MTHFR and urinary bladder cancer: In the current meta-analysis, a more precise estimation of MTHFR Ala222Val and Glu429Ala and bladder cancer was derived by including a pooled total of 3,463 cases and 3,927 controls for Ala222Val in 11 studies and 3,177 cases and 3,502 controls for Glu429Ala in 9 studies.