Cancer In Asian Population Research Articles

AXIN2 rs2240308 polymorphism contributes to increased cancer risk: evidence based on a meta-analysis.

BackgroundVariants in the axis inhibition 2 (AXIN2) gene might alter the protein’s structure or function or create a multiprotein destruction complex in the Wnt signaling pathway and thus affect an individual’s susceptibility to cancer. The objective of this study is to evaluate broadly the evidence available for the AXIN2 rs2240308 polymorphism and risk of cancer.MethodsA comprehensive literature search was undertaken for eligible studies in Embase, PubMed, and Cochrane Library up to Nov 30, 2014. Odds ratios (ORs) and the corresponding 95 % confidence intervals (CIs) were used to measure the strength of the models.ResultsEight articles (10 case-control studies with 1,502 cases and 1,590 controls) were included in this analysis. Overall, the AXIN2 rs2240308 polymorphism was associated with a significant increase in the risk of cancer (G allele vs. A allele: OR = 1.21, 95 % CI = 1.05–1.40, I2 = 39.5 % and PQ = 0.094 for heterogeneity; GG vs. AA: OR = 1.30, 95 % CI = 1.04–1.63, I2 = 35.9 % and PQ = 0.121 for heterogeneity; GG vs. GA + AA: OR = 1.36, 95 % CI = 1.17–1.58, I2 = 19.5 % and PQ = 0.263 for heterogeneity). Asian populations showed similar results. Stratified analysis by cancer types indicated that the AXIN2 rs2240308 polymorphism increases the risk of lung cancer (G allele vs. A allele: OR = 1.36, 95 % CI = 1.17–1.59; GA vs. AA: OR = 1.43, 95 % CI = 1.01–2.02; GG vs. AA: OR = 1.93, 95 % CI = 1.36–2.75; GG + GA vs. AA: OR = 1.65, 95 % CI = 1.18–2.30; GG vs. GA + AA: OR = 1.45, 95 % CI = 1.18–1.79. All I2 < 50 % and PQ > 0.100 for heterogeneity).ConclusionsThis study showed that the AXIN2 rs2240308 polymorphism contribute to increasing the risk of cancer, especially lung cancer in Asian populations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12935-015-0219-8) contains supplementary material, which is available to authorized users.

Association between the MTHFR C677T polymorphism and gastric cancer susceptibility: A meta-analysis of 5,757 cases and 8,501 controls.

Current data regarding the association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the risk of developing gastric cancer are insufficient to draw definite conclusions. Therefore, the present meta-analysis was conducted to achieve a more precise estimation of the association. MEDLINE, EMBASE and Wanfang database searches resulted in the identification of 28 eligible studies describing 5,757 cases and 8,501 controls. The strength of the association between the MTHFR C677T polymorphism and gastric cancer risk were evaluated using crude odds ratios (ORs), with 95% confidence intervals (CIs). The pooled ORs were determined using homozygous (TT vs. CC), heterozygous (CT vs. CC), dominant (TT+CT vs. CC) and recessive (TT vs. CC+CT) models. When all studies were pooled into the meta-analysis, significant associations were identified between the MTHFR C677T polymorphism and the risk of gastric cancer (homozygous model: OR, 1.39; 95% CI, 1.20-1.62; heterozygous model: OR, 1.18; 95% CI, 1.05-1.32; dominant model: OR, 1.23; 95% CI, 1.10-1.38; recessive model: OR, 1.26; 95% CI, 1.12-1.42). Stratification of the data by ethnicity identified a statistically significantly elevated risk of gastric cancer in Asian MTHFR C677T polymorphism populations (homozygous model: OR, 1.64; 95% CI, 1.43-1.90; heterozygous model: OR, 1.30; 95% CI, 1.16-1.45; dominant model: OR, 1.39; 95% CI, 1.25-1.54; recessive model: OR, 1.41; 95% CI, 1.25-1.51), but not in Caucasian populations (homozygous model: OR, 1.15; 95% CI, 0.89-1.48; heterozygous model: OR, 1.03; 95% CI, 0.84-1.25; dominant model: OR, 1.05; 95% CI, 0.86-1.28; recessive model: OR, 1.09; 95% CI, 0.91-1.31). Following adjustment for heterogeneity, the current meta-analysis demonstrated that the MTHFR C677T polymorphism was not associated with the risk of gastric cancer in Caucasian individuals. Furthermore, no evidence of publication bias was observed. Thus, the current meta-analysis indicates that the MTHFR C677T allele may be a low-penetrant risk factor for the development of gastric cancer in Asian populations.

