the world, accounting for approximately 4.8% of global blindness . Over ti(PPARγ)  for the primary meta-analysis to ensure adequate statistical power.The subjects in this study were from different geographical areas, and each subpopulation was treated as a separate comparison. The subgroup analyses were defined as Caucasians and Asians.2). Statistically significant heterogeneity was considered present with Pheterogeneity<0.05 and I2>50%. In the presence of substantial heterogeneity (I2>50%), the random effect model (REM) was adopted as the pooling method; otherwise, when I2<50%, the fixed effect model (FEM) was used as the pooling method. The leave one out sensitivity analysis was performed using I2 >50% as the criterion for evaluating the key studies with a substantial impact on between-study heterogeneity. The odds ratio (OR) of the Ala allele in DR was calculated with the Mantel–Haenszel test in FEM or the DerSimonian & Liard test in REM; p<0.05 is considered nominally significant. Meta-regression with restricted maximum likelihood estimation was performed to assess the potentially important covariates exerting a substantial impact on between-study heterogeneity. A funnel plot was performed to look for evidence of publication bias. The funnel plot should be asymmetric when there is publication bias or symmetric in the case of no publication bias. Beggar’s and Egger’s tests were used to find publication bias.Data were processed by RevMan . The distribution of genotypes was checked for the Hardy–Weinberg equilibrium (HWE). The HWE of each SNP in the control group of each study was examined by using χ2 analysis; studies not in the HWE were subjected to a sensitivity analysis. The between-study heterogeneity was tested with the chi-square-based Cochran’s statistic and the inconsistency index  than in Asian populations (7.56%).2<50%. Eight studies examining the relationship of the Pro12Ala polymorphism and DR in T2DM in the dominant model yielded a summary OR of 0.81 , which means the incidence of DR was lower in subjects with the Ala variant than in those without it. No significant association was found in the Caucasian and Asian subgroups, respectively; the FEM OR was 0.83  in Caucasians and 0.77  in Asians. In the sensitivity analysis, after Stefanski’s (2006) study [According to the forest plot , we adop6) study  excluded2 in this study was 46% (Pheterogeneity=0.07), which means the heterogeneity among the eight studies is acceptable. Between-study heterogeneity in Caucasians  was greater than in Asians , which led to the leave one out sensitivity analysis (via excluding the studies one by one) to explore the potential sources of between-study heterogeneity. After Stefanski’s (2006) [2=1%, Pheterogeneity=0.42), which indicated that this study can be identified as the main contributor of heterogeneity. We reevaluated Stefanski’s (2006) [The overall Is (2006)  study was (2006)  study inThe funnel plot was symmetric because no significant publication bias was found within the eight studies . ConsistPPARγ gene is associated with DR in T2DM. The Ala allele of the Pro12Ala polymorphism carried a protective effect against DR in T2DM patients. The PPARγ gene plays a key role in glucose metabolism, angiogenesis, and inflammation pathways, and the growing evidence of the anti-inflammatory, oxidative, and proliferative effects of the gene’s synthetic and natural ligands strongly suggest that this nuclear receptor is a primary target in DR treatment. The gene was also considered a potential candidate gene of DR development [This meta-analysis yielded evidence that the Pro12Ala polymorphism of the elopment ,23.PPARγ2 gene on DR, but the results were contradictory and inconclusive [PPARγ gene in cooperation with other factors should be elucidated. Therefore, this meta-analysis obtained a more definitive conclusion regarding the role of the Pro12Ala polymorphism in the risk of DR.Numerous studies have investigated the effects of the nclusive -25. The 2=61%), which could cover the true outcome.Our findings were based on eight gene-association studies, which involved 5,170 participants and were robust in terms of all the planned and performed sensitivity analyses. In the eight studies, two, Stefanski 2006)  and Petr06  and PFurthermore, we performed a sensitivity analysis to observe the source of heterogeneity and found Stefanski’s (2006) study  played aIndeterminate numbers of characteristics that vary among studies could be the cause of between-study heterogeneity. A potential source of variation was identified by Radha et al. . DifferePPARγ2 Ala allele carriers had higher BMI and fat-mass but not a worse metabolic profile, possibly because of a more favorable adipose tissue distribution. The main location of PPARγ expression is adipose tissue, which influences the lipid metabolism and adipocyte differentiation. The adipocytes