Common genetic variants at 1q22 and 10q23 and gastric cancer susceptibility in a Korean population

Genetic variants at 1q22 and 10q23 were identified as genetic markers of both gastric cancer and esophageal squamous cell carcinoma susceptibility by two genome-wide association studies. The aim of this study was to determine whether rs4072037A?>?G in MUC1 at 1q22 and rs2274223A?>?G in PLCE1 at 10q23 are associated with a risk of gastric cancer in a Korean population. We conducted a large-scale case–control study of 3,245 patients with gastric cancer and 1,700 controls. The allele frequencies of rs4072037G and rs2274223G were 11.2 and 25.5 % among patients with gastric cancer, compared with 12.8 and 26.4 %, respectively, among controls. We found that the rs4072037 AG genotype was significantly associated with a reduced risk of gastric cancer [odds ratios (OR)?=?0.78; 95 % confidence interval (CI)?=?0.67–0.91 for AG vs AA]. Compared with the rs2274223 AA genotype, we found a significant association between the rs2274223 AG genotype and a weakly reduced risk of gastric cancer (OR?=?0.87; 95 % CI?=?0.76–0.99 for AG vs AA). Our data suggest that genetic variants at 1q22 and 10q23 play a role in gastric carcinogenesis.     

PLCE1 rs2274223 polymorphism contributes to risk of esophageal cancer: evidence based on a meta-analysis

We sought to reassess the association of PLCE1 rs2274223 and susceptibility to esophageal cancer (EC) through a meta-analysis of published case-control studies. Using the PubMed and Embase, we identified nine articles including fourteen case-control studies (15,225 cases and 23,620 controls). ORs and 95 % confidence intervals (CIs) of GG vs. AA, GG + GA vs. AA, GG vs. GA + AA, G vs. A, and AG vs. AA genetic models were estimated for each study. All of the genetic models indicated a statistically significant positive association with EC risk. The association appeared most pronounced for carriers of GG genotype (GG vs. AA: OR, 1.35; 95 % CI, 1.17 to 1.57), and weakest for individuals carrying GA genotype (GA vs. AA: OR, 1.13; 95 % CI, 1.05 to 1.23). Stratification analyses showed similar results in the population of Asians and in esophageal squamous cell carcinoma (ESCC). This meta-analysis provides strong statistical evidence for an elevated risk of EC associated with PLCE1 rs2274223. The association remains significant in Asian population and ESCC. Further investigations are warranted to validate these findings.     

Association of Potentially Functional Genetic Variants of PLCE1 with Gallbladder Cancer Susceptibility in North Indian Population

Background and Objectives

Phospholipase C epsilon 1 (PLCE1) plays crucial roles in carcinogenesis and progression of esophageal and gastric cancers. In the present study, we investigated association of GWAS identified rs2274223 A>G and. rs7922612 T>C polymorphism of PLCE1 with susceptibility to gallbladder cancer (GBC).

Methods

The study involved genotyping of selected PLCE1 variants in 416 GBC cases and 225 controls. Haplotype analysis was done by SNPStats. In silico analyses were performed using bioinformatic tools.

Results

PLCE1 rs2274223 [AG] and rs7922612 [CC] genotypes were found to be significantly associated with an increased risk of GBC [OR?=?1.9, p?=?0.002; OR?=?2.0, p?=?0.04, respectively]. PLCE1 haplotype [G_rs2274223-C_rs7922612] also showed significant association with GBC [OR?=?1.8, p?=?0.04]. The association was significant in females and GBC patients with stones and female GBC patients with gallstones [OR?=?2.6, p?=?0.01; OR?=?3.3, p?=?0.007], respectively. However, no significant associations with other risk factors such as tobacco usage and age of onset were found. Functional prediction of rs2274223 A>G suggested change in protein coding and splicing regulation.

Conclusion

The present study found a significant association of PLCE1 rs2274223 and rs7922612 polymorphisms with susceptibility to GBC probably through gallstone-mediated inflammatory pathway.     

