Background: Prospective data regarding persistent organic pollutants (POPs) and risk of type 2 diabetes (T2D) are limited, and the results for individual POPs are not entirely consistent across studies.Objectives: We prospectively examined plasma POP concentrations in relation to incident T2D and summarized existing evidence in a meta-analysis.Methods: Plasma polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), and hexachlorobenzene (HCB) concentrations were measured in 1,095 women who were free of diabetes at blood draw in 1989–1990 and participated in two case–control studies in the Nurses’ Health Study. We identified 48 incident T2D cases through 30 June 2008. We conducted a literature search in PubMed and EMBASE through December 2011 to identify prospective studies on POPs in relation to diabetes. We used a fixed-effects model to summarize results.ptrend = 0.003) comparing extreme tertiles]. Other POPs were not significantly associated with diabetes. After pooling our results with those of six published prospective studies that included 842 diabetes cases in total, we found that HCB and total PCBs both were associated with diabetes: the pooled ORs were 2.00  and 1.70  for HCB and total PCBs, respectively.Results: After multivariable adjustment, plasma HCB concentration was positively associated with incident T2D [pooled odds ratio (OR) 3.59 (95% CI: 1.49, 8.64, Conclusions: These findings support an association between POP exposure and the risk of T2D. The prevalence of type 2 diabetes (T2D) is increasing rapidly worldwide, and this disease has posed an enormous public health challenge. It is widely considered that complex interactions between genetic and environmental factors may underlie the etiology of diabetes . GrowingPOPs are a variety of synthetic compounds that can accumulate in human adipose tissue and are characterized by slow degradation . Common In the present study, we aimed to prospectively evaluate plasma concentrations of PCB congeners, DDT, DDE, and HCB in relation to risk of T2D using existing data from the Nurses’ Health Study (NHS). We also conducted a meta-analysis to summarize existing prospective evidence on relevant associations.Study population. The NHS is an ongoing prospective cohort of 121,700 female registered nurses who were 30 to 55 years old at study inception in 1976 when each nurse completed a mailed questionnaire about her medical history and lifestyle (n = 290) in the NHL study  in 1994–1997 by single-column gas chromatography with electron capture detection . The limp-values < 0.01), and 0.10 for DDT (p = 0.59). The two data sets were analyzed separately, as described below.We found reasonable correlations between POP concentrations in 30 samples that were assayed using both methods. The Spearman correlation coefficients were 0.53 for PCB-118, 0.60 for PCB-138, 0.75 for PCB-153, 0.77 for PCB-180, 0.76 for HCB, 0.92 for DDE . To examine whether the associations could be due to reverse causation bias, in a further sensitivity analysis we excluded diabetes cases reported ≤ 2 years after blood sample collection in 1989–1990.trations  and dysltrations , the usetrations . Therefotrations  to derivStatistical analyses were performed using SAS version 9.1 . All reported p-values are two-sided, and α = 0.05 was used as the significance level.Meta-analysis. Study selection. We searched the National Institutes of Health U.S. National Library of Medicine’s PubMed (http://www.ncbi.nlm.nih.gov/pubmed/) and Elsevier’s EMBASE (http://www.embase.com/) databases for articles regarding POP exposures and diabetes risk that were published through 2 December 2011.  We applied the following study inclusion criteria: a) a prospective study design, and b) that point estimates of relative risk (RR) of diabetes with 95% CI or SEs were available or could be derived. We excluded animal studies, clinical trials, cross-sectional studies, reviews, commentaries, letters, and studies that examined irrelevant exposures or outcomes. Two investigators (H.W. and K.A.B.) independently screened all studies by title or abstract, and then by a full text evaluation. Any discrepancy between the two authors was solved by discussion with the senior investigator (Q.S.). Of 589 unique publications identified in the literature search, we identified six prospective studies , participant characteristics (age and sex), exposure (POP concentrations for each category) and measurement method of POPs, outcome ascertainment, and analysis strategy . Data extraction was conducted independently by two investigators (H.W. and K.A.B.), and any discrepancy was again solved by discussion with Q.S.Statistical analyses. Meta-analyses were performed using Stata version 10.0 . We used a fixed-effects model to summarize study estimates comparing extreme categories (highest category vs. reference category) of POPs in each individual study. In this analysis, we used logarithms of RRs and corresponding SEs that were derived from the 95% CIs in each individual study. We also used a random-effects model to pool RRs across studies. Heterogeneity among the results of these studies was evaluated using the I2 statistic. We further used the meta-regression approach (Stata METAREG command) to evaluate whether the associations of POPs were influenced by some study characteristics such as age, sex, demographic variables, baseline POP concentrations, diabetes diagnosis strategies, duration of follow-up, and whether blood lipid was adjusted for in the final model. We also conducted a dose–response meta-analysis by using the generalized least-squares method for trend estimation of summarized dose–response data (Stata GLST command) (command) . To evalcommand) . To be ccommand)  from thecommand) .NHS.http://dx.doi.org/10.1289/ehp.1205248). The incident rate of T2D  was significantly higher among cancer controls than cancer cases , probably because cancer cases had higher mortality than controls .http://dx.doi.org/10.1289/ehp.1205248)]. The four major PCB congeners were highly correlated with each other in both studies, and all of the pairwise correlation coefficients were > 0.53. Positive associations were also observed among DDT, DDE, and HCB, although the correlations were somewhat weaker in the breast cancer study than in the NHL study. In general, BMI at baseline was inversely correlated with PCBs in both studies, except PCB-118 in the NHL study for which the correlation was positive (Sr = 0.17). The correlations between BMI and DDT, DDE, and HCB were very weak (|Sr| < 0.10), with the exception of the correlation between BMI and DDT in the NHL study (Sr = 0.20).We examined age-adjusted Spearman correlations among plasma POPs, as well as between baseline BMI and POPs . In pooled analysis, total PCBs, total concentrations of the four major PCB congeners (ΣPCBs), and other individual POPs, except PCB-138, were also associated with a nonsignificantly increased T2D risk. Total POPs, which were the sum of total PCBs, DDT, DDE, and HCB, showed nonsignificantly positive association with risk of T2D: The multivariable-adjusted (ptrend = 0.27) and 1.50  comparing extreme tertiles in the breast cancer study and the NHL study, respectively. The pooled OR was 1.71  comparing the highest to the lowest tertile ]. HCB still showed the strongest association with risk of T2D. The pooled OR was 3.76  comparing extreme tertiles. Other POPs did not show significant association with diabetes based on this analysis. When we used a nonparametric approach to derive a standardized score to account for the between-study differences, we again found similar associations . For example, in comparison to women in the lowest HCB score tertile, women in the highest tertile had an OR of 3.79 , and other POPs were not significantly associated with diabetes. We observed largely similar results among cancer-free participants based on pooled fixed-effects estimates . After excluding T2D cases that occurred ≤ 2 years after blood collection (n = 7) or T2D cases that had any prior cancer diagnosis (n = 5), multivariable-adjusted ORs for the highest versus lowest tertiles of HCB were 3.91  and 3.03 , respectively. Estimates for other POPs were also comparable to those for the main analysis (data not shown).Meta-analysis. The characteristics of the six published prospective studies that evaluated circulating POP concentrations in relation to incident diabetes are shown in I2 = 16.3%, pheterogeneity = 0.30) for total PCBs and 2.00  for HCB. Of note, estimates for HCB based on data from two previous studies  for DDE, 1.20  for PCB-118, and 1.36  for PCB-138 . The pooled OR of diabetes for total PCBs increased from 1.70  to 2.05  after results from the Yucheng cohort were excluded (pnonlinearity = 0.99) , although the power for detecting such a relationship was limited in the present analysis. Assuming a linear relationship, we estimated an OR of 1.06  per nanogram per gram serum weight increase in total PCBs. We could not examine dose–response relations for individual POPs because of insufficient data.Meta-regression analysis indicated that the association between total PCBs and HCB and diabetes risk was not dependent on age, sex, other demographic variables, baseline total PCB or HCB concentrations, diabetes diagnosis strategies, duration of follow-up, or whether blood lipids were adjusted for in the final model  were significantly associated with prediabetes prevalence, but not with diabetes prevalence . In contp-dioxin and 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin, may impair glucose metabolism and regulation by reducing glucose uptake  developed abdominal obesity and insulin insensitivity . In addie uptake  or by ine uptake . Despitee uptake . Similarhe 1970s . Our finThe major strengths of our study included a prospective study design, a long follow-up of 18 years for the analysis of NHS data, and the use of meta-analysis to combine the NHS estimates with data from previous studies. There are several limitations of this study as well. First, we explored the association between POP concentrations and incident diabetes using existing data from two cancer case–control studies in the NHS. Because these studies were not designed to evaluate diabetes risk and because our participants were female registered nurses who were primarily white, results generated from these participants may have restricted generalizability, even within the entire NHS cohort. Further, we only accumulated a small number of diabetes cases from these two studies, resulting in limited statistical power. Second, the POP concentrations were measured by different methods in the two studies. However, we conducted study-specific analyses to account for between-study variation, and when we used a standardized score that minimized this between-study variation in a sensitivity analysis, we observed largely similar results. Third, the studies included in the meta-analysis measured various, intercorrelated individual POPs with different concentrations. We cannot exclude the possibility that the significant associations observed for HCB and total PCBs may be actually due to the effects of individual PCB congeners or other POPs. Fourth, we have limited statistical power for testing any nonlinear relationship between total PCBs and risk of diabetes in this meta-analysis. In addition, the dose–response relationship for individual POPs may be at least partly driven by individual or joint effects of POPs, which may vary depending on the concentrations of the individual POPs involved. Our estimates based on two prospective studies and a meta-analysis indicate that higher plasma HCB and total PCB concentrations are significantly associated with incident T2D. These findings support a positive association between POP exposure and risk of T2D.(365 KB) PDFClick here for additional data file.


