To optimize high-dose (HD)-MTX therapy and reduce related hematopoietic toxicity, it is necessary to detect the SNPs of MTHFR and ABCB1 before initiating HD-MTX and deciding the optimal dose of MTX and duration of leucovorin rescue, according to genetic tests and disease type in adults with hematological malignancies. This evidence concerns the gene ABCB1 and hematologic disorder.