OBJECTIVETo investigate the methylation, expression and clinical significance of miR-203 in pediatric acute leukemia.

METHODSThe methylation status of miR-203 promoter CpG islands was detected with methylation-specific polymerase chain reaction. The expression of miR-203 was detected by Taqman real- time quantitative polymerase chain reaction. And the clinical significance of miR-203 in pediatric acute leukemia (ALL) was also analyzed.

RESULTSThe promoter of miR-203 was unmethylated in all of 31 pediatric acute lymphoblastic leukemia, all of 15 pediatric acute myeloid leukemia (AML) and all of 23 controls. The relative expression levels of miR-203 in controls, pediatric acute leukemia, ALL and AML were 16.93±6.31, 48.97±10.38, 55.88±12.91, 24.28±9.10 respectively. The results indicated that miR-203 was significantly up- regulated in pediatric acute leukemia (P=0.011) and ALL (P=0.009), not in pediatric AML (P=0.514) compared with control. The expression of miR-203 was significantly related with the gender, immunophenotype, chromosome, fusion gene, BCR-ABL, SIL-TAL1 and prednisone experiment in pediatric ALL and the gender, chromosome, fusion gene, SIL-TAL1 in pediatric acute leukemia (P<0.05). And in risk stratification pairwise comparisons, the expression of miR-203 in the medium-risk and high-risk groups appeared significantly different (P=0.022).

CONCLUSIONmiR-203 may not be regulated with methylation mechanism in pediatric acute leukemia. miR- 203 may be a protooncogene involved in the formation of pediatric acute leukemia and ALL. Further analyses indicated that high expression of miR-203 may be associated with poor prognosis of pediatric ALL and acute leukemia.