Association between tumor necrosis factor-α rs1800629 polymorphism and risk of gastric cancer: a meta-analysis

Gastric cancer is mainly initiated by inflammation and chronic superficial gastritis, and tumor necrosis factor-α (TNF-α) is an inflammatory cytokine which plays an important role in the inflammation. TNF-α rs1800629 G/A polymorphism was proposed to be associated with gastric cancer risk, but previous studies on Caucasians reported conflicting results. We performed a meta-analysis to comprehensively assess the association between TNF-α rs1800629 polymorphism and gastric cancer risk in Caucasians. The pooled odds ratio (OR) with 95 % confidence interval (95 % CI) was calculated to assess the association. Eleven case–control studies with 7,427 subjects were finally included into the meta-analysis. Overall, TNF-α rs1800629 polymorphism was significantly associated with the increased risk of gastric cancer under four genetic comparison models (A versus G: OR?=?1.32, 95 % CI 1.12–1.56, P?=?0.001; AA versus GG: OR?=?1.76, 95 % CI 1.37–2.26, P?<?0.001; AA versus GG/GA: OR?=?1.62, 95 % CI 1.27–2.07, P?<?0.001; AA/GA versus GG: OR?=?1.35, 95 % CI 1.14–1.60, P?=?0.001). Meta-analysis of those studies with high quality showed that TNF-α rs1800629 polymorphism was still significantly associated with the increased risk of gastric cancer under four genetic comparison models. There was no risk of publication bias in the meta-analysis. The meta-analysis suggests that TNF-α rs1800629 polymorphism is associated with the increased risk of gastric cancer in Caucasians.     

Cleft lip and palate transmembrane protein 1 rs31489 polymorphism is associated with lung cancer risk: a meta-analysis

The potentially functional polymorphism, rs31489, in the promoter region of cleft lip and palate transmembrane protein 1 (CLPTM1L) gene has been implicated in cancer risk. However, individual published studies showed inconclusive results. To obtain a more precise estimate of the association between CLPTM1L rs31489 and risk of lung cancer, we performed a meta-analysis. Summary odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) were estimated using random-effects models. Ten individual case–control studies in eight publications with 20,680 cases and 28,330 controls were included. Overall, the variant genotypes were associated with a significantly increased lung cancer risk in different genetic models (CC + AC vs. AA: OR?=?1.20, 95 % CI 1.12–1.28, P?<?0.001; CC vs. AC + AA: OR?=?1.15, 95 % CI 1.07–1.23, P?<?0.001; CC vs. AA: OR?=?1.28, 95 % CI 1.17–1.41, P?<?0.001; CC vs. AC: OR?=?1.11, 95 % CI 1.05–1.17, P?<?0.001; C vs. A: OR?=?1.12, 95 % CI 1.06–1.18, P?<?0.001). In the stratified analyses, the increased lung risk remained for the studies of Caucasian populations. In conclusion, this meta-analysis suggested that CLPTM1L rs31489 was a potential biomarker for lung cancer risk in Caucasians.     

Tumor necrosis factor-α 238 G/A polymorphism and gastric cancer risk: a meta-analysis

Though many studies were performed to assess the association between tumor necrosis factor-α (TNF-α) 238 G/A polymorphism and gastric cancer risk, there were no conclusive findings. A meta-analysis of previous published studies was performed to get a comprehensive assessment of the association between TNF-α 238 G/A polymorphisms and gastric cancer. The pooled odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were calculated to assess the association. Fifteen studies with a total of 7,795 participants were finally included into this meta-analysis. Overall, there was an obvious association between TNF-α 238 G/A polymorphism and increased risk of gastric cancer (A vs. G: OR?=?1.32, 95 % CI 1.02–1.72, P?=?0.036; GA vs. GG: OR?=?1.32, 95 % CI 1.01–1.72, P?=?0.042; and AA/GA vs. GG: OR?=?1.34, 95 % CI 1.02–1.76, P?=?0.036). Subgroup analysis by ethnicity showed the statistically significant association between TNF-α 238 G/A polymorphism and gastric cancer was limited to Asian populations (A vs. G: OR?=?1.59, 95 % CI 1.29–1.97, P?<?0.001; GA vs. GG: OR?=?1.63, 95 % CI 1.29–2.04, P?<?0.001; and AA/GA vs. GG: OR?=?1.64, 95 %CI 1.31–2.05, P?<?0.001), and there was no obvious association in Caucasians. In conclusion, TNF-α 238 G/A polymorphism is significantly associated with increased risk of gastric cancer, especially in Asians.     

