HFE, MTHFR, and FGFR4 genes polymorphisms and breast cancer in Brazilian women

Association Between Multiple Single Nucleotide Polymorphisms in Folate Metabolism Pathway and Breast Cancer Risk in Georgian Women: A Case-Control Study

Background

The folate metabolism pathway plays an integral part in DNA synthesis, methylation, and repair. Methylenetetrahydrofolate reductase (MTHFR) and methylenetetrahydrofolate dehydrogenase (MTHFD1) are both enzymes that are involved in this pathway, and the single nucleotide polymorphisms (SNPs) in genes coding for them have modulatory effects on DNA expression. This study aimed to investigate the relationship between MTHFR C677T (rs1801133) and MTHFD1 G1958A (rs2236225) polymorphisms and the risk of developing breast cancer in Georgian women.

Methods

A case-control study was performed examining the MTHFR C677T and MTHFD1 G1958A SNP in breast cancer-confirmed cases and healthy matched controls. Real time-polymerase chain reaction (PCR) was used to genotype SNPs. The case individuals' pathology reports were obtained following surgeries for cancer characteristic data. Statistical analysis was performed to investigate the significance of the acquired data.

Results

Statistical analysis of MTHFR C677T SNP revealed that the CT genotype increased the risk of breast cancer by 2.17 folds in the over-dominant model. Statistical analysis of MTHFD1 G1958A SNP showed that the GA genotype increased the risk of breast cancer by 4.12 folds in the codominant model and 2.41 folds in the over-dominant model. No statistically significant link was found between genotypes and lymph node status, however, patients with the CT genotype had higher percentages of proliferative activity.

Conclusions

Breast cancer seems to have a statistically significant association with the CT genotype in MTHFR C677T and the GA genotype in MTHFD1 G1958A in Georgian women.

Association between folate metabolism polymorphisms and breast cancer: a case-control study

We investigated the association between methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), methionine synthetase (MTR A2756G), and methionine synthase reductase (MTRR A66G) polymorphisms involved in folate pathway and breast cancer risk, and the interaction between these polymorphisms and tobacco and alcohol consumption. Furthermore, we evaluated the association between these polymorphisms and clinicopathological variables. This case-control study included 606 Brazilian women, comprising 128 patients with breast cancer and 478 controls. MTHFR and MTR polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and MTRR polymorphisms using real-time PCR. Age ≥50 years (odds ratio [OR]: 2.65; 95% confidence interval [CI]: 1.65-4.26; p<0.001) and alcohol consumption (OR: 1.76; 95% CI: 1.0-2.85; p=0.021) were associated with an increased risk of breast cancer. For MTHFR A1298C, we observed a reduced risk of developing breast cancer in the codominant model (genotype CC-OR: 0.22; 95% CI: 0.06-0.74; p=0.014), recessive model (OR: 0.22; 95% CI: 0.07-0.76 p=0.004), and log-additive model (OR: 0.70; 95% CI: 0.49-0.98; p=0.035). Women aged ≥50 years and those who are alcohol consumers had increased susceptibility to breast cancer, and MTHFR A1298C modulated the risk for this disease. This is the first study to evaluate the association between polymorphisms in folate metabolism and breast cancer in the northwest region of São Paulo State, Brazil.

An updated meta-analysis of the association between fibroblast growth factor receptor 4 polymorphisms and susceptibility to cancer

Fibroblast growth factor receptor 4 (FGFR4) is a cell surface receptor tyrosine kinases (RTKs) for FGFs.

Several studies have focused on the association between FGFR4 polymorphisms and cancer development. This meta-analysis aimed to estimate the association between FGFR4 rs351855 (Gly³⁸⁸Arg), rs1966265 (Val¹⁰Ile), rs7708357, rs2011077, and rs376618 polymorphisms and cancer risk. Eligible studies were identified from electronic databases. All statistical analyses were achieved with the STATA 14.0 software. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to quantitatively estimate the association. Overall, no significant association was found among rs351855, rs2011077, and rs376618 polymorphisms with the risk of overall cancer. The rs1966265 polymorphism significantly decreased the risk of cancer in recessive (OR = 0.87, 95% CI = 0.78–0.97, P=0.009, TT vs CT+CC) genetic model. Whereas the rs7708357 polymorphism was positively associated with cancer risk in dominant (OR = 1.17, 95% CI = 1.02–1.36, P=0.028) genetic model. Stratified analysis revealed that rs351855 variant significantly increased the risk of prostate cancer in heterozygous (OR = 1.16, 95% CI = 1.02–1.32, P=0.025 AG vs GG), dominant (OR = 1.20, 95% CI = 1.06–1.35, P=0.004, AG+AA vs GG), and allele (OR = 1.22, 95% CI = 1.06–1.41, P=0.005, A vs G) genetic models.

