title: The association between reduced folate carrier-1 gene 80G/A polymorphism and methotrexate efficacy or methotrexate related-toxicity in rheumatoid arthritis: A meta-analysis.
abstract: Methotrexate (MTX), the most commonly used anti-rheumatic drug against RA, enters the cell via the action of the reduced folate carrier 1(RFC1). A major polymorphism of the RFC1 gene, 80G/A, has been reported to influence the activity of RFC1, resulting in variable intracellular MTX-polyglutamate (MTX-PG) levels. However, the association studies addressing the RFC1 80G/A polymorphism and MTX efficacy or toxicity in Rheumatoid arthritis (RA) has yielded conflicting results. In the present meta-analysis, we aimed to evaluate the association between the RFC1 80G/A polymorphism and MTX efficacy or toxicity in RA patients. A total 17 studies met our inclusion criteria. Among them, 12 studies with 2049 subjects reported the association between the RFC1 80G/A and MTX response, and 12 studies involving 2627 subjects were on MTX-related toxicity. Meta-analysis revealed significant association between RFC1 80G/A polymorphism and MTX efficacy (odds ratio (OR) for the A allele=1.29, 95% confidence interval (CI) 1.05-1.67, P=0.02; for AA genotype: OR=1.49, 95%CI 1.17-1.907, P=0.001). However, no association could be detected in the analysis of MTX-related toxicity. Stratification by ethnic population also indicated an association between this polymorphism and MTX efficacy in Asian group (P=0.002 for A allele; P=0.003 for AA genotype), but not in the Caucasian group (P=0.15 for A allele; P=0.05 for AA genotype). In both Asian and Caucasian sub-groups, no influence of the RFC1 80G/A polymorphism on MTX toxicity can be detected. In conclusion, the RFC1 G80A polymorphism is associated with responsiveness to MTX therapy, but may not be associated with MTX toxicity in RA patients.
authors.affiliation: College of Pharmacy, Southwest Medical University, Sichuan 646000, China.
authors.forename: XiaoBing
authors.initials: X
authors.lastname: Li
authors.affiliation: Division of Pharmacy, The Affiliated Hospital of Southwest Medical University, Sichuan 646000, China.
authors.forename: MingCai
authors.initials: M
authors.lastname: Hu
authors.affiliation: College of Pharmacy, Southwest Medical University, Sichuan 646000, China.
authors.forename: WanPing
authors.initials: W
authors.lastname: Li
authors.affiliation: College of Pharmacy, Southwest Medical University, Sichuan 646000, China.
authors.forename: Li
authors.initials: L
authors.lastname: Gu
authors.affiliation: College of Pharmacy, Southwest Medical University, Sichuan 646000, China.
authors.forename: MeiJuan
authors.initials: M
authors.lastname: Chen
authors.affiliation: Department of Biomedical Engineering, University of Houston, Houston, TX, USA.
authors.forename: HuiHua
authors.initials: H
authors.lastname: Ding
authors.affiliation: Department of Biomedical Engineering, University of Houston, Houston, TX, USA.
authors.forename: Kamala
authors.initials: K
authors.lastname: Vanarsa
authors.affiliation: Department of Biomedical Engineering, University of Houston, Houston, TX, USA. Electronic address: ydu9@central.uh.edu.
authors.forename: Yong
authors.initials: Y
authors.lastname: Du
mesh_terms: D018501:Antirheumatic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000235:genetics*; D064420:Drug-Related Side Effects and Adverse Reactions / Q000235:genetics*; D005006:Ethnicity; D005787:Gene Frequency; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D008727:Methotrexate / Q000009:adverse effects / Q000627:therapeutic use*; D011110:Polymorphism, Genetic; D058978:Reduced Folate Carrier Protein / Q000235:genetics*; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D058978:Reduced Folate Carrier Protein; C548699:SLC19A1 protein, human; D008727:Methotrexate
keywords: 80G/A polymorphism; Efficacy; Meta-analysis; Methotrexate; Reduced folate carrier 1; Rheumatoid arthritis; Toxicity