Interleukin (IL)-13, a T-helper type 2 cytokine, plays a critical role in the development of chronic obstructive pulmonary disease (COPD). This meta-analysis was performed to assess the association of IL-13 −1112 C/T promoter polymorphism with COPD susceptibility.Published case-control studies from Pubmed and China National Knowledge Infrastructure (CNKI) databases were retrieved. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated.Eight case-control studies in seven articles were included in this meta-analysis. Pooled effect size showed IL-13 −1112 C/T was associated with COPD susceptibility in a codominant genetic model , indicating individuals with TT genotype had an increased risk for COPD compared with those with CT or CC genotype. According to ethnicity, results indicated IL-13 −1112 C/T was correlated with COPD susceptibility in Arabians . Moreover, after excluding the study without Hardy-Weinberg equilibrium, the pooled results were robust and no publication bias was found in this study.This meta-analysis suggests IL-13 −1112 C/T promoter polymorphism is associated with the risk of COPD in Arabians. Interleukin (IL)-13 is a T-helper type 2 (Th2) cytokine and its gene position is together with the IL-4 gene located within 15 kb on chromosome 5q31, a region associated with asthma, airway hyper-responsiveness and IgE levels Unfortunately, IL-13 gene was not selected as a candidate gene for COPD in recent genome-wide association studies (GWAS) However, difference in ethnicity and sample size in individual studies may result in inconsistent results with lower statistical powers, and a meta-analysis could be a useful means to pool the independent statistical powers and thus achieve a quantitative understanding of the associations. Accordingly, in the present study, a meta-analysis was performed to determine IL-13 −1112 C/T promoter polymorphism and the risk of COPD.http://www.cnki.net/) databases. The languages were limited to English and Chinese. The following search terms were utilized: interleukin 13 or IL 13, and gene polymorphism or polymorphism or variant, and chronic obstructive pulmonary disease or COPD. The PRISMA flow diagram   not case-control genetic study, 2) duplicated report, 3) no useful data reported, 4) other IL-13 polymorphisms except −1112 C/T . Unpublished data were not considered. Disagreement was resolved by discussion before reaching a consensus. If more than one article was published by the same group using the same cases, the study with higher sample size was selected.χ2 test was used to determine whether the observed frequencies of genotypes in controls conformed to the Hardy–Weinberg equilibrium (HWE). Studies with controls that depart from HWE (p<0.05) were subjected to a sensitivity analysis in order to check the consistency of the overall effect size. Funnel plots, as well as the Begg’s rank correlation test and Egger’s linear regression test, was used to inspect the potential publication bias, and p<0.05 was considered significant publication bias. All analyses were conducted using Revman 5.0  and Stata 11.0 .Categorical variables were presented as odds ratio (OR) with 95% confidence interval (CI). CC, CT and TT are the genotypes of IL-13 −1112 C/T polymorphism. OR1, OR2 and OR3 were calculated as follows: 1) TT vs CC; 2) CT vs CC; 3) TT vs CT. These pairwise differences  were used to indicate the most appropriate genetic model as follows: if OR1 = OR3≠1 and OR2 = 1, then a recessive model was suggested; if OR1 = OR2≠1 and OR3 = 1, then a dominant model was suggested; if OR2 = 1/OR3≠1 and OR1 = 1, then a complete overdominant model was suggested; if OR1>OR2>1 and OR1>OR3>1 (or OR1<OR2<1 and OR1<OR3<1), then a codominant model was suggested. Once the best genetic model was identified, this model was used to collapse the three genotypes into two groups (except a codominant model) and to pool the results again Thirteen studies were relevant to the search terms. After reviewing the titles, abstracts and articles, six studies were excluded and thus seven studies with 1319 cases and 831 controls matched the inclusion criteria Figure 1In order to indicate the most appropriate genetic model, OR1 (TT vs CC), OR2 (CT vs CC) and OR3 (TT vs CT) were calculated. Results showed OR1 = 2.02, OR2 = 1.28 and OR3 = 1.82 respectively, suggesting a codominant genetic model (TT vs CT and TT vs CC). Using a codominant genetic model, pooled effect size showed an association of IL-13 −1112 C/T with the risk of COPD , but not TT vs CT comparison , and the source of heterogeneity for TT vs CC comparison was detected by ethnicity. When stratified by ethnicity, no heterogeneity was observed in the studies on TT vs CC comparison in Caucasians and Arabians, suggesting heterogeneity between the studies in Asians and Uygur contributed significantly to the overall heterogeneity in TT vs CC comparison.Significant heterogeneity was revealed between all studies in TT vs CC comparison , indicating this study contributed more to the overall heterogeneity in TT vs CC comparison.In the present meta-analysis, only one study The funnel plots showed no sigificant asymmetry in this meta-analysis Figure 4IL-13, a Th2 cytokine, contributes to the development of COPD. Recently, association of IL-13 −1112 C/T promoter polymorphism with COPD risk caught more attention, owing to its potential in regulation of IL-13 production and correlation with cigarette smoke-induced airflow limitation In this meta-analysis, IL-13 −1112 C/T was found to be correlated with COPD in a codominant model (the most appropriate genetic model), indicating individuals with TT genotype had a higher risk for COPD than those with CT or CC genotype, which is consistent with the reports by Sadeghnejad et al. Interestingly, no heterogeneity was revealed between the studies in TT vs CT comparison, however, there was significant heterogeneity between the studies in TT vs CC comparison. To identify the source of heterogeneity in TT vs CC comparison, subgroup analysis was performed according to ethnicity. No heterogeneity was observed in the studies for TT vs CC comparison in Caucasians and Arabians, suggesting heterogeneity between the studies in Asians and Uygur contributed significantly to the overall heterogeneity. Futher results indicated IL-13 −1112 C/T was correlated with COPD susceptibility in Arabians but not Caucasians with homogeneity in both TT vs CT and TT vs CC comparisons. After exclusion of the study without HWE by Jiang et al However, some limitations should be considered in this meta-analysis. First, large sample size studies were lacked and the pooled statistical powers could not be very enough. Second, the pooled estimates were not based on adjustment by confused factors, such as sex, age, smoking history. Third, lack of the original data in the studies limited our further analysis of the potential interactions between gene and gene, or gene and environment, which might modulate COPD risk.In conclusion, although the pooled estimates should be interpreted with caution, our meta-analysis suggests that IL-13 −1112 C/T promoter polymorphism is associated with the risk of COPD in Arabians. However, large sample size studies with unbiased genotyping methods, standardized defined COPD cases and matched controls in different populations, and more detailed data about individual and environment are warranted.Figure S1PRISMA flow diagram.(DOC)Click here for additional data file.Table S1PRISMA checklist.(DOC)Click here for additional data file.