In summary, the findings of this meta-analysis indicate that rs1966265, rs7708357, and rs351855 polymorphisms are correlated to cancer development. Further well-designed studies are necessary to draw more precise conclusions.

Effects of FGFR4 G388R, V10I polymorphisms on the likelihood of cancer

The correlation between G388R or V10I polymorphisms of fibroblast growth factor receptor (FGFR) 4 gene and the risk of carcinoma has been investigated previously, but the results are contradictory. Odds ratios (ORs) with 95% confidence intervals (95%CIs), in silico tools, and immunohistochemical staining (IHS) were adopted to assess the association. In total, 13,793 cancer patients and 16,179 controls were evaluated in our pooled analysis. Summarization of all the studies showed that G388R polymorphism is associated with elevated susceptibility to cancer under homozygous comparison (OR = 1.21, 95%CI = 1.03–1.43, P = 0.020) and a recessive genetic model (OR = 1.21, 95%CI = 1.04–1.41, P = 0.012). In the stratification analysis by cancer type and ethnicity, similar findings were indicated for prostate cancer, breast cancer, and individuals of Asian descendant. Polyphen2 bioinformatics analysis showed that the G388R mutation is predicted to damage the protein function of FGFR4. IHS analysis indicated that FGFR4 expression is increased in advanced prostate cancer. These findings may guide personalized treatment of certain types of cancers. Up-regulation of FGFR4 may be related to a poor prognosis in prostate cancer.

MTHFR, XRCC1 and OGG1 genetic polymorphisms in breast cancer: a case-control study in a population from North Sardinia

BACKGROUND

Despite conflicting results, considerable evidence suggests the association between single nucleotide polymorphisms in MTHFR, XRCC1 and OGG1 genes and, risk of developing breast cancer. Here a case-control study is reported, including 135 breat cancer patients and 112 healthy women, all representative of Northern Sardinian population.

METHODS

Polymerase chain reaction/restriction fragment length polymorphism method was used to determine the genotypes of five polymorphisms: MTHFR C677T (rs1801133) and A1298C (rs1801131), XRCC1 Arg194Trp (rs1799782) and Arg399Gln (rs25487) and OGG1 Ser326Cys (rs1052133). Allelic, genotypic and haplotype association analyses with disease risk and clinicopathological parameters were performed.

RESULTS

A nominally significant association with breast cancer risk was observed for MTHFR C677T polymorphism heterozygous genotype in the codominant model (OR: 0.57, 95% CI: 0.32-1.00, p = 0.049) and for Cys/Cys genotype of the OGG1 Ser326Cys polymorphism in the recessive model (OR: 0.23, 95% CI: 0.05-1.11, p = 0.0465). No significant differences were found at genotype-level for A1298C polymorphism of the MTHFR gene and Arg194Trp and Arg399Gln of the XRCC1 gene. Furthermore, the OGG1 and XRCC1 rs25487 polymorphisms were nominally associated with PgR, Her2 status and with sporadic breast cancer, respectively.

CONCLUSIONS

Based on genetic characteristics of individuals included in this study, results suggest that MTHFR CT and OGG1 Cys/Cys genotypes have a protective effect that may have an influence on breast cancer risk in a representative Northern Sardinian population.

C677T and A1298C methylenetetrahydrofolate reductase polymorphisms and breast cancer susceptibility among Latinos: a meta-analysis

BACKGROUND

Previous meta-analyses have shown an ethnic dependency of the C677T and the A1298C methylenetetrahydrofolate reductase (MTHFR) polymorphisms, with no focus on the Latino population. For Latinos, many studies have examined these polymorphisms and breast cancer susceptibility, yielding no concise result. Therefore, we undertook this meta-analysis to determine the effect these polymorphisms have on breast cancer risk for Latinos.

METHODS

PubMed, EBSCO, LILACS, Scopus, and Latin American-specific databases were searched for studies exploring the association between the MTHFR polymorphisms and breast cancer susceptibility in Latinos until January 2019. Genotype distributions were extracted and, depending on the level heterogeneity determined by the ψ²-based Q test and the I² test, fixed-effects or random-effects models were used to calculate pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) for the heterozygous, homozygous, dominant, recessive, and allelic genetic models. No publication bias was detected by the Begg-Mazumdar's test and Egger's test.

