Objective: We aimed to investigate the role of polymorphisms in IL-16 genes on the susceptibility of Coronary Artery Disease (CAD).Methods: A total of 260 CAD cases and 281 health controls were collected between January 2008 and November 2011. Genotyping of IL-16 rs8034928, rs3848180, rs1131445, rs4778889 and rs11556218 was conducted by polymerase chain reaction (PCR) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry technologies.Results: The frequencies of rs8034928 C allele and rs3848180 G allele in the CAD cases in CAD group were significantly higher than in controls. Compared with rs8034928 T/T genotype, a significant higher risk of CAD was found in C/C genotype , and variant of rs8034928 showed a significant increased risk of CAD in dominant  and recessive model . The rs3848180 G/G was found to be associated with risk of CAD, and G allele carries had a significant risk of CAD . Conclusions: Our study indicated that rs8034928 and rs11556218 polymorphisms are associated with CAD risk in a Chinese population, and IL-16 gene polymorphisms may be used as a predictor to the susceptibility of CAD. However, the results are inconsistent.3,9,10 Two previous studies reported the negative association between polymorphisms of IL-6 and risk of CAD. 9,10Interleukin-16 (IL-16) is a proinflammatory and immunoregulatory cytokine, and is reported to be related with the inflammation and immunity.Therefore, the present study was aimed to investigate the role of polymorphism in IL-16  on the susceptibility of CAD in a case-control study.Patients: This case-control study enrolled 260 CAD cases and 281 health controls. 308 patients were first diagnosed from January 2008 to November 2011 at the Second People’s Hospital of Ji’nan. The diagnosis of CAD was based on angiographic evidence of ≥70% stenosis of one major coronary artery and/or≥50% of the left main coronary artery. Initially, a total of 287 patients were collected, and 260 patients agreed to participate in our study, with a participation rate of 90.6%. A total of 313 controls who received a regular health examination were included into control group. Finally, 281 controls were enrolled in our study, with a participation rate of 89.9%. Controls with known CAD or other heart disease were excluded. This study was approved by the ethics committee of the Second People’s Hospital of Ji’nan, and written informed consent was obtained from all the cases and controls. All patients were asked to provide 5 ml venous blood. Genotyping: All candidate loci of IL-16 for tag single nucleotide polymorphisms (SNPs) in the NCBI dbSNP database and SNP info. We selected common variants with the minor allele frequency should ≥10% of the Chinese population, and the SNP could influence the microRNA binding sites activity. Finally five SNPs, rs8034928, rs3848180, rs1131445, rs4778889 and rs11556218, were selected.The genomic DNA was extracted by the method of buffy-coat fractions with TIANamp blood DNA kit . Genotyping of rs8034928, rs3848180, rs1131445, rs4778889 and rs11556218 was performed in a 384-well plate format on the Sequenom MassARRAY platform , and methods of polymerase chain reaction (PCR) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry technologies. The ingle base extension (SBE) and PCR primers were designed using Sequenom Assay Design 3.1 software  . Each PCStatistical analysis: Continuous variables were shown as mean±SD and analyzed by students t test. Categorical variables were expressed as frequency and percentage and analyzed by chi-square test. The Hardy-Weinberg equilibrium and genotype distributions between groups were analyzed using chi-square test. Odds ratios (OR) and the corresponding 95% confidence intervals (CI) were taken to evaluate the effect of IL-16  on the risk of CAD. Multivariable logistic regression analysis was conducted to calculate the OR (95% CI) after adjusting for potential confounding factors of CAD, such as sex, smoking, BMI, hypertension, diabetes, TC, TG, LDL-C and HDL-C. All statistical analyses were conducted by SPSS 11.0 software , and P value<0.05 was regarded as statistically significant.P<0.05 for all comparisons). The control group had significantly higher TC, HDL-C and LDL-C levels when compared with CAD patients.This study included 260 CAD cases  and 281 health controls  . CompareP>0.05).The genotype distributions of the five SNPs were shown in Multivariate logistic regression analysis was taken to analyze the effect of IL-16 rs8034928 and rs3848180 polymorphisms on the CAD risk, adjusted for sex, BMI, smoking, diabetes, hypertension, TC, HDL-C, LDL-C and TG. The IL-16 rs8034928 C/C genotype showed a significant increased risk of CAD in codominant mode , and the variant of IL-16 rs8034928 showed a significant increased risk of CAD in dominant  and recessive model . For polymorphism of IL-16 rs3848180, the IL-16 rs3848180 G/G genotype showed increased risk of CAD after adjusting potential risk factors , and G allele genotype was associated with increased CAD risk in dominant model .The combined effect of IL-16 rs8034928 and rs3848180 on the CAD risk was analyzed by multivariate logistic regression analysis, adjusted for sex, BMI, smoking, diabetes, hypertension, TC, HDL-C, LDL-C and TG. Individuals carrying both IL-16 rs8034928 C allele and rs3848180 T/T genotypes significantly increased the risk of CAD when compared with those carrying both IL-16 rs8034928 T/T and rs3848180 T/T genotypes . Moreover, individuals with both IL-16 rs8034928 T/T and rs3848180 G allele genotypes had a significant increased risk of CAD than double wild-type genotypes .In the present study, we have found that variants of IL-16 rs8034928 and rs3848180 may be associated with CAD risk in a Chinese population. Our study suggests that IL-16 rs8034928 and rs3848180 polymorphisms may influence the susceptibility to CAD risk. 11Recently, the identification of novel genetic variants for evaluating the early risk of CAD is attracting increasing interest of investigators on cancer risk worldwide. Based on the genetic information, we could determine the disease etiology in terms of genetic determinants to be used for identifying the high-risk individuals and perform targeting therapy to the individual’s genetic make-up.12 The polymorphisms of IL-16 rs8034928 and rs3848180 polymorphisms are located on the intron region, and thus the polymorphisms could influence the susceptibility of human disease. Previous studies have reported that polymorphism of IL-16 rs11556218 and rs8034928 T/C are associated with various human cancers, such as allergic contact dermatitis, systemic lupus erythematosus, nasopharyngeal carcinoma and renal cell carcinoma.6-8,13 Previous two studies have shown that polymorphisms of IL-16 rs11556218 and rs8034928 are associated with risk of CAD.14,15It is reported that IL-16 gene consists of 7 exons and 6 introns convering approximately 12.8kb of genomic DNA.14 In additionally, this study has shown that haploptypes TTTT and TGGT of IL-16 rs8034928, rs3848180 and rs1131445 significantly increased risk to CAD, whereas haplotypes of CTTT and TTGT referred to protection of CAD.14 Similarly, we have found that IL-16 rs8034928 polymorphism is associated with a higher risk of CAD in our study, which is in line with previous reports.14,15A study conducted in China with 651 CAD patients and 428 health controls has showed that rs8034928 C/C genotype is associated with a significant increased risk of CAD in a Chinese population, with the OR(95% CI) of 1.33(1.15-1.47).16 This study has shown that IL-16 rs8034928 T/C polymorphism is in linkage disequilibrium with other casual genetic variants.16 In our study, we found that IL-16 rs8034928 T/C polymorphism could influence the risk of CAD. Huang has reported that IL-16 rs3848180 polymorphism is associated with risk of CAD, and the rs3848180 polymorphism may influence IL-16 rs8034928 gene expression.14 The results of our study also support the association between polymorphism of IL-16 rs8034928 and CAD risk. Further confirmation of our results is strongly needed in future studies.A recent study has shown that intronic sequences encode microRNAs, which are associated with RNA-mediated gene silencing.There are several limitations in our study. Firstly, the subjects were collected in a single hospital, and the samples could not well represent all the other populations. Secondly, CAD is a disease induced by multiple genes and environmental factors, and more genetic and environmental factors should be considered in further study.In conclusion, our study indicates that the variants of IL-16 rs8034928 and rs3848180 are associated with risk of CAD. However, we did not find statistically association of polymorphisms in rs1131445, rs4778889 and rs11556218 of IL-16 gene with CAD risk. The IL-16 gene polymorphisms may be used as a predictor to the susceptibility of CAD.THF & WW designed and performed the study, did statistical analysis & editing of manuscript.YYY, ZJ, GSP & LHM did data collection and manuscript writing.