ApoB-100 gene polymorphisms and the risks of GS and GBC have yielded conflicting results. Therefore, we performed a meta-analysis to clarify the effects of ApoB-100 gene polymorphisms on the risks of GS and GBC.Gallstones (GS) is the major manifestation of gallbladder disease, and is the most common risk factor for gallbladder cancer (GBC). Previous studies investigating the association between A computerized literature search was conducted to identify the relevant studies from PubMed and Embase. Fixed or random effects model was selected based on heterogeneity test. Publication bias was estimated using Begg’s funnel plots and Egger’s regression test.ApoB-100 XbaI, EcoRI, or insertion/deletion (ID) polymorphisms and the GS risks, respectively, while 3 studies were included in the analysis for the association between XbaI polymorphism and GBC risk. The combined results showed a significant association in Chinese , but not in Indians or Caucasians. Null association was observed between EcoRI or ID polymorphisms and GS risks. With regard to the association between XbaI polymorphism and GBC risk, a significant association was detected when GBC patients were compared with healthy persons and when GBC patients were compared with GS patients. A significant association was still detected when GBC patients (with GS) were compared with the GS patients .A total of 10, 3, and 3 studies were included in the analyses of the association between ApoB-100 X+ allele might be associated with increased risk of GS in Chinese but not in other populations, while the ApoB-100 X+X+ genotype might be associated with reduced risk of GBC. Further studies with larger sample sizes are needed to confirm these results.The results of this meta-analysis suggest that the  Gallstone disease (GS) is the major manifestation of gallbladder diseases, and is one of the most common digestive disorders worldwide, especially in Western countries The liver is the major organ involved in the regulation of cholesterol metabolism. It could acquire cholesterol from plasma lipoproteins via endocytosis or selective cholesterol uptake mediated by the interactions of apolipoproteins with various cell surface molecules including low-density lipoprotein (LDL) receptor, LDL receptor- related protein, hepatic lipase, and scavenger receptor class B type 1 (SR-B1) http://onlinelibrary.wiley.com/doi/10.1002/hep.20867/full - bib13 ApoB on the LDL particle acts as a ligand for LDL receptors in various cells throughout the body. High levels of ApoB can lead to plaques that cause vascular disease (atherosclerosis), leading to heart disease ApoB-100 gene, located on 2p24-p23, is 43 kb in length with 81 bp signal sequence. Numerous polymorphisms have been identified in ApoB-100, among which the XbaI polymorphism (−2488C>T), a single base alteration in the exon 26, has been demonstrated to be associated with interindividual variability of lipid levels ApoB-100 gene, EcoRI (−4154G>A) and insertion/deletion (ID) polymorphisms have also been reported Apolipoprotein B-100 (ApoB-100) is a key protein involved in lipid metabolism. It is the sole component of LDL particles and plays an important role in the homeostasis of LDL cholesterol in plasma ApoB-100 gene polymorphisms and the risks of GS or the risks of GBC, but the obtained results were conflicting. Some of the studies supported strong associations between ApoB-100 polymorphism and the diseases ApoB-100 gene polymorphisms and the risks of GS and GBC.To date, a series of epidemiological studies have been performed to investigate the relationship between A computerized literature search was performed for the available relevant studies from PubMed and Embase. The following keywords were jointly used: (“Apolipoprotein B” or “Apo B”) and (“polymorphism” or “mutation” or “variation”) and . Additional studies were identified by a hand search of all the references of the retrieved articles. If more than one article was published using the same case series, only the study with largest sample size was selected. The literature search was updated to 30 November 2012.ApoB-100 gene polymorphisms and the risks of GS or GBC, (2) case-control or cohort design, and (3) provided sufficient data for the calculation of odds ratios (ORs) with the corresponding 95% confidence interval (95%CI).The included studies must meet the following criteria: (1) evaluated the associations between The following information was extracted from each study: (1) name of the first author, (2) publication year, (3) country of origin, (4) ethnicity of the study population, (5) source of the control subjects, (6) numbers of cases and controls, (7) gender and age of the enrolled subjects, and (8) number of genotypes in the cases and controls. The data were extracted independently by 2 investigators who reached a consensus on all of the items.ApoB-100 gene polymorphisms and risks of GS or GBC were estimated by calculating the pooled ORs and 95%CI. The significance of the pooled effect size was determined by the Z test. Heterogeneity among the studies was assessed using the Q test and the 2I test as performed in other studies I2 statistic. The data analysis was performed using STATA version 10 .The associations of the ApoB-100 XbaI, EcoRI, ID polymorphisms and the risks of GS, respectively. Among these included studies, 3 studies were performed in Chinese, 4 in Indian subjects, 2 in Caucasians, 1 in Chile, and 1 in Mexico. For the association between the ApoB-100 gene polymorphisms and the GBC risks, 3 studies were retrieved et al.et al.As depicted in ApoB-100 XbaI polymorphism and the GS risk. However, the subgroup analyses by ethnicity showed a significant association in the Chinese  . With respect to the associations between the EcoRI polymorphism and the GS risk, no significant association was detected . Similarly, no significant association was observed between the ID polymorphism and the GS risks . As limited studies were included in the analyses of the EcoRI and ID polymorphisms and the risks of GS, we did not perform subgroup analysis.Overall, no significant association was observed between the 55–3.92) Figure 2ApoB-100 XbaI polymorphism and the GBC risk were shown in  and vs. X−, OR = 0.64, 95%CI 0.45–0.92; X+X+/X+X− vs. X−X−, OR = 0.54, 95%CI 0.30–0.97) when GBC patients were compared with healthy persons. However, the subgroup analysis based on the types of GBC (with or without GS) showed no significant association between the XbaI polymorphism and GBC risk when GBC patients without GS were compared with healthy persons . For the comparisons between the GBC patients and GS patients, significant association was also detected for the homozygous comparison . Furthermore, significant association could still be detected when the GBC patients with GS were compared with the GS patients .The results of the pooled analysis for the association between the ApoB-100 ID polymorphism and GS risk. A moderate heterogeneity was detected in the analysis of the association between the ApoB-100 XbaI polymorphism and GS risk (2<I50% in most comparisons). The heterogeneity was significantly reduced in the subgroup analyses stratified by ethnicity, suggesting that ethnicity might be a major contributor to the between-study heterogeneity (ApoB-100 EcoRI polymorphism and GS risk and between the ApoB-100 XbaI polymorphism and GBC risk (2>I50% in most comparisons). Although we did not perform the subgroup analysis due to the limitations of the studies included, ethnicity might also be a major contributor to the heterogeneity. Sensitivity analysis was performed by the sequential omission of individual studies in every comparison, and the data showed that no study significantly influenced the pooled effects based on the omission of any single study. The exclusion of the studies that deviated from HWE did not change the results significantly.No significant heterogeneity was detected in the analysis between the ogeneity Table 3.vs. X−X−, D vs. I, DI vs. II, and DD/DI vs. II in the analyses between the ApoB-100 gene polymorphisms and the risks of GS. No significant publication bias was detected in any other comparison .Potential publication bias was detected by Egger’s test in the comparisons of X+X+/X+X− ApoB-100 is of particular interest, as it is the major protein component of LDL ApoB-100 variant may be related to a higher incidence of GS and GBC. Unfortunately, previous epidemiological studies investigating the associations between ApoB-100 gene polymorphisms and the risks of GS/GBC have yielded conflicting results. The discrepancy may be attributed to multiple factors, such as the ethnicity of the population, the type of GS, and the sample size. Thus, a timely meta-analysis is necessary.GS is a common digestive disease worldwide and is also a major risk factor for GBC ApoB-100 XbaI, EcoRI, and ID polymorphisms, and the risks of GS, respectively. The combined results showed a significant association in Chinese  but not in Indians or Caucasians . These data suggest that the ApoB-100 X+ allele might be associated with an increased GS risk in Chinese, whereas the X+X+ genotype might be associated with a reduced risk of GBC.In this study, we performed a comprehensive literature search and included a total of 10, 3, and 3 studies for the analyses between the ucasians Table 3.ApoB-100 XbaI polymorphisms and the GS risks in different populations, as GS is the results of the interaction between genetic and environmental factors ApoB-100 XbaI polymorphism could still influence the risks of GS for Chinese. For GBC, the results of the current meta-analysis showed that X+ might be related to a reduced risk of GBC. It is difficult to explain by what mechanisms the X+ allele decreases the risks of GBC.The X+X+ genotype has been reported to be associated with higher serum levels of LDL compared with the X−X− genotype et al. scanned >500,000 SNPs in 280 individuals with GS and 360 controls, and identified the ABCG8 as a susceptibility factor for human GS ApoB-100 gene polymorphisms and the risks of GS were obtained from case-control studies performed in different populations. Furthermore, limited experimental studies have focused on the roles of ApoB-100 in the pathogenesis of GS. In one study, Zhao et al. found that high cholesterol diet fed rabbits showed higher concentrations of plasma ApoB-100, which might enhance the secretion of biliary cholesterol into bile, ant thus facilitate the formation of GS ApoB-100 gene deficiency did not reduce biliary cholesterol secretion and cholelithogenesis, while the mice deficiency of ApoB-48 displayed significantly lower secretion rates of biliary cholesterol and significant decreases in prevalence rates, numbers, and sizes of GS So far, most genetic association studies about the gene polymorphisms and GS risks are in case-control design and have not been replicated in larger population cohorts and other ethnic groups Some limitations of this meta-analysis should be noted in interpreting the results. First, the present meta-analysis was based on unadjusted effect estimates and CIs because most studies did not provide the adjusted ORs and 95%CI. Second, GS/GBC are multifactor diseases, however, the interaction of gene-gene and gene-environment were not addressed in the current study, and thus the potential roles of the above gene polymorphisms might be masked or magnified by other gene-gene/gene-environment interactions. Third, the possibility of a selection bias cannot be completely excluded because only published studies were included. Although we searched multiple databases, we may have still failed to include some papers.ApoB-100 X+ allele might be associated with increased risk of GS in Chinese but not in other populations, while the ApoB-100 X+X+ genotype might be associated with reduced risk of GBC. Further studies with larger sample sizes are needed to confirm these results.In conclusion, the current meta-analysis suggests that the PRISMA Checklist S1(DOC)Click here for additional data file.