RESULTS

Of the 280 retrieved publications, 9 studies were included: 9 for the C677T polymorphism and 5 for the A1298C polymorphism. For the C677T polymorphism, there was an elevated risk for the homozygous (OR 1.42, 95% CI 1.05-1.92), the dominant (OR 1.16, 95% CI 1.02-1.31), the recessive (OR 1.33, 95% CI 1.01-1.75), and the allelic model (OR 1.17, 95% CI 1.03-1.33, p < 0.01). No association between the A1298C polymorphism and the risk to develop breast cancer was determined.

CONCLUSION

The results indicated that, for Latinos, the C677T polymorphism is associated with a significant risk for developing breast cancer, whereas the A1289C polymorphism does not.

Functional FGFR4 Gly388Arg polymorphism contributes to cancer susceptibility: Evidence from meta-analysis

Fibroblast growth factor receptor 4 (FGFR4) is a member of receptor tyrosine kinase family. A functional Gly388Arg (rs351855 G>A) polymorphism in FGFR4 gene causes a glycine-to-arginine change at codon 388 within the transmembrane domain of the receptor. Although the FGFR4 rs351855 G>A polymorphism has been implicated in cancer development, its association with cancer risk remains controversial. Here, we have systematically analyzed the association between the rs351855 G>A polymorphism and cancer risk by performing a meta-analysis of 27 studies consisting of 8,682 cases and 9,731 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure the strength of the association. The rs351855 G>A polymorphism was associated with an increased cancer risk under the recessive model (OR=1.19, 95% CI=1.01-1.41). Stratified analysis by cancer type indicated the rs351855 G>A polymorphism was associated with an increased risk of breast and prostate cancer, but a decreased risk of lung cancer. This meta-analysis demonstrates the FGFR rs351855 G>A polymorphism is associated with increased cancer risk and suggests it could potentially serve as a chemotherapeutic target or biomarker to screen high-risk individuals.

Analysis of single nucleotide variants of HFE gene and association to survival in The Cancer Genome Atlas GBM data

Human hemochromatosis protein (HFE) is involved in iron metabolism. Two major HFE polymorphisms, H63D and C282Y, have been associated with an increased risk of cancers. Previously, we reported decreased gender effects in overall survival based on H63D or C282Y HFE polymorphisms patients with glioblastoma multiforme (GBM). However, the effect of other single nucleotide variation (SNV) in the HFE gene on the cancer development and progression has not been systematically studied. To expand our finding in a larger sample, and to identify other HFE SNV, we analyzed the frequency of somatic SNV in HFE gene and its relationship to survival in GBM patients using The Cancer Genome Atlas (TCGA) GBM (Caucasian only) database. We found 9 SNVs with increased frequency in blood normal of TCGA GBM patients compared to the 1000Genome. Among 9 SNVs, 7 SNVs were located in the intron and 2 SNVs (i.e., H63D, C282Y) in the exon of HFE gene. The statistical analysis demonstrated that blood normal samples of TCGA GBM have more H63D (p = 0.0002, 95% Confidence interval (CI): 0.2119–0.3223) or C282Y (p = 0.0129, 95% CI: 0.0474–0.1159) HFE polymorphisms than 1000Genome. The Kaplan-Meier survival curve for the 264 GBM samples revealed no difference between wild type (WT) HFE and H63D, and WT HFE and C282Y GBM patients. In addition, there was no difference in the survival of male/female GBM patients based on HFE genotype. There was no correlation between HFE expression and survival. In conclusion, the current results suggest that somatic HFE polymorphisms do not impact GBM patients’ survival in the TCGA data set of GBM.

Can MTHFR C677T and A1298C Polymorphisms Alter the Risk and Severity of Sporadic Breast Cancer in Brazilian Women?

INTRODUCTION

Polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR) modify the risk and severity of sporadic breast cancer (BC). In this context, the MTHFR C677T and A1298C polymorphisms have been associated with risk and severity of sporadic BC.

PATIENTS AND METHODS

In total, 253 women with BC and 257 controls were enrolled in this study. Polymorphisms were analyzed using restriction fragment length polymorphism - polymerase chain reaction. Epidemiology, tumor characteristics, and reproductive factors were considered in the analysis. Statistical tests included the χ² test, the Fisher exact test, and the Mann-Whitney and Kruskal-Wallis tests, or parametric equivalents.

