RT-qPCR, MSP, and western blot assay displayed that in bone marrow of CML patients, DNMT1, DNMT3A, and DNMT3B were heightened, among which the change of DNMT1 expression was the greatest, so DNMT1 was selected for follow-up experiments. The gene discussed is DNMT3B; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.