Association of MTHFR gene polymorphisms with non-Hodgkin lymphoma risk: Evidence from 31 articles

Background: Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms, particularly C677T and A1298C, have been implicated in various cancers, including non-Hodgkin lymphoma (NHL); however, their association with NHL risk remains inconclusive. Methods: We conducted an updated meta-analysis to assess the relationship between MTHFR gene polymorphisms (C677T and A1298C) and NHL risk. Relevant studies were identified through systematic literature searches in multiple databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the strength of the associations. Results: The meta-analysis included 32 studies (8222 cases vs. 12956 controls) for MTHFR C677T and 26 studies (6930 cases vs. 11611 controls) for the A1298C polymorphism. Our meta-analysis revealed no significant associations between MTHFR gene polymorphisms (C677T and A1298C) and NHL risk. However, subgroup analysis stratified by ethnicity and NHL subtype yielded interesting findings for the C677T polymorphism. Specifically, in the subgroup analysis of Caucasians, the C677T polymorphism was significantly associated with NHL risk (heterozygous: OR=1.16, 95% CI=1.02-1.32; allele comparison: OR=1.07, 95% CI=1.01-1.13). Furthermore, in the analysis stratified by NHL subtype, the C677T polymorphism was significantly associated with increased follicular lymphoma (FL) risk (homozygous: OR=1.25, 95% CI=1.02-1.53; recessive: OR=1.28, 95% CI=1.06-1.56). False-positive result possibility (FPRP) analysis verified that the association of the MTHFR C677T polymorphism with NHL risk for Caucasians and FL subtypes was a true positive and deserves attention. We also determined that the C677T polymorphism is an expression quantitative trait locus (eQTL) since it is associated with MTHFR gene expression. Conclusion: There was no overall association between MTHFR gene polymorphisms (C677T and A1298C) and NHL risk, but stratified analyses revealed significant associations in specific subgroups. While meta-analyses inherently build upon existing studies, our work distinguishes itself by incorporating recent data, applying rigorous analytical techniques, and providing more evidence of the MTHFR C677T polymorphism as an eQTL.