Here, we aimed to investigate whether SNP rs895819 was associated with the development of renal cell cancer (RCC) in a Chinese population.MicroRNAs (miRNAs) are a class of small non-coding RNAs to regulate cell differentiation, proliferation, development, and apoptosis. The single nucleotide polymorphism (SNP) rs895819 is located at the terminal loop of In this case-control study, we recruited 594 RCC patients and 600 cancer-free controls with frequency matched by age and sex. We genotyped this polymorphism using the TaqMan assay and assessed the effect of this polymorphism on RCC survival. Logistic regression model was used to assess the genetic effects on the development of RCC and interactions between rs895819 polymorphism and risk factors.Compared with AA homozygote, individuals carrying AG/GG genotypes had a statistically significant reduced susceptibility to RCC . Furthermore, AG/GG genotypes were associated with reduced RCC susceptibility in localized clinical stage , and similar effects were observed in well differentiated and poorly differentiated RCC . We also observed that rs895819 had multiplicative interactions with age and hypertension. However, the polymorphism did not influence the survival of RCC.pre-miR-27a rs895819 polymorphism can predict RCC risk in a Chinese population. Larger population-based prospective studies should be used to validate our findings.Our results suggest that the  Renal cell cancer (RCC) accounts for more than 90% of kidney carcinomas, and clear-cell renal carcinoma is the most common type in RCC MicroRNAs (miRNAs) are a class of endogenous, small and non-coding RNAs (∼22 nt), which are initially transcribed from genomic DNA to long primary transcripts (pri-miRNAs) and then are cleaved by nuclear Drosha into 60–70 nt hairpin-shaped precursor RNAs (pre-miRNAs) pre-miR-27a and involves an A>G nucleotide transition. Sun et al.et al.et al. reported that in breast cancer cells, transfection of antisense miR-27a lead to increased expression of Zinc finger and BTB domain containing 10 (ZBTB10)( a putative Sp repressor) and these responses were accompanied by decreased expression of Sp-dependent survival and angiogenic genes, including survivin, vascular endothelial growth factor (VEGF), and VEGF receptor 1 (VEGFR1) pre-miR-27a polymorphism and RCC susceptibility.One study has systematically identified 323 SNP in 227 known human miRNAs, and 12 SNPs are located within the miRNA precursors miR-27a, we hypothesized that the pre-miR-27a polymorphism was associated with RCC susceptibility. To test this hypothesis, we genotyped this particular SNP rs895819 and assessed the association with risk of RCC in our ongoing case–control study in a Chinese population.Based on our knowledge regarding the new polymorphism and biological function of This study comprised 594 patients and 600 cancer-free controls. All subjects in our study are ethnic Han Chinese with no genetic relationship. All the patients were newly diagnosed with histopathologically confirmed incident RCC. Those cases that received chemotherapy or radio-therapy before surgery or had other type of cancer were excluded from the present study. Consecutive RCC patients were recruited between May 2004 and August 2010 at The First Affiliated Hospital of Nanjing Medical University, Nanjing, China. Disease was classified according to World Health Organization criteria and staged according to the American Joint Committee on Cancer TNM classification. The Fuhrman scale was used to assess tumor nuclear grade For the survival analysis, 296 RCC cases enrolled in our ongoing cohort study from May 2004 to October 2009 were used. The patients were followed up prospectively every 6 months from the date receiving a confirmed diagnosis until death or last time of follow-up. The maximum follow-up time was 72 months (last follow-up in August 2010) and the median follow-up time was 19.3 months.Genomic DNA was isolated from leukocytes of venous blood by proteinase K digestion and phenol/chloroform extraction. Genotyping was performed with the TaqMan SNP Genotyping Assay using the 384-well 7900HT real time PCR System and the SDS 2.3 software for allelic discrimination . The sequence of primers and probes are summarized in in vivo, 25 surgically removed normal renal tissue samples containing 100% normal cells adjacent to tumors from patients of different genotypes were collected. Total RNA was extracted from these samples using Trizol Reagent  according to the manufacturer's protocol. Applied Biosystems 7900HT Real Time PCR System was used to perform real-time quantification PCR  based on the SYBR-Green method . The primers used for amplification of hsa-miR-27a mRNA were 5′- ACACTCCAGCTGGGTTCACAGTGGCTAAG-3′ (forward) and 5′- TGGTGTCGTGGAGTCG-3′ (reverse), and the primers for U6 were 5′- CTCGCTTCGGCAGCACA-3′ (forward) and 5′- AACGCTTCACGAATTTGCGT-3′ (reverse). All reactions were conducted in triplicate. Fold changes were normalized to the expression levels of U6.To further evaluate correlation between hsa-miR-27a expression and rs895819 polymorphism t-test (for continuous variables) or Pearson's χ2-test . Hardy-Weinberg equilibrium (HWE) of the controls' genotype frequencies was assessed by a goodness-of-fit χ2 test. The association between the SNP rs895819 polymorphism and RCC risk were estimated by computing odds ratios (ORs) and their 95% confidence intervals (CIs) from unconditional logistic regression analysis with the adjustment for possible confounders. The Kaplan-Meier method, log-rank test, univariate and multivariate Cox regression analyses were used to evaluate the effects of pre-miR-27a genotypes on the overall survival of patients with RCC. P<0.05 was considered statistically significant. All the statistical analyses were done with Statistical Analysis System software  with two-sided P values. The statistical power was calculated by using the PS software (http://biostat.mc.vanderbilt.edu/twiki/bin/view/Main/PowerSampleSize).Differences in the distributions of selected demographic variables and frequencies of genotypes between the cases and controls were evaluated by using the Student's P = 0.642), body mass index (BMI) (P = 0.074), sex (P = 0.222), smoking status (P = 0.127), pack-years of smoking (P = 0.251) and drinking status (P = 0.714). However, there were more hypertension patients (36.4%), and diabetics (13.5%) among the cases than among the controls . The majority of patients (84.0%) had conventional clear cell carcinoma. Other patients who had papillary carcinoma, chromophobe carcinoma and unclassified were counted ninety-five (16%). Approximately 63.5% of patients were in stage I, 18.4%, 6.7%, and 11.4% was found to be in stage II, III, and IV, respectively. In addition, the frequencies of nuclear grades from I to IV were 18.2%, 48.0%, 24.7%, and 9.1%, respectively. The frequency distributions of selected demographic characteristics of the cases and controls are shown in pre-miR-27a rs895819 polymorphism in patients and controls are shown in 2 = 0.795, P = 0.373). The frequencies distribution of G allele significantly differentiated from A allele among cases and controls (P = 0.019). After adjusting for possible confounding factors , logistic regression analysis revealed that when comparing with AA homozygote, AG heterozygote was associated with a significantly reduced RCC risk  and individuals with AG/GG genotype also had a reduced susceptibility to RCC .Allele frequencies and genotype distributions of Furthermore, in the stratified analysis by age, BMI, sex, smoking status, drinking status, hypertension and diabetes, we found that the reduced risk was more pronounced in young subjects , subjects with BMI≤24 , males , non-smokers , non-drinkers , subjects without hypertension  and subjects without diabetes  .pre-miR-27a rs895819 polymorphism and the clinical characteristics of RCC was also examined. Results showed that AG/GG genotype was associated with reduced susceptibility in localized clinical stage  and similar effects were observed in well differentiated and poorly differentiated RCC   .2, males, nonsmokers, nondrinkers, subjects without hypertension and subjects without diabetes when compared with AA carriers. We further observed rs895819 had multiplicative interactions with age and hypertension (Pinteraction = 0.035 for age and Pinteraction = 0.030 for hypertension).We have evaluated whether there were existence of interactions between rs895819 polymorphism and age, BMI, sex, smoking status, drinking status, hypertension and diabetes. As shown in In addition, Kaplan-Meier curves and log-rank tests were used to assess the association between the genotypes and survival of RCC. However, we did not find the rs895819 genotypes to be associated with the patients' overall survival. In the stepwise Cox regression, the results suggested that clinical stage was the best prognostic factor for RCC survival followed by tumor grade (data not shown).P = 0.08) (data not shown). Further functional studies were warranted when we collected large samples.We have collected 25 surgically removed normal renal tissue samples adjacent to tumors with different genotypes of rs895819, and the frequency distribution of the AA, AG, GG genotypes was 13, 10, and 2, respectively. We further assessed the association between the polymorphism and hsa-miR-27a expression levels using quantitative real-time RT-PCR. The samples with GG genotype was added to the samples of AG genotype for analysis. However, due to small samples of GG genotypes, we did not find any association between rs895819 and the expression of hsa-miR-27a  and homozygote (GG) the equality of that tested to observe a nonsignificant P-value of 0.568 suggesting a dominant model, we combined AG and GG genotypes as a dominant genetic model in the following association analysis. We found that individuals with AG/GG genotypes were associated with a significantly reduced RCC risk, compared with those carrying AA genotype. In addition, the effect was even stronger in non-smokers, young subjects, males and individuals without hypertension or diabetes. Besides, the subjects carrying G allele also had a reduced susceptibility to localized clinical stage, well differentiated and poorly differentiated RCC. To our knowledge, this is the first study to investigate the role of the pre-miR-27a rs895819 polymorphism in the