SU‐E‐J‐265: Feasibility Study of Texture Analysis for Prognosis of Local Tumor Recurrence Within 5‐Years for Pharyngeal‐Laryngeal Carcinoma Patients Received Radiotherapy Treatment

Purpose:Pharyngeal and laryngeal carcinomas (PLC) are among the top leading cancers in Asian populations. Typically the tumor may recur and progress in a short period of time if radiotherapy fails to deliver a successful treatment. Here we used image texture features extracted from images of computed tomography (CT) planning and conducted a retrospective study to evaluate whether texture analysis is a feasible approach to predict local tumor recurrence for PLC patients received radiotherapy treatment.Methods:CT planning images of 100 patients with PLC treated by radiotherapy at our facility between 2001 and 2010 are collected. These patients were received two separate CT scans, before and mid‐course of the treatment delivery. Before the radiotherapy, a CT scanning was used for the first treatment planning. A total of 30 fractions were used in the treatment and patients were scanned with a second CT around the end of the fifteenth delivery for an adaptive treatment planning. Only patients who were treated with intensity modulated radiation therapy and RapidArc were selected. Treatment planning software of Eclipse was used. The changes of texture parameters between two CT acquisitions were computed to determine whether they were correlated to the local tumor recurrence. The following texture parameters were used in the preliminary assessment: mean, variance, standard deviation, skewness, kurtosis, energy, entropy, inverse difference moment, cluster shade, inertia, cluster prominence, gray‐level co‐occurrence matrix, and gray‐level run‐length matrix. The study was reviewed and approved by the committee of our institutional review board.Results:Our calculations suggested the following texture parameters were correlated with the local tumor recurrence: skewness, kurtosis, entropy, and inertia (p&lt;0.0.05).Conclusion:The preliminary results were positive. However some works remain crucial to be completed, including addition of texture parameters for different image features, sensitivity of tumor segmentation variations, and effect of image filtering.

Opportunities for targeted focal treatment in Japan.

Widespread prostate-specific antigen screening has led to an increase in prostate cancer diagnoses in Asian populations, reflecting changes in socioeconomic status and epidemiological features in these countries. In this setting, the present review explores opportunities for target focal therapy in Japan. Our review examines several topics relating to focal therapy in Asia, and discusses the current status of prostate cancer diagnosis and treatment in that region. First, we summarize the prevalence of prostate cancer in Asian populations. Second, we examine prostate cancer diagnosis and treatment options such as mapping biopsy and MRI fusion biopsy in Japan. Third, we review treatment strategies for localized prostate cancer, especially robotic-assisted surgery, active surveillance, and high-intensity focused ultrasound. Lastly, we discuss the potential for focal therapy in Japan. The number of localized prostate cancer patients is expected to increase in Asia. Accordingly, the need for precise diagnosis in terms of localization of prostate cancer foci will also expand. MRI fusion target biopsies are being performed in Asia, particularly in some Japanese academic institutions, but as pilot studies. In recent years, an increase in robotic-assisted surgery in East Asia has yielded new options in prostate cancer treatment. Although active surveillance is a practical choice for low-risk prostate cancer in some Asian countries, focal therapy is expected to see increasing interest as another alternative in Japan.

Causal relevance of circulating high-density lipoprotein cholesterol with cancer: a Mendelian randomization meta-analysis.

We summarized published data on the associations of apolipoprotein E (APOE) gene ε2/ε3/ε4 polymorphism with both cancer risk and circulating lipid profiles, aiming to examine the causal relevance between lipids and cancer risk. Article identification and data abstraction were conducted in duplicate and independently by two authors. Data were analyzed by STATA software. Twenty-five articles that examined the associations of APOE gene ε2/ε3/ε4 polymorphism with either cancer risk (n = 22) or circulating lipid changes (n = 4) were eligible. The presence of ε2 and ε4 alleles showed no overall associations with overall cancer risk when compared with ε3 allele. The ε4 allele was significantly associated with 1.40-fold (odds ratio or OR = 1.40; 95% confidence interval or CI: 1.00–1.94; P = 0.047) increased risk of developing cancer in Asian populations, and the presence of heterogeneity was low (I2 = 37.6%). Carriers of ε3/ε4 genotype had a significant reduction in circulating HDL-C (WMD = −2.62; 95% CI: −4.19 to −1.04; P = 0.001) without heterogeneity (I2 = 16.6%). The predicted odds of having cancer for 1 mg/dL reduction in circulating HDL-C was 1.14 (95% CI: 1.00 to 1.89). The findings of this Mendelian randomization meta-analysis demonstrate that reduced circulating HDL-C might be a potentially causal risk factor for the development of overall cancer in Asians.

