Search

Numerous studies have investigated the risk of cancer associated with the polymorphism of epidermal growth factor (EGF) 61A>G, but results have been inconsistent. We performed this meta-analysis to drive a more precise estimation of the association between this polymorphism and risk of glioma. A comprehensive search was conducted to identify all case-control studies on the EGF +61A>G polymorphism and glioma risk. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to assess the strength of the association. Statistical analysis was performed with the software program Stata (version 12.0). A total of ten eligible studies, including 1,888 cases and 2,836 controls were included in this work. Overall, there was a significant association between EGF +61A>G polymorphism and glioma risk in the allele model (OR = 1.419, 95% CI = 1.144-1.759, P = 0.001). In the subgroup analysis by ethnicity, significant associations were also found in Asian populations under all different genetic models (homozygote model: OR = 1.727, 95% CI = 1.310-2.275, P = 0.000; heterozygote model: OR = 1.202, 95% CI = 1.023-1.413, P = 0.025; dominant model: OR = 1.279, 95% CI = 1.096-1.491, P = 0.002; recessive model: OR = 1.590, 95% CI = 1.221-2.070, P = 0.001; and A-allele versus G-allele OR = 1.600, 95% CI = 1.145-2.236, P = 0.006). However, no significant associations were found among Caucasians in all comparison models. In conclusion, the results suggest that there is a significant association between EGF +61A>G polymorphism and glioma risk among Asians.

Many studies have investigated on the association between TP53 Arg72Pro polymorphism and risk of glioma, but the impact of TP53 Arg72Pro polymorphism on glioma risk is unclear owing to the obvious inconsistence among those studies. To shed light on these inconclusive findings and get a quantitative assessment of the association between the TP53 Arg72Pro polymorphism and risk of glioma, we conducted a meta-analysis of eligible studies. We searched PubMed and Embase databases for studies investigating on the association between the TP53 Arg72Pro polymorphism and risk of glioma. The pooled odds ratios (OR) with their 95% confidence intervals (95% CI) was calculated to assess the association between the TP53 Arg72Pro polymorphism and risk of glioma. A total of 12 studies were finally included into the meta-analysis. Meta-analysis of the 12 studies showed that TP53 Arg72Pro polymorphism was not associated with the risk of glioma (OR(Pro vs. Arg) = 1.07, 95% CI 0.93∼1.22; OR(ProPro vs. ArgArg) = 1.02, 95% CI 0.85∼1.22; OR(ProPro/ArgPro vs. ArgArg )= 1.06, 95% CI 0.85∼1.34; and OR(ProPro vs. ArgArg/ArgPro) = 1.07, 95% CI 0.91∼1.27). Subgroup analyses by ethnicity further identified that TP53 Arg72Pro polymorphism was not associated with the risk of glioma in Caucasians. However, there was a mild association between the TP53 Arg72Pro polymorphism and risk of glioma in Asians (OR(ProPro vs. ArgArg/ArgPro) = 1.42, 95% CI 1.00∼2.02). Thus, there is limited evidence for the association between the TP53 Arg72Pro polymorphism and risk of glioma, and more studies are needed to provide a more comprehensive assessment of the association in Asians.

Glutathione S-transferase P1 (GSTP1) gene Ile105Val polymorphism has been suggested to be involved in the development of glioma. However, the results from the studies regarding the association between GSTP1 Ile105Val polymorphism and glioma risk have been inconsistent. Thus, we performed a meta-analysis to investigate this association. Pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were calculated using random or fixed effects model. Nine studies with 2,078 cases and 3,970 controls were finally included into this meta-analysis. The results suggested there was no association between GSTP1 Ile105Val polymorphism and glioma risk under recessive model (OR = 1.138, 95%CI = 0.966-1.341, Pheterogeneity = 0.088, P = 0.123). Subgroup analyses by ethnicity showed there was also no association between GSTP1 Ile105Val polymorphism and glioma risk in mixed populations under recessive model (OR = 1.199, 95%CI = 0.928-1.549, Pheterogeneity = 0.060, P = 0.166) and Caucasian populations (OR = 1.097, 95%CI = 0.885-1.360, Pheterogeneity = 0.186, P = 0.398). In conclusion, the meta-analysis suggests that there is no association between GSTP1 Ile105Val polymorphism and glioma risk. However, more well-designed and larger studies are needed to further assess this association.