risk of RCC.In the present study, we investigated the association between the et al. defined 7 SNPs in 7 pre-miRNAs, and 10 SNPs in 8 pri-miRNAs, but none of them had a significant influence on RCC risk et al. suggested that genetic polymorphisms of the miRNA-machinery genes might affect RCC susceptibility individually and jointly.Nowadays, increasing studies have suggested that miRNAs, which play an important role in cancer progress as tumor oncogenes or tumor suppressors are involved in crucial biological processes, including development, differentiation, apoptosis and proliferation pre-miR-27a with two different sequences, but the G variation of rs895819 affected neither the conformation nor the free energy of pre-miR-27a (data not shown). In a word, the processing and maturation of miRNA was more complex and subtle than predicted. Zeng et al. observed that Drosha selectively cleaves RNA hairpins bearing a large terminal loop. When the loop is shortened by mutation or deletions, the maturation process will be impaired pre-miR-27a, rs895819 is located in the center of the terminal loop, the rs895819 A>G transition may reduce the size of the loop. Consequently the cleavage by Drosha would be blocked, and the maturation process is thereby inhibited. In conclusion, rs895819 might play an important role in the maturation of miR-27a. However, due to we only had 2 individuals with GG genotypes, we did not find any association between rs895819 and the expression of hsa-miR-27a, these findings need to be confirmed by further studies.SNP rs895819 was found in pre-miRNA regions of hsa-miR-27a, which was in chromosome 19, and it was located at position 40 relative to the first nucleotide. It has been reported that a variation causing structural change in the crucial region of miRNA could affect the maturation and the process of miRNA et al. found miR-27a functions as an oncogene in gastric adenocarcinoma by targeting prohibitin et al. suggested that oncogenic miR-27a was a target for anticancer agent in colon cancer cells pre-miR-27a had higher frequency in cases than in controls, whereas individuals carrying variant G allele had a reduced RCC risk, indicating that miR-27a was more likely to be an oncogene, which was consistent with previous studies et al. reported that in breast cancer cells, transfection of antisense miR-27a lead to increased expression ZBTB10 and these responses were accompanied by decreased expression of survivin, Moreover, survivin is a structurally unique member of the inhibitor of apoptosis protein family that suppresses apoptosis and regulates cell division. Despite the redundancy of cell death pathways, survivin appears to be required for cancer cell viability, and interference with survivin expression/function has been associated with catastrophic defects of mitotic transition and induction of mitochondrial-induced cell death pre-miR-27a polymorphism in RCC patients.To our knowledge, many human miRNA transcripts have target sequences in the 3′-UTR to which miRNAs bind and exert posttranscriptional repression. Liu In this study, there were more hypertension patients and diabetics among the cases than among the controls, indicating that there was potential association between the two factors and RCC. We also found that rs895819 had multiplicative interactions with hypertension. It has been reported that certain types of renal tumors and cancer treatment could cause hypertension miR-27a polymorphism is involved in the etiology of RCC, that does not necessarily mean that it affects the outcome.As to the association between genotypes and overall survival of RCC, there was no significant result. The reason for this discrepancy may be that the mortality rate of our survival analysis is low due to our short follow-up time and the biological mechanisms that underlie the incidence of RCC may be different from those underlying prognosis, and even if the pre-miR-27a rs895819 polymorphism and susceptibility to RCC. Secondly, we matched cases and controls by age and sex, and we obtained the results by adjustment of age, sex, smoking, drinking status, hypertension, and diabetes, which could reduce the influence of confounding factors.When interpreting our results, several limitations should be concerned. Firstly, our case-control study was a hospital-based study and it could not provide a good representation of overall populations. Nevertheless, the G allele frequency in our controls was similar to that in the HapMap database. Besides, the genotype distributions of the polymorphism in our controls conformed to HWE. Thus, the selection bias was unlikely to be substantial. Secondly, our sample size was relatively small. However, we had 83% power to detect a minimal OR of 0.68 with an exposure frequency of 30% under the current sample size. Thirdly, we did not perform the gene-environment interaction analysis due to lack of the detailed information of environment factors, such as occupational exposures, diet, and physical activities. However, our study also had several strengths. Firstly, it was the first study to investigate the association between pre-miR-27a rs895819 polymorphism to the risk of RCC in Chinese population. Although the association appeared to be statistically significant in our population, these findings should be further validated by larger, preferably prospective studies. For polymorphisms often vary in different ethnic groups, additional studies are also needed to clarify the association of this polymorphism with RCC risk in diverse ethnic populations.In conclusion, our results provided the first insight into the contribution of Table S1The sequences of the primers and probe used to genotype the rs895819 polymorphism.(DOC)Click here for additional data file.Table S2Interaction analyses of rs895819 polymorphism and risk factors.(DOC)Click here for additional data file.


Background: Chronic high arsenic exposure is associated with squamous cell carcinoma (SCC) of the skin, and inorganic arsenic (iAs) metabolites may play an important role in this association. However, little is known about the carcinogenicity of arsenic at levels commonly observed in the United States.Objective: We estimated associations between total urinary arsenic and arsenic species and SCC in a U.S. population.Methods: We conducted a population-based case–control SCC study  in a U.S. region with moderate arsenic exposure through private well water and diet. We measured urinary iAs, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA), and summed these arsenic species (ΣAs). Because seafood contains arsenolipids and arsenosugars that metabolize into DMA through alternate pathways, participants who reported seafood consumption within 2 days before urine collection were excluded from the analyses.Results: In adjusted logistic regression analyses , the SCC odds ratio (OR) was 1.37 for each ln-transformed microgram per liter increase in ln-transformed ΣAs concentration [ln(ΣAs)] . Urinary ln(MMA) and ln(DMA) also were positively associated with SCC . A similar trend was observed for ln(iAs) . Percent iAs, MMA, and DMA were not associated with SCC.Conclusions: These results suggest that arsenic exposure at levels common in the United States relates to SCC and that arsenic metabolism ability does not modify the association.http://dx.doi.org/10.1289/ehp.1206178Citation: Gilbert-Diamond D, Li Z, Perry AE, Spencer SK, Gandolfi AJ, Karagas MR. 2013. A population-based case–control study of urinary arsenic species and squamous cell carcinoma in New Hampshire, USA. Environ Health Perspect 121:1154–1160;  Nonmelanoma skin cancer is the most common type of malignancy among whites and has considerable related morbidity and health costs . The incChronic exposure to arsenic (As) has been associated with SCC in regions of Taiwan where high exposures through drinking water were common ; howeverV), which is then reduced to monomethylarsonous acid (MMAIII). In a second step, MMAIII is methylated to dimethylarsinic acic (DMAV), which is then reduced to dimethylarsinous acid (DMAIII)  . This prxcretion . Althouged to As , they haed to As .V and DMAV are considered less toxic than iAs and are easily excreted  and driver’s license records provided by the New Hampshire Department of Transportation (for those < 65 years of age), frequency matched to cases on sex and age  . To be eAfter study participants gave written informed consent, a study staff member who was blinded to their case/control status interviewed them in person to obtain sociodemographic, lifestyle, medical, and sun exposure information. Home tap water samples were collected from participants’ homes into a commercially washed  high-density polyethylene bottle that meets U.S. Environmental Protection Agency standards for water collection  by study staff wearing individually packed, clean, powderless gloves and following a strict protocol to limit contamination . A urineWater As analysis. Tap water samples were tested at the Trace Element Analysis Core at Dartmouth using inductively coupled plasma mass spectrometry (ICP-MS) with a quadrupole collision cell 7500c Octopole Reaction System ICP mass spectrometer (Agilent) and helium as a collision gas to remove polyatomic interferences, as described previously by Urinary analysis. Urine samples from cases and controls were frozen at –80°C within 24 hr of collection and shipped on dry ice to the University of Arizona, where they were analyzed using a high-performance liquid chromatography (HPLC) ICP-MS system and previously described methods (III and iAsV) and organic As species . No cases or controls had concentrations below the DMA LOD (0.11 μg/L); 3.6% of cases and 4.5% of controls were below the MMA LOD (0.14 μg/L); 32.3% of cases and 31.8% of controls were below the iAsIII LOD (0.15 μg/L); and 82.1% of cases and 87.5% of controls were below the iAsV LOD (0.10 μg/L). Urinary As concentrations < LOD were set to one-half LOD. methods . This AsWe calculated the sum of urinary iAs and methylated As species (ΣAs) by summing concentrations of iAs, MMA, and DMA. AsB was excluded from this analysis because it is thought to pass through the body without being metabolized and is nontoxic . The perData analysis. We first evaluated the association between individual urinary As species and factors that could potentially influence urinary As concentrations in