Dataset Information

MTHFR, MTR, and MTRR polymorphisms in relation to p16INK4A hypermethylation in mucosa of patients with colorectal cancer.

ABSTRACT: We recently analyzed the hypermethylation status of the p16INK4a (p16) gene promoter in normal-appearing mucosa obtained from patients with colorectal cancer. Hypermethylation of p16 was associated with reduced survival of these patients. In the present study, germ line polymorphisms in the folate- and methyl-associated genes, methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR) and methionine synthase reductase (MTRR), were analyzed in the same patient cohort to find a possible link between these genetic variants and p16 hypermethylation. Genomic DNA was extracted from blood of patients (n = 181) and controls (n = 300). Genotype analyses were run on an ABI PRISM(®) 7900HT sequence-detection system (Applied Biosystems), using real-time polymerase chain reaction and TaqMan chemistry. The results showed that the genotype distributions of the patient and control groups were similar. No significant differences in cancer-specific or disease-free survival of stage I-III patients according to polymorphic variants were detected, nor were any differences in cancer-specific or disease-free survival detected when patients were subgrouped according to the MTHFR or MTR genotype groups and dichotomized by p16 hypermethylation status in mucosa. However, patients with the MTRR 66 AA/AG genotypes were found to have a significantly worse cancer-specific survival when the mucosa were positive, compared with negative, for p16 hypermethylation (hazard ratio 2.7; 95% confidence interval 1.2-6.4; P = 0.023). In contrast, there was no difference in survival among patients with the MTRR 66 GG genotype stratified by p16 hypermethylation status. These results indicate a relationship between genetic germ-line variants of the MTRR gene and p16 hypermethylation in mucosa, which may affect the clinical outcome of patients with colorectal cancer.

SUBMITTER: Wettergren Y

PROVIDER: S-EPMC2935958 | biostudies-literature | 2010 Sep-Oct

REPOSITORIES: biostudies-literature

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MTHFR, MTR, and MTRR polymorphisms in relation to p16INK4A hypermethylation in mucosa of patients with colorectal cancer.

Wettergren Yvonne Y Odin Elisabeth E Carlsson Göran G Gustavsson Bengt B

Molecular medicine (Cambridge, Mass.) 20100611 9-10

We recently analyzed the hypermethylation status of the p16INK4a (p16) gene promoter in normal-appearing mucosa obtained from patients with colorectal cancer. Hypermethylation of p16 was associated with reduced survival of these patients. In the present study, germ line polymorphisms in the folate- and methyl-associated genes, methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR) and methionine synthase reductase (MTRR), were analyzed in the same patient cohort to find a possibl ...[more]

PMID: 20549016

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Project description:AimThe aim of the study was to explore and describe the effect of polymorphisms in folate-associated genes regarding the levels of different folate forms and their distribution in tumors and mucosa in patients with colorectal cancer.Materials and methodsTumor and mucosa tissues from 53 patients with colorectal cancer were analyzed. The concentrations of tetrahydrofolate (THF), 5-methylTHF, and 5,10-methyleneTHF were measured by liquid chromatography-mass spectrometry. Genotyping of polymorphisms in the folate-associated genes methylenetetrahydrofolate reductase (MTHFR, C677T), methionine synthase (MTR, A2756G), and thymidylate synthase (TS, 5'-TSER 28 bp tandem repeat and 3'-TSUTR 6 bp deletion/insertion), were done by real-time polymerase chain reaction. Folate levels and distributions were determined in the total patient cohort and after subgrouping by genotypes.ResultsThe total folate level, as well as the THF and 5,10-methyleneTHF levels, were significantly higher in the tumor compared with mucosa tissue (P = 0.030, 0.031, and 0.015, respectively). The individual variation in folate levels in both tumor and mucosa were larger than the variation found when the patients were subgrouped by the gene polymorphisms. No significant differences in the mean concentration of any folate in the mucosa or tumor tissue were found in relation to the analyzed polymorphisms. The percentage level of 5,10-methyleneTHF in tumors was highest in patients with the MTHFR 677 CC genotype, and lowest in patients with the TT genotype (P = 0.033). A significantly lower percentage level of the 5,10-methyleneTHF level was found in tumors of patients with the 5'-TSER 3R/3R genotype (P = 0.0031).ConclusionA significant difference was found between the percentage level of 5,10-methyleneTHF in tumor tissues in relation to the MTHFR C677T and 5'-TSER 28 bp repeat polymorphisms. However, no differences were found in the actual tissue folate levels, or in their distribution, in relation to the polymorphisms in the MTHFR, MTR, or TS genes. These findings could be of importance for further research in the field by explaining some of the difficulties of obtaining reproducible and uniform results when using a few selected polymorphisms as predictive markers.