The association of CTLA-4 A49G polymorphism with colorectal cancer risk in a Chinese Han population.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is expressed in T cells and plays an important role in the regulation of T cell. CTLA-4 has long been considered to be associated with various kinds of diseases. With the attempt to examine the association between CTLA-4 A49G polymorphism and colorectal cancer risk in a Chinese Han population, we employed TaqMan assay to genotype the CTLA-4 A49G polymorphism in 311 colorectal cancer cases and 389 cancer-free controls. We found evidence of the association between CTLA-4 A49G polymorphism and colorectal cancer risk (GG vs. AA: OR = 2.01, 95% CI = 1.29-3.07, P = 0.002; GA vs. AA: OR = 2.32, 95% CI = 1.53-3.57, P = 0.001; GA + GG vs. AA: OR = 2.16, 95% CI = 1.46-3.21, P = 0.001). Next, we performed a meta-analysis to comprehensively examine the association between CTLA-4 A49G polymorphism and colorectal cancer risk. We found a significant association between CTLA-4 A49G polymorphism and colorectal cancer risk among Asians, which is consistent with our result. However, we found no evidence for the association between CTLA-4 A49G polymorphism and colorectal cancer risk among Caucasians. In conclusion, we demonstrated that the CTLA-4 A49G polymorphism increased the susceptibility of colorectal cancer in Asian population.

Association of IL-17 polymorphisms with gastric cancer risk in Asian populations.

To investigate associations between the IL-17 rs2275913 G>A and rs763780 T>C polymorphisms and susceptibility to gastric cancer in Asian populations. We reviewed studies published up to 2014 on IL-17 polymorphisms with gastric cancer susceptibility systematically. Relevant articles were identified in the MEDLINE, Science Citation Index, Cochrane Library, PubMed, EMBASE, CINAHL and Current Contents Index databases. We used version 12.0 STATA statistical software to evaluate the statistical data. Two reviewers abstracted the data independently. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated. Seven independent, case-control studies were chosen for the meta-analysis, which included 3210 gastric cancer patients and 3889 healthy controls. The overall estimation showed a positive association between the IL-17 rs2275913 G>A polymorphism and the occurrence of gastric cancer for five genetic models (all P < 0.05) and similar results were observed for the IL-17 rs763780 T>C variation with four genetic models (all P < 0.05), but not for the dominant model (P > 0.05). Subgroup analysis by country revealed that the rs2275913 G>A and rs763780 T>C polymorphisms may be the main risk factor for gastric cancer in Chinese and Japanese populations. The IL-17 gene may be significantly correlated with gastric cancer risk in Asian populations, especially those carrying the rs2275913 G>A and rs763780 T>C polymorphisms.

Folate pathway gene MTHFR C677T polymorphism and risk of lung cancer in Asian populations.

Previous studies concerning the association between the 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism with lung cancer in Asian populations have provided inconclusive findings. A meta-analysis was performed to investigate a more reliable association between MTHFR C677T polymorphism and lung cancer in Asians. A comprehensive search was conducted to identify all case-control studies of MTHFR polymorphisms and lung cancer in Asia, using odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of any association. Meta-analysis results suggested that the MTHFR C677T polymorphism contributed to an increased lung cancer risk in Asian populations (for T vs C: OR=1.11, 95%CI=1.0-1.23; for CT vs CC: OR= 1.1, 95%CI= 0.95-1.2 ; for TT+CT vs CC: OR=1.13, 95%CI=1.0-1.30; for TT vs CC: OR=1.25, 95%CI=1.01-1.30; for TT vs CT+CC: OR=1.16, 95%CI=1.0-1.36). MTHFR C677T polymorphism is significantly associated with lung cancer in Asians.

