MTHFR and chronic myelogenous leukemia, BCR-ABL1 positive: In patients with TLBL, ALL and CML-LBC when the dose of MTX was 2.5-5 g/m2, with regard to MTHFR rs1801133, patients with the CT and TT genotypes had a significantly higher risk of hematopoietic toxicity than patients with the CC genotype had (p=0.003) (Table 11).