SLCO1B1 polymorphisms and the development of statin-induced myopathy. In the scenario of the Brazilian population, being one of the most heterogeneous in the world, the main aim here was to evaluate SLCO1B1 polymorphisms according to ethnic groups as an initial step for future pharmacogenetic studies.Recent studies reported the association between SLCO1B1 rs4149056  and SLCO1B1 rs4363657  polymorphisms were detected by polymerase chain reaction followed by high resolution melting analysis with the Rotor Gene 6000® instrument.One hundred and eighty-two Amerindians plus 1,032 subjects from the general urban population were included. Genotypes for the SLCO1B1 rs4149056 and rs4363657 C variant allele were higher in Amerindians (28.3% and 26.1%) and were lower in African descent subjects (5.7% and 10.8%) compared with Mulatto (14.9% and 18.2%) and Caucasian descent (14.8% and 15.4%) ethnic groups . Linkage disequilibrium analysis show that these variant alleles are in different linkage disequilibrium patterns depending on the ethnic origin.The frequencies of the SLCO1B1 rs4149056 C risk allele frequency among Brazilians. These data will be useful in the development of effective programs for stratifying individuals regarding adherence, efficacy and choice of statin-type.Our findings indicate interethnic differences for the  Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA), are widely prescribed drugs to reduce cardiovascular morbidity and mortality and their use is well tolerated by the majority of patients ,2. NonetSLCO1B1 polymorphisms and the development of musculoskeletal side effects [SLCO1B1 gene (Gene ID: 10599) encodes the organic anion-transporting polypeptide 1B1 (OATP1B1) that plays a crucial role in the hepatic uptake and clearance of albumin-bound organic compounds [SLCO1B1 rs4149056 functional polymorphism  in exon 5, leads to higher statin circulating concentration [SLCO1B1 rs4149056 was associated with an odds ratio for myopathy of 4.5  per copy of the C allele and 16.9  among CC homozygotes as compared with the TT genotype, in a genome-wide association study plus replication in a trial of simvastatin 40 mg daily involving 20,000 participants [SLCO1B1 polymorphisms vary significantly among different world-wide populations, leaving the impact of pharmacogenetic testing for these variants extremely dependent on a particular population genetic architecture.In addition, some recent studies reported the association between  effects -10. The ompounds . In partntration ,13. SLCOSLCO1B1 polymorphisms according to ethnic groups as an initial step for future pharmacogenetic studies and screening programmes.The Brazilian population is one of the most heterogeneous in the world, being a mixture of different ethnic groups, composed mainly of European (Caucasian descent), African descent and Amerindians ,15. ThusThis study included 1,032 subjects of the general urban population selected from the Hearts of Brazil Project (HBP) . The uniSLCO1B1 rs4149056  and SLCO1B1 rs4363657  polymorphisms were detected by polymerase chain reaction (PCR) followed by high resolution melting (HRM) analysis with the Rotor Gene 6000® instrument  [® , an automated instrument, was used according to instructions to optimize the sample preparation step (approximately 30 minutes). One specific disc is able to genotype 96 samples for these polymorphisms.Genomic DNA from subjects was extracted from peripheral blood following standard salting-out procedure . Genotyp France) -20. The 2; 200 μM of each dNTP; 0.5 U Taq DNA Polymerase; 200 nM of each primer; 10 ng of genomic DNA template) with addition of fluorescent DNA-intercalating SYTO9® .Amplification of the fragments was performed using the primer sense 5'-TTGTTTAAAGGAATCTGGGTCA-3' and antisense 5'-GAGTCTCCCCTATTCCACGA-3' (77 pairs base) for the rs4149056; and sense 5'-GAGTCCTTCTTTCTCAATTTTTCA-3' and antisense 5'-AAAAGCCCTAGACCAAATGC-3' (107 pairs base) for the rs4363657. A 35-cycle PCR was carried out with the following conditions: denaturation of the template DNA for first cycle of 94°C for 120 s, denaturation of 94°C for 20 s, annealing of 53.4°C (rs4149056) or of 50.5°C (rs4363657) for 20 s, and extension of 72°C for 22 s. PCR was performed using a 10 μL reactive solution  or of 68-77°C (rs4363657). Melting curve were generated by the decrease in fluorescence with the increase in the temperature; and in analysis, nucleotide changes result in three different curve patterns . The two methods gave identical results in all tests. The wild-type, heterozygous and mutant homozygous genotypes for the rs4149056 and rs4363657 could be easily discernible by HRM analysis. In addition, 4% of the samples were randomly selected and reanalyzed as quality controls and gave identical results.In the HRM phase, the Rotor Gene 6000SLCO1B1 polymorphism frequencies according to ethnicity . Chi-square test was also performed for the comparative analysis between our data and previous reports. Hardy-Weinberg equilibrium and linkage disequilibrium analyses were conducted with Haploview 4.0. All statistical analyses were carried out using the SPSS software (v. 16.0), with the level of significance set at p < 0.05.Chi-square test was performed for comparative analysis of the Of the 1,214 subjects (mean age 43.1 ± 14.2), 647 (53.3%) were female and 567 (46.7%) male. Ethnic group distribution was: African descent 8.0% (n = 97), Mulatto 27.3% (n = 332), Caucasian descent 49.7% (n = 603), and Amerindians 15.0% (n = 182).SLCO1B1 rs4149056 C variant allele and of the homozygous genotype (CC) were higher in Amerindians (28.3% and 9.9%) and were lower in African descent subjects (5.7% and 0%) compared with Mulatto (14.9% and 2.4%) and Caucasian descent (14.8% and 4.1%) ethnic groups   were also higher in Amerindians (26.1% and 6.6%) and were lower in African descent subjects (10.8% and 0%) compared with Mulatto (18.2% and 1.5%) and Caucasian descent (15.4% and 2.7%) ethnic groups    Figure .SLCO1B1 rs4149056 polymorphism associated with statin-induced myopathy, according to ethnicity in the Brazilian general population. To our knowledge this is the first study indicating that Brazilian Amerindians present higher frequencies of rs4149056 C variant allele (28.3%) and probably higher risk for statin-induced myopathy. These findings could be useful in the strategic planning of the implementation of pharmacogenetic testing according to ethnicity.The main finding of the present study was to observe significant differences between the allelic and genotypic frequencies of SLCO1B1 rs4149056 C variant allele frequency found in our study was higher (p < 0.001) in Amerindian subjects (28.3%) compared with other ethnic groups and with Turkish [The  Turkish  (12.2%); Turkish  (14.3%); Turkish  (15.0%)  Turkish  (2.3%),  Turkish  (3.9%),  Turkish  (6.0%) sSLCO1B1 rs4363657 polymorphism, C allele frequency found in Caucasian descent in our study (15.4%) was similar (p > 0.050) to that reported in English subjects (13.0%) who participated as controls in a genome-wide association study (GWAS) [SLCO1B1 rs4149056 and rs4363657 are in different linkage disequilibrium patterns depending on the ethnic origin. The African descent (LD = 89) and Mulatto (LD = 81) ethnic groups present higher degree of linkage disequilibrium. This highlights two main points: first, even with the different linkage disequilibrium among ethnic groups, the haplotype analysis are not need because only the rs4149056 polymorphism have been described as functional [For the y (GWAS) . The nony (GWAS) . In our nctional ,24. Seconctional , which mSLCO1B1 rs4149056 with myopathy  was observed in 85 subjects with myopathy taking 80 mg of simvastatin daily as part of a trial involving 12,000 participants; plus replication in a trial of 40 mg of simvastatin daily involving 20,000 participants [SLCO1B1 gene are strongly associated with an increased risk of statin-induced myopathy and genotyping may help to obtain benefits of statin therapy more safely and effectively [The association between Other studies were performed to replicate this association. Brunham et al observed that rs4149056 genotype was significantly associated  with myopathy in patients receiving simvastatin (mean ~30 mg daily), but not in patients who received atorvastatin . In thisThere are potential limitations in our study. First, the self-referred ethnicity could be creating wrong separation. However, this form of classification is the one most probable to be encountered in real-life situations in the clinical practice. In addition, even self-referred ethnicity was able to clearly differentiate groups of individuals with rather different allele and genotype frequencies. Second, in order to implement a genotyping program in this context, some points could still be evaluated, for example: other genetic markers, primary disease, use of concomitant medications, types of statins, age and gender .SLCO1B1 rs4149056 C risk allele frequency among Brazilian general population plus Amerindians. Recent studies indicated the genotyping for this functional polymorphism as an important clinical tool in future patient-tailored programs. Data of the present study will be useful in the development of effective programs for stratifying individuals regarding adherence, efficacy and choice of statin-type for patients who need statin, specially in high-dose .Our findings indicate interethnic differences for the The authors declare that they have no competing interests.PCJLS carried out the molecular genetic studies, statistical analysis and drafted the manuscript. RAGS carried out the molecular genetic studies. ACP participated in the design of the study, statistical analysis and manuscript preparation. RMN, GLLMC, JGM, JEK participated in the design of the study and were responsible for individual selection and characterization. All authors contributed critically to the manuscript, whose present version was read and approved by all.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2350/12/136/prepub


IL-13 polymorphisms and asthma susceptibility.Associations between interleukin-13 (IL-13) polymorphisms and asthma risk remained controversial and ambiguous. Therefore, we performed a meta-analysis to assess the associations between Pubmed, EMBASE, Chinese National Knowledge Infrastructure (CNKI) and Wangfang databases were searched. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to calculate the strength of association in the random-effects model.IL13 -1112C/T polymorphism was significantly associated with asthma risk  in a dominant genetic model. When stratifying for race, IL13 -1112C/T polymorphism exhibited increased asthma risk in Caucasians , while no significant association was found in Asians and African Americans. In the subgroup analysis based on atopic status, significant association was observed in atopic patients  but not in the non-atopic patients. In addition, a significant association between IL13+2044A/G polymorphism and asthma risk was observed . In the subgroup analysis by ethnicity, there were significant associations between IL13+2044A/G polymorphism and asthma risk in Asians  and Caucasians  but not in African Americans. In the subgroup analysis stratified by atopic status, a marginal significant association was found in atopic patients .Thirty-four studies were included in this meta-analysis. The results indicated that IL13 -1112C/T and +2044A/G polymorphisms were risk factors for asthma.This meta-analysis suggested that the  IL-13 gene may be a susceptibility gene of asthma.Asthma is one of the most common chronic respiratory diseases, characterized by wheezing, cough, and bronchial hyperresponsiveness. It is believed to be a multifactorial disorder with a strong genetic component IL-13 gene polymorphisms and susceptibility of asthma IL-13+2044A allele was associated with an increased risk of asthma among Asians but not among Caucasians. However, Cui et al. IL-13+2044A/G polymorphism was associated Caucasians but not Asians. In addition, these two meta-analyses did not evaluate the association between IL-13 polymorphisms and atopic asthma. Hence, we performed a meta-analysis of all eligible studies to derive more precise estimation of the associations of IL-13 −1112C/T and +2044A/G polymorphisms with asthma risks. This was, to our knowledge, the most comprehensive meta-analysis of the