Methylenetetrahydrofolate reductase gene polymorphisms association with the risk of follicular lymphoma: a meta-analysis

C677T and A1298C polymorphisms of methylene tetrahydrofolate reductase in non-Hodgkin lymphoma: southeast Iran

PURPOSE

Polymorphisms of the methylene tetrahydrofolate reductase (MTHFR) gene have been reported as risk factors for non-Hodgkin lymphoma (NHL) in some populations. Our goal was to evaluate the potential role of A1298C and C677T polymorphisms of MTHFR in risk of NHL in southeast Iran.

METHODS

In the present case-control study, 127 patients with newly diagnosed NHL along with 150 ethnicity- and age-matched controls were examined. The A1298C and C677T polymorphisms were genotyped using the Tetra Amplification Refractory Mutation System polymerase chain reaction method.

RESULTS

There were no significant differences in genotype frequencies between cases and controls regarding either A1298C polymorphism. For this polymorphism, 53.8% of the controls and 54.3% of the patients with NHL showed homozygous wild-type (AA) genotype. Variant 1298C allele was recognized with overall frequency of 34.6% in both groups. Frequencies of CC, CT, and TT genotypes of C677T polymorphism were observed in 73.1%, 25.8%, and 1.3% of the controls, and 64.5%, 33.1%, and 2.4% of the patients with NHL (p>0.05). In combination, CT + TT conferred a significantly higher risk of NHL (odds ratio [OR] 1.5, 95% confidence interval [CI] 0.9-2.4, p = 0.03). Overall, variant 677T allele presented with higher frequency in the patients with NHL than the controls (26.7% versus 21.3%, respectively; OR 1.3, 95% CI 0.8-2.1, p>0.05). Although statistically insignificant, the highest risk of NHL was identified in patients with C677T; A1298C: CT; CC haplotype (OR 4.7, 95% CI 0.4-46.4, p = 0.1).

CONCLUSIONS

Combination of CT and TT genotypes of C677T polymorphism conferred a significantly higher risk for NHL. It is recommended to investigate further the potential role of this polymorphism in NHL development.

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism: epidemiology, metabolism and the associated diseases

The Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism is associated with various diseases (vascular, cancers, neurology, diabetes, psoriasis, etc) with the epidemiology of the polymorphism of the C677T that varies dependent on the geography and ethnicity. The 5,10-Methylenetetrahydrofolate reductase (MTHFR) locus is mapped on chromosome 1 at the end of the short arm (1p36.6). This enzyme is important for the folate metabolism which is an integral process for cell metabolism in the DNA, RNA and protein methylation. The mutation of the MTHFR gene which causes the C677T polymorphism is located at exon 4 which results in the conversion of valine to alanine at codon 222, a common polymorphism that reduces the activity of this enzyme. The homozygous mutated subjects have higher homocysteine levels while the heterozygous mutated subjects have mildly raised homocysteine levels compared with the normal, non-mutated controls. Hyperhomocysteinemia is an emerging risk factor for various cardiovascular diseases and with the increasing significance of this polymorphism in view of the morbidity and mortality impact on the patients, further prevention strategies and nutritional recommendations with the supplementation of vitamin B12 and folic acid which reduces plasma homocysteine level would be necessary as part of future health education. This literature review therefore focuses on the recent evidence-based reports on the associations of the MTHFR C677T polymorphism and the various diseases globally.