Potential single-nucleotide polymorphisms (SNPs) of interleukin-4 receptor alpha (IL-4Rα) rs1801275 and rs1805015 have been implicated in glioma risk; however, the findings of previous published case-control studies are conflicting and inconclusive. We performed the updated meta-analysis with the aim to provide a more precise estimate for the role of interleukin-4Rα SNPs in glioma risk. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of the gene association. Overall, the pooled analysis showed that the IL-4Rα rs1801275 polymorphism was associated with a decreased risk of glioma in the comparison of G vs. A (OR = 0.87, 95% CI = 0.76-0.99, P OR = 0.041). Subgroup analysis by ethnicity revealed that the IL-4Rα rs1801275 variant G and GG + AG exerted a decreased risk effect on the development of glioma among Asians, but not Caucasians (G vs. A, OR = 0.81, 95% CI = 0.69-0.95, P OR = 0.011; GG + AG vs. AA, OR = 0.80, 95% CI = 0.66-0.96, P OR = 0.018). However, the IL-4Rα rs1805015 polymorphism did not modify the risk of glioma. Sensitivity analysis confirmed the reliability for all of the results. Our meta-analysis suggests that the polymorphism of IL-4Rα rs1801275 but not IL-4Rα rs1805015 plays a protective role in the glioma pathogenesis, particularly among Asians.

Methylenetetrahydrofolate reductase (MTHFR) gene plays key roles not only in folate metabolism but also in carcinogenesis. The single nucleotide polymorphism MTHFR C677T has been indicated in the development of various tumors. The effect of the MTHFR C677T polymorphism on brain tumors remains poorly understood. We performed the present meta-analysis and aimed to provide a better understanding of the pathogenesis of brain tumors. A literature search of the PubMed, Embase, Web of Science, and Wanfang databases was carried out for potential relevant publications. We calculated the pooled odds ratio (OR) with corresponding 95% confidence interval (95% CI) to assess the association of MTHFR C677T with the susceptibility to brain tumors. We also performed stratified analysis and sensitivity analysis to further estimate the genetic association. All statistical analyses were conducted by the use of STATA 11.0 (STATA Corporation, College Station, TX, USA). Eight case-control studies involving a total of 3,059 cases and 3,324 controls were retrieved according to the inclusion criteria. The overall ORs suggested that the MTHFR C677T variant can exert a risk effect on brain tumor development under the following contrast models (OR(TC vs. CC) = 1.14, 95% CI 1.02-1.27, P OR = 0.018; OR(TT + TC vs. CC)= 1.23, 95% CI 1.01-1.51, P(OR) = 0.043). No significant correlation was identified among the Caucasians, but not among the Asians. In addition, the TC genotype carriers were more susceptible to meningioma when compared with the CC genotype carriers (OR(TC vs. CC) = 1.38, 95% CI 1.15-1.65, P(OR) < 0.001). The MTHFR C677T polymorphism seemed to exert no effect on glioma risk. The current meta-analysis firstly provides evidence that the MTHFR C677T polymorphism may modify the risk for brain tumors, particularly meningioma. The role of the MTHFR C677T variant in brain tumor pathogenesis across diverse ethnicities needs further elucidation by more future studies with large sample size.

Common variants of multiple genes play a role in glioma onset. However, research related to astrocytoma, the most common primary brain neoplasm, is rare. In this study, we chose 21 tagging SNPs (tSNPs), previously reported to be associated with glioma risk in a Chinese case-control study from Xi'an, China, and identified their contributions to astrocytoma susceptibility. We found an association with astrocytoma susceptibility for two tSNPs (rs6010620 and rs2853676) in two different genes: regulator of telomere elongation helicase 1 (RTEL1) and telomerase reverse transcriptase (TERT), respectively. We confirmed our results using recessive, dominant, and additive models. In the recessive model, we found two tSNPs (rs2297440 and rs6010620) associated with increased astrocytoma risk. In the dominant model, we found that rs2853676 was associated with increased astrocytoma risk. In the additive model, all three tSNPs (rs2297440, rs2853676, and rs6010620) were associated with increased astrocytoma risk. Our results demonstrate, for the first time, the potential roles of RTEL1 and TERT in astrocytoma development.

The incidence of brain metastasis (BM) from colorectal carcinoma (CRC) is increasing. The objectives of the present study were to explore the clinical characteristics and potential prognostic factors in CRC patients with BM. Between April 1991 and December 2010, all CRC patients treated in the Sun Yat-sen University Cancer Center were retrospectively reviewed and 60 patients were identified to have BM (36 males and 24 females). The association between patients and their tumor characteristics, treatment modality, and survival were statistically analyzed. The median age at diagnosis of BM was 62.5 years. Fifty-three patients (88.3%) developed extracranial metastases at diagnosis of BM. The cause of death was systemic disease in 19 patients and neurological disease in 23 patients. Brain metastases were primarily treated with either whole brain radiation therapy (WBRT; 15 patients), stereotactic radiosurgery (SRS; nine patients), or surgical resection (seven patients). Ten patients received WBRT and SRS, and 19 patients (31.7%) were treated with steroids alone. The median survival after diagnosis of BM was 8 months (95% confidence interval = 4.2-11.8 months). Recursive partitioning analysis (RPA) class, the number of brain lesions, and treatment modality type were significantly associated with survival. Although BM from CRC is a late-stage phenomenon with an extremely poor prognosis, some subsets of patients would benefit from a multidisciplinary management strategy. A low RPA class and a limited number of brain lesions may predict increased survival after therapy for CRC patients with BM.