OBJECTIVETo investigate the expression of microRNA-155(miR-155) in bone marrow mononuclear cells (BMMNC) of the patients with acute myeloid leukemia(AML) and its clinical significance.

METHODSReal-time quantitative PCR (qPCR) was used to detect the expression level of miR-155 in bone marrow mononuclear cells from 80 cases of AML and 11 cases of negative control patients.

RESULTSCompared with the negative control group ,the expressions of miR-155 in initial diagnosis group and remission group both increased (P<0.01), that in the initial treatment group was significantly higher than the remission group (P<0.05). The expression level of miR-155 did not significantly correlate with the clinical features of patients. Between different cytogenetic groups in AML patients, miR-155 expression levels in the moderate prognostic group and poor prognositic group were significantly higher as compared with the favorable prognosis group P<0.05, P<0.05）, but there was no significant difference between poor and moderate progrestic groups(P>0.05). The results of tracking the situation after induction therapy of newly diagnozed AML patients showed that the remission rate of initial induction in miRNA155 high expression group and low expression group were 59.09% and 87.5% (X(2) =4.8, P<0.05), and the expression level of miR-155 in initial diagnosis of patients without complete remission after chemotherapy was significantly higher than that in patients with complete remission after chemotherapy (P= 0.042).

CONCLUSIONThe expression of miR-155 in AML patients is high and reduced the rate of complete remission. The high expression of miR-155 is an poor prognostic factor for patients with AML.