Association between MTHFR C677T polymorphism and thyroid cancer risk: a meta-analysis

In the light of the relationship between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and thyroid cancer (TC) exist objection, a meta-analysis of the MTHFR C677T polymorphism with thyroid cancer risk was performed. All the available studies were identified through a search of the PubMed, Embase, Web of Science, and Chinese Biomedical Literature Database (CBM) up to March 2014. The association between the MTHFR C677T polymorphism and thyroid cancer risk was conducted by odds ratios (ORs) and 95 % confidence intervals (95 % CIs). A total of five independent studies with 2,554 cases and 2,671 controls were included in our meta-analysis. Significant association was found between MTHFR C677T polymorphism and thyroid cancer risk in recessive model in overall populations (TT vs. TC/CC: OR?=?1.88, 95 % CI?=?1.59–2.21, P?=?0.00), but there was no association between MTHFR C677T polymorphism and thyroid cancer risk found in other four models in overall populations (T vs. C: OR?=?1.25, 95 % CI?=?0.96–1.62, P?=?0.10; TT vs. CC: OR?=?1.11, 95 % CI?=?0.93–1.33, P?=?0.26; TC vs. CC: OR?=?1.23, 95 % CI?=?0.84–1.82, P?=?0.29; TT/TC vs. CC: OR?=?1.28, 95 % CI?=?0.89–1.84, P?=?0.19). In the subgroup analysis base on the ethnicity, the results suggested that MTHFR C677T polymorphism was significantly associated with thyroid cancer risk both in Caucasian and Asian populations in recessive model: (Caucasians: TT vs. TC/CC: OR?=?2.28, 95 % CI?=?1.11–4.67, P?=?0.025; Asians: TT vs. TC/CC: OR?=?1.86, 95 % CI?=?1.57–2.20, P?=?0.00). In conclusions, our meta-analysis suggested that the MTHFR C677T polymorphism is associated with thyroid cancer both in Caucasians and Asians.     

The MTHFR C677T polymorphism and prostate cancer risk: new findings from a meta-analysis of 7306 cases and 8062 controls

Methylenetetrahydrofolate reductase (MTHFR) is an essential enzyme involved in folate metabolism; a single nucleotide polymorphism (SNP) C677T has been reported to be linked with altered incidences of several diseases. We here conducted a meta-analysis of 15 published epidemiological studies with a total of 7306 cases and 8062 controls to evaluate its association with prostate cancer risk with overall and subgroup analyses. No statistical relationship was found overall with any genetic model (TT vs. CC: OR = 0.80, 95%CI = [0.62, 1.04], P = 0.094; CT vs. CC: OR = 0.97, 95%CI = [0.84; 1.12], P = 0.667; Dominant: OR = 0.94, 95%CI = [0.82; 1.07], P = 0.343; Recessive: OR = 0.81, 95%CI = [0.64; 1.04], P = 0.104), but after the exclusion of several studies, we could observe the homozygote TT to confer less susceptibility to prostate cancer in carriers; moreover, different effects of the polymorphism on prostate cancer risk was detected from subgroup analysis stratified by participants' residential region: significant reduced prostate cancer risk was found to be associated with the polymorphism from Asian studies (TT vs. CC: OR = 0.47, 95%CI = [0.33; 0.67], P< 0.001; CT vs. CC: OR = 0.73, 95%CI = [0.60; 0.90], P = 0.002; Dominant: OR = 0.67, 95%CI = [0.56; 0.82], P< 0.001; Recessive: OR = 0.55, 95%CI = [0.40; 0.76], P< 0.001) while studies from Europe indicated a slight increased risk under dominant model with marginal significance (OR = 1.14, 95%CI = [0.99; 1.30], P = 0.064). Moreover, the protective effect of the polymorphism against prostate cancer was also shown by studies performed in yellow Asians (TT vs. CC: OR = 0.48, 95%CI = [0.31; 0.75], P = 0.001; CT vs. CC: OR = 0.68, 95%CI = [0.51; 0.90], P = 0.006; Dominant: OR = 0.63, 95%CI = [0.48; 0.82], P < 0.001; Recessive: OR = 0.57, 95%CI = [0.39; 0.84], P = 0.004). We propose that these phenomena should be viewed with the consideration of folate metabolism profile and different gene background as well as living habits of different populations, and more relevant studies should be conducted to confirm our hypothesis and provide a comprehensive and clear picture concerning this topic.     