PLCE1 rs2274223 Polymorphism and Susceptibility to Esophageal Cancer: a Meta-analysis

Purpose: To investigate and study the relationship between the PLCE1 rs2274223 gene polymorphism andsusceptibility to esophageal cancer by meta-analysis. Materials and Methods: The literature was searched inWanfang, CNKI, PubMed, CBM, Web of Science, MEDLINE, EMBASE, Springer, Elsevier and Cochranedatabases from the date of January 1st 2004 to April 1st 2014 to collect case-control studies on the PLCE1polymorphism and susceptibility to esophageal cancer. For the population genotype distributions of bothesophagus cancer and control groups, their odds ratios (ORs) and 95% confidence intervals (CIs) were takenas effect indexes. Disqualified studies were excluded. Odds ratios of PLCE1 rs2274223 genotype distributionsin the group of patients with esophageal cancer and the group of healthy control were calculated. The metaanalysissoftware, RevMan5.0, was applied for heterogeneity test, pooled OR and 95% confidence intervals.Sensitivity analysis and publication bias were also explored. Results: A total of twelve case-control studies wereincluded, covering a total of 9, 912 esophageal cancer cases and 13, 023 controls were included. The pooledodds ratio of PLCE1 rs2274223 genotype GA vs AA was 1.29 (95%CI=1.17~1.43), p<0.01, GG vs AA was 1.65(95%CI=1.32~2.05), p<0.01, GG/GA vs AA was 1.30 (95%CI=1.16~1.46), p<0.01 and GG vs GA/AA was 1.48(95%CI=1.22~1.80), p<0.01. The PLCE1 rs2274223 polymorphism was thus associated with risk of esophagealcancer in all genetic models. In the stratified analysis by ethnicity, and source of controls, no significantlyincreased risk was observed for white persons. There was no obvious publication bias detected. Conclusions:This meta-analysis showed there was a significantly association between PLCE1 rs2274223 polymorphism andesophageal cancer in yellow race populations. Due to some minor limitations, our findings should be confirmedin further studies.     

Association of rs2233678 and rs2233679 polymorphisms in the PIN1 gene with cancer risk: a meta-analysis

To data, epidemiological studies have assessed the association between peptidyl-propyl-cis/trans isomerase 1 (PIN1) gene polymorphisms and cancer risk, including breast cancer, hepatocellular carcinoma, lung cancer, esophageal cancer, head and neck squamous cell carcinoma, and laryngeal squamous cell cancer. However, the results of these studies remain controversial. We aimed to examine the associations between two SNPs (rs2233678 and rs2233679) of PIN1 gene and cancer risk by conducting a meta-analysis of case–control studies. A total of seven publications were included in this meta-analysis for both rs2233678 and rs2233679. Overall, rs2233678 polymorphism was found to be associated with decreased cancer risk in four genetic models (C-allele vs. G-allele: odd ratio (OR)?=?0.73, 95 % confidence interval (CI): 0.60–0.88; CC vs. GG: OR?=?0.55, 95 % CI: 0.36–0.84; CC+CG vs. GG: OR?=?0.72, 95 % CI 0.58–0.90; CC vs. CG+GG: OR?=?0.58, 95 % CI 0.38–0.89). However, the rs2233679 polymorphism of PIN1 gene did not appear to have an influence on caner susceptibility. In the subgroup analysis by cancer type, we observed that the PIN1 rs2233678 polymorphism was significantly associated with decreased breast cancer risk (C-allele vs. G-allele: OR?=?0.73, 95 % CI: 0.60–0.89; CC+CG vs. GG: OR?=?0.71, 95 % CI 0.57–0.89). Further subgroup analyses showed that the PIN1 rs2233678 polymorphism was associated with decreased cancer risk among Asian people (C-allele vs. G-allele: OR?=?0.63, 95 % CI: 0.51–0.79; CC vs. GG: OR?=?0.44, 95 % CI: 0.25–0.80; CC+CG vs. GG: OR?=?0.63, 95 % CI 0.50–0.79; CC vs. CG+GG: OR?=?0.47, 95 % CI 0.26–0.86). In conclusion, PIN1 rs2233678 polymorphism might be a potential biomarker for cancer risk among Asians, especially for breast cancer. Further large and well-designed studies are needed to confirm this conclusion.     

