Previous studies of the association between X-ray cross-complementing group 1 (XRCC1) gene polymorphisms and the gliomas risk have yielded conflicting results, and thus a meta-analysis was performed to provide a more accurate estimation.

The diagnosis of malignant mesothelioma (MM) remains a clinical challenge and the fluorescence in situ hybridization (FISH) assay has been reported to be one promising tool. The present meta-analysis aimed to establish the overall diagnostic accuracy of FISH for diagnosing MM. After a systematic review of English language studies, the sensitivity, specificity and other measures of accuracy of FISH in the diagnosis of MM were pooled using random-effects models. Summary receiver operating characteristic curves were applied to summarize overall test performance. Nine studies met our inclusion criteria, the pooled sensitivity and specificity for FISH for diagnosing MM being 0.72 (95% CI 0.67-0.76) and 1.00 (95% CI 0.98-1.00), respectively. The positive likelihood ratio was 34.5 (95% CI 14.5-82.10), the negative likelihood ratio was 0.24 (95% CI 0.16-0.36), and the diagnostic odds ratio was 204.9 (95% CI 76.8-546.6), the area under the curve being 0.99. Our data suggest that the FISH assay is likely to be a useful diagnostic tool for confirming MM. However, considering the limited studies and patients included, further large scale studies are needed to confirm these findings.

To investigate the association of transforming growth factor-beta 1 (TGF-β1) C-509T polymorphism and susceptibility to cancer by means of meta-analysis.

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been reported to be associated with pancreatic cancer, but the published studies have yielded inconsistent results. This study assessed the relationship between MTHFR gene polymorphisms and the risk for pancreatic cancer using a meta-analysis approach.

The conclusions of published reports on the relationship between the glutathione S-transferase M3 (GSTM3) A/B gene polymorphism and the risk of lung cancer are still debated. This meta-analysis was performed to evaluate the association between GSTM3 and the risk of lung cancer.

Polymorphisms of the Taq I gene have been associated with prostate cancer risk.

The results from studies on associations of the glutathione S-transferase T1 (GSTT1) gene polymorphism and hepatocellular carcinoma (HCC) risk in Chinese populations are still conflicting. This meta- analysis was performed to evaluate the relationship in detail.

Glutathione-S-Transferase T1 (GSTT1) gene has been shown to be involved in the development of esophageal cancer. However, the results have been inconsistent. In this study, the authors performed a meta- analysis to clarify the association between GSTT1 polymorphism and esophageal cancer risk among Chinese Han population.

The mouse double minute 2 (MDM2) gene plays a key role in the p53 pathway, and the SNP 309T/G single- nucleotide polymorphism in the promoter region of MDM2 has been shown to be associated with increased risk of cancer. However, no consistent results were found concerning the relationships between the polymorphism and prostate cancer risk. This meta-analysis, covering 4 independent case-control studies, was conducted to better understand the association between MDM2-SNP T309G and prostate cancer risk focusing on overall and subgroup aspects. The analysis revealed, no matter what kind of genetic model was used, no significant association between MDM2-SNP T309G and prostate cancer risk in overall analysis (GT/TT: OR = 0.84, 95%CI = 0.60-1.19; GG/TT: OR = 0.69, 95%CI = 0.43-1.11; dominant model: OR = 0.81, 95%CI= 0.58-1.13; recessive model: OR = 1.23, 95%CI = 0.95-1.59). In subgroup analysis, the polymorphism seemed more likely to be a protective factor in Europeans (GG/TT: OR = 0.52, 95%CI = 0.31-0.87; recessive model: OR = 0.58, 95%CI = 0.36-0.95) than in Asian populations, and a protective effect of the polymorphism was also seen in hospital-based studies in all models (GT/TT: OR = 0.74, 95%CI = 0.57-0.97; GG/TT: OR = 0.55, 95%CI = 0.38-0.79; dominant model: OR = 0.69, 95%CI = 0.54-0.89; recessive model: OR = 0.70, 95%CI = 0.51-0.97). However, more primary studies with a larger number of samples are required to confirm our findings.

Previous studies on the association between the TP53 Arg72Pro polymorphism and hepatocellular carcinoma (HCC) risk obtained controversial findings. This study aimed to quantify the strength of the association by meta-analysis.