IGFBP3 A-202C polymorphism and breast cancer susceptibility: a meta-analysis involving 33,557 cases and 45,254 controls

Published data on the association between insulin-like growth factor binding protein 3 (IGFBP3) A-202C polymorphism and breast cancer risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. Crude ORs with 95% CIs were used to assess the strength of association between them. A total of 27 studies including 33,557 cases and 45,254 controls were involved in this meta-analysis. Overall, significantly elevated breast cancer risk was associated with IGFBP3 C allele when all studies were pooled into the meta-analysis (CC vs. AA: OR = 1.06, 95% CI = 1.02–1.11; dominant model: OR = 1.04, 95% CI = 1.00–1.07). In the subgroup analysis by ethnicity, significantly increased risk was found for Caucasians (AC vs. AA: OR = 1.04, 95% CI = 1.00–1.08; CC vs. AA: OR = 1.05, 95% CI = 1.01–1.10; dominant model: OR = 1.04, 95% CI = 1.00–1.08) and Asians (CC vs. AA: OR = 1.35, 95% CI = 1.02–1.78; recessive model: OR = 1.38, 95% CI = 1.05–1.82). When stratified by study design, statistically significantly elevated risk was found among population-based studies (CC vs. AA: OR = 1.06, 95% CI = 1.01–1.11; dominant model: OR = 1.03, 95% CI = 1.00–1.07). In the subgroup analysis by menopausal status, no statistically significantly increased risk was found among premenopausal or postmenopausal women. In conclusion, this meta-analysis suggests that the IGFBP3 C allele is a low-penetrant risk factor for developing breast cancer.     

MTHFR C677T polymorphism contributes to prostate cancer risk among Caucasians: A meta-analysis of 3511 cases and 2762 controls

Published data regarding the association between 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms and prostate cancer risk have been conflicting. To derive a more precise estimation of the relationship, a meta-analysis was performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association between MTHFR C677T and A1298C polymorphisms and prostate cancer risk. Six studies including 3511 cases and 2762 controls described C677T genotypes, among which four articles totalling 838 cases and 1121 controls described A1298C genotypes, were involved in this meta-analysis. Overall meta-analysis indicated that the 677T allele was more likely to exert a protective effect on prostate cancer risk (OR = 0.81, 95% CI: 0.68–0.98) with a recessive genetic model. No association was found for the 677CT genotype and the 677TT mutant homozygote with prostate cancer risk compared with 677CC, with OR = 1.13 (95% CI: 0.88–1.45) and OR = 0.85 (95% CI: 0.71–1.03), respectively. No evidence of an association of MTHFR A1298C polymorphism with prostate cancer was found. This meta-analysis supports that the C677T of the MTHFR gene is a low-penetrance susceptibility gene for prostate cancer, and might provide protective effects against prostate cancer risk.     

Positive association between MTHFR C677T polymorphism and oral cancer risk: a meta-analysis

Methylenetetrahydrofolate reductase (MTHFR) is a central enzyme involved in regulating the metabolic function of folate, which plays a pivotal role in DNA synthesis, repair, and methylation. The role of MTHFR C677T polymorphism in oral cancer risk has been reported with conflicting evidence. We conducted this study to appropriately estimate the effect size. We searched eligible studies in medicine-specific databases (PubMed, EMBASE, and Web of Knowledge) using (polymorphism) OR (polymorphisms) AND (methylenetetrahydrofolate reductase) OR (MTHFR) AND (oral cancer). A total of seven studies were summarized. This meta-analysis of the combined data showed a marginal association of MTHFR C677T polymorphism with oral cancer risk [odds ratio (OR)?=?0.86, 95 % confidence interval (CI)?=?0.73–1.00 for CT vs. CC]. We also found decreased oral cancer risk in Asian population and hospital-based studies. Moreover, heavy drinkers were found to have a significantly higher risk of developing such cancer as compared to the non-heavy drinkers. These results suggest that MTHFR C677T polymorphism may play a role in oral cancer carcinogenesis in Asian population and heavy drinkers.     

