MTHFR and acute lymphoblastic leukemia: In patients with TLBL, ALL and CML-LBC when the dose of MTX was 2.5-5g/m2, with regard to MTHFR rs1801133, patients with the CT and TT genotype had a significantly higher risk of developing hematopoietic toxicity than those with the CC genotype (p=0.003) (Table 11).