association between IL-13 polymorphisms and asthma susceptibility.So far, a lot of studies investigated the association between the Published studies were identified through a computerized search of Pubmed, EMBASE, Chinese National Knowledge Infrastructure (CNKI) and Wangfang databases . The search terms were used as follows: (asthma or asthmatic) and (interleukin-13 or IL-13) and (polymorphism or mutation or variant). We also perused the reference lists of all retrieved articles and relevant reviews. There was no language restriction.IL-13 gene and asthma risk, (2) using a case-control design, (3) genotype distributions in both cases and controls should be available for estimating an odds ratio (OR) with 95% confidence interval (CI).Studies included in the current meta-analysis should meet the following criteria: (1) evaluation of the polymorphisms in IL-13 or asthma risk, (2) not designed as case-control studies, (3) genotype frequencies or number not offered, (4) non-clinical studies, (5) editorials, reviews and abstracts, and (6) not consistent with Hardy-Weinberg equilibrium (HWE). In the case of overlapping studies, only the one with the largest sample numbers was included.Studies were excluded if one of the following existed: (1) not relevant to Data were extracted from all eligible studies independently by two of the authors (Nie and Liu). The relevant data were extracted into predesigned data collection forms. The following information was collected from each study: first author’s name, year of publication, original country, ethnicity, age group, atopic status, sample size, genotyping method, and genotype number in cases and controls. We verified accuracy of data by comparing collection forms from each investigator. If a decision could not be made regarding inclusion, the full text of the article was examined.Two authors (Nie and Liu) assessed the quality of each study independently. The quality scoring system was based on traditional epidemiologic considerations and asthma genetic issues IL-13 polymorphisms and asthma risk was measured by ORs and 95% CIs. The statistical significance of summary OR was determined with Z test. OR1, OR2, and OR3 were calculated for the genotypes: 1). TT vs. CC (OR1), TC vs. CC (OR2), and TT vs. TC (OR3) for the -1112C/T polymorphism, 2). AA vs. GG (OR1), AG vs. GG (OR2), and AA vs. AG (OR3) for the +2044A/G polymorphism. These pairwise differences were used to indicate the most appropriate genetic model When the data from at least 3 similar studies were available, meta-analysis was performed. The strength of the association between the 2I statistic. 2I takes a value of 0–100% . A chi-square based Q-test was also performed to check the betweenstudy heterogeneity, which was considered to be significant for P<0.10. To explore the source of the heterogeneity and evaluate the ethnic-specific, atopic-specific effects, subgroup analyses were performed by ethnicity and atopic status. To access the stability of the meta-analysis, one-way sensitivity analyses were carried out. We did cumulative meta-analysis by undertaking sequential random-effects pooling, starting with the earliest studies. Results were presented as a series of mini meta-analyses, which were ordered chronologically in a forest plot to show the consequence of adding studies on the effect size. Departure from HWE in controls was tested by the chi-square test. Publication bias was assessed by visual inspection of funnel plots, in which the standard error of log (OR) of each study was plotted against its log (OR). Funnel plot asymmetry was assessed by Egger’s linear regression test Heterogeneity among studies was examined with P value <0.05 was considered statistically significant.All statistical tests were performed by using the Revman 5.1 software  and STATA 11.0 software . A The flow chart in P = 0.002), 1.17 (P = 0.002), and 1.12 (P = 0.21) (P = 0.0009) . In the stratified analysis by ethnicity, a statistically significant association was found for studies with Caucasians . However, no significant association was observed in Asians and African Americans  but not with non-atopic asthma risk . Of note, heterogeneity was significantly decreased in atopic asthma subgroup and non-atopic asthma subgroup .Twenty-two studies determined the association between −1112C/T polymorphism and asthma. The sample sizes for case and control groups were 5834 and 8110, respectively. The estimated OR1, OR2 and OR3 were 1.32 ( = 0.21) Table 3.IL-13 −1112C/T polymorphism association were also conducted. The inclination toward significant association with asthma risk was found (P = 0.021).We conducted one-way sensitivity analysis to evaluate the stability of the meta-analysis. As shown in as found Figure 4IL-13+2044A/G polymorphism and asthma risk. A total of 8118 cases and 11147 controls were included in this meta-analysis. The estimated OR1, OR2 and OR3 were 1.28 (P = 0.0001), 1.15 (P = 0.0007), and 1.11 (P = 0.08), respectively (P = 0.0002)  was found. Subgroup analysis was performed by ethnicity. Statistically significant findings were witnessed in Asians  and Caucasians  but not in African Americans. In terms of atopic status, borderline yet significant increased asthma risk was found among atopic asthma patients , but no statistically significant finding was found among non-atopic asthma patients . Again, significant decreased heterogeneity was found in atopic asthma subgroup and non-atopic asthma subgroup .Thirty-one case-control studies identified an association between ectively Table 3.P = 0.684).In the one-way sensitivity analysis, there was little modification of the estimates after exclusion of individual study Figure 7IL-13 gene targeting in mice prevented and reversed established mucus cell changes, suggesting a key role of IL-13 in mucus hyperproduction IL-13 was one of the most studied of the candidate genes for asthma. IL-13 −1112C/T polymorphism led to increased IL-13 transcription in polarized TH2 cells and enhanced IL-13 secretion by mitogen-stimulated mononuclear cells IL-13+2044A/G polymorphism may be a functional variant. Studies demonstrated that the AA genotype resulted in decreased affinity of IL-13 for IL-13Rα2 and increased expression of IL-13 Hallmarks of asthma include airway inflammation predominated by eosinophils, mucus hyperproduction, and airway hyperresponsiveness (AHR) IL-13 −1112C/T and +2044A/G polymorphisms and asthma risk, including 34 eligible case-control studies. For IL-13 −1112C/T polymorphism, 5834 cases and 8110 controls were included. We found that individuals with the −1112T allele (TT or TC) showed an increased risk of asthma in the overall population. The results from meta-analysis showed that carriers of the TT or TC genotype had 20% increased asthma risk compared to those individuals with the CC carriers. In the stratified analysis by ethnicity, the significant association was observed in Caucasians, but not in Asians and African Americans. It is possible that different genetic backgrounds may account for these differences. However, there were only four studies using African Americans. Thus, the positive association between African Americans and asthma could not be ruled out because studies with small sample size may have insufficient statistical power to detect a slight effect. In addition, significant heterogeneity  may also distort the result. In the subgroup analysis by atopic status, we found IL-13 −1112C/T polymorphism exhibited increased atopic asthma risk. For IL-13+2044A/G polymorphism, 8118 cases and 11147 controls were included. There was a significant association between this polymorphism and asthma risk. When subgroup analysis was performed according to ethnicity, significant associations were showed in Asians and Caucasians, but not in African Americans. Only three studies were performed with African Americans, thus the positive association still can not be excluded. The subgroup analysis based on atopic status found that IL-13+2044A/G polymorphism was marginally associated with allergic asthma risk. Taken together, these results suggested that IL-13 polymorphisms may play a role in the etiology of allergic asthma.In the present meta-analysis, we explored the association between the IL-13 polymorphisms interactions. Third, the methodological issues for meta-analysis, such as, one-way sensitivity analysis and cumulative meta-analysis were well investigated.A recent meta-analysis performed by Yang et al. IL-13 −1112C/T and +2044A/G polymorphisms. We used subgroup analysis to explore the sources of heterogeneity. After subgroup analysis by atopic status, the heterogeneity was effectively decreased and disappeared. Therefore, the main source of heterogeneity was from atopic status. Moreover, funnel plots and Egger’s tests were used to find potential publication bias. The results indicated that there was significant publication bias for IL-13 −1112C/T polymorphism. Thus, our results should be interpreted with caution and more studies are still needed to evaluate the effect of IL-13 −1112C/T polymorphism on asthma risk.Results from one-way sensitivity analysis and cumulative meta-analysis suggested high stability and reliability of our results. Besides, we had to mention the importance of heterogeneity and publication bias, which might influence the results of meta-analysis. In our study, moderate heterogeneity was observed for the IL-13 −1112C/T and +2044A/G were in high linkage disequilibrium. However, we did not carry out haplotype analysis due to limited data.Several limitations need to be addressed. First, the numbers of published studies were not sufficient for a comprehensive analysis, particularly for African Americans. Second, our results were based on unadjusted estimates. Lacking of the original data of the eligible studies limited the evaluation of the effects of the gene-gene and gene-environment interactions in asthma. Third, Vercelli IL-13 −1112C/T and +2044A/G polymorphisms may be associated with the risk of asthma. Well-designed studies with larger sample size and more ethnic groups should be considered to further confirm these associations, especially in African Americans.In conclusion, this meta-analysis suggested that


Multiple chemical sensitivity (MCS) is a chronic medical condition characterized by symptoms that the affect an individual’s response to low-level chemical exposure. In this study, we identified a chemical sensitive population (CSP) and investigated the effect of genetic polymorphisms on their risk of chemical sensitivity.A quick environment exposure sensitivity (QEESI) questionnaire was used to survey 324 Japanese male workers whose DNA samples had been collected and stored. The following genes, which encode enzymes affecting the metabolic activation of a large number of xenobiotic compounds, were selected and analyzed in order to determine their influence on genetic predisposition to CSP: cytochrome P450 (CYP) 2E1, N-acetyl transferase (NAT) 2, glutathione S-transferase (GST) M1, GSTT1, GSTP1, low Km aldehyde dehydrogenase (ALDH2), and superoxide dismutase (SOD) 2.SOD2 polymorphisms and allele frequency distribution in high chemical sensitive subjects. Both the significant adjusted OR of 4.30  and 4.53  were observed in SOD2 Ala/Ala and Val/Ala compared to Val/Val and in SOD2 Ala/Ala compared to Val/Ala compared to Val/Val genetic analysis in the high chemical sensitivity case-control study.Significant case-control distributed differences were observed in SOD2 polymorphisms.We observed that high chemical sensitive individuals diagnosed by using Japanese criteria as MCS patients were more significantly associated with  Individuals experiencing multiple chemical sensitivity (MCS) often report symptoms from various organs related to inhalation of multiple unrelated airborne chemicals in concentrations below what is normally associated with toxicological responses . MCS is The variation in individual responses to multiple environmental chemicals is exceptionally wide. This variation is accounted for by differences in metabolic capacity, DNA repair capacity, or genetic predisposition. The existence of several well-known genetic polymorphisms affecting the activity of enzymes metabolizing xenobiotics have prompted research into whether these polymorphisms are associated with MCS and chemical sensitivity in general populations –8. EitheRsaI, which