RAD51 G135C polymorphism is associated with breast cancer susceptibility: a meta-analysis involving 22,399 subjects

Several studies have investigated the associations between RAD51 G135C polymorphism and the susceptibility to breast cancer, but results have been inconclusive. In order to derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 17 case control studies, including 12,153 cases and 10,245 controls, were selected. Overall, significant decreased risk was found for the additive model (OR = 0.995, 95% CI = 0.991–0.998) and dominant model (OR = 0.994, 95% CI = 0.991–0.998). In the subgroup analysis by ethnicity, statistically significantly decreased risk was found in Asians (additive model: OR = 0.977, 95% CI = 0.954–1.000 and dominant model: OR = 0.981, 95% CI = 0.963–1.000). In conclusion, this meta-analysis suggests that the RAD51 G135C polymorphism is a low-penetrant risk factor for developing breast cancer.     

Significant association between MTHFR C677T polymorphism and hepatocellular carcinoma risk: a meta-analysis

Previous studies investigated the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and hepatocellular carcinoma risk, but the impact of MTHFR C677T polymorphism on hepatocellular carcinoma was still unclear, owing to the obvious inconsistence from those studies. This study aimed to quantify the strength of the association between MTHFR C677T polymorphism and hepatocellular carcinoma risk by performing a meta-analysis. We searched the PubMed and Wanfang databases for studies on the association between MTHFR C677T polymorphism and hepatocellular carcinoma risk. We estimated the pooled odds ratios (ORs) with their 95 % confidence intervals (95 % CIs) to assess the association. Fifteen studies with 8,625 participants were finally included into the meta-analysis. Meta-analyses of total 15 studies suggested that MTHFR C677T polymorphism was significantly associated with an increased risk of hepatocellular carcinoma under two main genetic models (for TT versus CC, OR?=?1.19, 95 % CI 1.03–1.37, P?=?0.016; for TT versus CT/CC, OR?=?1.14, 95 % CI 1.01–1.28, P?=?0.032). Subgroup meta-analyses suggested that MTHFR C677T polymorphism was associated with an increased risk of hepatocellular carcinoma in Asians, but not in Caucasians. Thus, individuals with homozygote genotype TT of MTHFR C677T have obviously increased risk of hepatocellular carcinoma.     

FASLG T844C polymorphism and susceptibility to breast cancer: a meta-analysis

Many studies were published to assess the association between FASLG T844C polymorphism and susceptibility to breast cancer, but the data were controversial. A meta-analysis was performed to assess the association comprehensively. We performed a comprehensive search in PubMed, Embase, and Web of Science to find eligible studies. Six studies with a total of 6,784 participants were finally included into the meta-analysis. There were a total of 3,382 cases with breast cancer and 3,402 controls in those six studies. Odds ratio (OR) with 95 % confidence interval (95 %CI) was used to evaluate the association. Overall, there was an obvious association between FASLG T844C polymorphism and breast cancer under all four contrast models (for C versus T: OR?=?1.26, 95 %CI 1.05–1.50, P _OR?=?0.011; for CC versus TT: OR?=?1.42, 95 %CI 1.11–1.81, P _OR?=?0.005; for CC versus TT/TC: OR?=?1.41, 95 %CI 1.06–1.88, P _OR?=?0.019; for CC/TC versus TT: OR?=?1.16, 95 %CI 1.01–1.33, P _OR?=?0.038). In the subgroup analysis by ethnicity, there was an obvious association between FASLG T844C polymorphism and breast cancer in Asians, but there was no obvious association in Caucasians. The meta-analysis suggests that there is an association between FASLG T844C polymorphism and susceptibility to breast cancer, especially in Asians.     

MTHFR C677T polymorphism and colorectal cancer risk in Asians, a meta-analysis of 21 studies

Background: Previous studies concerning the association between methylenetetrahydrofolate reductase(MTHFR) C677T polymorphism and colorectal cancer risk in Asian populations generated conflicting results.A meta-analysis was therefore performed to allow a more reliable estimate of any link. Methods: Relevantstudies concerning the association between the MTHFR C677T polymorphism and risk of colorectal cancer wereincluded into this meta-analysis. The quality of the studies was assessed according to a predefined scale. Oddsratios (ORs) and 95% confidence intervals (CIs) were determined for this gene-disease association using fixedor random effect models according to the heterogeneity between included studies. Results: Finally, 21 studieswith a total of 6692 cases and 8266 controls were included. Meta-analyses showed that there was an obviousassociation of the MTHFR 677T allele with decreased risk of colorectal cancer (OR = 0.91, 95%CI=0.85-0.98,P=0.011). Subgroup analyses by country further identified this association, with dietary folate as the main sourceof heterogeneity. Conclusion: The MTHFR 677T allele is associated with a lower risk of colorectal cancer inAsian populations, and there is effect modification by population plasma folate.     

