The protective effect of methylenetetrahydrofolate reductase C677T polymorphism against prostate cancer risk: Evidence from 23 case–control studies

• This meta-analysis will be helpful in clarifying current controversies.
• The homozygote TT of MTHFR C677T should be viewed as a protective effect against prostate cancer risk.
• Such prediagnostic genetic test is required to screen unsuspected cancers for clinical practice.

Genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) were considered to have some influence on both folate metabolism and cancer risk. Previous studies on the relation between MTHFR C677T polymorphism and prostate cancer (PCa) risk remained controversial. To derive a more precise estimation of the relationship, we carried out an update comprehensive meta-analysis to assess the associations of the MTHFR C677T polymorphism with the susceptibility of PCa. Twenty-three trials with a total of 24,024 participants on the MTHFR C677T polymorphism that met inclusion criteria were analyzed in the current study. Overall, no statistical relationship was found with any MTHFR C677T genetic model associated with susceptibility to PCa (TT versus CC, OR = 0.83, 95% CI 0.68–1.02, P = 0.07; CT versus CC, OR = 0.95, 95% CI 0.85–1.07, P = 0.43; Dominant, OR = 0.93, 95% CI 0.83–1.03, P = 0.17; Recessive, OR = 0.84, 95% CI 0.70–1.02, P = 0.09.). Nevertheless, subgroup analysis found a reduced PCa risk associated with polymorphism in Asian population (TT versus CC, CT versus CC, dominant and recessive model). Moreover, the protective effect of polymorphism against PCa risk was also shown upon hospital-based studies (TT versus CC, and recessive model). When benign prostate hyperplasia was chosen as controls, both TT versus CC and recessive model showed significant difference. In addition, the protective effect of homozygote TT against high aggressive PCa was proved to have significant difference. Taken together, the existing evidence indicates the homozygote TT of MTHFR C677T should be viewed as a protective factor against PCa risk for clinical practice with the consideration of different gene background, study design as well as specific controls.