is located in the 5′-flanking region of CYP2E1 gene, was reported to be associated with the transcriptional regulation of gene expression [N-acetylation and O-acetylation pathways, which are responsible for their activation and/or deactivation, respectively [GSTP1 gene has been found to modify the enzyme’s specific activity and affinity for electrophilic substrates [*2(ALDH2K504) mutant allele. Individuals possessing either 1 or 2 copies of the mutant allele show alcohol-related sensitivity responses, including facial flushing and hangovers [Chemicals that enter cells are subjected to biotransformation by oxidative phase I enzymes in the cytoplasm as cytochrome P450 (CYP) s. CYP2E1 represents a major CYP isoform in the human liver and is also expressed in extrahepatic tissue. It can be induced by certain chemicals such as ethanol although large interindividual variations have been observed in its induction, suggesting that genetic polymorphisms may be involved . A polympression . The N-aectively . Functioectively . Glutathectively . The absectively . The Ilebstrates . Low Km bstrates . Approxibstrates . This isangovers .202 [SOD2 gene creates a sense mutation of alanine-to-valinein in the SOD2 protein [Many lifestyles are closely associated with oxidative stress, which is augmented by smoking, drinking, and an irregular diet. Many environmental factors can also generate oxygen radicals that induce DNA damage and reactive oxygen species (ROS) production . Superox202 . The 47  protein .The present study was conducted at a paper pulp producing company between 2002 and 2006 in Kyushu, Japan. A total of 324 male subjects whose purified DNA had been obtained and stored by the company were asked to complete QEESI questionnaires and were eligible for this study. Subjects with a diagnostic history of cancer, chronic obstructive lung disease, cardiovascular disorder or diabetes were excluded from the study. All study subjects completed the QEESI questionnaire, which also covered the history of drinking and smoking. The distribution of smoking, drinking, age, diagnosis history, score status of survey subscales, and the CSP-diagnosed criterion of the participants are presented in We used the QEESI questionnaire (Japanese version) translated by Ishikawa and Miyata for the survey . We usedThe chemical sensitivity section of the survey asked the subjects to list various odors or chemical exposures that made them feel sick . The symptom severity section asked about symptoms the subjects may have experienced commonly . The life impact section of the survey asked if the subjects were sensitive to certain chemicals or foods and if the sensitivities had affected various aspects of their life .Hojo et al. designed a study to establish the cut-off value for Japanese using the QEESI for screening MCS patients . The cut® Blood and Tissue Genomic DNA Extraction Miniprep system  according to the manufacturer’s instructions and stored at −20° C.Genomic DNA was isolated from whole blood using the ViogeneGenes encoding enzymes affecting the biotransformation of a large number of xenobiotic compounds were selected for determination of their ability to predispose to CSP, namely, CYP2E1, NAT2, GSTM1, GSTT1, GSTP1, ALDH2, and SOD2.CYP2E1 genetic polymorphism was determined by polymerase chain reaction (PCR) amplification run on a GeneAmp PCR System 9700 (Applied Biosystems), followed by digestion with RsaI  since the predominant allele (C1) is sensitive while the C2 allele is resistant to RsaI digestion [CTP2E1 genotypes were categorized as the homozygous genotype of C1/C1 or C2/C2 and the heterozygous genotypes of C1/C2. The NAT2 alleles examined were WT , M1 (*5), M2 (*6), and M3 (*7). The *5, *6, and *7 single nucleotide variations have all been associated with decreased enzyme activity [*6  and *7  alleles were analyzed by real-time PCR. The *5 allele was analyzed by PCR restriction fragment length polymorphism (PCR-RFLP) and digestion with the restriction enzyme KpnI . The NAT2 rapid acetylator genotypes are those with none mutant alleles (*4/ *4); slow acetylator genotypes are those with 2 mutant alleles ; intermediate acetylator genotypes are those with 1 mutant allele . A multiplex PCR method was used to detect the presence or absence of GSTM1 and GSTT1. In this method, both the GST and β-globin primers  are included in the same PCR reaction. The absence of a 219-bp band indicates the GSTM1 null genotype, and the absence of a 480-bp band indicates the GSTT1 null genotype; β-globin was coamplified in all samples [GSTP1 genotype was determined by using PCR-RFLP as previously described [GSTP1 genotypes were categorized as the homozygous genotypes of A/A or G/G and the heterozygous genotype of A/G. The ALDH2 E504K polymorphism , and the SOD2 Val16Ala polymorphism  were analyzed by real-time PCR. All real-time PCR reactions were performed in 48-well plates on a StepOne Real-Time PCR system (Applied Biosystems) and were prepared by using a TaqMan® Universal PCR Master Mix, TaqMan® SNP genotyping assay mix, DNase-free water, and 10 ng of genomic DNA in a final volume of 10 μL per well. The cycling conditions were 30 s at 60° C, 10 min at 95° C, 35 cycles of 15 s at 95° C and 1 min at 60° C, with a final step of 30 s at 60° C. The standard mode reaction time was 90 min. The allelic discrimination results were determined after the amplification by performing an end-point read in an allelic discrimination graph . The genotypes of ALDH2 were categorized as the homozygous genotypes of *1/ *1 or *2/ *2 and the heterozygous genotype of *1/ *2. The genotypes of SOD2 were categorized as the homozygous genotypes of Val/Val or Ala/Ala and the heterozygous genotype of Val/Ala.The activity . The NAT samples . The GSTescribed . The GSTStatistical power calculations were performed using Epistat . The study sample size had at least 80% power  to detect an OR of at least 2.5, following the calculations used in previous studies ,16,25–27P values <0.05 were considered statistically significant. Statistical analysis was carried out using SPSS version 18 .The frequency distribution of genotypes and alleles in cases and controls was determined by analysis using the Pearson’s chi-square test or Fisher’s exact test. To determine an association between each SNP and CSPs, we computed the overall genotypic test of association in the dominant or recessive genetic models and in the additive genetic models. Relative association in the case-control designs were assessed by calculating odds ratios (ORs) and 95% confidence intervals (95% CIs) in logistic regression analyses; two-tailed The Ethics Review Boards of Miyazaki University  and Kumamoto University  approved this study, following the ethical guidelines for human genome research. All participants provided their written informed consent to participate in this study, and the complete protection of their personal data was agreed in a written form.CYP2E1, NAT2, GSTP1, ALDH2, and SOD2 in all the cases and controls were checked and found to not differ significantly from those predicted by the Hardy–Weinberg law (p > 0.05), indicating no evidence of non-random selection. The Hardy-Weinberg equilibrium could not be tested in GSTM1 and GSTT1 polymorphisms because of the inability of the present PCR protocol to separate heterozygous carriers of the deletion polymorphisms. There was no significant difference in the distribution of drinking and smoking statuses between cases and controls . Significant frequency differences in SOD2 genotypes and alleles were observed in high chemical sensitive individuals compared to controls. Instead of the genotype, only the allele-frequency difference in GSTP1 was observed in middle chemical sensitive individuals compared to controls.The genotype distributions of controls . The prop = 0.03) and the adjusted OR of 4.30  was observed in SOD2 Ala/Ala and Val/Ala variants compared to the Val/Val genotype. The significant crude OR of 3.67  and adjusted OR of 4.53  were observed in SOD2 additive genetic model analysis of Ala/Ala vs. Val/Ala vs. Val/Val in the Case 3 study. The GSTP1 genetic analysis of G/G vs. A/G vs. A/A obtained a significant crude OR in the Case 2 study. However, the OR value decreased and lost statistical significance after adjusting by age, smoking, and drinking status.In addition, we determined the association between genetic polymorphisms and CSP risk in the 3 case-control designs using logistic regression analyses as shown in NAT2, GSTM1, GSTT1—although there was a significant association between middle chemical sensitivity and the genetic polymorphism in GSTP1 before adjusting for other confounding factors. In addition, no significant results were obtained when the genetic polymorphisms in CYP2E1 and ALDH2 were compared to chemical sensitivity. However, results from this case-control study indicated that there was an increased risk of high chemical sensitivity associated with SOD2 Ala allele genotypes. The diagnostic criterion for high chemical sensitivity fit with all the 3 cut-off values of the QEESI subscales that are used to diagnose MCS patients using Japanese criteria [This study focused on determining if there were any associations between chemical sensitivity and genetic polymorphisms. There were no significant associations between chemical sensitivity and the genetic polymorphisms in the previously studied genes—criteria .NAT2 genetic polymorphisms associated with chemical sensitivity have been investigated in several studies with inconsistent results. The effect of NAT2 activity was not found in the case-control study of MCS by Berg et al [p = 0.04) [p = 0.01) was significantly higher in MCS cases than in controls [NAT2 slow or inter compared to rapid acetylator genotype showed gradually lower OR from low to high chemical sensitivity cases in this study, but no statistical significance was found. This may be due to the different characteristics of the research subjects; the genetic polymorphisms of NAT2 may not have been sensitive enough in our case-control designs. GST genetic polymorphisms have been associated with atopy  [GSTP1 genetic polymorphism is associated with asthma and airway hyperresponsiveness [GSTM1 and GSTT1 genes were significantly deleted homozygously more often (homozygous-null) in self-reported chemical sensitivity cases than in controls, although no case-control differences were observed in the genotype frequencies of GSTP1 [GSTT1 and GSTM1 were observed in the present study, but a gradually higher OR was found in GSTM1 homozygous-null compared to non-null genotype from low to high chemical sensitivity cases. In the case 2 study, significant results were observed in the GSTP1 allele frequency and in the crude OR, although the logistic regression analysis lost significance after adjusting for confounding factors. In a review study, cleaning agents, pesticides, perfumes, and vehicle exhaust were the products most often reported to trigger MCS that were not due to smoking and drinking [GSTP1 genetic polymorphism. Further research and larger sample sizes will be necessary to evaluate the statistical significance of the interaction between the GSTP1 genetic polymorphisms and CSPs by stratification according to these multiple factors. Alcohol consumption is associated with many health problems, including alcohol-related metabolic syndrome and hypertension [ALDH2 or drinking status and CSP risk. This may be due to the fact that alcohol consumption was very common in the research participants, which were composed of mostly middle-aged men.CYP2E1 is a major contributor to ethanol-induced oxidant stress and to ethanol-induced liver injury . Individrg et al . However = 0.04) . The stucontrols . The NATmatitis) . A studysiveness . Schnakeof GSTP1 . No signdrinking . The trirtension . The SNPrtension . We fail2O2, a major contributor to oxidative stress [2O2 can also be transformed into hypochlorous acid (HOCl) through a myeloperoxidase (MPO)-catalyzed reaction, thus inducing cell damage [SOD2 allows more efficient SOD2 importation into the mitochondria. This generates more active SOD2 compared with the Val-variant and is related to the induction of oxidative stress [SOD2 genetic polymorphismis related to oxidative stress and associated with the CSP risk. In the high chemical sensitivity group, a significantly high crude OR of 3.67 was observed