Emerging evidence indicates that common functional polymorphisms in the estrogen receptor 1 (ESR1) gene may have an impact on an individual's susceptibility to endometrial cancer, but individually published results are inconclusive. The aim of this meta-analysis is to derive a more precise estimation of the associations between eight polymorphisms in the ESR1 gene and endometrial cancer risk.

Methionine synthase (MTR), which plays a central role in maintaining adequate intracellular folate, methionine and normal homocysteine concentrations, was thought to be involved in the development of colorectal cancer (CRC) and colorectal adenoma (CRA) by affecting DNA methylation. However, studies on the association between MTR A2756G polymorphism and CRC/CRA remain conflicting. We conducted a meta-analysis of 27 studies, including 13465 cases and 20430 controls for CRC, and 4844 cases and 11743 controls for CRA. Potential sources of heterogeneity and publication bias were also systematically explored. Overall, the summary odds ratio of G variant for CRC was 1.03 (95% CI: 0.96-1.09) and 1.05 (95% CI: 0.99-1.12) for CRA. No significant results were observed in heterozygous and homozygous when compared with wild genotype for these polymorphisms. In the stratified analyses according to ethnicity, source of controls, sample size, sex, and tumor site, no evidence of any gene-disease association was obtained. Results from the meta-analysis of four studies on MTR stratified according to smoking and alcohol drinking status showed an increased CRC risk in heavy smokers (OR = 2.06, 95% CI: 1.32-3.20) and heavy drinkers (OR = 2.00, 95% CI: 1.28-3.09) for G allele carriers. This meta-analysis suggests that the MTR A2756G polymorphism is not associated with CRC/CRA susceptibility and that gene-environment interaction may exist.

Several studies have investigated the association between the Toll-like receptor 4 (TLR4) gene +896A/G polymorphism and gastric carcinogenesis, including gastric cancer and precancerous gastric lesions. However, published results are inconsistent. So, we performed a meta-analysis to assess whether the TLR4 +896A/G single-nucleotide polymorphism (SNP) is a risk factor in gastric cancer development. We searched PubMed and Embase databases for studies that reported the odds ratio (OR) and 95 % confidence interval (CI) for the association between the TLR4 +896A/G SNP and the risk of gastric cancer and/or precancerous lesions with the last update of November 2012. Data were analyzed using Review Manager (Version 5.1), and publication bias was estimated. We included 10 study populations, comprising 2,233 cases and 2,849 controls from 8 publications. The pooled OR was 2.00 (95 % CI = 1.59-2.53) for the G allelic model. Analysis stratified by different stages and anatomic sites of neoplasia resulted in a significantly increased risk associated with gastric cancer (OR = 1.87, 95 % CI = 1.44-2.44), especially the non-cardia subtype (OR = 2.03, 95 % CI = 1.51-2.72). Besides, the G allele emerged as a strong risk factor for precancerous gastric lesions (OR = 2.47, 95 % CI = 1.57-3.88). A subsequent subgroup analysis by Helicobacter pylori-positive ratio in cases (>80 %) indicated an enhancement in the association with precancerous lesions (OR = 3.43, 95 % CI = 1.92-6.13). The TLR4 +896A/G SNP is a risk factor in gastric carcinogenesis, especially in H. pylori-infected patients with precancerous lesions.

Despite the long-standing and extensive use of mitoxantrone (MTZ) for the treatment of aggressive forms of multiple sclerosis (MS), especially in Europe, its benefit-risk profile remains controversial. In particular, the risk of developing therapy-related acute leukemia (TRAL) and cardiotoxicity have led to treatment restrictions for MTZ; however, the precise risk for these severe complications is still unclear. Here we review current data on TRAL incidence, research strategies aimed at individual risk stratification, and provide recommendations for hematologic monitoring. A recent meta-analysis indicates a TRAL risk of approximately 0.81%, more than 10-fold higher than in previously reported meta-analyses (0.07%). There also appear to be considerable differences among countries, with recent TRAL risk estimates from Italy as high as 0.93%, compared to the 0.25%-0.41% risk reported from Germany and France. Whereas methodologic differences may partly account for some of these differences, high regional variability may point to exogenous factors such as heterogeneous treatment protocols and cotreatments. In addition, genetic risk factors (MTZ metabolism, DNA repair) might contribute to the individual risk profile. The case of potentially curable MTZ-induced secondary leukemia highlights the need for close hematologic monitoring during and after therapy. Intensive collaboration between neurologists and hematologists will likely provide benefits both for research efforts aimed at unraveling TRAL pathogenesis and for clinical practice with improved identification and monitoring of patients at higher risk of MTZ-induced TRAL. This is of particular importance, since treatment alternatives, especially in secondary progressive MS, are sparse.