Associations between Fas/FasL polymorphisms and susceptibility to cervical cancer: a meta-analysis

Genetic polymorphisms in the Fas/Fas ligand (FasL) gene were proposed to be associated with susceptibility to cervical cancer, but previous studies reported controversial findings. We performed a meta-analysis to assess the associations between Fas/FasL polymorphisms and susceptibility to cervical cancer. We carried out a literature search in PubMed and Embase databases for studies on the associations between Fas/FasL polymorphisms and susceptibility to cervical cancer. The associations were assessed by odds ratio (OR) together with its 95 % confidence intervals (CIs). Eleven individual studies with a total of 6,919 subjects were finally included into the meta-analysis. Overall, there was no association between Fas 1377G?>?A polymorphism and susceptibility to cervical cancer (A vs. G: OR?=?0.99, 95 % CI 0.88–1.12, P?=?0.91; AA vs. GG: OR?=?1.00, 95 % CI 0.76–1.32, P?=?0.99; AA/GA vs. GG: OR?=?0.95, 95 % CI 0.81–1.12, P?=?0.54; AA vs. GG/GA: OR?=?1.11, 95 % CI 0.85–1.43, P?=?0.45). In addition, there was also no association between FasL 844 T?>?C polymorphism and susceptibility to cervical cancer (C vs. T: OR?=?1.12, 95 % CI 0.91–1.36, P?=?0.28; CC vs. TT: OR?=?1.17, 95 % CI 0.90–1.51, P?=?0.24; CC/TC vs. TT: OR?=?1.13, 95 % CI 0.92–1.39, P?=?0.24; CC vs. TT/TC: OR?=?1.11, 95 % CI 0.83–1.50, P?=?0.47). In subgroup analysis by ethnicity, there were also no associations between Fas/FasL polymorphisms and susceptibility to cervical cancer in Asians and Africans. In conclusion, Fas 1377G?>?A polymorphism and FasL 844 T?>?C polymorphism are both not associated with susceptibility to cervical cancer.     

The effect of RAD51 135 G>C and XRCC2 G>A (rs3218536) polymorphisms on ovarian cancer risk among Caucasians: a meta-analysis

Genetic polymorphisms of RAD51 135 G>C and XRCC2 G>A (rs3218536) have been reported to change the risk of ovarian cancer, but the results are controversial. To get a more precise result, a meta-analysis was performed. A comprehensive literature search in PubMed, Excerpta Medica Database, and China National Knowledge Infrastructure was carried out to get case–control studies published up to November 2013. The pooled odds ratio (OR) and its corresponding 95 % confidence interval (CI) were conducted to estimate the effect of RAD51 135 G>C and XRCC2 G>A (rs3218536) polymorphisms on ovarian cancer risk. A total of 13 independent case–control studies with 5,927 cases and 10,303 controls were included in this meta-analysis. There was no significant association between RAD51 135 G>C polymorphism and risk of ovarian cancer. However, the result of total studies indicated the XRCC2 G>A (rs3218536) polymorphism could reduce the risk of ovarian cancer (heterozygote model AG vs. GG: OR?=?0.877, 95 % CI?=?0.770–0.999, P?=?0.048; dominant model AA/AG vs. GG: OR?=?0.864, 95 % CI?=?0.763–0.979, P?=?0.022). The result was still significant after Hardy–Weinberg equilibrium-violating studies were excluded (allele contrast A vs. G: OR?=?0.836, 95 % CI?=?0.74–0.943, P?=?0.004; homozygote model AA vs. GG: OR?=?0.562, 95 % CI?=?0.317–0.994, P?=?0.048; heterozygote model AG vs. GG: OR?=?0.859, 95 % CI?=?0.753–0.98, P?=?0.023; dominant model AA/AG vs. GG: OR?=?0.842, 95 % CI?=?0.74–0.958, P?=?0.009). In the stratified analysis by ethnicity, significantly reduced risk was observed among Caucasians in dominant model (AA/AG vs. GG: OR?=?0.867, 95 % CI?=?0.764–0.984, P?=?0.027). No significant association was found between the RAD51 135G>C polymorphism and the risk of ovarian cancer. Interestingly, XRCC2 G>A (rs3218536) polymorphism might reduce the risk of ovarian cancer. Larger-scale and well-designed studies are needed to further clarify the association.     