Impact of epoxide hydrolase 1 polymorphisms on lung cancer susceptibility in Asian populations.

Inconsistent association of microsomal epoxide hydrolase (mEH) polymorphisms (Tyr113His, His139Arg) and lung cancer susceptibility have been reported in earlier studies. This study was undertaken to assess if mEH Tyr113His and His139Arg represent risk factors for lung cancer in Asian population. We exhaustively searched multiple databases to identify all eligible studies. Odds ratios were calculated to estimate the strength of genetic associations. This meta-analysis finally combined 2,522 subjects for Tyr113His and 2,725 subjects for His139Arg. In the analysis of Tyr113His, the His/His genotype carriers were found to have 29 % higher risk of lung cancer compared to the Tyr/Tyr carriers (His/His vs. Tyr/Tyr, odds ratio, 1.29, 95 % confidence interval, 1.06-1.58). A significantly increased risk was also seen in His/His versus His/Tyr + Tyr/Tyr (odds ratio, 1.29, 95 % confidence interval, 1.07-1.55). Likewise, His139Arg demonstrated a significant association with lung cancer (Arg/His vs. His/His, odds ratio, 1.2 6, 95 % confidence interval, 1.06-1.49; odds ratio, 1.24, 95 % confidence interval, 1.05-1.46). Stratified analysis by ethnicity showed both of the polymorphisms were associated with lung cancer in Chinese populations. These results suggest that the genetic associations exist between mEH polymorphisms and lung cancer susceptibility in Asian populations.

The AURKA gene rs2273535 polymorphism contributes to breast carcinoma risk - meta-analysis of eleven studies.

The rs2273535 polymorphism in the AURKA gene had proven to be associated with breast carcinoma susceptibility. Nevertheless, the results of different studies remain contradictory. A meta-analysis covering 28, 789 subjects from eleven different studies was here carried out in order to investigate the association in detail. The random effects model was used to analyze the pooled odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs). A significant relationship between the rs2273535 polymorphism and breast tumors was found in an allelic genetic model (OR: 1.076, 95% CI: 1.004-1.153, p=0.040, Pheterogeneity=0.002). No significant association was detected in a homozygote model (OR: 1.186, 95% CI: 0.990-1.423, P=0.065, Pheterogeneity=0.002), a heterozygote model (OR: 1.016, 95% CI: 0.959-1.076, p=0.064, Pheterogeneity=0.000), a dominant genetic model (OR: 1.147, 95% CI: 0.992-1.325, p=0.217, Pheterogeneity=0.294) and a recessive genetic model (OR: 1.093, 95% CI: 0.878- 1.361, p=0.425, Pheterogeneity=0.707). A significant relationship between the rs2273535 polymorphism in the AURKA gene and breast tumor in Asian group was found in an allelic genetic model (OR: 1.124, 95% CI: 1.003-1.29, p=0.044, Pheterogeneity=0.034), a homozygote model (OR: 1.229, 95% CI: 1.038-1.455, p=0.016, Pheterogeneity=0.266) and a recessive genetic model (OR: 1.227, 95% CI: 1.001-1.504, p=0.049, Pheterogeneity=0.006). A significant association was thus observed between the rs2273535 polymorphism in the AURKA gene and breast cancer risk. Individuals with the rs2273535 polymorphism in the AURKA gene have a higher risk of breast cancer in Asian populations, but not in Caucasians.

Diagnostic value of circulating microRNAs for gastric cancer in Asian populations: a meta-analysis.