A variety of studies have evaluated the associations between polymorphisms in the promoter regions of the hMLH1 and cancer risk. However, the results remain inconclusive. To better understand the roles of the hMLH1 polymorphisms and cancer risk, we conducted a comprehensive meta-analysis to investigate the association between the hMLH1 -93G/A and 1151T/A (Val384Asp) polymorphisms and cancer risk in Asian population.

The vascular endothelial growth factor (VEGF) plays a major role in angiogenesis. The association between VEGF 936 C>T (rs3025039) gene polymorphisms and oral cancer (OC) risk is still contentious and ambiguous. To assess the relationship between the VEGF 936 C>T genotype and the risk of developing OC, we performed a meta-analysis to summarize the possible association.

Glutathione S-transferases (GSTs) have proved to be involved in the detoxifying several carcinogens and may play an important role in carcinogenesis of cancer. Previous studies on the association between Glutathione S-transferase T1 (GSTT1) polymorphism and gastric cancer risk reported inconclusive results. To clarify the possible association, we conducted a meta-analysis of eligible studies.

To assess the association between the variant of Cytochrome P450 2A6 whole gene deletion (CYP2A6*4) polymorphism and risk of lung cancer.

Interstitial lung disease associated with gefitinib is a critical adverse reaction. When geftinib was administered to EGFR-unknown patients, the interstitial lung disease incidence rate was approximately 3-4% in Japan, and usually occurs during the first 4 weeks of treatment. However, it has not been fully investigated in EGFR-mutated patients.

CYP3A5 is a cytochrome P450 superfamily member which is involved in the metabolism of drugs, steroid hormones, and other xenobiotics. Emerging evidences suggest that CYP3A5*3 (rs776746 A>G) polymorphism may play a role in the etiology of carcinogenesis and affect an individual's susceptibility to cancer in humans, but individually published studies showed inconclusive results. This meta-analysis aimed to derive a more accurate estimation of the correlation between CYP3A5*3 polymorphism and cancer risk. A literature search of PubMed, Embase, Web of Science, and China BioMedicine databases was conducted on articles published before January 1, 2013. Seventeen case-control studies were included with a total of 7,458 cancer patients and 7,166 healthy controls. The meta-analysis results showed that CYP3A5*3 polymorphism may increase the risk of cancer, especially in acute leukemia, chronic leukemia, and colorectal cancer. However, no statistically significant associations were found in prostate cancer, liver cancer, and other cancers. Further subgroup analysis by ethnicity indicated that CYP3A5*3 polymorphism was associated with an increased risk of cancer among Asian and Caucasian populations, but not among African populations. In conclusion, the current meta-analysis suggests that CYP3A5*3 polymorphism may play an important role in the development of acute and chronic leukemia and colorectal cancer, especially among Asian and Caucasian populations.

This study aimed to investigate the association between PASD8 gene and cancers. For 1772 C/T polymorphism (rs11549465), it included 5552 cases and 8044 controls, and for 1790 G/A (rs11549467), 3381 cases and 5830 controls. The allele-analysis results showed that 1772 C/T (rs11549465) was significantly associated with cancers (OR: 1.177, 95% CI: 1.011-1.369, p=0.035). And results of genotype-analysis indicated that 1790 G/A (rs11549467) had a significant relationship with cancers. (OR: 0.736, 95% CI: 0.595-0.910, p=0.005). For 1790 G/A (rs11549467), the association was significant when subdivided by different kinds of cancers. And no association existed when subdivided into population-type subgroups. In conclusion, PASD8 gene played an important role in the development of cancers.

