title: Methylene tetrahydrofolate reductase gene polymorphisms and their association with methotrexate toxicity:  a meta-analysis.
abstract: OBJECTIVE
  A systematic review and a meta-analysis were conducted, to investigate the possible association of methylene tetrahydrofolate reductase (MTHFR) gene polymorphisms with adverse effects related to methotrexate (MTX).
  
  
  METHODS
  A systematic literature search in PubMed retrieved a total of 44 studies (42 unique articles). Two polymorphisms were included in the meta-analysis: C677T and A1298C. Random effect models were used in the analysis. Odds ratios along with their 95% confidence intervals were computed to compare the distribution of alleles and genotypes between cases and controls.
  
  
  RESULTS
  The analysis highlighted a significant association of C677T polymorphism with overall MTX toxicity, hepatotoxicity, hematological toxicity, and neurotoxicity. It also revealed an association with MTX toxicity in patients with rheumatoid arthritis. In contrast, a protective effect of C677T MTHFR polymorphism on acute graft-versus-host disease and on patients treated with hematopoietic cell transplantation was found. As for the A1298C polymorphism, a statistically significant association with overall MTX toxicity and a protective role of the polymorphism in rheumatoid arthritis patients was detected.
  
  
  CONCLUSIONS
  These results indicate the association of MTHFR polymorphisms with MTX toxicity. However, further studies are needed to reveal the underlying biological mechanism of the association.
authors.affiliation: Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Greece.
authors.forename: Kalliopi P
authors.initials: KP
authors.lastname: Spyridopoulou
authors.forename: Niki L
authors.initials: NL
authors.lastname: Dimou
authors.forename: Stavros J
authors.initials: SJ
authors.lastname: Hamodrakas
authors.forename: Pantelis G
authors.initials: PG
authors.lastname: Bagos
mesh_terms: D000483:Alleles; D000964:Antimetabolites, Antineoplastic / Q000633:toxicity; D018501:Antirheumatic Agents / Q000633:toxicity; D005838:Genotype; D006801:Humans; D008727:Methotrexate / Q000633:toxicity*; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D011110:Polymorphism, Genetic
chemical_list: D000964:Antimetabolites, Antineoplastic; D018501:Antirheumatic Agents; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D008727:Methotrexate