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). The gene discussed is MTHFR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.