Gastric cancer (GC) accounts for one of the highest mortality worldwide and particularly in East Asia. Many studies have reported on the potential value of microRNAs (miRNAs) detection for diagnosing GC, but their results have proven inconclusive. The present meta-analysis was conducted to assess the diagnostic value of circulating miRNAs for GC diagnosis. A literature search was carried out in databases (PubMed, Embase, Web of Science, The Cochrane Library, and CNKI) and other sources using combinations of keywords relating to GC, miRNAs, and diagnosis. The values of sensitivity, specificity, positive likelihood ratios (PLR), negative likelihood ratios (NLR), and diagnostic odds ratio (DOR) reported in individual studies were pooled using random-effects models. Potential sources of heterogeneity were assessed with subgroup and meta-regression analyses. The summary receiver operating characteristic (SROC) curve and the area under the curve (AUC) were used to assess the diagnosis accuracy of miRNAs. This meta-analysis included 1,279 patients with GC and 954 healthy controls from 20 publications. The pooled sensitivity, specificity, PLR, NLR, DOR, and AUC were 0.78 (95% CI: 0.73-0.81), 0.80 (95% CI: 0.76-0.84), 4.0 (95% CI: 3.1-6.0), 0.28 (95% CI: 0.23-0.34), 14 (95% CI: 10-21), and 0.86 (95% CI: 0.83-0.89), respectively. Subgroup analyses showed that early stages (I and II) GC were more easily detected than later stages and that multiple miRNAs assays were more accurate than single miRNA assays. Our meta-analysis suggests that miRNAs have a high diagnostic value for GC, especially in its early stages (I and II). In addition, multiple miRNAs assays have a better diagnosis value than single miRNA assays. In conclusion, circulating miRNAs might be used as noninvasive biomarkers for the confirmation of GC detection in Asian populations.

Genetic association between AGPHD1 variant and lung cancer risk.

The knowledge of molecular mechanism that underlies the genetic predisposition to lung cancer is yet limited. Results from previous studies addressing the association of AGPHD1 variant rs8034191 with lung carcinogenesis remain inconclusive. Herein, we combined these data and re-examined the association. We performed a meta-analysis of Asian studies identified through various ways. Using the data collected from each eligible study, we combined the effect estimates (ORs and its 95 % CIs) with the fixed effects model (Mantel-Haenszel method). Statistical analyses were done using STATA software. Data from nine studies (29,290 subjects) carried out in Asian populations were analyzed in this work. There was no overall association between variant rs8034191 and lung cancer risk under the allele frequency model (OR = 1.03, 95 % CI = 0.93-1.13, P heterogeneity = 0.522). We observed the same associations under other genetic models and in the subgroup analyses by ethnicity and smoking status. Our results indicate that variant rs8034191 in the AGPHD1 gene may not modify the genetic risk of lung cancer in Asian populations.

The methylenetetrahydrofolate reductase C677T polymorphism and breast cancer risk in Asian populations.

Methylenetetrahydrofolate (MTHFR) is the key enzyme of the folate metabolic pathway and several studies have pointed to association between the MTHFR C677T polymorphism and breast cancer risk. Although significant association was observed in some studies, in others no clear link could be established. A meta-analysis of published Asian case control studies was therefor carried out to shed further light on any C677T breast cancer association. PubMed, Springer Link, Google Scholar and Elsevier databases were searched for case control studies of associations between MTHFR C677T polymorphism and breast cancer risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. A total of 36 studies including 8,040 cases and 10,008 controls were included in the present meta-analysis. Overall, a significantly elevated breast cancer risk was associated with the T allele and TT genotype in homozygote comparison and dominant genetic models when all studies were pooled into the meta-analysis (T vs C (allele contrast model): OR=1,23, 95%CI=1.13-1.37, p=0.000 ; TT vs CC(homozygote model): OR=1.38, 95%CI=1.16-1.63, p=0.0003; TT+CT vs CC (dominant model): OR=1.12, 95%CI=1.01-1.23, p=0.02). The present meta-analysis strongly suggested a significant association between the MTHFR C677T polymorphism and risk of breast cancer in Asian populations.

The XRCC1 Arg194Trp and Arg280His polymorphisms in head and neck cancer susceptibility: a meta-analysis.

The XRCC1 Arg194Trp and Arg280His polymorphisms are likely to be implicated with the development of head and neck cancer. However, studies of association have been inconsistent. This meta-analysis of the available literature was performed to make a more precise estimation of the risk associated with these polymorphisms. A comprehensive literature search was conducted to identify all case-control studies of the XRCC1 Arg194Trp and Arg280His polymorphisms in head and neck cancer. Summary odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association. A total of 20 eligible studies were selected for this meta-analysis, including 3,362 cases and 5,796 controls for the XRCC1 Arg194Trp polymorphism and 1,932 cases and 2,757 controls for the XRCC1 Arg280His polymorphism. Overall, no significant associations were found in all genetic models when the studies were pooled into the meta-analysis for the Arg194Trp and Arg280His polymorphisms. When stratified by ethnicity, significant associations were found for Arg194Trp polymorphism in CT vs CC (OR = 1.26, 95% CI = 1.05-1.52) and the recessive model (OR = 1.28, 95% CI = 1.07-1.53) in Asian population, and no significant associations were found in non-Asian population in all genetic models. This meta-analysis suggests that the XRCC1 Arg194Trp polymorphism is a risk factor for head and neck cancer in Asian populations.

