Overexpressed miR-155 is associated with initial presentation and poor outcome in Chinese pediatric acute myeloid leukemia.

OBJECTIVE: Acute myeloid leukemia (AML) is the second leading leukemia in children. There is growing evidence that microRNAs (miRNAs) are crucial regulators involved in leukemogenesis. This study aimed to investigate the role of miR-155 in Chinese pediatric AML by evaluating its diagnostic and prognostic significance. PATIENTS AND METHODS: The expression of miR-155 and miR-25 in bone marrow specimens from 83 AML and 29 non-malignancies children were analyzed by TaqMan probe-based real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). RESULTS: The expression level of miR-155 was significantly higher in AML patients than in controls. Besides, a lowest miR-155 level was found in favorable prognosis group and t (15; 17)/M3 subgroup compared to the rest, while a higher level in C-Kit/FLT3-ITD mutation and relatively lower level existed in "Negative" mutation group. Moreover, miR-155 level was positively associated with the white blood cell (WBC) count, serum lactate dehydrogenase (LDH) and C-reaction protein (CRP) value in peripheral blood (PB), as well as miR-25/miR-196b expression levels. Survival analysis showed a statistically negative association with overall survival (OS) in the expression of miR-155 in chemotherapy group. CONCLUSIONS: These finding suggested that miR-155 expression cannot only be promising biomarker for the early detection of pediatric AML but also predict poor outcome. MiR-155 would be a novel biomarker for diagnosis, prognosis and therapy in pediatric AML.