produce hormones, cytokines, and free fatty acids. All of these factors may cause structural and functional dysfunction of the retina vasculature.The mechanism behind the effects of the Pro12Ala polymorphism on DR has not yet been investigated in detail. A study  reportedOur report combined multiple studies from different subpopulations, increased generalizability, and overall strength, and helped to overcome the prior inconsistencies in the literature.PPARγ2 gene has been shown to be associated with BMI, total cholesterol, and diabetic nephropathy. A report conducted a meta-analysis [PPARγ2 gene have been identified; however, we selected only the Pro12Ala polymorphism because this polymorphism was the most extensively studied. Meta-analyses that investigate the association of other polymorphisms in the PPARγ2 gene with DR should be performed in the future. Third, it was difficult to get full papers published in various languages; we included only studies published in English and Chinese.The current meta-analysis has several limitations that may affect the conclusions. First, the analysis  on the aPPARγ2 gene and DR in T2DM. The Ala carriers have a lower chance of developing DR than the Pro allele carriers, so we can draw the hypothesis that the Ala allele of the Pro12Ala polymorphism in the PPARγ2 gene has a protective effect in the incidence of DR in patients with T2DM. We also found ethnic differences existed, in which the Ala allele demonstrated protection in Caucasians but not in Asians. Further detailed explorations are required to detect the role of the PPARγ gene in DR.In conclusion, this meta-analysis identified the significant relationship between the Pro12Ala polymorphism in the


CD209 promoter polymorphisms  and tuberculosis (TB) risk has been widely reported, but results of previous studies remain controversial and ambiguous. To assess the association between CD209 polymorphisms and TB risk, a meta-analysis was performed.The association between CD209 polymorphisms and TB risk. The pooled odds ratio (OR) with 95% confidence intervals (CIs) were calculated.Based on comprehensive searches of the PubMed, Embase, Web of Science, Weipu, and CBM databases, we identified outcome data from all articles estimating the association between CD209 -336A/G polymorphism and TB risk . However, the significant association was revealed for Asians in GG vs. AA  and GG vs. AG+AA . For the CD209 -871A/G polymorphism, lack of an association was also found .A total of 14 studies with 3,610 cases and 3,539 controls were identified. There was no significant association between CD209 promoter polymorphisms  were unlikely to substantially contribute to TB susceptibility. However, the GG genotype of CD209 -336A/G polymorphism might be a genetic risk factor that increases TB susceptibility for Asians in GG vs. AA and GG vs. AG+AA.The present meta-analysis suggested that  Mycobacterium tuberculosis; however, only one-tenth of infected individuals will ever develop active TB Mycobacterium tuberculosis Tuberculosis (TB) constitutes a serious threat to public health throughout the world, particularly in developing countries CD209 gene, located on human chromosome 19p13.2–3, is composed of 7 exons and 6 introns, and is about 13 kb in length Mycobacterium tuberculosis on human dendritic cells Mycobacterium tuberculosis interacts with DC-SIGN to activate the Raf-1-acetylation-dependent signaling pathway that is involved in the regulation of adaptive immune response to tuberculosis. Furthermore, the DC-SIGN could suppress Toll-like receptor signaling leading to cytokine secretion. This effect may be a part of immune evasion to TB progression CD209 gene might play a crucial role in host immunity to TB and might be one of the candidate genes for susceptibility of TB.The CD209 polymorphisms  and TB risk, but the results have been inconsistent due to limited sample sizes and different study populations. To derive a more comprehensive and precise estimation of the relationship, we carried out a meta-analysis on all eligible case-control studies to estimate the effect of CD209 polymorphisms on the risk of TB and to quantify the potential between-study heterogeneity.A relatively large number of studies evaluated the association between Eleven publications, including 3,610 cases and 3,539 controls, met the inclusion criteria CD209 -336A/G polymorphism and TB risk in different ethnicities, significant association was revealed for Asians in GG vs. AA  and GG vs. AG+AA  . Forest plots on the basis of all studies were shown in = 0.001) . On subgCD209 -871A/G polymorphism indicated that the G allele had no significant association to TB susceptibility as compared to the A allele under the fixed effects models , GG vs. AA , dominant genetic model , and recessive genetic model . To explain the heterogeneity, Galbraith plots were performed in all genetic