Methylenetetrahydrofolate reductase C677T polymorphism and cervical cancer risk: a meta-analysis

Background: Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the metabolism of folate,and the role of MTHFR C677T polymorphism in cervical carcinogenesis is still controversial. Method: Weperformed a meta-analysis of all relevant case-control studies that examined any association between the C677Tpolymorphism and cervical cancer risk. We estimated summary odds ratios (ORs) with their confidence intervals(CIs) to assess links. Results: Finally, 10 studies with a total of 2113 cervical cancer cases and 2804 controls wereincluded. Results from this meta-analysis showed that significantly elevated cervical cancer risk was associatedwith the MTHFR T allele in the Asian population under conditions of two genetic comparison models (for TTvs. CC, OR = 1.37, 95%CI 1.00-1.87, P = 0.050; for TT vs. TC+CC: OR = 1.34, 95%CI 1.01-1.77, P = 0.039).However, there was no obvious association between the MTHFR C677T polymorphism and cervical cancer riskin the other populations. Conclusion: The MTHFR C677T polymorphism is associated with cervical cancer riskin Asians, while any possible link in the Caucasian population needs further studies.     

MTHFR C677T and colorectal cancer risk: A meta-analysis of 25 populations

The common functional methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism may influence the risk of colorectal cancer (CRC), but data from published studies with individually low statistical power are conflicting. To clarify the role of MTHFR C677T genotype in CRC, we considered all available studies in a meta-analysis. Studies reporting on MTHFR C677T genotype and CRC were searched in PubMed up to April 2006. The principle prior hypothesis was that homozygosity for MTHFR 677TT would be associated with reduced risk of CRC. Data were available for 29,931 subjects, including 12,243 with CRC, from 25 independent populations. Compared to the homozygous CC genotype, the MTHFR 677TT genotype was associated with a reduced risk of CRC (odds ratio (OR): 0.83; 95% confidence interval (CI): 0.75-0.93; p = 0.001). There was some heterogeneity among the results of individual studies, but this was not statistically significant (heterogeneity p = 0.12; I2 = 25.8%). Heterozygosity for MTHFR 677 did not influence CRC risk (OR: 0.99; 95% CI: 0.94-1.04). These findings indicate that individuals homozygous for the MTHFR 677TT genotype are at moderately reduced risk of CRC, and support the proposal that common genetic variation in the MTHFR gene contributes to CRC susceptibility, probably accounting for at least 9% of the total incidence.     

The MTHFR C677T polymorphism, estrogen exposure and breast cancer risk: a nested case-control study in Taiwan

BACKGROUND: We evaluated the effects of the MTHFR C677T polymorphism and its interaction with estrogen exposure on breast cancer risk in a nested case-control study conducted in Taiwan. MATERIALS AND METHODS: A total of 88 histologically confirmed breast cancer cases and 344 cancer-free controls were recruited between July 1992 and December 2000. The MTHFR C677T genotype was determined by a PCR-RFLP-based assay. All subjects completed in-person interviews. RESULTS: There was a significant trend of breast cancer in relation to prolonged exposure to estrogens prior to the first full-term pregnancy (FFTP) (p for trend = 0.0015). In contrast, there was no statistically significant association between the risk of breast cancer and the MTHFR C677T genotype. However, a significantly elevated risk of breast cancer predisposed by the MTHFR 677T variant genotype (CT and TT) was observed in women with prolonged exposure to estrogens prior to FFTP (adjusted OR = 4.98, 95% CI = 2.00-12.43). CONCLUSION: The results of this study suggest that the MTHFR 677T variant genotype per se may have no overall association with breast cancer risk, but a sizable association could be observed in the presence of relevant environmental exposure.     