Published data on the association between miR-196a2 rs11614913 polymorphism and risk of gastrointestinal (GI) cancers are inconsistent among studies. To clarify the association, we performed a comprehensive literature search and a meta-analysis. We searched multiple databases to identify genetic association studies investigating the effect of miR-196a2 rs11614913 polymorphism on GI cancers with the last report up to January 18, 2012. The odds ratio (OR) and its 95 % confidence interval (95 % CI) were calculated to assess the strength of association. A total of 13 studies including 4,947 cases and 5,642 controls based on the search criteria were involved in this meta-analysis. In the overall analysis, it was suggested that variant C allele of miR-196a2 rs11614913 polymorphism could significantly increase risk of GI cancers in different genetic models (C vs T: OR = 1.17, 95 % CI = 1.07-1.28, P = 0.0008; CT + CC vs TT: OR = 1.26, 95 % CI = 1.08-1.48, P = 0.004; CC vs CT + TT: OR = 1.23, 95 % CI = 1.08-1.39, P = 0.002; CC vs TT: OR = 1.55, 95 % CI = 1.24-1.94, P = 0.0001; CT vs TT: OR = 1.20, 95 % CI = 1.02-1.40, P = 0.03). When stratified by ethnicity, we found a significant association in Asian population, as well as Caucasian population. When stratified by cancer types, we found a significant association in colorectal cancer, as well as esophageal cancer. We did not find a significant association between miR-196a2 rs11614913 polymorphism and hepatocellular carcinoma risk. For gastric cancer, a significantly increased cancer risk was observed only in homozygote comparison. This meta-analysis demonstrates that miR-196a2 rs11614913 polymorphism is significantly associated with risk of GI cancers.

Genetic polymorphism (rs762551A>C) in gene encoding cytochrome P450 1A2 (CYP1A2) has been shown to influence the inducibility of CYP1A2 expression and thus might be associated with risk of several types of human cancer. However, the results of previous studies on the associations of this polymorphism with risk of cancer are not all consistent. To clarify the potential contribution of CYP1A2 rs762551 to cancer risk, we performed a meta-analysis of the published case-control studies.

The prognostic significance of angiogenic markers remains controversial. Many studies have suggested that vascular endothelial growth factor (VEGF) or vascular endothelial growth factor receptor (VEGFR) overexpression correlates with poorer survival in adult patients with acute myeloid leukemia (AML), but some studies suggest a greater probability of survival. To investigate the prognostic significance of VEGF overexpression in adult AML, we performed a meta-analysis of the published studies that provided survival information according to VEGF expression status. Pooled hazard ratios (HRs) indicated that VEGF overexpression had a poor impact on the survival of adult patients with AML. The combined hazard ratio for event-free survival (EFS) was 1.40 and summary HR for overall survival was 1.54. The pooled HR was 1.92 in AML by enzyme-linked immunosorbent assay and 1.67 in AML by immunohistochemistry. These findings indicate that VEGF overexpression has an adverse impact on prognosis for patients with AML. VEGF may become a useful prognostic factor in the context of targeted therapy for patients with adult AML.

MicroRNAs (miRNAs) participate in diverse biological pathways and may act as either tumor suppressor genes or oncogenes. Single nucleotide polymorphisms (SNPs) in miRNA may contribute to cancer development with changes in the microRNA's properties and/or maturation. Polymorphisms in miRNAs have been suggested in predisposition to cancer risk; however, accumulated studies have shown inconsistent conslusionss. To further validate determine whether there is any potential association between the four common SNPs (miR-196a2C>T, rs11614913; miR-146aG>C, rs2910164; miR-499A>G, rs3746444; miR-149C>T, rs2292832) and the risk for developing risk, a meta-analysis was performed according to the 40 published case-control studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the extent of the association. The results demonstrated that the rs11614913TT genotype was significantly associated with a decreased cancer risk, in particular with a decreased risk for colorectal cancer and lung cancer, or for Asian population subgroup. In addition, the rs2910164C allele was associated with decreased risk for esophageal cancer, cervical cancer, prostate cancer, and hepatocellular carcinoma (HCC), in particular in Asian population subgroup. Similarly, the rs3746444G allele was observed as a risk factor for cancers in the Asian population. It is concluded that two SNPs prsent in miRNAs(rs11614913TT, and rs2910164C) may protect against the pathogenesis of some cancers, and that the rs3746444 may increase risk for cancer.

Published data on the association between mouse double minute 2 (MDM2) 309 T/G single nucleotide polymorphism (SNP) and head and neck cancer (HNC) risk are inconclusive. To derive a more precise estimation of the relationship, we performed a meta-analysis.

CYP2C9 encodes a member of the cytochrome P450 superfamily of enzymes which play a central role in activating and detoxifying many carcinogens and endogenous compounds thought to be involved in the development of colorectal cancer (CRC). In the past decade, the relationship between CYP2C9 common polymorphisms (R144C and I359L) and CRC has been reported in various ethnic groups; however, these studies have yielded contradictory results. To investigate this inconsistency, we performed this meta-analysis.