Project description:Neural tube defects (NTDs) are the most common congenital defects of the central nervous system among neonates and the folate status during pregnancy was considered as the most important etiopathogenesis of NTDs. Besides, methionine synthase (MTR) gene and methionine synthase reductase (MTRR) gene were folate metabolism involved genes and had been investigated in several previous studies with inconsistent results. Hence, we aimed to explore the association of 4 selected single-nucleotide polymorphisms (SNPs) on MTRR/MTR gene and the susceptibility of NTDs in a Chinese population.Seven SNPs were selected from HapMap databases with Haploview 4.2 software. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to genotype the polymorphisms from blood samples of 165 NTDs patients and 280 healthy controls. The correlation between these SNPs and NTDs risk was tested by Student t test and Chi-square test by STATA 11.0 software. Furthermore, we performed a meta-analysis of relevant studies to investigate the association between the SNPs MTRR 66A>G and MTR 2756A>G and the susceptibility of NTDs.An increased risk of NTDs was verified to be significantly associated with MTRR 66A>G (G allele vs. A allele: OR = 1.36 (1.03-1.80), P = 0.028; GG + AG vs. AA: OR = 1.60 (1.05-2.43), P = 0.027) and MTR 2756A>G (G allele vs. A allele: OR = 1.45 (1.06-1.98), P = 0.021; GG + AG vs. AA: OR = 1.51 (1.02-2.23), P = 0.038) in our study. However, the other SNPs in our analysis showed no significant association with NTDs risk (all P > 0.05). Furthermore, the result of the meta-analysis supported the association between MTRR 66A>G and NTDs risk (G allele vs. A allele: OR = 1.32, 95% CI = 1.09-1.61, GG + GA vs. AA: OR = 1.49, 95% CI = 1.06-2.09, GG vs. AA: OR = 1.61, 95% CI = 1.04-2.49).Our study confirmed that the MTRR 66A>G and MTR 2756A>G were significantly associated with the increased NTDs risk in a Chinese population. The further meta-analysis enhance that MTRR 66A>G was connected with the susceptibility of NTDs widely. Further investigations based on more detailed stratification were recommended.

Project description:BackgroundParadoxically epidemiological data illustrate a negative relationship between dietary folate intake and colorectal cancer (CRC) risk. The occurrence and progression of CRC may be influenced by variants in some key enzyme coding genes in the folate metabolic pathway. We investigated the correlation between genetic variants in methionine synthase reductase (MTRR) and methylenetetrahydrofolate reductase (MTHFR) and CRC survival.MethodsThis study used data collected from the Newfoundland Familial Colorectal Cancer Study. A total of 532 patients diagnosed with CRC for the first time from 1999 to 2003 were enrolled, and their mortality were tracked until April 2010. DNA samples were genotyped by Illumina's integrated quantum 1 million chip. Cox models were established to assess 33 tag single-nucleotide polymorphisms in MTRR and MTHFR in relation to overall survival (OS), disease-free survival (DFS) and CRC-specific survival.ResultsThe MTRR and MTHFR genes were associated with DFS and CRC-specific survival in CRC patients at the gene level. After multiple comparison adjustment, MTRR rs1801394 A (vs. G) allele was associated with increased DFS (p = 0.024), while MTHRT rs3737966 (G vs. A), rs4846049 (T vs. G), rs1476413 (A vs. G), rs1801131 (C vs. A), rs12121543 (A vs. C), rs1801133 (C vs. T), rs4846052 (T vs. C), rs2066471 (A vs. G) and rs7533315 (T vs. C) were related to worse CRC-specific survival. Additionally, significant interactions were seen among pre-diagnostic alcohol consumption with MTRR rs1801394, rs3776467, rs326124, rs162040, and rs3776455, with superior OS associated with those protective variant alleles limited to patients with alcohol consumption under the median. The MTHFR rs3737966 (G vs. A) allele seemed to be detrimental to CRC survival only among subjects with fruit intake below the median.ConclusionsPolymorphic variants in MTRR and MTHFR genes that code for key enzymes for folate metabolism may be associated with survival in patients with CRC. The gene-CRC outcome association seems modulated by alcohol drinking and fruit intake.

Dataset Information

MTHFR, MTR, and MTRR polymorphisms in relation to p16INK4A hypermethylation in mucosa of patients with colorectal cancer.

Publications

MTHFR, MTR, and MTRR polymorphisms in relation to p16INK4A hypermethylation in mucosa of patients with colorectal cancer.

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