Objective: To investigate the methylation status of miR-378 promoter in chronic myeloid leukemia (CML) and to analyze its clinical significance.
Methods: The unmethylation level of miR-378 gene promoter in bone marrow mononuclear cells of 25 healthy donors and 53 patients with CML was detected by using real-time quantitative methylation-specific PCR (RQ-MSP).
Results: The hypomethylation of miR-378 gene promoter was found in 17/53 (32.1%) patients, but only in 1/25 (4.0%) of controls. The difference between the two groups was very statistically significant (P < 0.01). The frequency of miR-378 unmethylation in CML patients at chronic phase (CP), accelerated phase (AP) and blastic phase (BP) was 35.0% (14/40), 40.0% (2/5), and 12.5% (1/8), respectively. However, there were no significant differences in the unmethylation level of miR-378 among CML patients at different sexes, stages and karyotypes. No significant differences could be observed in age, white blood cell counts, platelet count, hemoglobin level and BCR/ABL1 transcript level (P > 0.05). CONCLUDSION: The miR-378 hypomethylation is a common molecular event in CML, especially at chronic or accelerated phases.