The Glutathione S-transferase P1 (GSTP1) polymorphism have been considered a risk modifier for developing head and neck cancer (HNC) in many studies; however, the results of such studies are inconsistent. The aim of this study was to evaluate the possible association between the GSTP1 Ile105Val polymorphism and risk of HNC.

Associations between adiponectin (ADIPOQ) genetic polymorphisms (rs2241766 G/T and rs266729 G/C) and cancer risk have been extensively studied in the past decade, while conflicting results were reported. Therefore, this study would explore the associations by using a meta-analysis. The databases of Medline, Embase, and Wangfang were retrieved, and the latest updated time was 1 August 2012. Effect sizes of odds ratio and 95 % confidence interval (OR and 95 % CI) were calculated by using a fixed- or random-effect model. A total of 12 studies with 10,368 participants were identified for association between ADIPOQ rs2241766 G/T and risk of cancer, and ten studies with 12,665 participants were for association between ADIPOQ rs266729 G/C and risk of cancer. Overall combined analyses indicated that neither ADIPOQ rs2241766 G/T nor rs266729 G/C was associated with risk of cancer incidence (OR (95 % CI), 0.89 (0.61-1.30) for GG vs. TT and 0.94 (0.83-1.06) for G carriers vs. T carriers for rs2241766 G/T; 0.99 (0.85-1.16) for GG vs. CC and 0.96 (0.87-1.06) for G carriers vs. C carriers for rs266729 G/C). When stratified analyses were conducted according to the participants' ethnicity, sources of controls, types of cancer, and sample size, we found that G allele of ADIPOQ rs2241766 G/T was significantly associated with decreased risk of cancer based on population-based case-control studies (OR (95 % CI), 0.65 (0.50-0.85) for GG vs. TT and 0.88 (0.79-0.98) for G carriers vs. T carriers). In contrast, there was no association between rs266729 G/C polymorphism and risk of cancer when subgroup analyses were conducted. In summary, this meta-analysis indicated that ADIPOQ rs2241766 G/T rather than rs266729 G/C polymorphism was closely associated with risk of cancer development.

Published data regarding the association between the apurinic/apyrimidinic endonuclease 1 (APE1) Asp148Glu polymorphism and bladder cancer risk showed inconclusive results. This meta-analysis of literatures was performed to draw a more precise estimation of the relationship. We systematically searched PubMed, Embase, Elsevier and Springer for relevant articles with a time limit of Jan. 2012. The strength of association between APE1 Asp148Glu polymorphism and bladder cancer risk was assessed by odds ratio (OR) with the corresponding 95 % confidence interval (95 % CI) using the software STATA(version10.0).A total of 11 case-control studies including 4,292 cases and 4,761 controls based on the search criteria were included for analysis. Overall, for GG versus TT, the pooled OR was 0.952 (95 % CI = 0.778-1.166), for the the G allele carriers (TG + GG) versus homozygote TT, the pooled OR was 0.984 (95 % CI = 0.897-1.078). In the stratified analysis by ethnicity, significantly risks were not found among Asians for GG versus TT (OR = 0.469; 95 % CI = 0.162-1.357) nor (TG + GG) versus TT (OR = 0.921, 95 % CI = 0.742-1.143). Similarly, for non-Asians, significantly risks were also not found for GG versus TT (OR = 0.992; 95 % CI = 0.861-1.144) nor (TG + GG) versus TT (OR = 1.010, 95 % CI = 0.897-1.137). This meta-analysis suggested that the APE1 T1349G (Asp148Glu) polymorphism was not associated with bladder cancer risk among Asians nor non-Asians.

RAS association domain family protein 1a (RASSF1A) is a putative tumor suppressor gene located on 3p21, has been regarded playing important roles in the regulation of different types of human tumors. Previous reports demonstrated that the frequency of RASSF1A methylation was significantly higher in patients group compared with controls, but the relationship between RASSF1A promoter methylation and pathological features or the tumor grade of bladder cancer remains controversial. Therefore, A meta-analysis of published studies investigating the effects of RASSF1A methylation status in bladder cancer occurrence and association with both pTNM (p, pathologic stage; T, tumor size; N, node status; M, metastatic status) and tumor grade in bladder cancer was performed in the study. A total of 10 eligible studies involving 543 cases and 217 controls were included in the pooled analyses. Under the fixed-effects model, the OR of RASSF1A methylation in bladder cancer patients, compared to non-cancer controls, was 8. 40 with 95%CI=4. 96-14. 23. The pooled OR with the random-effects model of pTNM and tumor grade in RASSF1A methylated patients, compared to unmethylated patients, was 0. 75 (95%CI=0. 28-1. 99) and 0. 39 (95%CI=0. 14-1. 09). This study showed that RASSF1A methylation appears to be an independent prognostic factor for bladder cancer. The present findings also require confirmation through adequately designed prospective studies.