in the SOD2 Ala allele compared to the Val allele carriers in the additive genetic analysis, and increased to 4.53 after adjusting for other confounding factors. This result may indicate that the Ala-variant genotypes are associated with elevated SOD2 activity together with increasing oxidative stress and increased chemical sensitivity risk.Overexpression of SOD2 is associated with increased levels of He stress . In addil damage . The Alae stress ,37. We pFurthermore, in a clinical-based investigation, women were found to be more susceptible to MCS than men ,38. In cCYP2E1, NAT2, GSTM1, GSTT1, GSTP1, ALDH2, and SOD2. In conclusion, we observed that the high chemical sensitive individuals who were also diagnosed by Japanese QEESI criteria as MCS patients were more significantly associated with SOD2 polymorphisms. We hypothesize that our results reflect the gene-environment associations of increased chemical sensitivity in individuals, but further studies are needed to verify our observations. We were unable to confirm previous findings of substantial importance of genetic polymorphisms in GSTM1, GSTT1 and NAT2 to chemical sensitivity, but the research data are an important reference open to further exploration. A possible weakness of our study design is the lack of assessment of the environmental exposure to chemicals metabolized by the enzymes we studied. In addition, the participants of this study were limited to men from the same work site, and the cases were not classified according to any confounding factors due to sample size restriction. In future studies, we hope to classify research subjects into multiple categories according to confounding factors in order to examine the relationship between genetic polymorphisms and chemical sensitivity.The aim of this study was to examine the association between chemical sensitivity and genetic polymorphisms in


Prostate cancer (PCa) remains as one of the most common cause of cancer related death among men in the US. The widely used prostate specific antigen (PSA) screening is limited by low specificity. The diagnostic value of other biomarkers such as RAS association domain family protein 1 A (RASSF1A) promoter methylation in prostate cancer and the relationship between RASSF1A methylation and pathological features or tumor stage remains to be established. Therefore, a meta-analysis of published studies was performed to understand the association between RASSF1A methylation and prostate cancer. In total, 16 studies involving 1431 cases and 565 controls were pooled with a random effect model in this investigation. The odds ratio (OR) of RASSF1A methylation in PCa case, compared to controls, was 14.73 with 95% CI = 7.58–28.61. Stratified analyses consistently showed a similar risk across different sample types and, methylation detection methods. In addition, RASSF1A methylation was associated with high Gleason score OR=2.35, 95% CI: 1.56–3.53. Furthermore, the pooled specificity for all included studies was 0.87 (95% CI: 0.72–0.94), and the pooled sensitivity was 0.76 (95% CI: 0.55–0.89). The specificity in each subgroup stratified by sample type remained above 0.84 and the sensitivity also remained above 0.60. These results suggested that RASSF1A promoter methylation would be a potential biomarker in PCa diagnosis and therapy. Prostate cancer remains as one of the most common cause of cancer related death among men in the US, with an estimated 29,720 deaths projected in 2013 . Hence dMolecular studies have revealed important events in prostate cancer development and progression and the emergence of new biomarkers may improve the diagnosis of prostate cancer . AberranDespite a number of individual studies performed in prostate cancer patients, the diagnostic value of RASSF1A methylation status in prostate cancer and the relationship between RASSF1A methylation and pathological features or tumor stage remains controversial. Therefore, the purpose of this study was to conduct a meta-analysis on the prognostic value of RASSF1A methylation status in prostate cancer, and the relationship between RASSF1A methylation and pathological stage, Gleason score, and PSA level. We also assessed the sensitivity and specificity of RASSF1A methylation in the body fluids and tissues on prostate cancer detection.Previously published articles that studied RASSF1 promoter DNA methylation in prostate cancer were identified via an electronic search of PubMed using the following key words; Prostate cancer, PCa, RAS association domain family protein1A, and RASSF1A. Additional studies were found via the reference lists of the identified articles. Only studies published as full-text articles in English were included in this study. The last retrieval was conducted in March 2013.Studies were selected for analysis if they met the following criteria(1): measurement of DNA methylation in one of the following samples: blood, plasma, serum, urine or prostate tissues; (2) the subjects in every study comprised of prostate cancer patients and non-cancer controls; (3) Data was included in the analysis only if the full text of the article was in English. Exclusion criteria were: (1) RASSF1A methylation conducted only in the cell lines; (2) no raw data available or cannot retrieve any raw data; (3) review papers.For each study, two independent investigators extracted the following information which include the author’s last name, year of publication, country, race, type of cases and controls. In addition, information was also collected regarding the type of assay method (such as PCR), cancer clinical stage classification, PSA, Gleason score, primers location, CpG location and primers sequence. Details are summarized in Odds ratio (OR) with the corresponding 95% CI was used to examine the differences in the frequency of RASSF1A methylation between prostate cancer case and controls. Similarly the association between RASSF1A methylation and prostate cancer pathological stage, Gleason score, and PSA levels were also examined. To assess heterogeneity across the studies, a statistical test for heterogeneity was performed. If the studies were shown to be homogeneous with P>0.05 for the Q-statistics, the summary of OR was calculated by a fixed-effects model, otherwise, a random-effects model was selected. In addition, stratified analyses were also performed by samples and methods, meta-regression was used to study the heterogeneity source, and a sensitivity analysis, by which a single study in the meta-analysis was deleted each time to determine the influence of the individual data set to the overall pooled OR, was performed to assess the stability. The potential publication bias was examined visually by a funnel plot of log [OR] against its standard error (SE), and the degree of asymmetry was tested by Egger’s test. Finally a trim-and-fill method was used to draw stable conclusion. This meta-analysis was performed using the software STATA 11.0. All p-values were based on two-sided tests and p<0.05 was considered statistically significant.Sensitivity and specificity were analyzed using random-effects models and in this analysis, both the fluid and tissue subgroups were processed. We utilized the summary receiving operating characteristic (S–ROC) curve, to assess whether variation in the threshold definition of a positive result produced an association between sensitivity and specificity values across studies. Estimation of the linear regression of the log–odds ratio from each study on the sum of the logits of the true-positive and false-positive rates enabled S-ROC calculations. When the regression between these quantities was null, an independent analyses of pooled sensitivity and specificity using standard methods for binary data was adopted. Under these circumstances, data were analyzed on the log-odds scale ). All analyses were conducted in STATA 11.0.A total of 16 eligible studies involving 1431 cases and 565 controls were included in the pooled analyses based on our inclusion criteria -30. The 2=32.3%). Details are shown in Under the random-effects model, the pooled OR of RASSF1A methylation in prostate cancer cases, compared to non-cancer controls, was 14.73 with 95%CI = 7.58–28.61. In the 2 = 47.41%), However, other factors such as sample types (p=0.525), year of publication (p=0.608), and the origin of the patients (p=0.847) could not explain the heterogeneity. We also performed sensitivity analyses to determine the effects of omitting a single study on the overall effect where six independent studies were found to introduce some source of heterogeneity. Hence when we excluded the six studies that would likely introduce high heterogeneity due to different types of cases and controls, we observed a decrease in heterogeneity (p = 0.089) with stable conclusion   .We did not observe any publication bias , and further confirmed this observation by implementing a trim-and-fill method. Meta-analysis with or without the trim-and-fill method did not draw different conclusions, indicating that our results were statistically robust. The Egger’s test suggested the absence of publication bias (P>0. 05) in studies of association between RASSF1A methylation and pathological stage or Gleason score .The pooled specificity for all included studies was 0.87 (95% CI: 0.72–0.94), and the pooled sensitivity was 0.76 (95% CI: 0.55–0.89). For the traditional biomarker, the sensitivity of PSA varied, but the specificity was generally low at about 20%, which suggested that the RASSF1A methylation test has a much higher specificity than the PSA test. The p-value for heterogeneity was <0.001, indicating a significant heterogeneity. There was no evidence of publication bias (p=0.13). In addition, we classified all samples into two groups according to specimen type (fluid/tissue). Among the fluid studies (urine/blood/plasma), the pooled sensitivity and specificity was 0.60 (95% CI: 0.08–0.96) and 0.93 (95% CI: 0.75–0.98), respectively. For the tissue studies, the pooled sensitivity and specificity was 0.79 (95% CI: 0.64–0.89) and 0.84 (95% CI: 0.63–0.94), respectively and the S–ROC curve is presented in The results of our meta-analysis showed that RASSF1A methylation in prostate cancer was significantly associated with cancer risk when monitored in urine, blood or tissue samples. It was also associated with increased risk for high Gleason score. The pooled specificity (0.87) of RASSF1A was much higher than the specificity of PSA (20%). In addition the specificity in each subgroup stratified by sample type remained above 0.84 and the sensitivity of RASSF1A also remained high above 0.60. These results suggested that RASSF1A promoter methylation would be a valuable biomarker in diagnosing PCa.DNA methylation is a common mechanism for inactivating tumor-suppressor genes in cancers . MonitorAs shown previously, the PSA test had varying sensitivity and poor specificity (about 20%) . Tests tThe present study has several limitations. First, the heterogeneity in the methods employed such as MSP, Q-MSP and pyrosequencing to monitor gene promoter methylation. Based on studies conducted, it will be helpful if a consensus could be arrived for a standard testing. Sequencing based techniques are generally considered to have superior performance as compared to methodologies that employ PCR alone. The rapidly gaining momentum in using next generation sequencing (NGS) assays to monitor genomic and epigenomic changes will certainly usher in advancements in this area . One canThis meta-analysis has demonstrated that RASSF1A methylation in prostate cancer was associated with cancer risk across different study populations. RASSF1A is a promising biomarker for screening and identifying PCa especially when combined with the PSA test to bring down the rate of unnecessary biopsies. Future studies with larger sample cohort and novel assays based on next generation sequencing approaches will help in further strengthening our observations.Table S1Characteristics of studies included in the meta-analysis.(XLSX)Click here for additional data file.Table S2Details of studies included in the meta-analysis: Association between RASSF1A promoter methylation and pathological stage, Gleason score, and PSA levels.(XLSX)Click here for additional data file.Table S3Summary of primer sequences used in methylation study of RASSF1A.(XLSX)Click here for additional data file.


