Serum MicroRNA-370 as a potential diagnostic and prognostic biomarker for pediatric acute myeloid leukemia.

BACKGROUND Controversial data on the expression pattern of microRNA-370 (miR-370) in acute myeloid leukemia (AML) were previously reported. OBJECTIVE To clarify the expression pattern of miR-370 and its clinical implications in pediatric AML patients. METHODS Real-time quantitative PCR was performed to detect the expression of miR-370 in both bone marrow mononuclear cells and sera obtained from pediatric AML patients and healthy controls. RESULTS Compared with healthy controls, the expression levels of miR-370 in the bone marrow and sera of pediatric AML patients were both decreased significantly (both P=0.001). Importantly, serum miR-370 level could efficiently screen pediatric AML patients from healthy controls (Area under receiver operating characteristic curve, AUC =0.993). Then, low serum miR-370 level was significantly associated with French-American-British (FAB) classification subtype M7 subtype (P=0.02) and unfavorable karyotype (P=0.01). Moreover, pediatric AML patients with low serum miR-370 level had shorter relapse-free and overall survivals than those with high serum miR-370 level (both P=0.001). Multivariate analysis further identified serum miR-370 level as an independent prognostic factor for both relapse-free and overall survivals. Interestingly, the prognostic relevance of serum miR-370 level was more obvious in the subgroup of patients with intermediate-risk cytogenetics. CONCLUSIONS MiR-370 expression may be markedly and consistently decreased in pediatric AML patients and in turn contributes to aggressive progression of this malignancy. Serum miR-370 may serve as a potential non-invasive diagnostic/prognostic marker for pediatric AML patients.