To date, epidemiological studies have assessed the association between Toll-like receptor 2 (TLR2) gene polymorphisms and cancer risk. However, the results of these studies remain controversial. We aimed to examine the associations between three SNPs (Delta22, rs3804099 and rs3804100) of TLR2 gene and cancer risk by conducting a meta-analysis of case-control studies. A total of eight studies eligible for TLR2 Delta22 polymorphism (2,061 cancer cases and 3,490 controls), six studies for rs3804099 polymorphism (1,681 cases and 1,996 controls), and five studies for rs3804100 polymorphism (3,131 cases and 2,969 controls) were included in this meta-analysis. Our results suggested that Delta22 represented a risk factor on cancers (del-allele versus ins-allele, OR=1.35, 95% CI: 1.05-1.72; del/del versus ins/ins, OR=1.91, 95% CI: 1.03-3.56; del/del + del/ins versus ins/ins, OR=1.33, 95% CI: 1.02-1.73; del/del versus del/ins + ins/ins, OR=1.79, 95% CI: 1.02-3.13), especially in Caucasian population and among population-based studies. For TLR2 rs3804099 polymorphism, we found a decreased cancer risk associated with CC/CT genotype only in Asians compared with TT genotype. TLR2 rs3804100 polymorphism was significantly associated with an elevated cancer risk in overall analysis (CC versus CT, OR=1.70, 95% CI: 1.20-2.42; CC versus CT/TT, OR=1.61, 95% CI: 1.15-2.25). In a stratified analysis, a statistically significant correlation was also observed in non-Caucasian population and population-based studies. In conclusion, the Delta22 and rs3804100 polymorphisms in TLR2 are risk factors for cancer susceptibility while the TLR2 rs3804099 dominant genotype is a protective factor, especially in Asians. Further large and well-designed studies are needed to confirm these conclusions.

Epidemiological studies have investigated that functional polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene may play an essential role in bladder carcinogenesis, but the association between these single-nucleotide polymorphisms in the MTHFR gene and the susceptibility of bladder cancer (BC) was inconsistent in previous studies. The objective of this current study was to conduct an update analysis investigating the association between three polymorphisms in the MTHFR gene and the risk of BC. We performed a meta-analysis of 13 publications involving an association between BC and MTHFR gene three polymorphisms (C677T, A1298C, and G1793A). We assessed the strength of the association, using odds ratios (ORs) with 95% confidence intervals (CIs). On one hand, we found that the C677T polymorphism was associated with increased BC risk among Asians, however, with decreased BC risk among a mixed population. Interestingly, BC patients who carried the T-allele (TT+TC) had a higher percentage than the individuals who carried the CC genotype (OR=1.38, 95% CI=1.13-1.69, p=0.002). On the other hand, the A1298C polymorphism may increase BC risk among Asians and Africans, but played a decreased association among Europeans. Results from the current update analysis suggested that the C677T and A1298C polymorphisms in the MTHFR gene were associated with BC risk and disease progression.

CYP2C9 enzyme activity is involved in the metabolism of substances related to colorectal cancer (CRC), and it is functionally linked to a genetic polymorphism. Two allelic variants of the CYP2C9 gene, namely CYP2C9*2 and CYP2C9*3, differ from wild-type CYP2C9*1 by single amino acid substitutions. These mutated alleles encode enzymes with altered properties that are associated with impaired metabolism. In the past decade, a number of case-control studies have been carried out to investigate the relationship between the CYP2C9 polymorphism and CRC susceptibility, but the results were conflicting. To investigate this inconsistency, we performed a meta-analysis of 13 studies involving a total of 20,879 subjects for CYP2C9*2 and *3 polymorphisms to evaluate the effect of CYP2C9 on genetic susceptibility for CRC. Overall, the summary odds ratio of CRC was 0.94 (95%CI: 0.87-1.03, P = 0.18) and 1.00 (95%CI: 0.86-1.16, P = 0.99) for CYP2C9 *2 and *3 carriers, respectively. No significant results were observed in heterozygous and homozygous when compared with wild genotype for these polymorphisms. In the stratified analyses according to ethnicity, sample size, diagnostic criterion, HWE status and sex, no evidence of any gene-disease association was obtained. Our result suggest that the *2, *3 polymorphisms of CYP2C9 gene are not associated with CRC susceptibility.

The hOGG1 gene encodes a DNA glycosylase enzyme responsible for DNA repair. The Ser326Cys polymorphism in this gene may influence its repair ability and thus plays a role in carcinogenesis. Several case-control studies have been conducted on this polymorphism and its relationship with the risk of hepatocellular carcinoma (HCC) among East Asians. However, their results are inconsistent.

Aberrant methylation of CpG islands acquired in tumor cells in promoter regions plays an important role in carcinogenesis. Accumulated evidence demonstrates P(16INK4a) gene promoter hypermethylation is involved in non-small cell lung carcinoma (NSCLC), indicating it may be a potential biomarker for this disease. The aim of this study is to evaluate the frequency of P(16INK4a) gene promoter methylation between cancer tissue and autologous controls by summarizing published studies.