The polymorphism of EGFR 142285G > A exerts no risk effect on breast cancer

The association between the epidermal growth factor receptor (EGFR) 142285G?>?A polymorphism and the susceptibility to breast cancer is unclear. We conducted a meta-analysis of all published studies to estimate the association of EGFR 142285G?>?A polymorphism and breast cancer risk. Systematic computerized searching of the PubMed, Web of Science, and Wanfang databases was performed for relevant publications. Overall, there were three eligible case–control studies with 1,360 cases and 1,522 controls included into our study. The pooled ORs showed that the EGFR 142285G?>?A variant genotypes did not increase or decrease the risk of breast cancer under the following gene models: A vs. G, OR?=?1.07, 95 % CI 0.96–1.19, P _OR?=?0.240; AA vs. GG, OR?=?1.14, 95 % CI 0.91–1.42, P _OR?=?0.239; GA vs. GG, OR?=?0.99, 95 % CI 0.83–1.17, P _OR?=?0.892; GA?+?AA vs. GG, OR?=?1.03, 95 % CI 0.87–1.21, P _OR?=?0.727; AA vs. GG?+?GA, OR?=?1.17, 95 % CI 0.97–1.42, P _OR?=?0.096. The between-study heterogeneity was not significant among all studies. The current meta-analysis showed no evidence for significant association between EGFR 142285G?>?A polymorphism and breast cancer risk. Subsequent studies with large sample size are needed for further elucidation.     

CCL5-403, CCR5-59029, and Delta32 polymorphisms and cancer risk: a meta-analysis based on 20,625 subjects

Associations between CCL5-403, CCR5-59029, and Delta32 polymorphisms and cancer risk are inconclusive. To derive a more precise estimation of the association, we performed a meta-analysis by searching PubMed, EMBASE, Google scholar, and WanFang databases. A total of 20 eligible articles with 39 studies were included. Of those studies, there were 21 studies for CCR5-Delta32 polymorphism, 9 studies for CCR5-59029 polymorphism, and 9 studies for CCL5-403 polymorphism. Combined analysis revealed no associations between these polymorphisms and cancer risk. However, subgroup analysis by ethnicity suggested that CCR5-59029 polymorphism was associated with the risk of cancer among Asian populations (A vs. G: odds ratio (OR)?=?1.36, 95 % confidence interval (CI) 1.13–1.65, P _H?=?0.27; AA vs. GG: OR?=?2.07, 95 % CI 1.37–3.12, P _H?=?0.17; GA+AA vs. GG: OR?=?1.35, 95 % CI 1.03–1.77, P _H?=?0.92; AA vs. GA+GG: OR?=?1.98, 95 % CI 1.01–3.88, P _H?=?0.08), but not among Caucasian populations. CCL5-403 polymorphism was associated with the risk of cancer among African populations (A vs. G: OR?=?0.68, 95 % CI 0.55–0.83, P _H?=?0.14; AA vs. GG: OR?=?0.51, 95 % CI 0.33–0.77, P _H?=?0.52; AG vs. GG: OR?=?0.58, 95 % CI 0.42–0.80, P _H?=?0.14; AG+AA vs. GG: OR?=?0.56, 95 % CI 0.41–0.75, P _H?=?0.13), but not among Caucasian populations and Asian populations. Overall, this meta-analysis indicated that CCR5-Delta32 was not associated with the risk of cancer. CCR5-59029 polymorphism contributed to cancer risk among Asian populations, and CCL5-403 polymorphism was associated with the decreased risk of cancer among African populations.     