bivariate regression models among controls (n = 447). Urinary As concentrations were natural log (ln)-transformed to improve normality. Self-reported rice consumption, including cooked rice and rice cereals, was converted into equivalents of cooked rice using previously described methods (n = 596), so we used multiple imputation and fully conditional specification methods to account for missing data , water As concentration, and rice consumption. The three urinary As variables are highly correlated and thus ill-suited to be included in a single logistic regression model. The structural equation model permits iAs, MMA, and DMA to each load differently onto a single latent urinary As variable (UAM) based on their correlation structure; the loading score of each As species indicates its relative contribution to the variable. Robust weighted least-square estimators were used to estimate parameters in the model. We used the comparative fit index  and TuckZ test . For theThe mean (± SD) time between SCC diagnosis and interview/urine collection was 23 ± 10.2 months. Urine samples were collected from 470 SCC cases (92%) and 447 controls (75%), resulting in a total sample size of 917. The sex and age distributions and the percentage of urban versus rural residence did not differ for eligible cases and those who participated in our study. The sex distribution and percentage of urban versus rural residence also did not differ between identified controls and those who participated in our study; however, controls who did participate tended to be older (63 years vs. 56 years). In cases interviewed for our study, 98.5% of those 25–64 years of age had a valid driver’s license at the time of interview, and 98% of those 65–74 years of age were enrolled in Medicare, thus indicating that most would have been included in the data sources used to identify controls. The sex and age group distributions for SCC cases and controls were similar, and approximately 99% of all participants reported their race as white . In addiMedian urinary ΣAs, iAs, MMA, and DMA concentrations were higher in cases than controls . In bivaAmong participants who reported not eating seafood in the 2 days prior to urine collection , we observed a linear association between SCC and ΣAs, MMA, and DMA . After aUrinary MMA concentration was significantly associated with odds of SCC when urinary As was examined by tertiles of exposure . ParticiIn an analysis stratified by the median duration of current water supply usage, ORs for SCC were positively associated with unit increases in ln-transformed urinary As species in both strata (< 17 years and ≥ 17 years) . ORs werIn a structural equation model adjusted for the same set of covariates, iAs, MMA, and DMA each contributed significantly to the latent UAM variable  . The comparative fit index (> 0.90) and the Tucker Lewis Index (> 0.90) indicated a reasonable model fit. We found an association between the latent UAM variable and SCC [OR per 1-SD increase = 2.04 ]. Water As concentration was associated with the latent UAM variable [1-SD increase in UAM for each 10-μg/L increase in water As = 0.32 ]; the indirect association between water As concentration and SCC through UAM was also significant . The structural equation model that did not assume unobserved variables  also showed a significant, but weaker, association between ΣAs and SCC .In this U.S. population–based case–control study of participants living in a region with detectable As in drinking water, we estimated positive associations between SCC and urinary ΣAs, MMA, and DMA concentrations. The results of our structural equation model analysis suggest that a latent urinary As variable representing urinary iAs, MMA, and DMA is associated with SCC. In contrast, percentages and ratios of the individual metabolites were not associated with SCC in the study population.In our analysis, we were interested in ingested iAs and the products of its methylation: MMA and DMA. In our population, where water As concentrations are relatively low, dietary sources of iAs can play a more substantial role in overall As exposure . For exaIII was significantly higher among those with As-related skin lesions (n = 55) compared with those without (n = 21); however, there was no difference in concentrations of MMAV, DMAIII, DMAV, iAsIII, iAsV, or the sum of iAs and methylated As species  in southwest Taiwan, n = 26 cases, 26 controls), n = 859 cases, 868 controls), 10 percentage of MMA. At the relatively low levels of As exposure in our population in the present study, SCC was associated with the absolute concentrations of MMA and DMA measured in urine but not the relative proportions of MMA, DMA, and iAs. Thus, it is not clear whether differences in the proportion of As metabolites reflect susceptibility to skin cancers at lower levels of exposure.Previous ecological studies in the As endemic region of southwest Taiwan  support  species . The perin vitro study in human immortalized lung epithelial cells and adenocarcinoma cells, S-adenosylmethionine , Navas-Acien (2009) found that urinary As excretion (including As concentrations and percent of urinary As species) remained fairly constant over a 10-year period. In a study in Bangladesh that measured urinary As in 196 participants over 2 years, n = 73) (n = 81)   and the (n = 81)  reported(n = 81) . ORs str(n = 81) . Our stuUsing sensitive methods to measure urinary As exposure in a population-based study of SCC in residents of New Hampshire, we observed that urinary concentrations of ΣAs, MMA, and DMA were positively associated with SCC. These findings suggest that common exposure levels may influence cancer risk in the United States and elsewhere.In (1.7 MB) PDFClick here for additional data file.


GT dinucleotide repeat length polymorphism and the G2964A polymorphism in signal transducer and activator of transcriptional factor 6 gene are associated with asthma susceptibility, but others have conflicting results. Our meta-analysis aimed to elucidate the emerging paradigms.Several studies have reported that the We searched PUBMED, EMBASE, ISI web of knowledge, Chinese National Knowledge Infrastructure, and Wanfang databases. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to evaluate the strength of association. We applied Bonferroni step-down and Benjamini-Hochberg step-up methods to adjust the values for multiple comparisons.GT repeat polymorphism, the S allele had approximately 45% increased risk of asthma . Further analysis indicated that 13GT and 14GT contributed to asthma risk, whereas 15GT and 16GT were protective . Similar results were obtained in the subgroup analysis of Asian population. G2964A polymorphism analysis showed that the AA genotype moderately increased the risk of asthma by 47% compared with the GG genotype  in Chinese population, whereas the 2964A allele moderately increased the risk of asthma in Chinese population by 18% . However, none of the associations reached statistically significant levels particularly after correction for multiple testing.A total of 12 individual studies in 11 articles were included in the meta-analysis. For S allele (13GT and 14GT) of the GT repeat polymorphism confers significant risks to asthma. However, the G2964A polymorphism does not have an association with the susceptibility to asthma.This meta-analysis suggests that  Several studies have strongly indicated that asthma has a hereditary origin considering that asthma and asthma-related traits have been observed in families STAT6 gene is located at 12q13.314.1 STAT6 is normally activated by Th2-related cytokines such as interleukin-4 (IL-4) and IL-13 STAT6 is activated to induce Th2 cell differentiation from naïve T cells and IgE production STAT6 also regulates the expression of Th2 chemokines STAT6 gene polymorphisms and the susceptibility to asthma in various populations. Polymorphisms or haplotypes associated with asthma or serum IgE levels have also been reported GT dinucleotide repeat length polymorphism in exon 1 of STAT6 and G2964A polymorphism in the 3′-untranslated region are two of the most commonly investigated, but no inclusive result has been obtained in both polymorphisms. Different genotyping methods, a relatively small sample size, and population differences may partly account for such discrepancies.GT repeat length polymorphism and G2964A polymorphism) with the risk of asthma based on case-control studies. To the best of our knowledge, this study is the first genetic meta-analysis to identify the association between the STAT6 gene polymorphism and the risk of asthma.In this study, a meta-analysis was performed to delineate the association of these two polymorphisms  independently performed the abstract screening, full text review, and data collection by using a computer-based approach. Studies published online were searched in PUBMED, EMBASE, ISI web of knowledge, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases with the following search terms: “STAT6 polymorphisms (GT dinucleotide repeat length polymorphism and/or G2964A) and the risk of asthma. Allelic or genotypic distributions of both cases and controls were available. All types of asthma, including atopic or non-atopic were included regardless of the age of the investigated population. Some studies also included mixed types of allergic diseases such as atopic dermatitis; however, these studies were excluded because the number of asthma patients for each genotype or allele is unavailable. Among the studies with overlapping investigated population, only the study with the most extensive data was considered. Animal studies were excluded.The records included in the meta-analysis were case-control studies. Family or sibling pair-based designs were excluded. All of the studies investigated the association between et al.). The following data were obtained from each eligible study: first author’s name, year of publication, country of origin, ethnicity, age group of the study population, definitions of asthma and control, number of participants in the case group and the control group, and research methods for genotyping.All of the relevant records were initially scanned based on titles and abstracts. Studies that did not satisfy the aforementioned criteria were rejected. The remaining studies were evaluated after a full text review was conducted. Two authors (LZ and