In comparison to the reference MTHFR rs1801131AA/ rs1801133 CC/rs2236242 TT, the AC/CC/TT, AC/CC/TC as well as AA/CC/TC genotypes increased the risk of ALL (OR=3.68, 95%CI=1.26-10.78, p=0.017; OR=4.45, 95%CI=1.11-17.90, p=0.048 and OR=7.71, 95%CI=1.28-46.38, p=0.025, respectively). This evidence concerns the gene MTHFR and acute lymphoblastic leukemia.