models. The two studies of Zhuang et al. and Vannberg FO(a) et al. were outliers in the G vs. A, GG vs. AA, and recessive genetic model  in 2009 -336A/G polymorphism, 4 subgroups for -871A/G polymorphism) on CD209 gene were performed to provide the most comprehensive assessment of the relationship between polymorphisms and TB. For CD209 -336A/G polymorphism, the G allele of -336A/G polymorphism had no association with the TB susceptibility for the G vs. A, GG vs. AA, dominant genetic model, and recessive genetic model in overall populations. For the CD209 -871A/G polymorphism, lack of an association was also found. Currently, many meta-analyses have reported the association between gene polymorphisms and TB susceptibility. Compared with the CD209 gene polymorphisms, the interferon-γ (IFN-γ), natural resistance-associated macrophage protein 1(NRAMP1), and Vitamin D receptor (VDR) gene polymorphisms contribute to susceptibility to TB P2X7, Mannose-binding lectin 2 (MBL2), tumor necrosis factor-α (TNF-α), and Interleukin-10 (IL-10) gene polymorphisms are not associated with TB risk In this meta-analysis, 14 studies  repeat and DC-SIGN -871 A/G:MBL) influenced the risk of developing TB. Thus, the interaction between gene and gene might play a crucial role in the association of CD209 polymorphisms with TB risk.In view of the complex effect of genetic polymorphisms on disease progression, the lack of an association between  TB risk . de Wit CD209 -336A/G polymorphism, the G allele frequency has significant differences in different populations. Next, the association between CD209 -336A/G polymorphism and different ethnicities was explored. The significant association was revealed for Asians in GG vs. AA  and GG vs. AG+AA . The ethic-dependent association may attribute to interplay among different human alleles, locally predominant, and endemic mycobacterial lineages CD209 -336A/G polymorphism could increase the risk of infection with Mycobacterium tuberculosis Beijing but not non-Beijing strain in Russian male population. Thus, the TB in different host infected with the same genotype may manifest as different outcome in clinic.Due to different racial or ethnic populations with different frequencies of alleles, different genetic backgrounds may affect TB susceptibilities. Therefore, subgroup analyses were performed according to ethnicity. First, we detected whether there was G allele frequency of variation in different ethnicities. For CD209 -336A/G polymorphism. Then, we used the Galbraith plots to explore the sources of heterogeneity. We found all of the I2 values were less than 50% and Pheterogeneity were greater than 0.1 after excluding the studies of Zhuang et al., Vannberg FO(a) et al. and Barreiro LB et al, respectively. The results indicated that the three studies might be the major source of the heterogeneity for the CD209 -336A/G polymorphism. The results of subgroup analyses revealed that the ethnicity and sample type might contribute to the potential heterogeneity. Owing to the limited number of studies in this meta-analysis, we restricted meta-regression analysis to four factors , which are the most likely to cause the heterogeneity between studies. However, the four above-mentioned factors had no significant impact on the heterogeneity.In our meta-analysis, obvious heterogeneity was observed for CD209 polymorphisms. Thirdly, TB is a multifactorial disease and potential interactions among gene-gene and gene-environment should be considered. Moreover, as many other factors such as age or gender may participate in the progression of TB, we did not carry out subgroup analysis based on these factors due to limited data.There are some limitations to this meta-analysis. Firstly, the retrieved literature is potentially not comprehensive enough. We did not track the unpublished articles to obtain data for analysis. The potential effect of this publication bias is unknown. Secondly, the small sample sizes in some subgroup analyses may have limited statistical power to estimate the possible risk for CD209 promoter polymorphisms  may lack association with genetic susceptibility of TB. However, genotype GG of CD209 -336A/G polymorphism might play a role as risk factor for Asians in GG vs. AA and GG vs. AG+AA, which indicated the different genetic backgrounds may affect TB susceptibilities. Moreover, further studies with large sample size of different ethnic populations will be necessary to combine genetic factors together with poor economic conditions, malnutrition, stress and overcrowding.Conclusively, the CD209 or DC-SIGN” and “tuberculosis or TB” and “polymorphism or mutation or variant”. There were no language restrictions. We reviewed the bibliographies of all selection articles to identify additional relevant studies.This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria CD209 -336A/G or -871A/G polymorphisms and TB