QZ) independently extracted data from the included records. A final agreement was achieved after a consensus meeting  and 95% confidence intervals (CIs) were used to evaluate the strength of association between the STAT6 polymorphisms and the risk of asthma. In our study, only dichotomous data analysis was performed, and the data were presented as numbers of different genotypes or alleles in different groups. For the GT dinucleotide repeat length polymorphism, the alleles with repeat numbers 12, 13, 14, 15, 16, and 17 were simplified as 12GT, 13GT, 14GT, 15GT, 16GT, and 17GT, respectively. A cut-off point was set between 14GT and 15GT. Alleles ≤14 were defined as short alleles (S) and alleles ≥15 were regarded as long alleles (L). Pooled ORs and their corresponding 95% CIs were generated to compare allelic frequencies  and genotype frequencies with multiple genetic models . The significance of pooled ORs was determined with a Z test. Heterogeneity was evaluated with the χ2-based Q test and I2 index Hardy-Weinberg distribution of genotypes of the polymorphisms in STAT6 G2964A polymorphism. One article investigated two cohorts of population, and each cohort is regarded as two separate case-control studies GT dinucleotide repeat length polymorphism G2964A polymorphism GT repeat length polymorphism, four studies involved Asian populations, in which two focused on Chinese populations G2964A polymorphism, four studies were performed on a Chinese population AA, AG, and GG) in case and control groups. For the studies on Japanese and Caucasian cohorts, a recessive model was considered and only data of AA+AG and GG genotypes were available. Age was not considered as a restricted variable. Children/adults or both populations were included in the studies. However, three studies did not provide a detailed age group of the population investigated A total of 349 publications were initially identified from PUBMED, EMBASE, ISI web of knowledge, CNKI, and Wanfang databases. After titles and abstracts were screened, 306 articles were excluded because of duplication or irrelevance to the meta-analysis. The full texts of the remaining 43 records were carefully reviewed and 31 of these records were discarded because of several factors Fig. 1. STAT6 GT polymorphism and the risk of asthma were enrolled in the meta-analysis GT repeat length polymorphism in STAT6, no consensus of the optimal cut-off point was achieved to classify the alleles. In this meta-analysis, the cut-off point was set between 14 and 15. The alleles were then divided in two groups: short allele (S ≤14) and long allele (L ≥15). 13GT and 15GT were the two most common alleles found and categorized in the S group and the L group, respectively, allowing balance to the number of each group. The comparison of S allele and L allele between cases and controls revealed a significant association of the S allele and the risk of asthma .A total of five studies describing the association between the STAT6 G2964A polymorphism and susceptibility to asthma AA+AG vs. GG), no significant association was detected, with a pooled OR = 0.92 and 95% CI = 0.72–1.16  and no significant publication bias  were found. Sensitivity analysis yielded no significant change. Among the seven studies, four were performed in Chinese population and provided a detailed number of each genotype . A subgroup analysis of the Chinese population was also performed. Similarly, no significant result was obtained after comparison using the recessive models (AA+AG vs. GG), with OR = 1.16 and 95% CI = 0.82–1.62 (AA vs. AG+GG) was used, no significant association was observed with OR = 1.42 and 95% CI = 0.84–2.38 in a random-effect model . All of the studies except the study of Hu Table S2).Six articles presenting seven studies have demonstrated the association between the .72–1.16 Fig. 3A.STAT6 and the susceptibility to asthma. For the GT dinucleotide repeat length polymorphism in exon 1 of STAT6, the S allele (≤14 repeats) and the L allele (≥15 repeats) were compared, suggested a significantly strong association between the S allele and the susceptibility to asthma. The S allele had approximately 45% increased risk of asthma. Pair-wise comparisons showed that the 13GT allele significantly increased the risk of asthma by 38% compared with the 15GT allele. The 14GT allele was identified as an allele with a higher risk, which moderately increased the risk of asthma compared with the 13GT allele. No significant difference was observed between 15GT and 16GT alleles. Given that the frequencies of 14GT and 16GT alleles were extremely lower than those of 13GT and 15GT alleles, we considered 13GT and 15GT as the most dominant risk alleles of asthma for STAT6 GT repeat polymorphism.The present meta-analysis considered 12 case-control studies in 11 articles and was the first meta-analysis report to investigate the association between the two common polymorphisms in STAT6 GT repeat polymorphism and the risk of asthma. For instance, Gao et al. 13GT allele is significantly increased in atopic asthmatic subjects, but the frequency of 16GT allele is inversely correlated with asthma, indicating that 13GT allele may be a risk allele and 16GT allele is likely a protective allele of asthma. Suzuki et al. 15GT allele is lower in asthmatic patients, but the frequencies of short alleles 12GT, 13GT, and 14GT are higher. Shao et al. 15GT allele is the only difference detected. Other studies have also reported negative results S allele vs. L allele between asthma cases and controls. The mechanisms by which this polymorphism affects asthma could be possibly determined based on the previously published studies. GT dinucleotide repeat variant is located in exon 1, which is a coding region found in the 5′-untranslated region of STAT6 gene STAT6 gene expression. For instance, Gao et al. 13GT allele have significantly higher levels of total serum IgE, an important marker of asthma, than those with 16GT allele. Therefore, 13GT allele may increase the risk of asthma by upregulating the production of total serum IgE 2964A allele et al. 13GT allele can significantly increase the promoter activity of STAT6 gene probably by binding to transcriptional silencers and by forming non-β-form DNA conformations. As a result, STAT6 gene expression is increased and asthma is induced via an IL-4/IL-13 pathway.Various studies have investigated the G2964A polymorphism, the overall effect observed in a recessive genetic model (AA+AG vs. GG) and a dominant model (AA vs. AG+GG) did not show significant correlation with asthma. After pair-wise comparisons were performed, AA homozygote carriers moderately increased the risk of asthma by 47% compared with the GG homozygote in Chinese population. Further analysis of the allele studies revealed that the 2964A allele moderately increased the risk of asthma by 18% in the Chinese cohort. However, none of the comparisons generated statistically significant results.For G2964A polymorphism and the risk of asthma were inconsistent and inconclusive. For instance, a strong association between mild atopic asthma and this polymorphism is observed in a Japanese population but not in a British population et al. 2964A allele is a risk allele and the AA homozygote is a risk genotype to asthma. However, no association was found in replicated studies in either a Japanese population et al. et al. Previous studies on the ORMDL3-GSDMB, DENND1B, HLA-DP, SLC30A8, IL1RL1-IL18R1, IL33, SMAD3, TSLP, and NOTCH4STAT6 gene with asthma. The GT repeat variant has not been assayed on GWAS microarrays in these studies. To the best of our knowledge, no study has attempted to determine whether or not any SNP is in strong disequilibrium with this variant. A good proxy SNP of the GT variant should be represented in the future to provide an accurate conclusion about GWAS. In contrast to our study, G2964A polymorphism has not been highlighted in any of the GWA studies on asthma. Several limitations were observed in our current study. First, the meta-analysis only considered the published studies enrolled from the chosen databases; therefore, results from unpublished studies may have been missed and could result in a potential bias. To minimize publication bias, a comprehensive search strategy was used, such as setting no language restriction, enrolling as many databases as possible, and so on. However, data from a conference article were still unavailable STAT6 polymorphisms with other uninvestigated populations such as African populations should be carefully explained or predicted. Fourth, differences in most of the G2964A polymorphisms changed from moderate levels to significant levels after the study of Ding et al. was excluded et al. was excluded.Genome-wide association (GWA) studies on asthma have suggested that several polymorphisms in several genes, including STAT6 gene polymorphisms and the risk of asthma based on data published until December 8, 2012. The S allele (13GT and 14GT) of the GT repeat polymorphism indicates significant risks of asthma, whereas the G2964A polymorphism is possibly not associated with the susceptibility to asthma.In conclusion, our present study reported for the first time a comprehensive meta-analysis to determine the association between the Figure S1Association between G2964A polymorphism in STAT6 with the risk of asthma after removal of study of Ding et al. The results were shown by forest plots. Each study is shown by the first author name, year of publication, individual and overall ORs (odds ratio) and 95% CI . Box and horizontal line represent OR and 95% CI of the corresponding study, and the diamond represents the overall OR and 95% CI. (A) AA vs. AG+GG excluding Ding’s study in Chinese population, fixed-effects model; (B) A vs. G excluding Ding’s study in Chinese populations, fixed-effects model; (C) AA vs. GG excluding Ding’s study in Chinese population, fixed-effects model; (F) AA vs. AG excluding Ding’s study in Chinese population, fixed-effects model.(TIF)Click here for additional data file.Table S1Sensitivity analysis and publication bias test results of different genetic models in GT repeat polymorphism of STAT6 gene.(DOC)Click here for additional data file.Table S2Sensitivity analysis and publication bias test results of different genetic models in G2964A polymorphism of STAT6 gene.(DOC)Click here for additional data file.