Healthy ageing and longevity in humans result from a number of factors, including genetic background, favorable environmental and social factors and chance.In this article we aimed to overview the research on the biological basis of human healthy ageing and longevity, discussing the role of epidemiological, genetic and epigenetic factors in the variation of quality of ageing and lifespan, including the most promising candidate genes investigated so far. Moreover, we reported the methodologies applied for their identification, discussing advantages and disadvantages of the different approaches and possible solutions that can be taken to overcome them. Finally, we illustrated the recent approaches to define healthy ageing and underlined the role that the emerging field of epigenetics is gaining in the search for the determinants of healthy ageing and longevity. Proportionally, life expectancy at birth increased from a medium value of 44 years  in 1905 to more than 80 years  in 2011. Similar figures are reported for all developed countries, while in developing countries life expectancy grows very fast as soon as infant mortality is reduced, with the exception of some areas, namely in Africa, where AIDS infection dramatically affects life expectancy of adults [The past few decades witnessed a growing social and scientific interest in studies on human ageing and longevity. This interest is primarily due to the social burden connected to the extraordinary increase of the elder population in developed countries, which implies an increase of the subjects which are not autonomous and are affected by invalidating pathologies ,2. In ItEpidemiological evidence for a genetic component to variation in human lifespan comes from twin studies and family studies. By comparing life span in twins, researchers have found that approximately 25% of the overall variation in human lifespan can be attributed to genetic factors -5, whichFamily-based studies demonstrated that parents, siblings and offspring of long-lived subjects have a significant survival advantage when compared with the general population -12. MoreIn this paper we will review the literature on the studies on the genetic of human longevity and the discussions there has been on the different approaches that can be used in this field. In addition, we will report the new approaches that have been proposed to define the healthy ageing, as the correct definition of healthy ageing is the first step to understand its genetic basis. Finally, we will outline some recent advance in the epigenetic studies of ageing, as epigenetics, a bridge between genetics and environment, might explain many aspects of ageing and longevity.The studies aimed to understand the genetic basis of longevity in humans have been carried out under the hypothesis that unfavorable genotypes should be dropped out of the population by a sort of "demographic selection"  which fiTo date, many approaches have been adopted in order to disentangle the genetic from the environmental effects on human longevity, ranging from different sample design to data analysis approaches . Among tMTTP was identified as the gene most probably responsible for the observed linkage peak reported [At family level, the ASP design represents the typical nonparametric strategy allowing both linkage and association to be tested . At popureported . Howeverreported ,29.Among the studies using an ASP approach it is worth noticing the original study design adopted in the ECHA project . The autPopulation case-control studies comparing long lived samples with younger controls of the same population may provide a powerful and more efficient alternative, especially when associated to the recent advances in genomic and statistical techniques. They are more powerful than family designs for detecting genes with low effect and gene-gene interactions . HoweverMost gene-longevity association studies have focused on a single or a few candidate genes. However, common genetic variants with important effects on human longevity are unlikely to exist because of the rather low genetic contribution to the trait. In addition, given the complexity of the trait, the main effects of the individual loci may be small or absent, while multiple genes with a small effect may interact in an additive manner and affect survival at old ages. In such a case, a single-locus approach may not be suitable, failing in finding positive results of associations. Thus, given the technical improvement of typing techniques, multi-locus association approaches which takes into account epistatic interactions among different genes, have become of age .These approaches represent specific and important statistical challenges. A flexible framework to tackle these challenges and for modeling the relationship between multiple risk loci and a complex trait makes use of logistic regression techniques ,37. SincIn some studies, different loci clustered in haplotypes are analyzed. In general haplotype-based association analysis brings new possibilities and difficulties. They exhibit more power than single-marker analysis for genetic association studies since they incorporate linkage disequilibrium information -42. ConvFurther improvements in high-throughput technology, associated to the recent advances in genomic knowledge, have made whole genome genotyping  more accessible. Indeed, GWAS are at present widely used to find genetic variants contributing to variation in human lifespan ,46-52. IFrom a statistical point of view, the analysis of GWAS data presents several statistical challenges including data reduction, interaction of variables and multiple testing. Although these challenges are new to statistics, the magnitude of the present datasets is unprecedented.After all these considerations, the most reasonable approach, for taking into account a great number of single polymorphisms spread along the genome without losing the biological relevance of candidate genes in biochemical pathways, which may be reasonably related to the trait, seems to be to use a candidate regions approach combined with a minimal number of "tagging" SNPs, efficiently capturing all the common genetic variation in the assayed genomic region ,53-56. Tage-1, daf2, sir2, methuselah, p66) able to extend or reduce lifespan has been reported [By using the approaches described above, many candidate genes have been investigated to identify alleles that are either positively or negatively selected in the centenarian population as consequence of a demographic pressure. For many years, genetic analyses were focused on single genetic variants, by using the classical "candidate gene" approach. Candidates were found among human orthologous of experimental model genes, where the existence of specific mutations , to fruit flies (Drosophila), and mammals (mouse), pathways related to the regulation of energy homeostasis, cell maintenance, nutritional sensing, stress response signalling to internal or external environmental insults, by an efficient non inflammatory response, and DNA repair/maintenance have been shown to critically modulate lifespan [Recently, from the study of a single gene and starting again from the evidences in experimental models, which suggest the existence of evolutionary conserved networks that regulates lifespan and affects longevity across species, research moved into the study of whole metabolic pathways, where to find candidate genes for human longevity. From worms , antioxidant , inflammatory  pathways, silencing (SIRT1 and SIRT3), elements of lipid metabolism  and stress resistance (HSPA1A and HSPA1L) [[APOE and FOXO3A, were not reproduced in some of the replication studies [In humans, the most relevant results found by association studies in long lived cohorts, identified genes involved in GH/IGF-1/Insulin signaling (HSPA1L) [,33,75-81 studies ,82, prob studies .Coupled with the rapid advances in high-throughput sequencing technologies, it is now feasible to comprehensively analyze all possible sequence variants in candidate genes segregating with a longevity phenotype and to investigate the functional consequences of the associated variants. A better understanding of the functional genes that affect healthy longevity in humans may lead to a rational basis for intervention strategies that can delay or prevent age-related diseases. Genome-wide expression profiles in different tissues reported changes of gene expression occurring with age. In this sense, two main works deserve attention. Kerber and collaborators, who analyzed the gene expression profiles of 2151 house-keeping genes in cultured cell lines from 104 adults belonging to 31 Utah families, aged 57-97 years, searching for stable variation in gene expressions that affect or mark longevity. They found different genes exhibiting associations with either mortality or survival , 10% decHuman ageing is characterized by a gradual reduction in the ability to coordinate cellular energy expenditure and storage , and by a gradual decrease in the in the ability to mount a successful stress response . These pAn accumulation of mtDNA somatic mutations occurs with age, and many studies have reported an association between mtDNA mutations and ageing, particularly in post-mitotic neuronal cells . A numbeThe first experimental evidence that a similar mechanism has been maintained in higher organisms, including humans, comes from cytoplasmic hybrid or cybrid experiments (i.e. cell lines differ only in the source of their mtDNA), where it was found that cells characterized by different mtDNA haplogroups, differently expressed stress responder nuclear genes ,105, thuOn the whole, although the involvement of mtDNA variability in ageing and longevity is undisputed, the role of mtDNA and its mutations, either inherited or somatically acquired, in human longevity is far from being clear. The use of high-throughput technologies and the extensive analysis, possibly at the single cell level, of different tissues and cell types derived from the same individual will help in disentangling the complexity of mtDNA in ageing and longevity.Genomic instability has been widely recognized as a crucial mechanism in both ageing and age-related diseases. The progressive shortening of telomeres, probably the most important marker of chromosome integrity, is associated with increased risk of several age-related disease comprised cancer and mortality ,107. TelAlthough ageing is a general phenomenon, it is clear that a great inter-individual variability on the rate and quality of ageing can be observed . FollowiOn the whole, this approach, which is based on population-specific data under study and does not use any a priori thresholds, may be very promising for an objective identification of frail subject. This may be a very important task for future societies, helping to address specific medical care, by tailoring treatments on the basis of the real needs of each single patient, especially of pre-frail and frail older patients with multiple chronic conditions and reduced life expectancy, finally preventing the effects of frailty.Epigenetic modifications indicate the sum of heritable changes, such as DNA methylation, histone modification and miRNA expression, that affect gene expression without changing the DNA sequence . It is bDespite the enormous technical progresses, which allow to analyzed many single variants as well as the coordinated expression of many genes together by high-throughput platforms, many challenges still remain to be faced by the researchers trying to identify genetic and non genetic variants associated with human longevity. A close partnership between gerontologists, epidemiologists, and geneticists is needed to take full advantage of emerging genome information and technology and bring about a new age for biological ageing research. In addition, we believe that the next future will see much progresses in our understanding of the longevity trait, mainly coming from the integration of genetics and epigenetics information by multidisciplinary approaches, to the aim of obtaining an overall picture of what successful ageing is.ACE: Angiotensin I converting enzyme; ADL: Activity of Daily Living; APOE/B: Apolipoprotein E/B; APOC3: Apolipoprotein C-III; ASP: Affected Sib-Pairs; ATP: Adenosine triphosphate; CDC42: Cell division cycle 42; CETP: Cholesteryl ester transfer protein; CORO1A: Coronin, actin binding protein, 1A; DNA: Deoxyribonucleic Acid; ECHA: European Challenge for Healthy Aging; EM: Maximum Estimation; FOXO3A: Forkhead box O3; GEHA: Genetics of Healthy Aging; GH: Growth Hormone; GHR: Growth hormone receptor; GWAS: Genome-Wide Association Studies; HG: Hand grip; HSPA1A: Heat shock 70 kDa protein 1A; HSPA1L: Heat shock 70 kDa protein 1-like; IGF-1: Insulin Growth Factor 1; IGF1R: Insulin-like growth factor 1 receptor; IL6: Interleukine 6; miRNA: MicroRNA; MMSE: Mini Mental State Examination; mRNA: Messenger RNA; mtDNA: Mitochondrial DNA; mTOR: Mitochondrial Target Of Rapamycin; MTTP: Microsomal Triglyceride Transfer Protein; PON1: Paraoxonase 1; ROS: Reactive oxygen species; SOD1: Superoxide dismutase 1, soluble; SHRS: Self-reported health status; SIRT1/3: SIR2-like protein 1/3; SNP: Single Nucleotide Polymorphism; SOD: Superoxide dismutase; TOR: Target Of Rapamycin; UCP: Uncoupling Protein.The authors declare that they have no competing interests.AM and SD wrote the first draft; subsequent drafts were written by DB, GR and GP who also supervised the review process; all the authors edited the manuscript and approved its final version.