RESULTS

MTHFR polymorphisms were not a risk factor for BC. The 677CC genotype was associated with distant metastasis (odds ratio [OR] = 5.311; 95% confidence interval [CI] = 1.124-25.09) and lower estrogen receptor expression, whereas the 1298AA genotype was associated with stage 0 (OR = 0.244; 95% CI = 0.077-0.771) and increased estrogen receptor expression. In haplotype analysis, 677CC/1298AA was associated with hypertension (OR = 1.979; 95% CI = 1.036-3.782), and 677CT/1298AC was associated with invasive carcinoma of no special type (OR = 0.472; 95% CI = 0.243-0.918) and stage 0 (OR = 3.476; 95% CI = 1.341-10.47).

CONCLUSION

The MTHFR C677T and A1298C polymorphisms do not alter the risk of BC, but are associated with the clinical severity of BC.

Meta-Analysis of the Association between H63D and C282Y Polymorphisms in HFE and Cancer Risk

BACKGROUND

Previous studies suggested that the H63D and C282Y polymorphisms in the HFE genes were susceptible to many cancer types, nevertheless, the present results were inconclusive. Thus, the present study was aimed to evaluate the association between the HFE polymorphisms (H63D and C282Y) and cancer risk via meta-analysis.

MATERIALS AND METHODS

We retrieved PubMed, Google Scholar, Embase and Web of Science databases for all eligible studies up to April 1, 2015. All the statistical analysis was conducted by STATA 12.0.

RESULTS

Finally, a total of 20 publications including 24 case-control studies, comprising 6,524 cases and 31,080 controls for HFE-C282Y polymorphism and 19 publications including 21 case control studies, comprising 5,648 cases and 14,257 controls for HFE-H63D polymorphism were enrolled in our analysis. An increased risk for overall cancer risk was identified in HFE-H63D polymorphism under allele contrast (D vs H: OR=1.153; 95%CI=1.031- 1.289, Pheterogeneity=0.002), homozygotes vs wide type (DD vs HH: OR=1.449; 95%CI=1.182-1.777, Pheterogeneity=0.391), dominant model (DD+HD vs HH: OR=1.145; 95%CI=1.007-1.301, Pheterogeneity=0.002) and recessive model (DD vs HD+HH: OR=1.416 ; 95%CI=1.156-1.735, Pheterogeneity=0.549), as well as HFE- C282Y under homozygotes vs wide type (YY vs CC: OR=1.428, 95%CI=1.017-2.006, Pheterogeneity=0.220). In addition, in the stratified analysis by cancer type, an increased risk was identified in hepatocellular carcinoma and breast cancer in C282Y polymorphism, as well as pancreatic cancer in H63D polymorphism, whereas a decreased risk of colorectal cancer was identified in C282Y polymorphism.

CONCLUSIONS

Present study suggested that H63D and C282Y polymorphisms associated with an increased risk of overall cancer. Nevertheless, well- designed study with large sample size will be continued on this issue of interest.

The risk of new-onset cancer associated with HFE C282Y and H63D mutations: evidence from 87,028 participants

To investigate the association between mutation of HFE (the principal pathogenic gene in hereditary haemochromatosis) and risk of cancer, we conducted a meta‐analysis of all available case–control or cohort studies relating to two missense mutations, C282Y and H63D mutations. Eligible studies were identified by searching databases including PubMed, Embase and the ISI Web of Knowledge. Overall and subgroup analyses were performed and odds ratios (ORs) combined with 95% confidence intervals (CIs) were applied to evaluate the association between C282Y mutation, H63D mutation and cancer risk. Sensitivity and cumulative analyses were used to evaluate the stability of the results. A total of 36 eligible studies were included, comprising 13,680 cases and 73,348 controls. C282Y was significantly associated with elevated cancer risk in a recessive genetic model (OR: 1.991, 95% CI: 1.448–2.737). On subgroup analysis stratified by cancer type, statistically significantly increased cancer risks were found for breast cancer, colorectal cancer and hepatocellular carcinoma in a recessive model. When stratified by territory, a significantly increased risk of cancer was found in Oceanic populations in a recessive model and in Asian populations in an allele model and dominant model. H63D mutation did not significantly increase overall cancer risk in any genetic model. However, when, stratified by territory, an increased cancer risk was found in the Asian population in an allele and dominant. C282Y but not H63D mutation was related to elevated cancer risk. Further large‐scale studies considering gene–environment interactions and functional research should be conducted to further investigate this association.