GREM1-SCG5 and colorectal cancer.Several researchers have suggested that the rs4779584 (15q13.3) polymorphism is associated withan increased risk of developing colorectal cancer (CRC). However, past results remain inconclusive.We addressed this controversy by performing a meta-analysis of the relationship between rs4779584 ofWe selected 12 case-control studies involving 11,769 cases of CRC and 14,328 healthy controls.The association between the rs4779584 polymorphism and CRC was examined by the overall odds ratio(OR) with a 95% confidence interval (CI). We used different genetic model analyses,sensitivity analyses, and assessments of bias in our meta-analysis.GREM1-SCG5 rs4779584 polymorphisms were associated with CRC in all of thegenetic models that were examined in this meta-analysis of 12 case-control studies.GREM1-SCG5 rs4779584 polymorphisms may increase the risk of developingcolorectal cancer. GREM1 and SCG5 genes.GREM1 encodes gremlin 1, which is a signaling molecule in the transforming growthfactor-β (TGF-β) pathway. TGF-β signaling has been implicated in tumor invasion andmetastasis SCG5 encodes secretogranin V, which is an important neuroendocrine signalingmolecule that appears to influence cellular proliferation in the large bowel based on nutrientavailability or systemic hormonal effects Colorectal cancer (CRC) is the third most common malignancy and the fourth most common cause ofcancer-related death in the world Several research groups have reported associations between this single-nucleotide polymorphism(SNP) and the risk of CRC. However, because single studies are often underpowered due to inadequatesample sizes, the results from past studies are inconclusive. Thus, we performed a meta-analysis tomore precisely characterize the association between the rs4779584 polymorphism and colorectalcancer.We searched five electronic databases  to identify eligible studies that were published before September 2013. Articles weresought with the following key words: “colorectal cancer”, “rs4779584”,“polymorphism”, and “SCG5 or GREM1”. We also supplemented this search byreviewing the reference lists of all of the retrieved publications and identifying additionalrelevant articles.The following inclusion criteria were used to identify articles for our meta-analysis. (1) Thestudy involved unrelated individuals. (2) Sufficient genotype data were presented to allowcalculation of the odds ratios (ORs). (3) The study clearly described the diagnosis of CRC and thesources of the cases and controls. (4) The genotype distribution complied with theHardy–Weinberg equilibrium (HWE). In addition, we excluded reviews and redundant studies.Finally, we selected 11 available studies, which involved 11,769 cases of CRC and 14,328 healthycontrols.Two investigators used a standardized form to independently extract data to improve thereliability of our results. The following information was extracted from each study: first author,publication year, ethnicity (country), source of controls, number of cases and controls, and thegenotype frequencies of the cases and controls.2 test2values ranged from 0 to 100%, and values of 25%, 50%, and 75% wereconsidered to represent low, moderate, and high levels of heterogeneity, respectively. The funnelplot was drawn to assess publication biases. The test suggested was used to test the funnel-plotsymmetry. This test involved building a regression model, in which the standardized estimate of thesize effect was the dependent variable, and the inverse of the standard error was the independentvariable. If the intercept was significantly different from zero, the estimate of the effect wasconsidered biased. The significance of the pooled OR was determined with the Z test. Each study wasremoved in turn for sensitivity analyses, and the remaining studies were reanalyzed to assess thestability of results.All analyses were performed with the STATA Version 11.0 software . All P values in this study were two-sided, and P = 0.05 was set as thethreshold value for statistical significance. To evaluate associations between rs4779584polymorphisms and risk of CRC, the pooled odds ratio (OR) and associated 95% confidenceinterval (CI) were calculated. We used the following models to calculate different ORs: the allelemodel (A vs. a), the additive genetic model (AA vs. aa), the dominant genetic model (AA+Aa vs.aa), and the recessive genetic model (AA vs. Aa+aa). If the P value was greater than 0.100according to the Q-test, indicating a lack of heterogeneity among studies, the summary OR estimateof each study was calculated by a fixed-effects model (the Mantel–Haenszel method). Otherwise,the random-effects model (the DerSimonian-Laird method) was performed. Heterogeneity was estimatedwith the Cochran’s Q-statistic, and P<0.05 was considered to be an indication ofstatistically significant heterogeneity According to search, we identified 92 potentially relevant articles. On the basis of theabstract, 32 studies were reviewed in their entirety. During the extraction of data, 21 articleswere removed, because of these articles did not contain the case-control studies. Among the 11papers, four papers without sufficient data and one article that did not fit the HWE duringcalculations. Finally, we selected 6 researches eligible. After our meta-analysis found that theselected Asian population was extremely heterogeneous. Finally we selected 12 independentcase-control studies from 4 articles involved 11,769 cases of CRC and 14,328 healthy controls in ourmeta-analysis. The characteristics of the studies are listed in Different genetic models were used in our analysis . After pSignificant heterogeneity existed in all of the genetic models . The selBegger’s funnel plot and Egger’s linear regression test were performed to assess thepublication biases of the selected studies. The shape of the funnel plot for publication biasappeared to be symmetrical, although there was some uncertainty regarding the degree of symmetry. The estSensitivity analyses were performed after sequentially removing each eligible study. Thisapproach is regarded as an indispensable step for analyzing multiple criteria. The significance ofthe pooled ORs was not influenced by any single study in the recessive genetic model , indicatA growing number of studies suggest that the rs4779584 polymorphism is associated with anincreased susceptibility to colorectal cancer. However, the results of past studies have beencontroversial, with some studies supporting a significant association, whereas others refute thisassociation. In the present study, to confirm that the rs4779584 polymorphism plays a role in thedevelopment of CRC, we conducted a meta-analysis of 12 independent case-control studies, whichincluded 11,769cases and 14,328 controls. The major finding of the present meta-analysis was that15q13.3 rs4779584 was a risk factor for CRC in the Caucasian population. In comparison to previousmeta-analyses, our analysis included a greater number of studies. Therefore, a larger sample sizeand increased statistical power were obtained. Moreover, the present meta-analysis included anacceptable quality evaluation system, minimizing the potential for bias.http://www.hapmap.org/) demonstrated that T was aminor allele in the Caucasian population, whereas it is a major allele in the Asian population.Different allelic frequencies in different ethnic groups may account for these discrepancies.Heterogeneity may be due to many factors, such as differences in the characteristics of controls,diverse genotyping methods, small sample size, and a mixed population from different geographicregions.A statistically significant level of heterogeneity was found in the Asian population but not inCaucasians. Thus, we eliminated the Asian population (Chinese and Hong-Kong Chinese) from ourmeta-analysis. In addition, data in HapMap . Although the functionalrelevance of GREM1 rs4779584 is not completely understood, studies suggest thatGREM1 maps to human chromosome 15q13-q15, specifically at 15q13.3 GREM1)is a bone morphogenetic protein (BMP) antagonist and putative angiogenesis-modulating protein.GREM1 is silenced by promoter hypermethylation in human malignancies GREM1 is one of several BMP antagonists produced by sub-epithelial myofibroblasts.GREM1 binds to and inactivates the ligands BMP2 and BMP4, which are primarilyproduced by inter-cryptal stromal cells GREM1 initiates and maintains important developmental and disease-associatedactivities. Thus, GREM1 may increase tumor proliferation through stromal effectsSCG5 is genetically and functionally a less critical candidate thanGREM1, neuroendocrine signaling involving SCG5 may influence cellular proliferationin the large bowel based on nutrient availability or systemic hormonal effects Rs4779584 is located between There were some limitations in our meta-analysis. First, only published studies were included inthe present meta-analysis. Second, our meta-analysis was based on unadjusted ORs estimates, becausenot all of the studies reported adjusted ORs. In addition, in cases in which adjusted ORs werepresented, the ORs were not adjusted by the same potential confounders, such as ethnicity, age,gender, or geographic distribution. Finally, our meta-analysis focused on one population (theCaucasian population). We excluded the Asian population due to a relatively small sample size andsignificant heterogeneity.GREM1-SCG5rs4779584 polymorphism may be a risk factor for CRC among Caucasian subjects. Moreover, futureinvestigations into the combined effects of genes and the environment may improve currentunderstanding of the associations between GREM1-SCG5 rs4779584 and the risk ofdeveloping colorectal cancer. Further work will help clarify the clinical and biologicalimplications of these associations.In summary, this meta-analysis provides reliable evidence that the File S1PRISMA 2009 Checklist.(DOC)Click here for additional data file.