OBJECTIVETo screen the differential methylation patterns of tumor suppressor gene DAPK and evaluate its value as a biomarker for the diagnosis of leukemia.

METHODSThe methylation status of DAPK gene promoter's CpG island was analyzed in the genomes of normal human white blood cells and HL-60, U937 and Jurkat cell lines by bisulfite sequencing PCR (BSP). The effectiveness of differential methylation patterns of DAPK gene for diagnosis of leukemia was verified in the leukemia cell lines and peripheral blood samples by methylation specific PCR (MSP).

RESULTSThe methylation pattern of DAPK gene in different cell genomes displayed that the degree of unmethylation in normal cell genome was higher than that of leukemia cell lines. The differential CpG sites were found and could be used to differentiate HL-60 and the other 3 cell lines by MSP. Meanwhile, the differential methylation patterns in clinical specimens could distinguish acute non-lymphocytic leukemia (ANLL) and other types of leukemia by MSP. The diagnostic sensitivity, specificity and accuracy were 59.1%, 100% and 82.7% respectively. No relationship was found between MSP diagnosis results and clinical pathological typing.

CONCLUSIONThe differential methylation patterns of DAPK gene as potential tumor biomarker for diagnosis of leukemia can enrich the means of diagnosis of leukemia, provide idea and basis for finding all kinds of tumor's DNA methylation biomarkers in the future.