Association of XPC polymorphisms and lung cancer risk: a meta-analysis.

BackgroundXeroderma pigmentosum complementation group C gene (XPC) is a key member of nucleotide excision repair pathway and plays an important role in human DNA repair system. It is reported that several common polymorphisms of XPC are associated with susceptibility to lung cancer. However, the conclusion is still elusive.MethodThis meta-analysis was performed to determine the relationship between XPC polymorphisms (Lys939Gln, Ala499Val, and PAT) and lung cancer risk. Published literatures were identified by searching online databases and reference lists of relevant studies. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the association strength. Publication bias were detected by Egger’s and Begg’s test.ResultAfter strict screening, we identified 14 eligible studies in this meta-analysis, including 5647 lung cancer cases and 6908 controls. By pooling all eligible studies, we found that the homozygote Gln939Gln genotype was associated with a significantly increased risk of lung cancer in Asian population (GlnGln vs LysLys, OR = 1.229, 95% CI: 1.000–1.510; GlnGln vs LysLys/LysGln, OR = 1.257, 95% CI: 1.038–1.522). As for the PAT polymorphism, in Caucasian population, we found carriers of the −/− genotype were associated significantly reduced risk of lung cancer in homozygote comparison model (−/− vs +/+, OR = 0.735, 95% CI: 0.567–0.952).ConclusionIn this meta-analysis we found that Gln939Gln genotype was associated with significantly increased risk of lung cancer in Asian population; the PAT −/− genotype significantly reduced susceptibility to lung cancer in Caucasian population; while the XPC Ala499Val polymorphism was not associated with lung cancer risk.

Genetic polymorphism of APE1 rs1130409 can contribute to the risk of lung cancer

Accumulative evidence suggests that polymorphism in the APE1 gene may have association with the etiology of lung cancer by modulating DNA repair capacity. Many studies have evaluated the association with great discrepancies in the results. The present meta-analysis was undertaken to clarify the effects of this polymorphism on lung cancer. A meta-analysis of 15 studies with 4,932 lung cancer patients and 6,555 cancer-free controls was conducted to evaluate the strength of the association using odds ratios (ORs) with 95 % confidence intervals (CIs). Overall, no significant association was found between APE1 polymorphism and lung cancer risk. We also did not observe any statistical evidence of modified lung cancer risk either in smokes or in nonsmokers. In the stratified analysis by ethnicity, however, it was found that the Glu/Clu genotype carriers had 1.16-fold higher risk of suffering lung cancer compared with the carriers of Arg/Glu + Arg/Arg genotypes in Asian population (OR = 1.16, 95 % CI = 1.01-1.32, P = 0.242). This meta-analysis provides statistical evidence for a potential association between APE1 polymorphism and an increased risk of lung cancer in Asian population.

Association between MTHFR Gene Polymorphism and the Risk of Ovarian Cancer: A Meta-analysis of the Literature

Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme for DNA biosynthesis and the epigenetic process of DNA methylation. MTHFR gene polymorphisms have been implicated as risk factors for several types of cancers. However, reports on the association of MTHFR polymorphisms with ovarian cancers are inconclusive. The aim of this study is to summarize on the reported data and meta-analytically investigate the relationship between the MTHFR C677T and A1298C polymorphism and the risk of ovarian cancer. We searched for all published articles indexed in MEDLINE (1950-2012), EMBASE (1974-2012), and CNKI (1994-2012). Case-control or cohort studies that relating to MTHFR polymorphism and ovarian cancer women were included and data were extracted independently by two reviewers. The search yielded 21 articles, from which 7 studies met the inclusion criteria. We performed a metaanalysis involving 3493 patients with ovarian cancer and 3863 controls with Review Manager 5.1 software. Odds ratio (OR) and 95% confidence intervals (CIs) were used to evaluate the ovarian cancer risk. All the available data considered together, no association between the MTHFR C677T polymorphism and ovarian cancer risk was found in any genetic variations. However, in the subgroup analysis by ethnicity of Asian and Caucasian, MTHFR 677T was associated with significantly increased ovarian cancer risk among Asian [T allele vs. C allele: OR=1.50, 95% CI: 1.25-1.81, P<0.0001; CT + TT vs. CC (dominant model): OR=1.49, 95% CI: 1.18-1.88, P=0.0009; TT vs. CT + CC (recessive model): OR=2.33, 95% CI: 1.57-3.45, P<0.00001], while, there was no significant increased risk in Caucasian. As for MTHFR A1298C polymorphism, no marked association was found in either group of Caucasian population, while no data was available to analyze in Asian population. The C677T polymorphism of the MTHFR gene is associated with the susceptibility of ovarian cancer in Asian population, suggesting that TT genotype may serve as a risk factor of ovarian cancer among Asian but not Caucasians. In addition, there is no association between A1298C gene polymorphism and ovarian cancer, including Caucasian and Asian women.