risk, (2) case-control studied (family-based study design with linkage considerations was excluded), (2) sufficient data for estimating an odds ratio (OR) with 95% confidence intervals (CIs), (3) genotype distribution of control population in Hardy-Weinberg equilibrium (HWE), and (4) studies written in English or Chinese. For the studies with the same or overlapping data by the same authors, the most recent or largest population was selected.Two reviewers (K.C. and W.L.) independently screened titles and abstracts of all studies for relevancy. Disagreements were resolved by a third opinion (M.C.). Full-text publications were retrieved for relevant articles. The strength of the individual studies was weighed for relevance, based on the following items: (1) evaluation of the Data were extracted independently from each study by two reviewers (K.C. and S.D.) according to the inclusion criteria listed above. Agreement was reached after discussion for conflicting data. The following data were collected from each study: first author’s name, publication year, original country, ethnicity, sample size, sample types, TB definition, genotyping method, and genotype number in cases and controls.The quality of included studies was assessed independently by the same two investigators using the Newcastle-Ottawa Scale (NOS) . The NOS uses a ‘star’ rating system to judge quality based on 3 aspects of the study: selection, comparability, and exposure. Scores were ranged from 0 stars (worst) to 9 stars (best). Studies with a score of 7 stars or greater were considered to be of high quality. Disagreement was settled as described above.CD209 polymorphisms and TB risk was estimated by OR and corresponding 95% CIs. The pooled OR was calculated respectively for G vs. A, GG vs. AA, dominant genetic model (GG+AG vs. AA), and recessive genetic model (GG vs. AG+AA). Between-study heterogeneity was assessed by the Q-test and I2 test, Pheterogeneity<0.10 and I2>50% indicated evidence of heterogeneity. Then, the random-effects model (the DerSimonian and Laird method) The strength of association between Sensitivity analysis was mainly performed to assess the stability of the results, namely, a single study in the meta-analysis was deleted each time to reflect the influence of the individual data set to the pooled OR. Asymmetry funnel plots were inspected to assess potential publication bias. The Egger’s linear regression test Data were analyzed by using STATA 11.0  and Revman 5.0 (The Cochrane Collaboration).Figure S1Flow diagram of the selection of eligible studies.(TIF)Click here for additional data file.Figure S2Frequencies of the minor allele  of the CD209 -336A/G polymorphism among controls subjects stratified by ethnicity. The G allele frequencies were significant difference in Africans, Asians, Caucasians and Mixed populations (P = 0.007)(TIF)Click here for additional data file.Figure S3Forest plot of CD209 -336A/G promoter polymorphism and risk of TB in G vs. A for each subgroup. No significant association was found between the CD209 -336A/G polymorphism and TB risk in G vs. A.(TIF)Click here for additional data file.Figure S4Forest plot of CD209 -336A/G promoter polymorphism and risk of TB in GG vs. AA for each subgroup. The significant association was revealed for Asians in GG vs. AA .(TIF)Click here for additional data file.Figure S5Forest plot of CD209 -336A/G promoter polymorphism and risk of TB in dominant model for each subgroup. No significant association was found between the CD209 -336A/G polymorphism and TB risk in dominant model.(TIF)Click here for additional data file.Figure S6Forest plot of CD209 -336A/G promoter polymorphism and risk of TB in recessive model for each subgroup. The significant association was revealed for Asians in recessive model .(TIF)Click here for additional data file.Figure S7Funnel plots of all genetic models in overall studies. A. G vs. A; B. GG vs. AA; C. dominant model (GG+AG vs. AA); D. recessive model (GG vs. AG+AA). Funnel plots of dominant model seemed asymmetry. Each point represents a separate study for the indicated association.(TIF)Click here for additional data file.Figure S8Forest plot of the overall risk of TB associated with the CD209 -939G/A promoter polymorphism. No significant association was found between the CD209 -939G/A polymorphism and TB risk in all genetic models. Error bars indicate 95% CI. Solid squares represent each study in the meta-analysis. Solid diamonds represent pooled OR.(TIF)Click here for additional data file.Table S1Gene frequencies of all the individual studies used for the meta-analysis.(DOC)Click here for additional data file.Table S2Quality assessment of included studies.(DOC)Click here for additional data file.Table S3Meta-regression analysis of CD209 -336A/G promoter polymorphism and risk of TB after omitting the studies.(DOC)Click here for additional data file.