Methylenetetrahydrofolate reductase gene C677T polymorphism and breast cancer risk: Evidence for genetic susceptibility

There are several evidences supporting the role of 5–10 methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms in breast cancer (BC). Case control association studies on breast cancer have been repeatedly performed over the last two decades, but results are inconsistent. We performed a meta-analysis to confirm the association between MTHFR C677T polymorphism and BC risk.

The articles were retrieved by searching the PubMed, Google Scholar, and Springer Link databases. Crude odds ratios (OR) with 95% confidence intervals (CIs) was used to assess the strength of association between C677T polymorphism and BC. Publication bias was assessed by Egger's and Begg-Mazumdar tests. Meta-analysis was performed with Open Meta Analyst.

Total 75 studies with 31,315 cases and 35, 608 controls were found suitable for the inclusion in the present meta-analysis. The results of meta-analysis suggested that there were moderate significant association between C677T polymorphism and BC risk using overall comparisons in five genetic models (T vs. C: OR = 1.08, 95% CI = 1.03–1.13, p = < 0.001; TT + CT vs. CC: OR = 1.06, 95% CI = 1.02–1.09, p = < 0.001; TT vs. CC: OR = 1.17, 95% CI = 1.06–1.28, p = 0.001; CT vs. CC OR = 1.05, 95% CI = 1.01–1.08, p = 0.005; TT vs. CT + CC: OR = 1.12, 95% CI = 1.03–1.22, p = 0.005). In conclusion, results of present meta-analysis showed modest association between MTHFR C677T polymorphism with breast cancer in total studies. However, sub-group analysis results based on ethnicity showed strong significant association between TT genotype and breast cancer (TT vs. CC; OR°=°1.26; 95% CI: 1.06–1.51; p = 0.009) in Asian population but in Caucasian population such association was not observed (TT vs. CC; OR°=°1.08; 95% CI: 0.99–1.14; p = 0.05).

Is fibroblast growth factor receptor 4 a suitable target of cancer therapy?

Fibroblast growth factors (FGF) and their tyrosine kinase receptors (FGFR) support cell proliferation, survival and migration during embryonic development, organogenesis and tissue maintenance and their deregulation is frequently observed in cancer development and progression. Consequently, increasing efforts are focusing on the development of strategies to target FGF/FGFR signaling for cancer therapy. Among the FGFRs the family member FGFR4 is least well understood and differs from FGFRs1-3 in several aspects. Importantly, FGFR4 deletion does not lead to an embryonic lethal phenotype suggesting the possibility that its inhibition in cancer therapy might not cause grave adverse effects. In addition, the FGFR4 kinase domain differs sufficiently from those of FGFRs1-3 to permit development of highly specific inhibitors. The oncogenic impact of FGFR4, however, is not undisputed, as the FGFR4-mediated hormonal effects of several FGF ligands may also constitute a tissue-protective tumor suppressor activity especially in the liver. Therefore it is the purpose of this review to summarize all relevant aspects of FGFR4 physiology and pathophysiology and discuss the options of targeting this receptor for cancer therapy.

MTHFR 677C>T polymorphism and the risk of breast cancer: evidence from an original study and pooled data for 28031 cases and 31880 controls

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) acts at an important metabolic point in the regulation of cellular methylation reaction. It assists in the conversion of 5, 10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. The latter aids in remethylation of homocysteine to de novo methionine that is required for DNA synthesis. The objective of this study was to examine the effect of MTHFR 677 C>T polymorphism on the risk of breast cancer in the Indian sub-continent.

METHODS AND RESULTS

We genotyped 677 C>T locus in 1096 individuals that were classified into cases (N=588) and controls (N=508). Genotype data were analyzed using chi-square test. No significant difference was observed in the distribution of genotypes between cases and controls in north Indian (P = 0.932), south Indian (P = 0.865), and pooled data (P = 0.680). To develop a consensus regarding the impact of 677C>T polymorphism on breast cancer risk, we also conducted a meta-analysis on 28031 cases and 31880 controls that were pooled from sixty one studies. The overall summary estimate upon meta-analysis suggested no significant correlation between the 677C>T substitution and breast cancer in the dominant model (Fixed effect model: OR = 0.97, P=0.072, Random effects model: OR = 0.96, P = 0.084) or the recessive model (Fixed effect model: OR = 1.05, P = 0.089; Random effects model: OR= 1.08, P= 0.067).