Systematic review and meta-analysis on vitamin D receptor polymorphisms and cancer risk

The vitamin D receptor (VDR) can influence cancer susceptibility through binding to vitamin D. However, the previous studies were contradictory. Therefore this meta-analysis was conducted to clarify the association between VDR polymorphisms (BsmI, TaqI, FokI, and ApaI) and cancer risk. One hundred twenty-six studies were enrolled through PubMed. For VDR BsmI polymorphism, significantly increased cancer risks were observed in the overall analysis. In the further stratified analysis, increased risks were observed in colorectal and skin cancer, especially in Caucasian population. However, no significant associations were observed in other VDR polymorphisms in the overall analysis. In the further subgroup analysis, increased risks were found in oral, breast, and basal cell cancer while decreased risk was found in prostate cancer in t allele carriers of TaqI polymorphism. For VDR FokI polymorphism, increased risks were found in ovarian and skin cancer while decreased risk in glioma in f allele carriers. For VDR ApaI polymorphism, increased risk was observed in basal cell cancer, especially in Asian population in a allele carriers. In conclusion, these results indicated that b allele of BamI polymorphism was a risk factor for cancer susceptibility. Meanwhile, t allele of TaqI polymorphism was a risk factor for oral, breast, and basal cell cancer and a protective factor for prostate cancer. Moreover, f allele of FokI polymorphism was a risk factor for ovarian and skin cancer and a protective factor for glioma. Finally, a allele of ApaI polymorphism was a risk factor for basal cell cancer in Asian population.

MiRNA polymorphisms and risk of gastric cancer in Asian population.

miRNAs are endogenous 19- to 25-nt noncoding RNAs that can negatively regulate gene expression by directly cleaving target mRNA or by inhibiting its translation. Recent studies have revealed that miRNA plays a significant role in gastric cancer development either as a tumor suppressor gene or oncogene. miRNA-single-nucleotide polymorphisms (SNPs), as a novel class of functional SNPs/polymorphisms, have been identified as candidate biomarkers for gastric cancer susceptibility. On the basis of recent data, the present review summarizes current knowledge of the functional effects of miRNA-SNPs and their importance as candidate gastric cancer biomarkers. Additionally, this review also includes a meta-analysis of the most frequently studied miRNA-SNPs in gastric cancer.

HIF1A gene Pro582Ser polymorphism and susceptibility to digestive tract cancers: a meta-analysis of case-control studies.

Many existing studies have demonstrated that common polymorphisms in the hypoxia inducible factor-1α (HIF-1A) may contribute to the development of digestive tract cancers, but individually published studies showed inconclusive results. This meta-analysis aimed to derive a precise estimation of the relationships between HIF1A Pro582Ser polymorphism and the risk of digestive tract cancers. We searched CISCOM, CINAHL, Web of Science, PubMed, Google Scholar, EBSCO, Cochrane Library, and CBM databases from inception through May 1, 2013. Meta-analysis was performed using the STATA 12.0 software. We assessed 6 case-control studies that included a total of 911 digestive tract cancer patients and 2774 healthy controls. Our meta-analysis indicated that HIF1A Pro582Ser polymorphism was associated with an increased risk of digestive tract cancer. Subgroup analysis by ethnicity suggested that HIF1A Pro582Ser polymorphism might increase an individual's susceptibility to digestive tract cancer in Asian populations. However, similar association was not observed in Caucasian populations. In conclusion, our findings suggest that HIF1A Pro582Ser polymorphism may contribute to the risk of digestive tract cancers, especially in Asian populations.