MTHFR C677T polymorphism contributes to the risk for gastric cancer

Methylenetetrahydrofolate reductase (MTHFR) has been demonstrated to be involved in carcinogenesis. Increasing individual studies have investigated the role of MTHFR C677T polymorphism in gastric cancer pathogenesis, but with inconsistent findings. The aim of this study was to clarify the potential association of the MTHFR C677T polymorphism with gastric cancer risk by pooling all available data from published case–control studies. We searched the PubMed, Embase, Web of Science, and Wanfang databases for all relevant publications to date. The pooled odds ratio (OR) with corresponding 95 % confidence interval (95 % CI) was calculated. Stratified analysis and sensitivity analysis were also carried out to estimate the strength of this association. A total of 25 case–control studies with 6,572 cases and 9,584 controls were retrieved. Overall, the ORs under five contrast models indicated that the MTHFR C677T variant was positively associated with gastric cancer risk (OR_{T vs. C}?=?1.21, 95 % CI 1.10–1.34, P _OR?<?0.001; OR_{TT vs. CC}?=?1.47, 95 % CI 1.22–1.76, P _OR?<?0.001; OR_{TC vs. CC}?=?1.20, 95 % CI 1.03–1.40, P _OR?=?0.022; OR_{TT?+?TC vs.?CC}?=?1.27, 95 % CI 1.10–1.47, P _OR?=?0.001; OR_{TT vs.?CC?+?TC}?=?1.29, 95 % CI 1.15–1.46, P _OR?<?0.001). Stratified analyses according to ethnicity and source of controls further confirmed the significant correlations. The current meta-analysis provides strong evidence that the MTHFR C677T polymorphism may be a risk factor for gastric cancer among Asians and Caucasians.     

The MTHFR C677T polymorphism and colorectal cancer: the multiethnic cohort study.

Methylenetetrahydrofolate reductase (MTHFR) is a key regulatory enzyme in the metabolism of folate, a nutrient that has been inversely related to colorectal cancer risk. The common C677T variant in the MTHFR gene results in a reduced activity of this enzyme, thereby increasing the availability of folate for the production of thymidylate and purine for DNA synthesis and repair. We investigated the association of the 677TT genotype with colorectal cancer in a case-control study of 822 cases and 2,021 controls nested within the Multiethnic Cohort Study. The Multiethnic Cohort Study is a large prospective study of men and women of Japanese, White, African American, Latino, and Native Hawaiian origin, residing in Hawaii and Los Angeles. After adjusting for covariates, we found an inverse association between colorectal cancer risk and the TT genotype, with odds ratios (OR; and 95% confidence intervals) for the CC, CT, and TT genotypes of 1.00, 1.01 (0.84-1.21), and 0.77 (0.58-1.03), respectively. This association was similar in both sexes, stronger at high levels of folate intake, and limited to light and nondrinkers (P for interaction with ethanol = 0.02). An analysis by subsite (rectum versus colon) and stage (regional/distant versus in situ/localized) showed that the inverse association with the TT genotype was limited to colon tumors, especially those diagnosed at an advanced stage. The OR for the TT versus CC genotype for early- and late-stage colon cancer was 0.88 (0.58-1.33) and 0.52 (0.32-0.85), respectively (P for difference in OR = 0.04). The frequency of the T allele was relatively low in African Americans (0.13) and Native Hawaiians (0.22), consistent with their greater likelihood of presenting at a late stage when diagnosed with colorectal cancer. This study corroborates previous findings of an inverse association of the MTHFR 677TT genotype with colorectal cancer, especially at high levels of folate and low levels of ethanol intake. It also suggests that this effect may be specific to advanced colon cancer.     

Glutathione S-transferase M1 polymorphism and breast cancer susceptibility: a meta-analysis involving 46,281 subjects

Published data on the association between present/null polymorphism of glutathione S-transferase M1 (GSTM1) and breast cancer risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. Medline, PubMed, Embase, and Web of Science were searched. Crude ORs with 95% CIs were used to assess the strength of association between the GSTM1 present/null polymorphism and breast cancer risk. The pooled ORs were performed for null versus present genotype. A total of 59 studies including 20,993 cases and 25,288 controls were involved in this meta-analysis. Overall, significantly elevated breast cancer risk was associated with null genotype when all studies were pooled into the meta-analysis (OR = 1.10, 95% CI = 1.04–1.16). In the subgroup analysis by ethnicity, significantly increased risks were found for Caucasians (OR = 1.05, 95% CI = 1.00–1.10) and Asians (OR = 1.21, 95% CI = 1.08–1.35). When stratified by population-based studies or hospital-based studies, statistically significantly elevated risks were found among population-based studies (OR = 1.11, 95% CI = 1.03–1.20). In the subgroup analysis by menopausal status, statistically significantly increased risks were found among postmenopausal women (OR = 1.15, 95% CI = 1.04–1.28). In conclusion, this meta-analysis suggests that the GSTM1 null genotype is a low-penetrant risk factor for developing breast cancer.     