CONCLUSION

677 C>T substitution does not affect breast cancer risk in the Indo-European and Dravidian populations of India. Analysis on pooled data further ruled out association between the 677 C>T polymorphism and breast cancer. Therefore, 677 C>T substitution does not appear to influence the risk of breast cancer.

Evidence for the Influence of the Iron Regulatory MHC Class I Molecule HFE on Tumor Progression in Experimental Models and Clinical Populations

Proteins involved in iron regulation are modifiers of cancer risk and progression. Of these, the HFE protein (high iron gene and its protein product) is of particular interest because of its interaction with both iron handling and immune function and the high rate of genetic polymorphisms resulting in a mutant protein. Clinical studies suggest that HFE polymorphisms increase the risk of certain cancers, but the inconsistent outcomes suggest a more nuanced effect, possibly interacting with other genetic or environmental factors. Some basic science research has been conducted to begin to understand the implications of variant HFE genotype on cancer, but the story is far from complete. In particular, putative mechanisms exist for HFE to affect tumor progression through its role in iron handling and its major histocompatibility complex class I structural features. In this review, the current understanding of the role of HFE in cancer is described and models for future directions are identified.

Controversial roles of methylenetetrahydrofolate reductase polymorphisms and folate in breast cancer disease

Breast cancer (BC) represents a highly heterogeneous tumour at both the clinical and molecular levels. Single-nucleotide polymorphisms (SNPs) of the folate-metabolising enzyme methylenetetrahydrofolate-reductase (MTHFR) may modify the association between folate intake and BC and influence plasma folate concentration. The role of folate in BC is equivocal, association studies between the common MTHFR SNPs C677T and A1298C and BC risk are controversial. In this study, I have reviewed observed associations between folate intake, as well as its blood levels, and BC. The purpose of this review is to analyse the role of folate and the two SNPs associated with reduced enzyme activity in BC. I explored the most relevant and updated work that emphasises positive and negative associations among these variables. My findings indicate that no definitive conclusions can be drawn from the studies on this topic. However, this manuscript highlights variables that could be useful to explore in further association analyses.

A meta-analysis of genotypes and haplotypes of methylenetetrahydrofolate reductase gene polymorphisms in breast cancer

The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and breast cancer risk has been extensively explored, but their results are conflicting rather than conclusive. To derive a more precise estimation, we carried out not only an updated meta-analysis but also a combined analysis based on all the available studies estimating the association between MTHFR C677T and/or A1298C and breast cancer risk. With respect to C677T polymorphism, the results suggested that 677T allele was associated with significantly elevated breast cancer risk in overall analysis (T vs. C: OR 1.073, 95 % CI 1.028-1.120; TT vs. CC: OR 1.177, 95 % CI 1.072-1.293; TT vs. CC + CT: OR 1.175, 95 % CI 1.073-1.288); Stratifying by ethnicity, significantly increased risk was only found in East Asians (T vs. C: OR 1.150, 95 % CI 1.039-1.273; TT vs. CC: OR 1.441, 95 % CI 1.145-1.814; TT vs. CC + CT: OR 1.413, 95 % CI 1.148-1.739); When stratified by menopausal status, statistically significant association was found for postmenopausal women (CT + TT vs. CC: OR 1.092, 95 % CI 1.011-1.179). In regard to A1298C polymorphism, no significant associations were found between the polymorphism and breast cancer risk. With respect to MTHFR haplotypes, significantly elevated breast cancer risk was associated with 677T-1298C for overall result (OR 1.498, 95 % CI 1.143-1.962) and for Caucasians (OR 2.088, 95 % CI 1.277-3.416) when compared with 677C-1298A; Haplotype 677C-1298C might provide higher protection than 677C-1298A in East Asians (OR 0.840, 95 % CI 0.742-0.949). The combined genotypes for C677T and A1298C produced a significant OR for the 677TT/1298AC relative to 677CC/1298AA in overall population (OR 2.047, 95 % CI 1.275-3.288); When stratified by ethnicity, significant ORs were only found for East Asians (677CC/1298CC vs. 677CC/1298AA: OR 0.686, 95 % CI 0.478-0.985; 677TT/1298AC vs. 677CC/1298AA: OR 2.181, 95 % CI 1.179-4.035). The findings suggest that the MTHFR C677T polymorphism but not A1298C, and some variants on their combined genotypes or haplotypes may be involved with the development of breast cancer.