Association between Cyclin D1 polymorphism and oral cancer susceptibility: a meta-analysis

Data from several case–control studies on the relation between the Cyclin D1 (CCND1) G870A polymorphism and oral cancer susceptibility implicated conflicting conclusions. Thus, a meta-analysis was performed to derive a more precise evaluation of the association. We searched PubMed and Embase for related studies that had been published in English and eight available studies were finally included in the meta-analysis. Odd ratios (ORs) and 95 % confidence intervals (CIs) were calculated for each study. Our meta-analysis suggested that CCND1 G870A polymorphism was not associated with oral cancer risk (OR _{AA vs. GG}?=?1.08, 95 % CI?=?0.90–1.30, P _{heterogeneity}?=?0.175; OR _{AA + GA vs. GG}?=?1.02, 95 % CI?=?0.91–1.14, P _{heterogeneity}?=?0.781; OR _{AA vs. GA + GG}?=?1.16, 95 % CI?=?0.98–1.36, P _{heterogeneity}?=?0.107; OR _{A vs. G}?=?1.05 95 % CI?=?0.96–1.15, P _{heterogeneity}?=?0.211; OR _{GA vs. GG}?=?0.94, 95 % CI?=?0.82–1.08, P _{heterogeneity}?=?0.935). However, in the subgroup analysis by ethnicity, possible significance among Asian groups was indicated in two genetic models (OR _{AA vs. GA + GG}?=?1.27, 95 % CI?=?1.05–1.54, P _{heterogeneity}?=?0.572; OR _{allele A vs. allele G}?=?1.11, 95 % CI?=?1.00–1.24, P _{heterogeneity}?=?0.211). Taken together, the meta-analysis revealed that CCND1 G870A polymorphism might be correlated with the susceptibility of oral cancer in Asians.     

TERT rs2736100 polymorphism contributes to lung cancer risk: a meta-analysis including 49,869 cases and 73,464 controls

Some studies investigated the association of TERT rs2736100 polymorphism with lung cancer (LC). But the results were not consistent. We performed a meta-analysis to examine the association between rs2736100 and LC. Databases including PubMed, EMBASE, Wanfang, and China National Knowledge Infrastructure (CNKI) were searched. Data were extracted, and pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were calculated. A total of 19 studies including 49,869 cases and 73,464 controls were involved in this meta-analysis. Overall, a significant association between TERT rs2736100 polymorphism and LC risk was observed (OR?=?1.23, 95 % CI 1.18–1.28, P?<?0.00001). This polymorphism was also significantly associated with LC risk in Asians (OR?=?1.27, 95 % CI 1.22–1.33, P?<?0.00001), Caucasians (OR?=?1.14, 95 % CI 1.10–1.18, P?<?0.00001), female patients (OR?=?1.37, 95 % CI 1.24–1.51, P?<?0.00001), male patients (OR?=?1.23, 95 % CI 1.15–1.31, P?<?0.00001), adenocarcinoma patients (OR?=?1.35, 95 % CI 1.28–1.41, P?<?0.00001), squamous cell carcinoma patients (OR?=?1.13, 95 % CI 1.04–1.21, P?=?0.002), small cell lung cancer patients (OR?=?1.09, 95 % CI 1.03–1.16, P?=?0.004), current smokers (OR?=?1.22, 95 % CI 1.17–1.27, P?<?0.00001), former smokers (OR?=?1.14, 95 % CI 1.08–1.21, P?<?0.0001), and never smokers (OR?=?1.37, 95 % CI 1.31–1.43, P?<?0.00001), respectively. This meta-analysis suggested that TERT rs2736100 polymorphism was a risk factor for LC.     

Lack of association of XRCC1 rs1799782 genetic polymorphism with risk of pancreatic cancer: a meta-analysis