N-Acetyltransferase (NAT) 2 is an important enzyme involved in the metabolism of different xenobiotics, including potential carcinogens, whose phenotypes were reported to be related to individual susceptibility to colorectal cancer (CRC). However, the results remain conflicting. To assess the relationship between NAT2 phenotypes and CRC risk, we performed this meta-analysis.A comprehensive literature search was conducted to identify all case-control or cohort studies of NAT2 acetylator status on the susceptibility of CRC by searching of PubMed and EMBASE, up to May 20, 2011. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association.2 = 52.6%). While three studies contributed to the source of heterogeneity were removed, there was still null result observed . In addition, we failed to detect any associations in the stratified analyses by race, sex, source of controls, smoking status, genotyping methods or tumor localization. No publication bias was observed in this study.A total of over 40,000 subjects from 40 published literatures were identified by searching the databases. No significantly elevated CRC risk in individuals with NAT2 slow acetylators compared with fast acetylators was found when all studies pooled (OR = 0.95, 95% CI: 0.87–1.04, INAT2 phenotypes may not be associated with colorectal cancer development.This meta-analysis suggests that the  N-acetyltransferases (NAT) 1 and/or 2 that are coded by genes (NAT1 and NAT2) which are highly polymorphic. The carcinogenic amines can be metabolized more or less efficiently in individuals depending on their NAT genotypes. The NAT2 gene, which is located on chromosome 8p21.3–23.1, and encodes phase II xenobiotic metabolizing enzyme which plays an essential role in the metabolism of aromatic, heterocyclic amines and hydrazines via N-acetylation and O-acetylation NAT2 result in slow clearance of carcinogenic amines NAT2 acetylation polymorphism in individual risk to various cancers in which carcinogens exposure play an etiologic role is biologically plausible and has been the subject of numerous studies. The high frequency of the NAT2 acetylation polymorphisms in human populations together with ubiquitous exposure to aromatic and heterocyclic amines suggest that NAT2 acetylator genotypes are important modifier of human cancer susceptibility. So far, over sixty NAT2 genetic variants have been identified in human being, in which NAT2*4 is the most common allele associated with rapid acetylation and has historically been designated “wildtype”. The NAT2 alleles are regularly updated and listed at: http://www.louisville.edu/medschool/pharmacology/NAT.html by an international gene nomenclature committee. Detailed information on NAT2 alleles is also provided in a supplemental file. To date, a number of epidemiological studies have investigated the potential role of NAT2 polymorphisms in colorectal cancer development. However, the results were inconsistent rather than conclusive, probably due to the possible small effect of differential acetylator status on CRC risk or the relatively small sample size in individual studies. Therefore we performed a meta-analysis to get a more precise estimate of the relationship between NAT2 phenotypes and colorectal cancer risk.Colorectal cancer (CRC) is the third most common cancer among men and women in the U.S., and ranks third as a cause of cancer deaths NAT genes or on colorectal polyps or reviews. The rest 47 relevant studies were obtained for further full text evaluating. Seven literatures were also found by hand search of the reference lists. After information extraction and discussing, 14 studies were further excluded , resulting in 40 eligible studies with 13,896 CRC cases and 18,839 controls reporting the association between the NAT2 acetylator phenotypes and CRC risk for this meta-analysis et al. investigated African population A total of 186 potentially relevant articles were retrieved through electronic databases searching that met our criteria. After carefully reviewed the titles and abstracts, 139 articles were excluded for not about NAT2 slow phenotypes were not statistically significant associated with an increased risk to colorectal cancer compared with those carrying rapid phenotypes. The summary OR was 0.95 . There was substantial heterogeneity among these studies. Herein, we explored the source of heterogeneity. When the three studies removed 2 = 17.8%). The crude ORs were performed for slow versus rapid acetylation genotypes. Individuals with the In the subgroup analysis by ethnicity, no increased risk was found for either Caucasians  or Asians . So dose mixed populations . In addition, significant associated increasing risk was not detected in different source of controls . When stratified by genotyping methods, gender, smoking status and tumor site, similarly, few significant associations was found for all of these subgroup analyses. The main results of this meta-analysis and the heterogeneity tests are shown in et al., Yoshida et al. and Tiemersma et al. were the main origin of the heterogeneity. After excluding them, heterogeneity test was below statically significant.In sensitivity analysis, individual study was sequentially removed each time, and the results suggested that no individual study obviously affected the summary OR, which indicated that our results were statistically robust. However, sensitivity analyses also indicated that three separate studies by Mahid As shown in NAT2 phenotypes correlating with the risk of colorectal cancer. In addition, stratified analyses according to ethnicity, source of controls, phenotyping/genotyping methods, gender, smoking status and tumor site also indicate that NAT2 acetylator status is not associated with CRC predisposition based on the currently available data. As we know, this is the largest meta-analysis of the comprehensive assessment for the relationship between NAT2 phenotypes and CRC risk. The previous meta-analysis didn't support the hypothesis that NAT2 alone is an important risk factor for colorectal cancer and suggests that NAT2 rapid acetylation status has no specific effect on the risk of developing colorectal cancer This meta-analysis based on 40 studies involving over 40,000 subjects indicates that lack of sufficient evidence supporting the notion of NAT2 genetic polymorphisms are associated with some malignancies. Reports by Simon Sanderson et al. supported the evidence that a contribution of NAT2 slow acetylation status alone to bladder carcinogenesis and provided support for a NAT2-smoking interaction NAT2 slow or rapid acetylation phenotype NAT2 genetic polymorphisms in the development of CRC may be modified by confounding factors. Processed meat and smoking interact with N-acetyltransferases efficiency on colorectal cancer risk have received a great deal of attention in some studies. Moreover, an enhanced association between smoking and colorectal cancer risk in subjects with the NAT2 rapid genotype was detected and supported a role for NAT2 and tobacco smoke heterocyclic amines in the etiology of colorectal cancer NAT2 examined. Other genes, including other CYPs, GSTs, NAT1, and the aromatic hydrocarbon receptor gene, which positively regulates inducible expression of aromatic hydrocarbon hydroxylase, may further define genetic susceptibility to the exposure of carcinogenic amines Studies by meta-analysis have shown that NAT2 alleles, the ability to distinguish among multiple acetylator phenotypes is complex and a function of the sensitivity and specificity of the genotyping method. Furthermore, phenotypes are influenced by a number of factors including diet, disease, and drug therapy. Depending upon the probe drug and analytical method used, acetylation phenotypes often exhibit overlap due to numerous genetic and/or environmental factors, including the large number and diversity of NAT2 genotypes present in human populations  and their 95% confidence intervals (CIs). Abstracts, unpublished data were not considered. Investigations in subjects with family cancer risks or cancer-prone disposition were excluded. Besides, when the same study population was included by more than one article, we selected the study that included the largest number of individuals.We searched for relevant papers published before May 20, 2011 using the electronic PubMed and EMBASE databases with the following terms and their combinations: ‘We extracted the following information from each study: first author's surname, year of publication, country of origin, ethnicity, phenotyping/genotyping information, source of control groups , matching criteria and number of different genotypes in all subjects. The ethnicity of studies was categorized as Asians, Caucasians, African or Mixed. We defined carriers with at least one of the high-activity alleles as rapid acetylators, in accordance with the definition in most studies, whereas individuals carrying two low-activity alleles were considered as slow acetylators. All the data were extracted separately by two authors (Zhang LQ and Wang J), and the disagreement was solved by discussing.NAT2 slow/rapid acetylation polymorphisms. Crude ORs with 95% CIs were calculated using raw data, according to the method of Woolf B. 2, respectively. And the heterogeneity was considered significant, if P<0.10 for Q-test The meta-analysis was performed to estimate the risk of colorectal cancer associated with Table S1Main characteristics of studies included in the meta-analysis.(DOC)Click here for additional data file.