Adenomatous polyposis coli gene (APC) polymorphisms may influence the risk for colorectal neoplasia. However, results thus far have been inconclusive. We performed a systematic literature search of the Medline, Embase, Cochrane Collaboration, and HuGE databases and reviewed the references of pertinent articles through May 2012. Odds ratios with 95% confidence intervals were used to estimate the association between 3 APC polymorphisms (D1822V, E1317Q, and I1307K) and colorectal neoplasia. In total, 40 studies from 1997 to 2010 were included in this meta-analysis, and individuals with the D1822V variant homozygote VV genotype had a slight decrease in the risk for colorectal neoplasia compared with the wild-type homozygote DD genotype (pooled odds ratio = 0.87, 95% confidence interval: 0.77, 0.99). There was a small association between the APC E1317Q polymorphism and a risk for colorectal neoplasia (variant vs. wild-type: pooled odds ratio = 1.41, 95% confidence interval: 1.14, 1.76), particularly for colorectal adenomas (variant vs. wild-type: odds ratio = 2.89, 95% confidence interval: 1.83, 4.56). Compared with those who carried the wild-type I1307K, Ashkenazi Jews who carried the I1307K variant were at a significantly increased risk for colorectal neoplasia, with a pooled odds ratio of 2.17 (95% confidence interval: 1.64, 2.86). Our study suggests that APC is a candidate gene for colorectal neoplasia susceptibility.

Interleukin-4 (IL-4) plays an important role in the pathogenesis of cancer. The -590C/T polymorphism in the IL-4 gene has been implicated in susceptibility to cancer, but the results have been inconclusive. The aim of this study was to analyze the association between this polymorphism with the risk of cancer by meta-analysis. PubMed, Embase, CNKI, and Wanfang databases were searched for all publications concerning the association between this polymorphism and cancer risk. Statistical analyses were analyzed by using RevMan 4.2 and STATA10.0 softwares. A total of 8,715 cases and 9,532 controls in 23 case-control studies were included. The results suggested that there was no significant association between IL-4 -590C/T polymorphism and cancer risks (TT + TC vs. CC: OR = 0.97, 95 % CI = 0.90-1.04, P = 0.36). In the subgroup analysis by ethnicity, no significant association was detected in Asians and Caucasians. In the subgroup analysis by cancer types, no significant association was found in gastric cancer and colorectal cancer. The current meta-analysis suggested that the -590C/T polymorphism in the IL-4 gene might not be associated with increased/decreased risk of cancer. The -590C/T polymorphism might be not a risk factor for cancers.

The aim of the present work was to perform a meta-analysis to evaluate the association between the interleukin 10 (IL-10) -819C/T (rs1800871) polymorphism and cancer risk. A total of 73 studies, including 15,942 cancer cases and 22,336 controls, were identified in this meta-analysis. The odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the random-effects model. Overall, no significant association was identified between the IL-10 -819C/T polymorphism and cancer risk. In the subgroup analyses, the T allele and TT genotype were associated with a moderately reduced cancer risk in the Asian population (T allele vs. C allele: OR=0.93, 95%CI: 0.87, 0.99; TT vs. CC: OR=0.86, 95%CI: 0.76, 0.98; TT vs. CT/CC: OR=0.90, 95%CI: 0.82, 0.98). Individuals who were homozygous for the T allele (TT) were found to be associated with significantly reduced gastric cancer risk in the Asian population. The heterozygous variant (CT) and the dominant model (TT/CT vs. CC) were associated with an increased risk for cervical and ovarian cancer. However, the IL-10 -819C/T polymorphism was not significantly associated with breast cancer, colorectal cancer, lung cancer, hepatocellular carcinoma, prostate cancer, lymphoma, or melanoma. The depressed cancer risk of the TT genotype occurred in the studies of hospital-based case-control studies and the studies recruited less than 500 subjects, but no statistically significant results were found in the stratified analyses using genotyping method. The results suggest that the IL-10 -819TT genotype may be a protective factor for cancer in Asians, especially gastric cancer. In contrast, the CT genotype and the dominant model could be risk factors for cervical and ovarian cancer. The importance of stratifying by ethnicity, cancer type, study design, and sample size needs to be standardized in future studies, together with considering the association between the IL-10 -819C/T polymorphism and cancer risk. Furthermore, the linkage of -819C/T with other polymorphisms of the IL-10 gene may help explain the variability in findings.

Phosphatase and tensin homolog (PTEN) loss or activating mutations of phosphoinositol-3 (PI3) kinase (PIK3CA) may be related to trastuzumab resistance in in vitro studies; however, this issue in clinical studies is controversial. Therefore, we conducted a meta-analysis to assess the association between PTEN loss, PIK3CA mutation and the efficacy of trastuzumab-based treatment in HER2-positive breast cancer patients.