Emerging evidence suggests that genetic polymorphisms in X-ray repair cross-complementation group 1 (XRCC1) gene could be associated with pancreatic cancer risk. However, previous published studies on the association between XRCC1 rs1799782 genetic polymorphism and pancreatic cancer risk reported inconsistent results. For better understanding of the effects of XRCC1 rs1799782 genetic polymorphism on pancreatic cancer risk, we conducted a meta-analysis of previous published studies by calculating the pooled odds ratio (OR) with a 95 % confidence interval (95 % CI). A total of five eligible studies with 1,144 pancreatic cancer cases and 2,925 controls were eventually enrolled. Overall, we found that the XRCC1 rs1799782 genetic polymorphism was not associated with pancreatic cancer risk in total population under all genetic models (TT vs. CC: OR?=?1.11, 95 % CI 0.76–1.63, P?=?0.583; CT vs. CC: OR?=?1.39, 95 % CI 0.92–2.10, P?=?0.118; TT/CT vs. CC: OR?=?1.39, 95 % CI 0.92–2.10, P?=?0.121; TT vs. CT/CC: OR?=?1.07, 95 % CI 0.73–1.55, P?=?0.743; T vs. C: OR?=?1.31, 95 % CI 0.93–1.86, P?=?0.125). In the subgroup analysis based on ethnicity, there was no statistically significant association between XRCC1 rs1799782 genetic polymorphism and pancreatic cancer risk in Asians/Caucasians under all genetic models (all P values?>?0.05). No publication bias was detected in this study. Our meta-analysis suggests that the XRCC1 rs1799782 genetic polymorphism is not significantly associated with pancreatic cancer risk. Considering the limited sample size and ethnicity enrolled in this meta-analysis, further larger scaled studies are needed to provide a more precise estimation on the association.     

Cyclin D1 (CCND1) G870A polymorphisms and cervical cancer susceptibility: a Meta-analysis based on Ten case–control studies

Many studies have evaluated the association between cyclin D1 (CCND1) G870A polymorphism and cervical cancer susceptibility. However, these studies showed inconsistent results. The aim of this study was to derive a more precise estimation of this association. We searched PubMed and Embase for related studies that had been published in English, and ten case–control studies with a total of 2,864 cases and 3,898 controls were finally identified to be eligible studies in the meta-analysis. The association was assessed by summarizing the odds ratios (ORs) with the corresponding 95 % confidence intervals (CIs). Overall, there was no significant association between cyclin D1 (CCND1) G870A polymorphism and cervical cancer risk (for the allele model A vs. G: OR?=?1.02, 95 % CI 0.88–1.19, p?=?0.76; for the co-dominant model AA vs. GG: OR?=?1.03, 95 % CI 0.75–1.41, p?=?0.85; for the dominant model AA?+?GA vs. GG: OR?=?1.00, 95 % CI 0.78–1.28, p?=?0.99; for the recessive comparison AA vs. GA?+?GG: OR?=?1.06, 95 % CI 0.85–1.32, p?=?0.62). In subgroup analysis by ethnicity, no significant difference was found in both Asians and Caucasians. In summary, the present meta-analysis provides evidence that genotypes for the cyclin D1 (CCND1) G870A polymorphism may be not associated with genetic susceptibility of cervical cancer.     

A pooled analysis of the ERCC2 Asp312Asn polymorphism and esophageal cancer susceptibility

Published data regarding the association between the excision repair cross-complimentary group 2 (ERCC2) Asp312Asn polymorphisms and esophageal cancer susceptibility remained controversial. This meta-analysis of literatures was performed to assess the strength of association between the ERCC2 and esophageal cancer susceptibility using random effects model. We systematically searched PubMed, Embase and Web of Science with a time limit of September 15, 2013. Summary odds ratios (ORs) with 95 % confidence intervals (CIs) were used to assess the strength of association between the ERCC2 Asp312Asn polymorphism and esophageal cancer susceptibility using random effects model. A total of seven case–control studies including 1,831 cases and 2,728 controls were included for analysis. Overall, a significant association was found between ERCC2 Asp312Asn polymorphism and esophageal cancer susceptibility for GA vs. GG (OR?=?1.20, 95 % CI?=?1.03–1.40) and for the dominant model GA/AA vs. GG (OR?=?1.18, 95 % CI?=?1.03–1.35). However, the ERCC2 Asp312Asn polymorphism was a protective factor for AA vs. GA/GG (OR?=?0.63, 95 % CI?=?1.15–2.65) in esophageal squamous cell carcinoma. Our meta-analysis suggested that the ERCC2 Asp312Asn polymorphism might be associated with increased risk of esophageal adenocarcinoma and a protective factor for esophageal squamous cell carcinoma.     

