Role of Polymorphic Variants of MTR Gene A2756G and SHMT1 Gene C1420T in the Development of Prostatic Cancer in Residents of the Western Siberian Region of Russia

Interactions of SNPs in Folate Metabolism Related Genes on Prostate Cancer Aggressiveness in European Americans and African Americans

BACKGROUND

Studies showed that folate and related single nucleotide polymorphisms (SNPs) could predict prostate cancer (PCa) risk. However, little is known about the interactions of folate-related SNPs associated with PCa aggressiveness. The study's objective is to evaluate SNP-SNP interactions among the DHFR 19-bp polymorphism and 10 SNPs in folate metabolism and the one-carbon metabolism pathway associated with PCa aggressiveness.

METHODS

We evaluated 1294 PCa patients, including 690 European Americans (EAs) and 604 African Americans (AAs). Both individual SNP effects and pairwise SNP-SNP interactions were analyzed.

RESULTS

None of the 11 individual polymorphisms were significant for EAs and AAs. Three SNP-SNP interaction pairs can predict PCa aggressiveness with a medium to large effect size. For the EA PCa patients, the interaction between rs1801133 (MTHFR) and rs2236225 (MTHFD1), and rs1801131 (MTHFR) and rs7587117 (SLC4A5) were significantly associated with aggressive PCa. For the AA PCa patients, the interaction of DHFR-19bp polymorphism and rs4652 (LGALS3) was significantly associated with aggressive PCa.

CONCLUSIONS

These SNP-SNP interactions in the folate metabolism-related genes have a larger impact than SNP individual effects on tumor aggressiveness for EA and AA PCa patients. These findings can provide valuable information for potential biological mechanisms of PCa aggressiveness.

Update analysis on the association between Methionine synthase rs1805087 A/G variant and risk of prostate cancer

Previous studies have investigated the association of the rs1805087 A/G variant of Methionine synthase gene with the susceptibility to prostate cancer (PCa). Nevertheless, the conclusions remain divergent. We performed a systemic analysis with odds ratios (ORs) and 95% confidence intervals (95% CIs) to assess Methionine synthase rs1805087 A/G variant and PCa risk. Furthermore, we utilized in silico analysis to investigate the relationship between Methionine synthase expression and the overall survival (OS) time. Totally, 10,666 PCa patients and 40,750 controls were included. We observed that Methionine synthase rs1805087 A/G variant is associated with an elevated risk of PCa (G-allele vs. A-allele: OR = 1.06, 95% CI = 1.01–1.11, P = 0.013; heterozygous model: OR = 1.08, 95% CI = 1.02–1.14, P = 0.009; dominant model: OR = 1.08, 95% CI = 1.02–1.14, P = 0.007). During stratified analysis, similar results were obtained in Asian populations, hospital-based, high quality studies and that with large sample size. Moreover, in silico analysis indicated the Methionine synthase expression is down-regulated in both young and old PCa subjects (P < 0.05). Compared with the normal subjects, the down-regulated expression of Methionine synthase was found in PCa cases with Gleason score 6 to 9. Our study showed that Methionine synthase rs1805087 A/G variant may be associated with susceptibility of PCa, especially in Asian populations, hospital-based studies and that with high quality and large sample size. Furthermore, Methionine synthase rs1805087 A/G variant may be related to the prognosis of PCa.

Human methionine synthase A2756G polymorphism increases susceptibility to prostate cancer

Background/Aims: Previous results on the association between MTR gene A2756G polymorphism and PCa risk are inconclusive.

Methods: We used odds ratios (ORs) with corresponding 95% confidence intervals (95% CIs) to evaluate the correlation between MTR A2756G polymorphism and risk of PCa in meta-analysis. Serum expression of MTR was detected by ELISA and in-silico tools were utilized to assess this variant.

Results: Our study included 2,921 PCa patients and 3,095 control subjects. The results indicated that the MTR A2756G polymorphism is linked with an increased risk of PCa using three genetic models (G-allele vs. A-allele: OR = 1.16, 95%CI = 1.04 - 1.30; GA vs. AA: OR = 1.17, 95%CI = 1.02 - 1.33; GG+GA vs. AA: OR = 1.18, 95%CI = 1.04 - 1.34). Stratified analysis produced similar results. A significant association was also indicated in advanced PCa from the meta-analysis. Finally, our experiments showed evidence that serum MTR levels in PCa patients with AA genotypes were statistically higher than in those with GG/GA genotypes.

Conclusions: Our present study suggests that the MTR A2756G polymorphism may contribute to the risk of developing PCa, particularly in Asian and hospital-based studies. Moreover, serum MTR might be utilized in diagnosis of PCa.

A single-nucleotide polymorphism (rs1805087) in the methionine synthase (METH) gene increases the risk of prostate cancer

Methionine synthase (METH, i.e., MTR) is a key enzyme in the folate pathway, which plays a critical role in the synthesis, repair, and methylation of DNA. The association between METH gene polymorphisms and prostate cancer susceptibility remains ambiguous. Thus, we performed an updated meta-analysis of METH single-nucleotide polymorphism rs1805087 involving 12 independent case-control studies comprising 9986 prostate cancer patients and 40134 controls. The odds ratio and 95% confidence intervals were applied to evaluate the relation of this single-nucleotide polymorphism with prostate cancer. Statistical analysis was performed in STATA 11.0. A significant association was found between rs1805087 and increased prostate cancer risk, overall and with Hardy-Weinberg equilibrium. In subgroup analyses (based on ethnicity, source of control, genotyping methods, or publication status), similar associations were observed (e.g., genotype GA vs. AA: odds ratio 1.19, 95% confidence interval 1.01-1.40 among whites; G allele vs. A allele: odds ratio 1.14, 95% confidence interval 1.02-1.28 among hospital-based controls). Thus, the common polymorphism (rs1805087) of METH may be associated with increased prostate cancer risk. Further studies with a larger sample size and detailed gene-environment interactions should be conducted to identify the role of METH polymorphisms in prostate cancer susceptibility.