Although several reports have described a possible association between DNA repair genes and pancreatic cancer (PC) in smokers, this association has not been fully evaluated in an Asian population. We assessed the impact of genetic polymorphisms in the base excision repair (BER) pathway on PC risk among Japanese.OGG1, rs1799782 and rs25487 in XRCC1, rs1130409 in APE1, and rs1136410 in PARP1. SNPs were investigated using the TaqMan assay in 185 PC cases and 1465 controls. Associations of PC risk with genetic polymorphisms and gene–environment interaction were examined with an unconditional logistic regression model. Exposure to risk factors was assessed from the results of a self-administered questionnaire. We also performed haplotype-based analysis.This case-control study compared the frequency of 5 single-nucleotide polymorphisms (SNPs) of BER genes, namely rs1052133 in XRCC1 was significantly associated with PC risk in the per-allele model . Haplotype analysis of XRCC1 also showed a statistically significant association with PC risk. No statistically significant interaction between XRCC1 polymorphisms and smoking status was seen.We observed that the minor allele of rs25487 in XRCC1 polymorphisms affect PC risk in Japanese.Our findings suggest that  The study focused on 4 key genes in this repair pathway: X-ray repair cross-complementing group 1 , Nagoya, Japan, between January 2001 and November 2005. The control subjects comprised 1465 randomly selected non-cancer ACCH outpatients, during the same period, who had no history of any cancer. All subjects were enrolled in the Hospital-based Epidemiological Research Program II at ACCH (HERPACC-II) at the time of their first visit to ACCH. The framework of HERPACC-II has been described elsewhere.XRCC1, rs1130409 (Asp148Glu) in APE1, rs1052133 in OGG1 (Ser326Cys), and rs1136410  in PARP1. In our study, these 5 single-nucleotide polymorphisms (SNPs) were selected on the basis of their association with cancer risk or their expected influence on BER systems.13,14,17–22,27–29 DNA of each subject was extracted from the buffy coat fraction using a DNA Blood Mini Kit . All loci were examined by the TaqMan assay with probes and primers  and the Fluidigm EP1 SNP Genotyping 96.96 Dynamic Array . Approximately 10% of subjects were examined in duplicate to confirm the consistency of genotyping.We examined 5 non-synonymous polymorphisms in BER pathway genes, namely rs1799782 (Arg194Trp) and rs25487 (Arg399Gln) in sake (rice wine), shochu (distilled spirit), beer, wine, and whiskey. Cumulative smoking exposure was measured in pack-years (PYs), ie, the product of the average number of packs per day and the number of years of smoking. Height and body weight at baseline and weight at age 20 years were self-reported. Current body mass index (BMI) and BMI at age 20 were calculated by dividing the weight in kilograms by the height in meters squared. Family history of PC was considered positive when at least 1 parent or sibling had a history of PC.Exposure to potential PC risk factors was assessed from responses to the self-administered questionnaire, which was completed before diagnosis during the first visit to ACCH and reviewed by trained interviewers. Subjects were specifically questioned about their lifestyle before the onset of presenting symptoms. Daily alcohol consumption in grams was determined by summing the amount of pure alcohol in the average daily consumption of Japanese P-value less than 0.05 was considered statistically significant. Differences in characteristics between cases and controls were assessed using the chi-square test. Odds ratios (ORs) and 95% CIs were estimated using an unconditional logistic regression model adjusted for potential confounders. Potential confounders considered in multivariate analysis were age, sex, PYs of smoking , drinking habit , current BMI , BMI at age 20 , history of diabetes mellitus (yes or no), and family history of PC (yes or no). Interactions between environmental factors and genotypes were assessed by using likelihood ratio tests within logistic regression models, with and without interaction terms. In haplotype analysis, we used haplotype-effects logistic regression for case-control data.30 This haplotype analysis uses phased and unphased SNP genotype data to estimate haplotype effects and haplotype–environment interactions in a case-control study.30,31 It fits haplotype-effects logistic regression by using the retrospective likelihood method in a special case of a rare disease and a single candidate gene in the Hardy–Weinberg Equilibrium (HWE), under the assumption of gene–environment independence.30,31 Accordance with the HWE was assessed by the chi-square test.All statistical analyses were performed using Stata version 10 . A P = 0.005), a higher prevalence of a history of diabetes mellitus (P < 0.001), a lower current BMI (P = 0.021), and a higher BMI at age 20 (P = 0.018).The background characteristics of the subjects are shown in Table XRCC1 was significantly associated with PC risk in the per-allele model  and in the dominant model . No significant association with PC risk was observed for the remaining 2 loci.Table XRCC1 and rs1130409 in APE1 with known risk factors for PC, such as smoking, alcohol consumption, overweight, diabetes mellitus, and family history of PC. Because of the low frequency of minor homozygous subjects, these subjects were combined with heterozygous subjects in this analysis. The exposure variables used were current and former BMI (BMI <25 or ≥25 kg/m2), alcohol consumption (<23 or ≥23 g ethanol/day), smoking (<5 or ≥5 PYs), heavy smoking (<40 or ≥40 PYs), history of diabetes mellitus (yes or no), and family history of PC (yes or no). There were no statistically significant interactions  value between rs1799782 and rs25487 was 0.15. Haplotype CA in XRCC1 was associated with a statistically significant increase in PC risk  as compared with the most common haplotype, CG, in XRCC1. As shown in Table XRCC1 as a risk haplotype and analyzed the potential interactions between risk haplotype and known PC risk factors . The results showed significant interactions between a family history of PC and the risk haplotype in XRCC1 (interaction P = 0.020).Table XRCC1 was associated with increased risk of PC in a Japanese population. However, we did not detect any statistically significant interactions with smoking.In this case-control study, we found that the genetic polymorphism rs25487 in 21 Oxidative damage to DNA may lead to mutations that activate oncogenes or inactivate tumor suppressor genes and may eventually increase the probability of genetic alterations developing into neoplastic events.21 Sequence variants in BER genes are thought to modulate DNA repair capacity and are consequently suspected of being associated with altered cancer risk.20 With regard to the association between PC risk and DNA repair pathway, genetic polymorphisms in the BER pathway are the most widely studied in Western epidemiologic studies.14 To our knowledge, however, this is the first study to detect an association between XRCC1 polymorphisms and the development of PC in an Asian population.The BER pathway has a primary role in the repair of oxidative base lesions such as 8-hydroxyguanine, formamidopyrimidines, and 5-hydroxyuracil.XRCC1 are rs1799782 (in which T substitutes for C) and rs25487 (in which A substitutes for G), which lead to amino acid substitutions Arg194Trp and Arg399Gln, respectively.32 In particular, the minor allele (A) for rs25487, namely the 399Gln allele, was found to be associated with a higher frequency of glycophorin mutant, elevated DNA adduct levels, higher baseline sister chromatid exchange frequency, and increased sensitivity to ionizing radiation, all of which might be due to reduced BER function.18 In the present study, the minor allele of rs25487 in XRCC1 was associated with elevated PC risk. Thus, our finding is consistent with the potential mechanisms described above.Two common variants of XRCC1 gene polymorphisms are modulating factors for PC risk, particularly in smokers.17–21 A synergistic effect between these gene polymorphisms and tobacco smoking in relation to PC risk has been suspected.14 Oxidative DNA damage produced by smoking is expected to be repaired by the BER system, which includes the XRCC1 gene.33 In this study, we observed a significant main effect of rs25487 in XRCC1 but found no statistically significant interaction between XRCC1 loci and smoking. Although the reason for this difference is unclear, the results may have been affected by the heterogeneity of study populations, differences in ethnicity, the small sample size, and potential confounders. On the other hand, the minor allele of rs25487 in XRCC1 was associated with increased risk of PC among light but not heavy smokers. These findings are consistent with past reports, and possible explanations for the limited effect among heavy smokers include enhanced apoptosis at the time of cell division from heavy smoking and induction of DNA repair capacity in response to DNA damage.20,21It has been suggested that XRCC1 had a higher impact in those with a family history of PC than in those without such a history. To our knowledge, this phenomenon has not been reported previously and might be explained by family history acting as a surrogate for interaction with known/unknown genetic susceptibility factors. We did not observe any interaction with the ABO genotype, which has been reported to have a significant association with PC risk (data not shown).34 Given our small study population, the finding of an interaction with family history may have been due to chance. Further study is required to duplicate our findings in a larger cohort.In addition, we found that haplotype CG in 26 However, only 50% of patients agreed to the collection of a blood sample, and the characteristics of these participants might differ from those of the general population. Third, case-control studies have an intrinsic information bias. However, the HERPACC system is less prone to this bias than are typical hospital-based studies, as the data for all patients were collected before diagnosis. In addition, the results from our self-administered questionnaire may be inaccurate. However, any such misclassification would be nondifferential and would likely underestimate the causal association.35 Fourth, with regard to SNP analysis, because 2 SNPs (rs1052133 in OGG1 and rs1136410 in PARP1) were not in accordance with HWE in our study, further studies that include these factors are required. Fifth, residual confounding by known and unknown risk factors might be present; given the small number of cases, our findings require replication in a larger study. Finally, our study was limited to a Japanese population, and the results cannot necessarily be extrapolated to other populations.Our study has several methodological issues that warrant discussion. First, the control population was selected from non-cancer patients at ACCH. It is reasonable to assume that this was the same population from which the case subjects were derived, which would bolster the internal validity of our study. Second, with regard to external validity, we previously showed that individuals selected randomly from our control population were similar to the general population of Nagoya City in terms of the exposure of interest.XRCC1 and PC risk in a Japanese population. Further investigation of our findings in larger populations are warranted, and the biological mechanisms responsible for the association should be fully elucidated.In summary, this case-control study showed a significant association between genetic polymorphisms in eTables and the Japanese-language abstract for articles can be accessed by clicking on the tab labeled Supplementary materials at the journal website http://dx.doi.org/10.2188/jea.JE20120010.eTables.Abstract in Japanese.