TGFB1 L10P polymorphism is associated with breast cancer susceptibility: evidence from a meta-analysis involving 47,817 subjects

Published data on the association between TGFB1 L10P polymorphism and breast cancer risk are inconclusive. In order to derive a more precise estimation of the relationship, a meta-analysis was performed. Crude ORs with 95% CIs were used to assess the strength of association between them. A total of 30 studies including 20,401 cases and 27,416 controls were involved in this meta-analysis. Overall, significantly elevated breast cancer risk was associated with TGFB1 10P allele when all studies were pooled into the meta-analysis (LP vs. LL: OR = 1.046, 95% CI = 1.003–1.090; dominant model: OR = 1.052, 95% CI = 1.012–1.095). In the subgroup analysis by ethnicity, statistically significantly elevated risk was found in Caucasians (dominant model: OR = 1.045, 95% CI = 1.001–1.091). When stratified by study design, statistically significantly elevated risk was found based on population-based studies (dominant model: OR = 1.076, 95% CI = 1.019–1.136). In conclusion, this meta-analysis suggests that the TGFB1 10P allele may be a low-penetrant risk factor for developing breast cancer. However, large sample and representative population-based studies with homogeneous breast cancer patients and well-matched controls are warranted to confirm this finding.     

RAD51 135G>C polymorphism contributes to breast cancer susceptibility: a meta-analysis involving 26,444 subjects

RAD51 plays a key role in homologous recombination repair of double-stranded DNA breaks which may cause chromosomal breaks and genomic instability. We performed a meta-analysis of 9 epidemiological studies involving 13,241 cases and 13,203 controls that examined the association between RAD51 135G>C polymorphism and breast cancer. No significant association of RAD51 135G>C polymorphism with breast cancer was found in overall and European populations. However, after the studies which did not fulfill Hardy–Weinberg equilibrium were excluded, we observed an overall significant increased breast cancer risk (for the recessive model CC vs. GG/CG: OR = 1.35, 95% CI = 1.05–1.74, P _{heterogeneity} = 0.06). In summary, our meta-analysis suggested the RAD51 135G>C polymorphism may contribute to breast cancer susceptibility.     

TGF-β1 29T/C polymorphism and breast cancer risk: a meta-analysis involving 25,996 subjects

Transforming growth factor β1 (TGF-β1) is a cytokine, playing an important role in controlling cell proliferation and differentiation involved in breast cancer. It was reported the 29T/C polymorphism in TGF-β1 has been implicated in breast cancer risk. However, studies on the association between this polymorphism and breast cancer remain conflicting. To derive a more precise estimation of the relationship, a meta-analysis of 10,341 cases and 15,655 controls from fifty published case-control studies was performed. Our analysis suggested that 29T/C has no association with a trend of breast cancer risk when using both dominant [odds ratio (OR) = 1.01, 95% confidence intervals (CI) 0.96–1.07] and recessive models (OR = 0.98, 95% CI 0.89–1.08) to analyze the data. In ethnic subgroups analysis, 29T/C also did not appear to be risk factors for breast cancer. However, larger scale primary studies are required to further evaluate the interaction of TGF-β1 29T/C polymorphism and breast cancer risk in specific populations.     

Polymorphisms of MTHFR C677T and A1298C association with oral carcinoma risk: a meta-analysis

Investigations regarding association of MTHFR polymorphisms with oral carcinoma risk have yielded inconclusive results. Thus, meta-analyses were performed. Results showed that no associations of C677T polymorphisms with oral carcinoma were observed for the overall data. In subgroup analyses by drinking status, homozygous TT alleles exhibited elevated oral cancer susceptibility in heavy drinkers. For A1298C polymorphism, CC alleles presented a possible preventive role for oral cancer. Collectively, results suggest that MTHFR 677TT polymorphism might be a low-penetrant risk factor for oral carcinoma only in heavy drinkers. Conversely, 1298CC alleles might play a preventive role for oral cancer.