Association of 677 C>T (rs1801133) and 1298 A>C (rs1801131) polymorphisms in the MTHFR gene and breast cancer susceptibility: a meta-analysis based on 57 individual studies

OBJECTIVE

The 677 C>T and 1298 A>C polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene have been widely reported and considered to have a significant effect on breast cancer risk, but the results are inconsistent. A meta-analysis based on 57 eligible studies was carried out to clarify the role of MTHFR gene polymorphisms in breast cancer.

METHODS AND RESULTS

Eligible articles were identified by searching databases including PubMed, Web of Science, EMBASE, CNKI and CBM for the period up to August 2012. Finally, a total of 57 studies were included in this meta-analysis. Crude ORs with 95% CIs were used to assess the association between the MTHFR polymorphisms and breast cancer risk. The pooled ORs were performed with additive model, dominant model and recessive model, respectively. Subgroup analysis was also performed by ethnicity. The statistical heterogeneity across studies was examined with χ2-based Q-test. A meta-analysis was performed using the Stata 12.0 software. Overall, the 677 C allele was significantly associated with breast cancer risk (OR = 0.942, 95%CI = 0.898 to 0.988) when compared with the 677 T allele in the additive model, and the same results were also revealed under other genetic models. Simultaneously, the 1298 A allele was not associated with the breast cancer susceptibility when compared with the 1298 C allele (OR = 0.993, 95%CI = 0.978 to 1.009). Furthermore, analyses under the dominant, recessive and the allele contrast model yielded similar results.

CONCLUSIONS

The results of this meta-analysis suggest that 677 C>T polymorphism in the MTHFR gene may contribute to breast cancer development. However, the 1298 A>C polymorphism is not significantly associated with increased risks of breast cancer.

Premenopausal plasma ferritin levels, HFE polymorphisms, and risk of breast cancer in the nurses' health study II

BACKGROUND

Evidence from the Nurses' Health Study II (NHSII) suggests that red meat consumption is associated with increased breast cancer risk in premenopausal women. Iron may be responsible by contributing to oxidative stress or effects on immune function.

METHODS

We conducted a case-control study nested within the NHSII, examining prediagnostic plasma ferritin (n = 795 cases, 795 controls), 15 hemochromatosis gene (HFE) single-nucleotide polymorphisms (SNP; n = 765 cases, 1,368 controls), and breast cancer risk. Cases were diagnosed after providing blood samples between 1996 and 1999. ORs and 95% confidence intervals (CI) were calculated for ferritin levels by conditional logistic regression and for HFE SNPs by unconditional logistic regression.

RESULTS

We did not observe a significant association between ferritin levels and breast cancer (top vs. bottom quartile multivariate OR: 1.05; 95% CI, 0.77-1.45; PTrend = 0.77). Results did not change when restricted to women who were premenopausal at blood draw, and were similar when cases were examined by hormone receptor status, and menopausal status at diagnosis. No HFE SNPs were significantly associated with breast cancer in a log-additive manner. Among controls, ferritin levels were nominally associated with SNPs rs9366637 (PTrend = 0.04), rs6918586 (PTrend = 0.06), and rs13161 (PTrend = 0.07), but results did not remain significant after adjusting for multiple testing.

CONCLUSIONS

Ferritin levels and HFE SNPs were not associated with breast cancer risk in this population.

IMPACT

Components of red meat other than iron are likely responsible for its positive association with breast cancer in premenopausal women.

C282Y polymorphism in the HFE gene is associated with risk of breast cancer

The C282Y and H63D polymorphisms in the HFE gene have been implicated in susceptibility of breast cancer, but a number of studies have reported inconclusive results. The aim of this study is to investigate the association between the C282Y and H63D polymorphisms in the HFE gene and breast cancer risk by meta-analysis. We searched PubMed and Embase databases, covering all related studies until March 2, 2013. Statistical analysis was performed using STATA 10.0. A total of 7 studies including 1,720 cases and 18,296 controls for HFE C282Y polymorphism and 5 studies including 942 cases and 1,571 controls for HFE H63D polymorphism were included in the meta-analysis. The results showed that HFE C282Y polymorphism was significantly associated with increased risk of breast cancer under homozygotes vs. wild-type model (OR = 2.06, 95%CI = 1.19-3.58) and recessive model (OR = 1.98, 95%CI = 1.14-3.44) but not under heterozygotes vs. wild-type model (OR = 0.97, 95%CI = 0.70-1.35), dominant model (OR = 1.00, 95%CI = 0.72-1.40) and multiplicative model (OR = 1.04, 95%CI = 0.76-1.42). However, we did not find any association between HFE H63D polymorphism and breast cancer risk under all genetic models. This current meta-analysis suggested that C282Y polymorphism rather than H63D might be associated with increased risk of breast cancer.

