Impact of methylenetetrahydrofolate reductase (MTHFR) polymorphisms on methotrexate-induced toxicities in acute lymphoblastic leukemia: a meta-analysis

The associations between methylenetetrahydrofolate reductase (MTHFR) polymorphism and methotrexate (MTX)-induced toxicities in patients with acute lymphoblastic leukemia (ALL) have been evaluated in various populations, with the results remained conflicting. Therefore, we conducted a meta-analysis by combining available data to derive a more precise estimation of the association. PubMed, Embase, and China National Knowledge Infrastructure were searched until 21 September 2011 to identify eligible studies. A total of 14 studies were included, with all studies investigating MTHFR C677T polymorphism while nine of them investigating MTHFR A1298C polymorphism only. Results suggested that MTHFR C677T polymorphism was associated with significantly increased risk of MTX-induced toxicity, specifically liver toxicity (TT/CT vs. CC: odds ratio (OR) = 1.70, 95 % confidence interval (CI) = 1.05–2.75), myelosuppression (TT vs. CT/CC: OR = 2.82, 95 %CI = 1.25–6.34), oral mucositis (TT/CT vs. CC: OR = 3.68, 95 %CI = 1.73–7.85), gastrointestinal toxicity (TT/CT vs. CC: OR = 2.36, 95 %CI = 1.36–4.11), and skin toxicity (T vs. C: OR = 2.26, 95 %CI = 1.07–4.74). MTHFR A1298C polymorphism was found to be associated with decreased risk of skin toxicity (CC/AC vs. AA: OR = 0.11, 95 %CI = 0.01–0.85). Genotyping of MTHFR polymorphism, C677T particularly, prior to treatment for ALL is likely to be useful with the aim of tailoring MTX therapy and thus reducing the MTX-related toxicities. However, further studies with larger data set and well-designed models are required to validate our findings.