Association between NAD(P)H:quinone oxidoreductase 1 rs1800566 polymorphism and risk of bladder cancer

NAD(P)H:quinone oxidoreductase 1 (NQO1) rs1800566 (Pro187Ser) is a functional polymorphism which leads to a proline-to-serine amino acid substitution at codon 187 in the NQO1 protein and enzyme activity changes. NQO1 rs1800566 polymorphism was implicated to be associated with a risk of bladder cancer, but published studies showed inconclusive results. We performed a meta-analysis of nine publications with a total of 2,661 cases and 2,738 controls on the association between NQO1 rs1800566 polymorphism and risk of bladder cancer. Data were extracted from those included studies, and the pooled odds ratio (OR) with the corresponding 95 % confidence interval (95 % CI) was calculated to assess the association. We found that there was no association between NQO1 rs1800566 polymorphism and risk of bladder cancer under all four genetic models (Ser vs. Pro, OR?=?1.06, 95 % CI?=?0.97–1.16, P?=?0.21, I ²?=?31 %; SerSer vs. ProPro, OR?=?1.12, 95 % CI?=?0.89–1.42, P?=?0.33, I ²?=?44 %; SerSer/ProSer vs. ProPro, OR?=?1.08, 95 % CI?=?0.96–1.21, P?=?0.20, I ²?=?27 %; SerSer vs. ProPro/ProSer, OR?=?1.06, 95 % CI?=?0.85–1.32, P?=?0.59, I ²?=?36 %). Meta-analysis of those eight studies from Europeans also showed that there was no association between NQO1 rs1800566 polymorphism and risk of bladder cancer under all four genetic models (Ser vs. Pro, OR?=?1.02, 95 % CI?=?0.93–1.13, P?=?0.66, I ²?=?20 %; SerSer vs. ProPro, OR?=?0.99, 95 % CI?=?0.75–1.30, P?=?0.93, I ²?=?38 %; SerSer/ProSer vs. ProPro, OR?=?1.04, 95 % CI?=?0.92–1.17, P?=?0.55, I ²?=?6 %; SerSer vs. ProPro/ProSer, OR?=?0.98, 95 % CI?=?0.75–1.28, P?=?0.87, I ²?=?39 %). This meta-analysis suggests that the NQO1 rs1800566 polymorphism is not associated with a risk of bladder cancer. Further studies with larger samples are needed, especially for studies in Asians and Africans.     

Methylenetetrahydrofolate reductase polymorphisms and breast cancer risk in Chinese population: a meta-analysis of 22 case–control studies

The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and breast cancer risk in the Chinese population has been widely reported, but results were inconsistent. In order to derive a more precise estimation of the relationship, a meta-analysis was performed. Eligible articles were identified through search of databases including Medline, PubMed, Web of Science, Embase, Chinese Biomedical Literature Database (CBM, Chinese), China National Knowledge Infrastructure (CNKI, Chinese), and Wangfang Database (Chinese). The association between the MTHFR polymorphism and breast cancer risk was conducted using odds ratios (ORs) and 95 % confidence intervals (95 % CIs). Finally, a total of 22 studies with 6,103 cases and 7,913 controls were included in our meta-analysis: 13 studies with 3,273 cases and 4,419 controls for C677T polymorphism and 9 studies with 2,830 cases and 3,494 controls for A1298C polymorphism. With regard to C677T polymorphism, significant association was found with breast cancer risk under three models (T vs. C: OR?=?1.12, 95 % CI?=?1.02–1.23, P?=?0.015; TT vs. CC: OR?=?1.35, 95 % CI?=?1.10–1.67, P?=?0.005; TT vs. CC/CT: OR?=?1.37, 95 % CI?=?1.11–1.70, P?=?0.004). There was no significant association found between A1298C polymorphism and breast cancer risk under all genetic models (C vs. A: OR?=?0.96, 95 % CI?=?0.89–1.03, P?=?0.268; CC vs. AA: OR?=?0.98, 95 % CI?=?0.77–1.26, P?=?0.899; AC vs. AA: OR?=?0.95, 95 % CI?=?0.88–1.02, P?=?0.174; CC vs. AC/AA: OR?=?1.00, 95 % CI?=?0.78–1.28, P?=?0.996, CC/AC vs. AA: OR?=?0.96, 95 % CI?=?0.89–1.02, P?=?0.196). In summary, during this meta-analysis, we found that MTHFR C677T polymorphism was significantly associated with breast cancer risk in the Chinese population. Meanwhile, MTHFR A1298C polymorphism was not associated with breast cancer risk in the Chinese population.