ABCB1 and acute lymphoblastic leukemia: In patients with TLBL, ALL and CML-LBC when the dose of MTX was 2.5-5g/m2, hematopoietic toxicity occurred less frequently in patients with the ABCB1 rs1045642T allele (TT and CT) than in those with the CC genotype (p=0.055) (Table 11).