Association of MTHFR Ala222Val (rs1801133) polymorphism and breast cancer susceptibility: An update meta-analysis based on 51 research studies

BACKGROUND

The association between MTHFR Ala222Val polymorphism and breast cancer (BC) risk are inconclusive. To derive a more precise estimation of the relationship, a systematic review and meta-analysis was performed.

METHODS

A comprehensive search was conducted through researching MEDLINE, EMBASE, PubMed, Web of Science, Chinese Biomedical Literature database (CBM) and China National Knowledge Infrastructure (CNKI) databases before August 2012. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association.

RESULTS

A total of 51 studies including 20,907 cases and 23,905 controls were involved in this meta-analysis. Overall, significant associations were found between MTHFR Ala222Val polymorphism and BC risk when all studies pooled into the meta-analysis (Ala/Ala vs Val/Val: OR=0.870, 95%CI=0.789-0.958,P=0.005; Ala/Val vs Val/Val: OR=0.895, 95%CI=0.821-0.976, P=0.012; dominant model: OR=0.882, 95%CI=0.808-0.963, P=0.005; and recessive model: OR = 0.944, 95%CI=0.898-0.993, P=0.026; Ala allele vs Val allele: OR = 0.935, 95%CI=0.887-0.986, P=0.013). In the subgroup analysis by ethnicity, the same results were found in Asian populations, while no significant associations were found for all comparison models in other Ethnicity populations.

CONCLUSION

In conclusion, our meta-analysis provides the evidence that MTHFR Ala222Val gene polymorphisms contributed to the breast cancer development.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1966146911851976.

A literature review of MTHFR (C677T and A1298C polymorphisms) and cancer risk

5,10-Methlenetetrahydrofolate reductase (MTHFR) is one of the most important enzymes for folate metabolism. This enzyme is mapped on chromosome 1, which is located at the end of the short arm (1p36.3). The C677T and A1298C are MTHFR polymorphisms that decrease in vitro MTHFR enzyme activity. Folate metabolism plays a key role in cell metabolism. These reactions are associated with purine-pyrimidine synthesis: DNA, RNA, and protein methylation. Polymorphism is also a factor in biodiversity, and be affected by ethnic heritage and geographic locale. In the case of unknown outcomes, not only should all geographical regions be investigated to ascertain biodiversity, but all populations as well to fully understand the variations in the effect. PUBMED was searched from January 2006 to December 2011 to develop an investigatory pursuit strategy. MTHFR, cancer, C677T, A1298C, and polymorphisms were key words used to focus the search. The literature review included all published relevant cancer types and MTHFR polymorphisms for that 5 years period. All selected polymorphisms data for cancer types was listed in tables for easy access and retrieval.

Methylenetetrahydrofolate reductase C677T polymorphism and breast cancer risk in Moroccan women

BACKGROUND

Methylenetetrahydrofolate (MTHFR) enzyme plays an important role in folate metabolism which is involved in DNA methylation, repair, and synthesis.

OBJECTIVE

We investigated if the MTHFR C677T polymorphism modulates the risk of developing breast cancer in Moroccan women.

METHODS

Genotyping was performed by PCR-RFLP method on a sample of 96 patients with breast cancer and 117 controls.

RESULTS

A positive correlation was found between the MTHFR C677T polymorphism and progesterone receptors expression (p= 0.04). According to menopausal status, the heterozygous CT (OR = 2.29 and P = 0.03) was statistically significant in pre-menopausal women. There was a significant association between C677T polymorphism and breast cancer risk in both additive (OR = 2.2, 95% CI = 1.24-3.86, p = 0.007) and dominant (OR = 2.10, CI 95% = 1.21-3.64, p = 0.008) models. In addition, the T allele were associated with a high breast cancer risk (OR = 1.59, 95% CI = 1.04-2.44, p = 0.03).

CONCLUSION

In the light of our preliminary study, 677T allele and 677CT MTHFR genotype may represent a genetic determinant increasing breast cancer risk in Moroccan women. A larger study including a larger sample size and more information is needed to confirm our conclusions.