Objective      To determine the methylation status of secreted frizzled-related protein 2 (SFRP2) gene in chronic myeloid leukemia (CML) bone marrow cells

and try to find the role of its promoter methylation during the tumorigenesis of CML.       Methods      The expression of SFRP2 in CML cell line K562

bone marrow specimens of identified CML patients and health volunteers were detected with semi-quantitative PCR (RT-PCR).

The methylation status of SFRP2 promoter was detected in K562 cells and CML bone marrow specimens by methylation-specific PCR (MSP). After K562 cells was treated with pharmacological demethylation 5-aza-2’deoxycytidine (Aza) and trichostatin A(TSA)

the expression of SFRP2 was detected again with RT-PCR.       Results      SFRP2 was silenced in K562 cells

expressed in 22.0% (4/18) CML bone marrow specimens

and detected in all normal bone marrow samples (100.0%

8/8

P

<

0.05). The frequencies of SFRP2 promoter methylation were 100%

66% (25/38) and 0 (0/13) respectively in K562 cells

CML bone marrow and normal bone marrow specimens (

P

<

0.05). Pharmacological demethylation treatment dramatically induced mRNA expression of SFPR2

and this reactivation was associated with an increase of unmethylation alleles.       Conclusion      The promoter of SFRP2 gene are hypermethylated in CML

which be one of the molecular mechanisms of CML. Its hypermethylation might serve as a new biomarker for CML.