RESUMO
Objective To investigate the methylation situation of let‐7a‐3 promoter in patients with chronic myeloid leukemia (CML) and its clinical significance .Methods The methylation level of let‐7a‐3 promoter in the bone marrow mononuclear cells of 52 CML patients and 25 controls was detected by using the real‐time quantitative methylation‐specific PCR (RQ‐PCR) .Results The non-hypomethylation of let‐7a‐3 promoter was positive in 31 cases(59 .6% ) of 52 CML patients ,while only 1 case(4% ,1/25) in the control group ,the difference between the two groups were statistically significant (P0 .05) .The non-hypomethylation level of let‐7a‐3 in chronic phase and accel‐erate phase was significantly higher than that in blastic crisis of CML .Conclusion The hypomethylation level of let‐7a‐3 promoter is decreased with disease progression .